Construction Multi-Trades Health and Safety Manual - 2009

Construction Multi-TradesHealth and Safety Manual

Construction Safety Association of Ontario21 Voyager Court South, Etobicoke, Ontario M9W 5M7 Canada

(416) 674-2726 • 1-800-781-2726 • Fax: (416) [email protected] • www.csao.org

Developed by trade labour-management health and safety committees, this manual is fully adocument of accord between labour and management authorities.

In the past, members of the public have used printed information that was outdated bysubsequent improvements in knowledge and technology. We therefore make the followingstatement for their future protection.

The information presented here is, to the best of our knowledge, current at time of printingand is intended for general application. This publication is not a definitive guide to governmentregulations or to practices and procedures wholly applicable under every circumstance. Theappropriate regulations and statutes should be consulted. Although the Construction SafetyAssociation of Ontario cannot guarantee the accuracy of, nor assume liability for, theinformation presented here, we are pleased to answer individual requests for counselling andadvice.

© Construction Safety Association of Ontario, 2007ISBN-13: 978-0-919465-59-6

New Edition, October 2007Revised, January 2009

Labour-Management

The Construction Safety Association of Ontario thanks the following committees for contributingtheir knowledge, experience, and time in preparing this manual.

• Acoustical Drywall Labour-Management Health and Safety Committee• Boilermakers Labour-Management Health and Safety Committee• Carpenters Labour-Management Health and Safety Committee• Civil Engineering Labour-Management Health and Safety Committee• Commercial Diving Labour-Management Health and Safety Committee• ECAO/IBEW Electrical Labour-Management Health and Safety Committee• Elevator/Escalator Labour-Management Health and Safety Committee• High-Rise Forming Labour-Management Health and Safety Committee• Hoisting Operations Labour-Management Health and Safety Committee• Insulators Labour-Management Health and Safety Committee• Ironworkers Labour-Management Health and Safety Committee• Low-Rise Residential Labour-Management Health and Safety Committee• Masonry and Allied Trades Labour-Management Health and Safety Committee• Millwrights Labour-Management Health and Safety Committee• Occupational Disease and Research Labour-Management Health and Safety Committee• Painters Labour-Management Health and Safety Committee• Pipe Trades Labour-Management Health and Safety Committee• Refrigeration and Air-Conditioning Labour-Management Health and Safety Committee• Rodworkers Labour-Management Health and Safety Committee• Roofers Labour-Management Health and Safety Committee• Sheet Metal Labour-Management Health and Safety Committee• Sprinkler Fitters and Fire Protection Trades Labour-Management Health and Safety Committee

iv

CONTENTS

Legal Responsibilities and EmergenciesChapter 1 Legal responsibilitiesChapter 2 Emergency proceduresChapter 3 CommunicationChapter 4 Housekeeping and fire safety

HealthChapter 5 WHMISChapter 6 First aidChapter 7 Occupational healthChapter 8 Back care and materials handlingChapter 9 Asbestos: Controls for construction, renovation, and demolitionChapter 10 RadiationChapter 11 Heat stressChapter 12 Cold stressChapter 13 Moulds

Equipment, Techniques, and HazardsChapter 14 Personal protective equipment (PPE)Chapter 15 Eye protectionChapter 16 Head protectionChapter 17 Foot protectionChapter 18 Hearing protectionChapter 19 Respiratory protectionChapter 20 Hand/skin protectionChapter 21 High visibility clothingChapter 22 GuardrailsChapter 23 Personal fall protectionChapter 24 LaddersChapter 25 ScaffoldsChapter 26 Elevating work platformsChapter 27 Suspended access equipmentChapter 28 TrenchingChapter 29 Backing upChapter 30 Traffic controlChapter 31 Rigging

v

Chapter 32 Specialized riggingChapter 33 Helicopter liftingChapter 34 Hand and power toolsChapter 35 Welding and cuttingChapter 36 Lockout and taggingChapter 37 Electrical hazardsChapter 38 Propane

Special LocationsChapter 39 Confined spacesChapter 40 Pulp and paper millsChapter 41 Steel millsChapter 42 Mineral processing plantsChapter 43 Oil refineries and petrochemical plantsChapter 44 Thermal power plants

Trade-Specific InformationChapter 45 Ironworkers: Structural steelChapter 46 Sheet Metal

LegalResponsibilities

andEmergencies

1 – 1

LEGAL RESPONSIBILITIES

1 LEGAL RESPONSIBILITIES

GeneralThe health and safety responsibilities of all parties on aconstruction project are specified in the currentOccupational Health and Safety Act and Regulations forConstruction Projects.Responsibilities are prescribed in particular forconstructor, employer, supervisor, and worker. Each partyhas specific responsibilities to fulfill on a constructionproject.For more detailed information, consult the current Act andRegulations.Remember — safety begins with you!

Constructor• Appoint a supervisor if 5 or more workers are on the

project at the same time. Ensure that the project issupervised at all times.

• A project that lasts more than 3 months and has 20 ormore workers must have a Joint Health and SafetyCommittee.

• If a Joint Health and Safety Committee is not requiredand there are more than 5 workers, the workers mustselect a Health and Safety Representative.

• Complete a Ministry of Labour (MOL) registrationform.

• Keep a copy of all employer-approved registrationforms on site while employers are on the project.

• Send a notification of project to the MOL.• Develop written emergency procedures, make sure

your employees know what they are, and post themon site.

• Ensure ready access to a telephone, two-way radio,or other system in the event of an emergency.

• Report a fatality, critical injury, or other prescribedincident such as a critical injury to the MOL.

• Ensure all workers on site are at least 16 years ofage.

Employer• Read Sections 25 and 26 of the Occupational Health

and Safety Act. It lists many of your responsibilities.• Appoint a supervisor if 5 or more of the employer’s

workers are on the project at the same time. Ensurethat they are supervised at all times.

• Provide workers with training as required by law (e.g.,fall protection systems, WHMIS, etc.).

• Ensure workers are qualified to do work which mustbe done only by qualified workers (e.g., electricians,pipe fitters, etc.).

• Develop written procedures for rescuing a workerwhose fall has been arrested (a worker hanging by aharness).

SupervisorSupervisors must ensure that workers• use the methods, procedures, and equipment

required by the Occupational Health and Safety Actand Regulations for Construction Projects.

• use or wear the equipment or clothing that theemployer requires

Supervisors must also• tell workers about actual or potential dangers• give workers written instructions when required• take every precaution reasonable to protect workers.

Worker• Select worker representatives for the Joint Health and

Safety Committee.• Tell your supervisor or employer about equipment

problems or other hazards that could hurt you or otherworkers.

• You have the right to refuse work that you believeendangers your health or safety — or the health orsafety of others. See Section 43 of the OccupationalHealth and Safety Act.

• Follow your employer’s instructions to use or wearequipment, protective devices, or clothing.

• Never engage in horseplay on site (pranks,competitions, showing off your strength,roughhousing, or unnecessary running).

Health and Safety RepresentativeThe health and safety representative must be familiar with– the current Occupational Health and Safety Act and

Regulations for Construction Projects– procedures in the event of an emergency (see

chapter on Emergency Procedures in this manual)– procedures for refusal to work where health and

safety are in danger (Figure 1).

Right to Refuse Work whereHealth or Safety in Danger

(Occupational Health and Safety Act, Part V)

Workerrefuses towork andnotifies

employer orsupervisor.

Employer orsupervisor

investigates withworker and JHSCworker member,safety rep, or

worker chosen byunion or workers.

Workerstands by insafe placenear workstation.

UNRESOLVED

PROBLEM

RESOLVED

Worker continues to refusework. Ministry of Labourinspector is notified.

Inspector investigates inconsultation with worker,employer or supervisor, andworker rep involved earlier.

Other worker may do workif advised of refusal andreason for refusal.

Pending investigationand written decision

Worker standsby or is

assigned otherwork.

Employergives workerother

directions.

Decision made.

In favourof worker

Against worker

Correctiveacton taken.

WORK RESUMESFigure 1

1 – 2

Accidents and InjuriesAll accidents and injuries, regardless of severity, mustbe reported immediately.Procedures for reporting accidents — and the type ofaccidents that must be reported — are spelled out inthe Occupational Health and Safety Act andRegulations for Construction Projects.

Further information is available from the Workplace Safetyand Insurance Board and Ministry of Labour.

Certified Committee MembersWhere a project regularly employs 50 or more workers,the health and safety committee on the project must haveat least one member representing workers and onemember representing the constructor who are certified bythe Workplace Safety and Insurance Board (Figure 2).If no members of a health and safety committee are

certified, the workers and constructor must each selectone member of the committee to become certified.A certified member who receives a complaint regarding adangerous circumstance can investigate the complaintunder the authority of the Occupational Health and SafetyAct. The member may also ask a supervisor to investigatea situation where the member “has reason to believe” thata dangerous circumstance may exist.The supervisor must investigate the situation promptly inthe presence of the certified member.The certified member may also request that anothercertified member representing the other party at theworkplace investigate the situation if the first certifiedmember “has reason to believe” that the dangerouscircumstance still exists after the supervisor's investigationand remedial action, if any, has been taken.The second certified member must promptly investigatethe situation in the presence of the first certified member


Health and Safety Representatives and Committee Requirements Under the Occupational Health and Safety Act

• Obtain information from a constructor oremployer regarding the testing ofequipment, materials, or chemicals in theworkplace.

• Inspect the workplace at least once amonth, with the full cooperation ofconstructor, employers, and workers.

• Ask for and obtain information regardingexisting or potential hazards in theworkplace.

• Make health and safetyrecommendations to a constructor oremployer, who must respond in writingwithin 21 days, either giving a timetablefor implementation or giving reasons fordisagreeing with the recommendations.

• Where a person has been killed orcritically injured in the workplace,investigate the circumstances of theaccident and report findings to a directorof the Ministry of Labour.

• Exercise all the powers granted to thehealth and safety representative by virtueof a collective agreement.

Representativeselected by workersor union(s)

Selection ofMembers

Powers and Rights

• Identify situations that may be a sourceof danger or hazard to workers.

• Make recommendations regardinghealth and safety matters.

• Recommend the establishment,maintenance, and monitoring ofprograms.

• Obtain information from constructors oremployers regarding testing ofequipment or environments and bepresent when testing is initiated.

Worker representativesselected from the site byworkers or trade union(s)represented.Managementrepresentatives selectedby constructor oremployer.

Worker representativesselected from the site byworkers or trade union(s)represented.Managementrepresentatives selectedby constructor oremployer.

Members to be selectedby trade workers ortrade union(s) at the site.Members do not have tobe workers at the site.

Advise the joint health and safetycommittee of the health and safetyconcerns of the workers in the trades atthe workplace.

Figure 2

6-19 workersand morethan 3months

or

6+ workersand less than3 months

Size andDurationof Project

Representativeor Committee

Who CreatesCommittee

Number ofMembers

MembershipRequirements

5 Workersor Less

One Healthand SafetyRepresentative

20-49workers andmore than 3months

Joint Health andSafety Committee

Constructor At least two At least one non-management workerat the project andone managementrepresentative fromthe project ifpossible.

50+ workersand morethan 3months

Joint Health andSafety Committee

Constructor At least four Half non-managementworkers from theworkplace with at leastone certified.

Half managementrepresentatives fromthe workplace ifpossible with at leastone certified.

Worker TradesCommittee

Health andSafetyCommittee

At least oneworkerrepresentativefrom eachtrade

One workerrepresentative fromeach trade.

1 – 3

and, if both certified members agree, they may direct theconstructor or employer to stop work or stop the use ofany part of the workplace, including machines and otherequipment. The constructor or employer must immediatelycomply with the order.If both certified members do not agree that a dangerouscircumstance exists, either may request that a Ministry ofLabour inspector investigate the situation. The inspectormust investigate and provide both members with a writtenreport.

Ministry of Labour InspectorsThe inspector can visit a site at any time and exercisefairly broad powers to inspect, ask questions, and giveorders. If the inspector approaches a worker directly, theworker must answer questions and cooperate. Thesupervisor must be informed of any orders given orrecommendations made.In some cases the health and safety representative,worker member of a health and safety committee, orworker selected by fellow workers or the union has a rightto take part in accident investigation.The results of accident investigation and reporting shouldbe made known to all personnel on site.Recommendations should be implemented to prevent theaccident from happening again.

In all cases of injury, the EMPLOYER must do thefollowing.1. Make sure that first aid is given immediately, asrequired by law.

2. Record the first aid treatment or advice given tothe worker.

3. Complete and give to the worker a TreatmentMemorandum (Form 156) if health care is needed.

4. Provide immediate transportation to a hospital or aphysician's office, if necessary.

5. Submit to the Workplace Safety and InsuranceBoard (WSIB), within three days of learning of anaccident, an Employer's Report of anAccident/Injury/Industrial Disease (Form 7) andany other information that may be required.

6. Pay full wages and benefits for the day or shift onwhich the injury occurred when compensation ispayable for loss of earnings.

7. Notify the Ministry of Labour, health and safetyrepresentative and/or committee, and union asrequired by legislation.

The WORKER must do the following.1. Promptly obtain first aid.2. Notify the employer, foreman, supervisor, andworker safety representative immediately of aninjury requiring health care and obtain from theemployer a completed Treatment Memorandum(Form 156) to take to the physician or the hospital.Failure to report promptly can affect your benefitsand subject your employer to fines.

3. Choose a physician or other qualified practitionerwith the understanding that a change of physiciancannot be made without permission of the WSIB.

4. Complete and promptly return all report formsreceived from the WSIB.

New HiresStatistics show that about 20% of all injuries to workersoccur within their first 30 days on the job. This facthighlights the importance of orientation.The new hire may be young or old, male or female,experienced or inexperienced in construction. The workermay be new to the site, new to the type of work, or new tothe company. A worker coming to any project for the firsttime should be considered a "new hire."New employees must be told and, if necessary, trainedand shown what is expected of them in• work performance• safe operation of tools and equipment• procedures around hazardous materials• proper use of any required personal protective

clothing and equipment.

They must also be told, and preferably shown, thelocation of• first aid kit or first aid station• fire alarms and exits• fire extinguishers and standpipes• emergency telephones• eyewash station• supervisor's office• tool crib• washrooms• lunchroom.

These locations can be pointed out during a tour of theworkplace when the new hire is introduced to co-workers,supervision, and the health and safety representative. Tomake orientation successful, supervisors should followsome simple steps.• Talk to new hires. Put them at ease. Find out how

much they know already. Explain why their job mustbe done right, how it relates to the rest of theoperation, and what hazards may be involved.

• Explain assignments carefully to new workers. Tellthem, show them, ask questions to make sure theyunderstand. Cover one step at a time. Make keyoperations and safety points clear. Be patient and goslowly.

• Test the new hire's performance. Watch while the jobis being done. Commend good work. Whennecessary, show how the job can be done moresafely and efficiently.

• Let new workers continue on their own. Tell them whoto contact for help and encourage them to get helpwhen needed.

• Follow up. Check on work frequently at first. Look forany bad habits, unnecessary motions, or unsafe actsthat need correcting. Ease off when you're convincedthat workers are doing the job safely and correctly.


1 – 4

Jobsite Safety TalksJobsite talks can help prevent accidents and injuries bypromoting hazard awareness in the workplace.Supervisors should present safety talks on a regular basisand follow these guidelines.• Before presenting a prepared talk, look it over.

Instead of reading the talk to your crew, use your ownwords. Personnel will more likely accept your naturalmanner than a formal presentation.

• Choose subjects that are directly related to siteconditions or the company's health and safety policyand program.

• Encourage participation. Get the crew to talk aboutclose calls and hazards. Solutions to these problemscan become the subject of future talks.

• Make a note of any hazards the crew may mention aswell as any suggestions for improving health andsafety. Subjects requiring management attentionshould be referred to management.

• Always follow up. Tell the crew what has been done tocorrect problems and improve conditions on the job.

Safety Tips and Safety Talks are available from theConstruction Safety Association of Ontario. Check themout at www.csao.org.


2 – 1

EMERGENCY PROCEDURES

2 EMERGENCY PROCEDURES

TAKE COMMANDAssign the following duties tospecific personnel.

PROVIDE PROTECTIONProtect the accident scene fromcontinuing or further hazards - forinstance, traffic, operatingmachinery, fire or live wires.

GIVE FIRST AIDGive first aid to the injured as soonas possible. Information on basicfirst aid is included in this manual.

CALL AN AMBULANCECall an ambulance and any otheremergency services required. Insome locales, dialing 911 puts you intouch with all emergency services.

GUIDE THE AMBULANCEMeet and direct the ambulance tothe accident scene.

GET NAME OF HOSPITALFor follow-up, find out where theinjured is being taken.

ADVISE MANAGEMENTInform senior management. They canthen contact relatives, notify authorities,and start procedures for reporting andinvestigating the accident.

ISOLATE THE ACCIDENT SCENEBarricade, rope off or post a guard atthe scene to make sure that nothingis moved or changed until authoritieshave completed their investigation.

Emergency Procedures

1

2

3

4

5

6

7

8For more information refer to– Emergency Response Planning (B030), booklet

available from CSAO– Emergency Response (P103), poster available from

CSAO– rescue procedures for fall arrest (see the Personal

Fall Protection chapter in this manual).

3 – 1

COMMUNICATION

3 COMMUNICATION

In the construction trades, workers and supervisors mustconstantly act and react to their changing environment. Indoing so, they exchange facts, plans, and proposals. Theone essential ingredient in all of these activities iscommunication.Think for a moment of the types of communicationcommon to worksites in construction:• contracts• blueprints• safety talks• health and safety committee minutes• hand signals for hoisting and traffic control• radio transmissions• training sessions• accident reports• WSIB forms• instructions to new workers• specifications• WHMIS labels and material safety data sheets• regulations• operating manuals.All of these communications involve messages ofdifferent types being sent to and from senders andreceivers.

These are the elements in the communications cycle,which consists of a sequence of steps. If any step isinterfered with, blocked, or left incomplete the result willbe miscommunication or no communication at all.Step 1Using his or her knowledge and experience, a "sender"creates a message in his or her mind.Step 2The message is "encoded." This means the message isput into speech for oral communication; into writing forwritten communication; or into signals or images for visualcommunication.Step 3After encoding the message, the sender sends or"transmits" it. In verbal communication, the message istransmitted by speech. Written communications aredelivered by hand, mail, FAX, or over a computer network.In visual communication, a signal is transmitted by hand,flag, pictures, or images.Step 4The "receiver" receives, that is, hears, reads, or sees themessage.Step 5Using his or her own unique knowledge and experience,the receiver interprets the message.

Step 6The receiver acknowledges that the message has beenreceived and/or acts on the message. The full cycle hasnot been completed until the sender has some indicationthata) the message has been received andb) action has resulted from the communication.

All the steps in the communication cycle are of equalimportance. If you overlook or inadequately perform anyof them, the result will be miscommunication or, in somecases, a complete lack of communication.Understanding the communication cycle helps you toknow when your message is not being received or isbeing misunderstood. By checking each step in thecommunication cycle you can see where you've gonewrong. This provides a practical framework for solvingcommunications problems.Remember — to communicate effectively you must makesure that the communication cycle is complete for everymessage you send. Each step in the cycle must be taken,and each completed, every time.The following will ensure success in communication.• Gather all the information you need before putting

your message together.• Organize your facts.• Take the time to put together a message that makes

sense and can be understood.• Compose the message using words and/or visual aids

the receiver can understand.• Use a sending method (written, spoken, or visual) that

will get the message across clearly.

3 – 2

• Take the receiver’s ability to receive your messageinto account when choosing your method oftransmission; be willing to change your choice if youdiscover a problem in communication.

• Take the receiver's ability to interpret your messageinto account when formulating your message.

• Check with the receiver to ensure that your messagehas been received and understood.

• Check results to ensure that your message has beenproperly acted upon.

Effective communications result when• a message contains all the important details it should

contain to be complete• the message is delivered in a way which allows the

receiver to receive it clearly, and• the receiver understands the message completely and

acts upon it properly.To sum up, the three important elements ofcommunications are• message• delivery method• receiving method.A message is complete when it contains all theinformation the receiver needs to understand and, ifnecessary, to act upon the message.Try to include all the information necessary to answer anyquestions likely to arise in the mind of the receiver. Onegood way of doing this is to check whether the informationcovers• who• what• when• where• why• how.

Consider the following example."Hey! Make sure that pump is tagged and locked out."This can raise all sorts of questions in the receiver'smind: "Who's supposed to make sure? Which pump?Where? How should it be locked out?"On the other hand, consider a message like this."Hey Frank! (Who)Before we begin, (When)I want you to tag and lock out (What #1)that pump (What #2)in the washroom (Where #1)up on the sixth floor. (Where #2)We've got to be sure no one starts it while we're downhere (Why #1)or the place will be flooded. (Why #2)Use the lockout procedure we went over yesterday."(How)

The second message is more complete, leaves lessroom for error, and is therefore more effective.

Once a message is formed, the next step is delivery.There are three modes: verbal, written, and visual.Verbal communication involves two or more peoplesending messages and expecting feedback. Lots ofinformation can be exchanged in a short time.With written communication, the cycle is generally slower.It takes time for the sender to compose the message,time to deliver it, time to read it, and time for the receiverto compose and send a reply. But written communicationcan produce results when verbal communication cannot.Visual delivery includes such methods as hand signals tocrane operators and signs for traffic control.Receiving modes correspond to each of these deliverymodes. Verbal messages are heard or, better, listened to.Written messages are read. Visual messages are seen.All must be finally understood for the communication cycleto be complete.

COMMUNICATION

4 – 1

HOUSEKEEPING AND FIRE SAFETY

4 HOUSEKEEPING AND FIRESAFETY

Many injuries result from poor housekeeping, improperstorage of materials, and cluttered work areas. To maintaina clean, hazard-free workplace, all groups – management,supervision, and workers – must cooperate.GeneralRegulations for safehousekeeping require– daily jobsite cleanup

program– disposal of rubbish– individual cleanup

duties for all workers– materials piled,

stacked, orotherwise stored toprevent tipping andcollapsing

– materials stored away from overhead powerlines– work and travel areas

kept tidy, well-lit, and ventilated (Figure 8)– signs posted to warn workers of hazardous areas.The basics of good housekeeping are shown in Figure 9.

Specific• Gather up and remove debris as often as required to

keep work and travel areas orderly.• Keep equipment and the areas around equipment

clear of scrap and waste.• Keep stairways, passageways, and gangways free of

material, supplies, and obstructions at all times.• Secure loose or light materials stored on roof or on

open floors to prevent them being blown by the wind.• Pick up, store, or dispose of tools, material, or debris

which may cause tripping or other hazards.• Before handling used lumber, remove or bend over

protruding nails and chip away hardened concrete.• Wear eye protection when there is any risk of eye injury.• Do not permit rubbish to fall freely from any level of the

project. Lower it by means of a chute or other approveddevices (Figure 10).

• Do not throw materials or tools from one level toanother.

• Do not lower or raise any tool or equipment by its owncord or supply hose.

• When guardrails must beremoved to land, unload, orhandle material, wear fall-arrest equipment (Figure11). The area must also beroped off with warning signsposted.

In shops it is relatively easy tomaintain a clean work area. Barriersand warning lines can also be set up toisolate table saws and other equipment.On construction sites, arrangements aremore difficult. Equipment often sits inbasements, on decks, or in cornerswith insufficient working space andsometimes it’s open to the weather.The footing may simply consist ofa piece of plywood.Around table saws andsimilar equipment, keepthe immediate area clearof scrap to avoidtripping hazards andprovide sound footing.

Airborne wood dust can be a respiratory hazard, causingproblems ranging from simple irritation of the eyes, nose,and throat to more serious health effects. Dust collectorsshould be installed in shops to remove sawdust from airand equipment. Wood dust is also very flammable.In construction, saws and other tools are often operated inthe open air where dust presents no hazard. However,dust masks or respirators should be worn wheneverventilation is inadequate.

Figure 8Keep stairs and landings clear and well-lit.

Figure 9Good housekeeping means clear traffic and work areas, out-of-the-waystorage, adequate illumination, and cleanup of debris.

Figure 11

ChuteOpening

WarningSigns

Figure 10

Figure 12Secure material against the wind.

After removing material, resecure pile.

FallArrest

Travelrestraint

6 feet, 6 inches

6 feet, 6 inches

4 – 2

StorageStorage areas should be at least 1.8 metres (6 feet) fromroof or floor openings, excavations, or any open edgeswhere material may fall off (Figure 12).Near openings, arrange material so that it cannot roll orslide in the direction of the opening.

Flammable Materials• Use copper grounding straps

to keep static electricity frombuilding up in containers,racks, flooring, and othersurfaces (Figure 13).

• Store fuel only in containersapproved by the CanadianStandards Association(CSA) or Underwriters'Laboratories of Canada(ULC).

• Ensure that electric fixturesand switches are explosion-proof where flammablematerials are stored.

• See Figure 14 for pointerson safe storage.

Hazardous Chemicals• Refer to material safety data sheets (MSDSs) for

specific information on each product.• Follow manufacturer's recommendations for storage.• Observe all restrictions concerning heat, moisture,

vibration, impact, sparks, and safe working distance.• Post warning signs where required.• Have equipment ready to clean up spills quickly.

• To keep them separate for specialhandling and disposal later, store empty chemicalcontainers in secure area away from full containers.

Bags and Sacks• Do not pile bagged material more than 10 bags high

unless the face of the pile is supported by the walls of astorage bin or enclosure.

• Do not move piles more than 10 bags high unless fullybanded or wrapped.

• Cross-pile bags and sacks for added stability. Pile only toa safe and convenient height for loading and unloading.

Compressed Gas Cylinders• Store and move cylinders in the upright position. Secure

cylinders upright with chains or rope.• Lock up cylinders to prevent vandalism and theft.• Wherever possible, store cylinders in a secure area

outdoors.


Figure 13Dispensing and receivingcontainers should both be

grounded.

Figure 14Storage of Flammable Liquids

Appropriatefire extinguishershould belocatedconvenient tostorage area.

Replace bungs in drums.Make sure drumsare grounded.

A

B

C

D

Class “A”ExtinguishersFor fires in ordinary combustible materials such aswood, paper, and textiles where a quenching, coolingeffect is required.

Class “B”ExtinguishersFor flammable liquid and gas fires, such as oil,gasoline, paint and grease where oxygen exclusionor flame interruption is essential.

Class “C”ExtinguishersFor fires involving electrical wiring and equipmentwhere the non-conductivity of the extinguishingagent is crucial.This type of extinguisher should be present whereverfunctional testing and system energizing take place.

Class “D”ExtinguishersFor fires in combustible metals such as sodium,magnesium, and potassium.

How to Use the ExtinguisherAim the extinguisher at the base of the fire toextinguish the flames at their source.

Figure 15

4 – 3

• Keep full cylinders apart from empty cylinders.• Store cylinders of different gases separately.• Keep cylinders away from heat sources.• When heating with propane, keep 45-kilogram (100 lb.)

cylinders at least 3 metres (10 feet) away from heaters;keep larger tanks at least 7.6 metres (25 feet) away.

Lumber• Stack on level sills.• Stack reusable lumber according to size and length.

Remove nails during stacking.• Support lumber at every 1.2-metre (4-foot) span.• Cross-pile or cross-strip when the pile will be more

than 1.2 metres (4 feet) high.Fire ProtectionHousekeeping includes fire prevention and fire protection.Workers must be trained to use fire extinguishersproperly.Fire extinguishers must be– accessible– regularly inspected– promptly refilled after use.Extinguishers must be provided– where flammable materials are stored, handled, or

used– where temporary oil- or gas-fired equipment is being

used– where welding or open-flame cutting is being done– on each storey of an enclosed building being

constructed or renovated– in workshops, for at least every 300 square metres of

floor area.

Fire extinguishers are classified according to theircapacity to fight specific types of fires (Figure 15).Workers must be trained to use fire extinguishersproperly.For most operations, a 4A40BC extinguisher is adequate.Extinguishers have a very short duration of discharge –usually less than 60 seconds. Be sure to aim at the baseof the fire.


Health

WHMIS

5 WHMISFrequently construction trades are required to work withnew hazardous materials or previously installedhazardous materials requiring repair, maintenance, orremoval. Some materials used for many years andthought to be harmless are now known to be hazardous.Proper handling requires careful planning, training, anduse of personal protective equipment or controls.Some hazardous materials common in construction are– compressed gas (acetylene, nitrogen, oxygen)– flammable and combustible materials (solvents)– oxidizing materials (epoxy hardeners)– solvents, coatings, and sealers– asbestos and silica– acids and alkalis.

Right to KnowThe Workplace Hazardous Materials InformationSystem (WHMIS) gives everyone the right to knowabout the hazards of materials they work with andprovides the means to find out that information. Itdoes this through– labels– material safety data sheets– worker training and education.

All employers are required by law to provide WHMIStraining for specific controlled products the worker will beworking with or near. Training should be provided as newproducts are introduced – with a general updating on newproducts at least annually.Controlled products under WHMIS include six classes,identified by symbols (Figure 6).The requirements for supplier and workplace labels areshown in Figure 7.

Supplier labels are required on controlled products with avolume of more than 100 millilitres and must include– product identifier– appropriate hazard symbol(s)– risk phrases (such as “dangerous if inhaled”)– precautions (such as “wear rubber gloves”)– first aid measures– supplier identifier– statement that a material safety data sheet (MSDS) is

available for the product.

Workplace labels are required when controlled productsare produced onsite or have been transferred from asupplier-labelled container to a different container.Workplace labels must include– product identifier– safe handling instructions– statement that an MSDS is available for the product.

If details on the ingredients, health effects, handling, andother aspects of a hazardous product are not availablefrom suppliers or employers, call the Construction SafetyAssociation of Ontario at 1-800-781-2726 and provide thefollowing information.• Product name (for example, Solvex 100)• Manufacturer's name and place of manufacture (for

example, ABC Chemical, Montreal, Quebec)• What is the product being used for? (for example, to

clean parts)• How is it being used? (for example, sprayed on)• Is it being mixed with something else?• Is it being heated?• In what area is it being used? (for example, outdoors

or in a holding tank)• What does the label say?• How can information be conveyed to you?

Figure7

Figure 6

CLASS SYMBOL EXAMPLE

Class A: Compressed Gas oxygen

Class B: Flammable andCombustible Material acetone

Class C: Oxidizing Material chromic acid

Class D: Poisonous andInfectious material1. Materials causing immediate ammoniaand serious toxic effects

2. Materials causing other asbestostoxic effects

3. Biohazardous Infectious contaminatedMaterial blood products

Class E: Corrosive Material hydrochloric acidsodium hydroxide

Class F: DangerouslyReactive Material acetylene

5 – 1

5 – 2

Designated Substances“Designated substances” are substances that have beentargeted for special regulation by the Ministry of Labour.Generally these substances are well-known toxicmaterials which present serious risk of illness.Designated substances encountered in constructioninclude asbestos, lead, coal tar products, and silica. If anydesignated substances are present where construction,maintenance, or renovation is planned, the partiesinvolved must be notified and informed.The Occupational Health and Safety Act requires thatowners notify contractors of the presence of anydesignated substance. Contractors also have aresponsibility to advise subcontractors. This notificationmust take place before binding contracts are arranged.For more information on designated substances, contactthe Ministry of Labour.

WHMIS

6 – 1

FIRST AID

6 FIRST AIDAccording to St. John Ambulance, “First aid isemergency help given to an injured or suddenlyill person using readily available materials.” Itmay be as simple as cleaning and bandaging aminor cut on a worker’s finger, or it can becomplicated, such as providing care for aworker who has been struck by a piece ofmoving equipment.

The objectives of first aid are the same,regardless of the situation. They are to

• preserve life

• prevent the injury or illness from becomingworse

• promote recovery.

The First Aid Requirements Regulation(Regulation 1101 under the Workplace Safety andInsurance Act) details the obligations ofemployers regarding first aid equipment, facilities,trained personnel, and first aid procedures in allworkplaces. The Act authorizes the WSIB topenalize employers who do not comply withthese requirements. Here is a brief outline.

EquipmentEmployers must provide and maintain a first aidstation in the workplace. Pick a location for thekit that it is accessible at all times. Companieswho use service vehicles should ensure that firstaid kits are provided for each vehicle. As well,provide a first aid kit when workers areoperating heavy construction and maintenanceequipment at a distance from the first aid station.The contents will vary according to the numberof employees regularly employed in thatworkplace. Regulation 1101 provides the detailsof the contents. Inspect each kit at leastquarterly, then sign and date the inspection card.

Facilities

In a workplace with few employees, the first aidstation may be as simple as a first aid kit placed

in an accessible area. Large companies (over 200employees) are required to have a first aid room.On construction projects, it’s the responsibility ofthe general contractor to provide the first aidstation. It should be located in the site office. Ona large project, set up additional first aid stationsto ensure timely access to treatment. In all cases,the regulation requires you to post the WSIBForm 82 (“In Case of Injury at Work” poster), afirst aid kit inspection card, and the valid first aidcertificates of the first aid providers in theworkplace.

Trained personnel

Employers must ensure that first aid is providedby trained and knowledgeable workers.Regulation 1101 specifies training either to theSt. John Ambulance Emergency or Standard FirstAid levels (or equivalent) depending on thenumber of workers in the workplace.

Emergency-level first aid training generallyincludes the following mandatory topics

• Emergency Scene Management

• Shock, Unconsciousness, and Fainting

• Choking—Adult

• Severe Bleeding

• One Rescuer CPR—Adult

Standard-level first aid training is a moreextensive program that generally includes the

First aid station

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FIRST AID

five mandatory topics from emergency first aid,as well as elective topics. Some elective topicssuitable for first aid providers are

• Fractures

• Head and Spinal Injuries

• Joint Injuries

• Chest Injuries

• Hand injuries

• Eye injuries

• Multiple injury management

• Pelvic, abdominal, and crush injuries

• Burns

• Poisoning

• Medical conditions (diabetes, epilepsy,convulsions, and allergies)

• Environmental illnesses and injuries(exposure to heat or cold)

• Artificial respiration – Adult

• Automated External Defibrillator(additional instruction time must be addedto the course to accommodate thiscomponent and a separate certificationcard must be issued for AED certification)

Since procedures may change from time to time,it is important that training be kept up to date.Recertification is usually required every threeyears (check with your training organization fordetails).

In a workplace with five or fewer workers, theemployer must ensure that a worker trained inat least St. John Ambulance Emergency First Aid(or equivalent) is available to provide first aid.This also applies when a crew of two to fiveworkers is working away from their companyfacility, such as a painting crew working in avacant office. When six or more workers areemployed in a workplace, the regulationrequires St. John Ambulance Standard First Aid

(or equivalent) training for the first aid provider.Additional workers should be trained in theevent of the designated provider’s absence.

First Aid Procedures

To ensure that an injured or ill worker receivesappropriate and timely first aid treatment, anemployer should have a written first aidprocedure as part of their Health and SafetyProgram. The procedure should cover

• mandatory reporting and recordingrequirements

• provision of first aid kits

• availability of trained first aid providersand training recertification

• transportation to medical treatment

• document posting requirements.

The First Aid Requirements Regulation requiresthat each first aid kit contain a current edition ofthe St. John Ambulance First Aid Manual. Themanual contains details of first aid treatment fora worker who is injured or who suddenlybecomes ill. The first aid provider can use it asa reference for specific protocols.

For details on signs, symptoms, and treatment ofillnesses and injuries related to heat or coldexposure, refer to the chapters on Heat Stressand Cold Stress in this manual.

The First Aid Requirements Regulation

7 – 1

OCCUPATIONAL HEALTH

7 OCCUPATIONALHEALTH

Routes of entryHazardous materials in the workplace may cause diseasein the body at four main sites:• where they enter the body—entry routes such as the

lungs, skin, and intestines• in the blood that carries the hazardous materials

throughout the body• in the central nervous system• in the organs which have the ability to remove toxic

agents from the body:i.e., the liver, kidneys, and bladder (exit routes).

This section briefly describes four routes of entry—inhalation, absorption, ingestion, and injection—and someof the workplace hazards and diseases commonlyassociated with them.

InhalationThe body’s respiratory—or breathing—system is one ofthe most common routes of entry for a toxic substance.The substance may cause damage to the system itself orit can pass through the lungs to other parts of the body.The main function of the respiratory system is to absorboxygen from the air and pass it on to the blood. It alsoremoves carbon dioxide—the waste gas produced by thebody’s processes—from the blood and releases it inexhaled air.Air reaches the lungs through a branching system oftubes, starting with the trachea, or windpipe, whichdivides to form two bronchi, one to each lung. Eachbronchus, in turn, branches into many smaller divisions,finally ending in a small cluster of tiny air sacs which areknown as alveoli. The oxygen and carbon dioxideexchange takes place through a very thin membranesurrounding these air sacs.The lung is covered by a delicate lining known as thepleura. (Mesothelioma, one of the cancers caused byasbestos, is a cancer of the pleura.)

CancerIt's not well understood exactly how a chemical producescancer. Some carcinogens (cancer-causing substances)are thought to interact with the genetic material of the cell;others may interact with the immune system; and stillothers are thought to act with other agents, but not initiatecancer themselves. Whatever the mechanism, the effectis very often delayed, sometimes up to 30 years.Defining a chemical as carcinogenic usually involves animalstudies as a first step. If the substance causes cancer inanimals, particularly those that have biological systemssimilar to humans, it is classed as a suspected carcinogen.Two examples are silica and refractory ceramic fibres whichcause lung cancer. Some chemicals have also been shownto be cancer-causing through industrial experience. Theseinclude asbestos (cancer of the larynx, lung, and abdomen),vinyl chloride (liver cancer), coal tar pitch (skin cancer),chromium (lung cancer), and benzidine (bladder cancer). Allchemicals which have been classified as carcinogensshould be handled with extra care.

AsbestosInhaling asbestos dust has been shown to cause thefollowing diseases:• asbestosis• lung cancer• mesothelioma (cancer of the lining of the chest and/or

abdomen).

Asbestosis is a disease of the lungs caused by scar tissueforming around very small asbestos fibres deposited deep inthe lungs. As the amount of scar tissue increases, the abilityof the lungs to expand and contract decreases, causingshortness of breath and a heavier workload on the heart.Ultimately, asbestosis can be fatal.Lung cancer appears quite frequently in people exposed toasbestos dust. While science and medicine have not yetbeen able to explain precisely why or how asbestos causeslung cancer to develop, it is clear that exposure to asbestosdust can increase the risk of contracting this disease.Studies of asbestos workers have shown that the risk isroughly five times greater than for people who are notexposed to asbestos.Cigarette smoking, another cause of lung cancer, multipliesthis risk. Research has shown that the risk of developingcancer is at least fifty times higher for asbestos workers whosmoke than for workers who neither smoke nor work withasbestos.Mesothelioma is a relatively rare cancer of the lining of thechest and/or abdomen. While this disease is seldomobserved in the general population, it appears frequently ingroups exposed to asbestos.Other illnesses—There is also some evidence of anincreased risk of cancer of the stomach, rectum, and larynx.However, the link between asbestos exposure and thedevelopment of these illnesses is not as clear as with lungcancer or mesothelioma.The diseases described above do not respond well tocurrent medical treatment and, as a result, are often fatal.See the chapter on Asbestos in this manual.

THE RESPIRATORY SYSTEM

7 – 2

How hazardous materials evade thelung’s defencesThe airways of the respiratory system have developed anelaborate system of defences which trap all but thesmallest dust particles. This system consists of hairs inthe nose and mucus in the trachea or bronchi. The mucusis produced continuously by special cells in the walls ofthe larger airways. It is moved upward and to the back ofthe throat by the whipping action of cilia—tiny, hair-likeprojections on the cells of the trachea and bronchi.Large dust particles are trapped in the mucus and areeither swallowed or spit out. Particles smaller than 0.5microns (1 inch has 25,400 microns) may remain airborneand are exhaled. The most dangerous size of dustparticles is 0.5-7.0 microns. Much too small to be seenwith the naked eye, they can evade the defence systemand reach the lungs. Once in the lungs, these tinyparticles of dust may cause extensive scarring of thedelicate air sacs. This scarring starts the disease processwhich produces severe shortness of breath.Most dust particles are too large to pass through the wallsof the alveoli, but gases, vapours, mists, and fumes canall enter the bloodstream through the lungs. In addition,welding fumes or truck exhausts can stimulate the lung’sdefences to produce large amounts of phlegm, causingthe condition known as chronic bronchitis. These samesubstances can destroy the delicate air sacs of the lungs,causing emphysema.The lungs are the prime target for occupationalcarcinogens because the lungs

• are in intimate contact with workplace air pollutants• have such a large surface area (100-140 m2).

AsphyxiantsChemicals that interfere with the transfer of oxygen to thetissues are called asphyxiants. The exposed individualliterally suffocates because the bloodstream cannot supplyenough oxygen for life.There are two main classes of asphyxiants—simple andchemical. Simple asphyxiants displace oxygen in the air,thereby leaving less or none forbreathing. Chemical asphyxiantscause the same effect byinterfering with the body’s abilityto take up, transport, or useoxygen.Simple asphyxiants are a majorhazard in confined spaces, wherebreathable air can be displacedby gas from sewage, for instance.When the normal oxygen level of21% drops to 16%, breathing andother problems begin, such aslightheadedness, buzzing in theears, and rapid heartbeat. Simpleasphyxiants in constructioninclude argon, propane, andmethane. These chemicals usuallyhave no other toxic properties.

Carbon monoxide is one example of a chemicalasphyxiant. It combines with the oxygen-carryingcompound in the blood and reduces its ability to pick up“new” oxygen. Hydrogen sulphide, on the other hand,interferes with the chemical pathways which transfer theoxygen, while hydrogen cyanide paralyzes the respiratorycentre of the brain.

AbsorptionAbsorption through the skin is another common form ofentry for toxic substances (e.g., organic solvents).The skinis the largest organ of the body, with a surface area of1 to 2 m2. Some chemicals can penetrate through theskin, reach the bloodstream, and get to other parts of thebody where they can cause harm. Toluene and Cellosolveare examples of chemicals which are absorbed throughthe skin. Mineral spirits and other solvents used in themanufacturing of paint can easily penetrate the skin.

The skinThe skin protects the internal organs of the body from theoutside environment. Its outer layer is composed ofhardened, dead cells which make the skin resistant todaily wear and tear. Sweat glands cool the body when theenvironment is hot. Sebaceous glands produce oils whichrepel water. A network of small blood vessels, orcapillaries, plays a key role in controlling bodytemperature. These capillaries open when it is hot,radiating heat outward into the air, and constrict when it iscold, conserving heat in the body. The skin also has aprotective layer of oils and proteins which helps to preventinjury or penetration by harmful substances.A substance may be absorbed and travel to another partof the body, or it may cause damage at the point of entry(the skin), and start the disease process. Suchsubstances are usually identified in an MSDS with anotation “skin” along with their exposure limits, indicatingthat the exposure can occur through the skin, mucousmembranes, or eyes, or may damage the skin itself.

OCCUPATIONAL HEALTH

THE SKIN

7 – 3

Skin irritationDermatitis is an inflammation of the skin which can becaused by hundreds of workplaces substances likesolvents (paints), epoxy resins, acids, caustic substances,and metals. Dermatitis appears as redness, itchiness, orscaling of the skin. There are two types of dermatitis:• primary irritation dermatitis (contact dermatitis), and• sensitization dermatitis (allergic dermatitis).Major dermatitis hazards in construction are listed in Table 1.Contact dermatitis is caused by friction, heat or cold,acids, alkalis, irritant gases, and vapours. Skin in contactwith the chemical turns red, becomes itchy, and maydevelop eczema (collection of fluid droplets under theskin’s surface). Typical hazards in construction includecaustics, acids, many chlorinated solvents, wet concrete,chromic acid, and calcium hydroxide.Allergic contact dermatitis, on the other hand, is the resultof an allergic reaction to a given substance. Sensitizationmay be the result of prolonged or repeated contact andbecomes established usually within 10 to 30 days. Theprocess could also take years.Once sensitized, even a minute exposure can produce asevere reaction. Substances like organic solvents (paints),chromic acid, and epoxy resins can produce both primaryand contact dermatitis. Sensitizers include epoxymaterials (especially the hardener), nickel, and chromium.Certain agents such as coal tar and creosote can have astrong sensitizing effect when combined with exposure tosunlight—they are known as photosensitizers.

SolventsKeratin solvents: These injure or dissolve the outer layerof the skin producing dry, cracked skin. All the alkalis suchas ammonium hydroxide, sodium hydroxide, and calciumchloride are keratin solvents.

Fat and oil solvents: These remove the surface oils of theskin so that it can no longer hold water efficiently. Dry,cracked skin results. Organic solvents such as tolueneand xylene will cause this condition.Keratin stimulants: On contact these primary irritantscause a change in the skin so that unusual growthappears, as with exposure to coal tar pitch and arsenic.Some hazardous materials used in the workplace havebeen linked with skin cancer. A number of them are listedin Table 2.

IngestionA third major route of entry for toxic substances is throughthe mouth and digestive tract. Toxic materials may reachthe stomach when food or drink is consumed, whencigarettes are smoked in a dusty work area, when cleanlunchrooms are not provided, when workers fail to washtheir hands before eating or smoking, or when food is leftunwrapped in a dusty place. Lead dust, for example, iseasily ingested in this way and can have serious healtheffects. Once swallowed, the substances enter thedigestive tract and may enter the bloodstream.The digestive tract is a continuous tube that extends fromthe mouth to the rectum. The organs of the digestivesystem provide the means of ingestion, digestion, andabsorption of food. Almost all digestion and absorption offood and water take place in the small intestine. The largeintestine generally absorbs vitamins and salts.

OCCUPATIONAL HEALTH

TABLE 1MAJOR DERMATITIS HAZARDS IN CONSTRUCTION

MATERIAL TYPE OCCUPATION/ACTIVITY CONTROLS

Some Suspected Workplace Causes of Skin Cancer

Pitch Arsenic Ultraviolet LightAsphalt Tar X-RaysBenzo(a)pyrene Creosote AnthraceneShale Oil Cutting Oils Soot

TABLE 2

Wet Concrete

Epoxy Materials

Coal Tar

Solvents/Degreasers

Cleaners

Allergic/Corrosive

Allergic/Defatting (solventsmay aggravate allergy)

Allergic

Defatting

Corrosive/Defatting

- Concrete Workers

- Cement Finishers- Seamless Floor Installers- Painters- Tile/Terrazzo Installers

- Roofers- Waterproofers

- Mechanics- Painters- Service Trades- Millwrights

- Labourers- Service Trades

- Rubber boots, rain pants,rubber gloves if necessary.

- Barrier creams- Gloves resistant to specific

solvents (see Glove SelectionChart in this manual)

- Good personal hygiene

- Change work clothing daily ifdoing dusty work

- Barrier creams usually workwell


- Appropriate gloves (see GloveSelection Chart in thismanual)

- Minimize skin contact- Good personal hygiene

- Usually rubber gloves, bootsand maybe rain pants


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Once swallowed, the toxic substances enter the digestivetract, where they may enter the bloodstream and move onto the liver. The liver and kidneys try to remove thepoisons and make the substances less harmful to thebody, but they are not always successful.

InjectionIn rare cases the chemical may enter the body byinjection. Skin can be punctured by paint from a high-pressure spray gun or oil from a high-pressure hydraulichose. This is very serious and requires prompt medicalattention. Chemicals in the paint or oil can damage theimmediate area and be transported by the blood to atarget organ. Chemicals can also be injected into the bodyby means of puncture wounds from nails or staples, forexample.

Hazardous substancesin the bodyThe circulatory systemThe circulatory system is not usually in direct contact withhazardous materials. Once in the bloodstream, however,harmful substances can be transported to any part of thebody.The centre of the circulatory system is the heart. It pumpsblood outward through a vast network of blood vesselswhich branch like a tree, becoming smaller and smaller asthey go. The vessels branch so extensively that no cell ismore than a few millimeters from a blood vessel orcapillary.

Hazards to the circulatory systemFood and oxygen reach every cell in the body throughcapillaries, but so do toxic substances from the workplace.Oxygen is carried by a protein called hemoglobin, which iscontained in the red blood cells. Oxygen binds strongly tohemoglobin, but unfortunately, so does carbon monoxide,a common workplace hazard produced by combustionengines in trucks, machinery, etc. In fact, carbon monoxidebinds or attaches to hemoglobin about 200-300 timesmore readily than oxygen.In high concentration, carbon monoxide can kill because itoverloads the hemoglobin in the red cells and replacesthe oxygen which the body needs to survive. But even lowlevels of repeated carbon monoxide exposure may haveserious effects on the heart and the central nervous system.

OCCUPATIONAL HEALTH

THE DIGESTIVE SYSTEM

Some Substances Which May Cause AnemiaArsine Gas CadmiumSelenium CopperLead GalliumStibine Mercury CompoundsBeryllium Benzene

Toluene

Table 3

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Many toxic substances attack the blood cells directly. Thebody forms blood cells continually in the marrow cavityinside the bones. Hazardous materials like benzene caninterfere with this formative process and cause anemia, ashortage of red blood cells. Table 3 lists some of thematerials which may cause anemia.

The liverThe liver is the chemical factory of the body. The cellswhich make up the liver contain enzymes which canconvert certain toxic substances into forms that are moreeasily handled by the body. But the liver itself maybe damaged if it is overwhelmed by toxic substances.The liver may become inflamed, producing the conditionknown as hepatitis. This disease may be caused by avirus or by chemicals like alcohol, carbon tetrachloride,and other chlorinated hydrocarbons. Repeated bouts ofhepatitis may lead to liver scarring and a disease calledcirrhosis of the liver. Generally speaking, it means thatthere are not enough normal liver cells remaining todetoxify body chemicals.Overexposure to chemicals like acrylonitrile, benzene,carbon tetrachloride, DDT, chloroform, phenol, styrene,tetrachloroethane, and tetrachloroethylene may alsocause liver damage. Vinyl chloride, a substance used inthe production of plastics, has been linked to a rare anddeadly form of liver cancer called angiosarcoma. Table 4lists some substances that may cause liver damage.

The kidneys and bladderThe kidneys act as a filter for substances in the blood.Each kidney contains over a million small filters. Thesefilters clean the blood, removing a number of impuritieswhich they deposit in the urine. The urine then passes tolittle tubes which monitor the levels of acid and theamount of water in the body, and keep them balanced.From these tubes, the urine moves to the bladder, whichstores it until it is released from the body.Since the kidneys act as filters, they can be seriouslyinjured by toxic substances passing through the body.Kidney disorders may result in high or low blood pressure,which in turn may cause heart strain or heart failure.Kidney malfunction may also upset the body’s delicatechemical balance, resulting in further harm to the body.

Just as the lungs are vulnerable to hazardous materialsbecause they are a major route of entry, the kidneys andbladder are vulnerable because they are a major route ofexit.

The nervous systemTo stay alive, we must breathe continuously, our heartmust pump constantly, and all the other organs mustfunction. We also think and respond to emotions andsensations. All these functions performed by the mind andbody are controlled by the nervous system.

OCCUPATIONAL HEALTH

Some Substances Suspected of Causing Liver Damage

Antimony Acrylonitrile Ethylidene DichlorideArsine Benzene HydrazineBeryllium Carbon Tetrabromide Methyl AlcoholBismuth Carbon Tetrachloride Methyl ChlorideCadmium Chlorinated Benzenes Methylene DianilineCopper Chloroform NaphthaleneIndium Cresol PhenolManganese DDT PyridineNickel Dimethyl Sulfate StyrenePhosphorus Dioxane TerachloroethyleneSelenium Epichlorohydrin Toluene

Ethyl Alcohol TrichloroethaneEthylene Chlorohydrin Trichloroethylene

Table 4

Suspected of Causing Kidney Damage

Lead NaphthaleneMercury Carbon TetrachlorideCadmium TetrachloroethaneChromates Carbon MonoxideCopper Gasoline VapoursUranium TurpentineBeryllium BismuthArsenic Oxalic AcidArsine Intense HeatSodium Fluoride VibrationIodine High Voltage ShocksCarbon Disulfide Blood Loss

Table 5 shows some of the suspected causes of kidneydamage.

Table 5

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The central nervous system is the control centre. Thespinal cord connects the brain to the nervous system. Partof the nervous system reaches the outer areas and iscalled the peripheral nervous system.Most injuries of the central nervous system are permanent,although damage to the peripheral nervous system cansometimes be reversed. Exposure to metals like lead andmercury may interfere with nerve impulses and result intremors and loss of reflexes or feeling.Central nervous system depression covers effects such asheadache, lightheadedness, drowsiness, andunconsciousness. The organ affected is the brain and theresult is depressed performance. Many solvents such astoluene, xylene, ether, and acetone produce this effectif the vapour concentration is high enough. Workersexposed to these chemicals in cleaning solvents, paints,thinners, and degreasers may have experienced theseeffects.The brain needs a constant supply of oxygen. Some toxicchemicals interfere with the functioning of the centralnervous system and disrupt the oxygen supply. The firstwarning signs are dizziness and drowsiness. Warning signsshould be heeded immediately and appropriate actiontaken. For example, you should immediately leave the areaand seek medical assistance.The operations of the nervous system are very complicated.It is a delicately balanced system and several chemicals candamage it, such as those shown in Table 6.

The reproductive systemWorkplace hazards affect the worker, but the problemreaches into the worker’s home as well.The reproductive organs—the testes in men and the ovariesin women—produce the cells that allow us to reproduce.Any damage to these cells can have disastrousconsequences. Deformities in children may result or thedeveloping embryo may be so severely damaged that it isunable to survive and is miscarried.Some chemicals cause miscarriages or birth defects byattacking the genetic material of cells or the systems whichcontrol its functions. Similar damage may also be involved incancer—cancer-causing substances are often the cause ofbirth defects and miscarriages.

Effects of hazardous substancesThe effects of exposure to workplace safety hazards aresometimes immediate, painful, and obviously damaging,but it is not always easy to observe when and how thebody’s cells are attacked by hazardous materials inthe workplace. Many of the most serious diseases do notoccur until 10 to 30 years after exposure.

OCCUPATIONAL HEALTH

Some Chemicals That May Affect the Nervous System

Table 6

Depression ofCentral Nervous System

AcetatesAlcoholsBrominated chemicalsChlorinated chemicalsEthersKetones

Brain Poisoning

Carbon disulfideHydrogen cyanideHydrogen sulfideStibineArsine

Brain Damage byOxygen Deprivation

Asphyxiating gasesCarbon monoxide

Nerve FunctionDisorders

Organo-phosphate pesticidesOrgano-phosphate plasticizersHeavy MetalsMercuryLeadManganeseArsenic

Legend:= Male exposure= Female exposureSource: Finland’s Institute for Occupational Health, Helsinki.

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Latency of workplace diseaseLatency refers to the time lag between exposure to ahazardous material and the eventual development of adisease. The latency period does not refer to the totalduration of exposure to a substance, but to the time that haselapsed since the first exposure. For many occupationalhazards, the latency period is from ten to twenty years. Itmay even be as long as thirty or forty years.Latency has a number of important implications for theworker. An individual exposed to a highly dangeroussubstance may feel no ill effects at the time of exposure.The effects may only show up many years later.For instance, exposure to ionizing radiationor asbestos causes very little in the way of symptoms atthe time of actual exposure, but the long-term effects canbe deadly.Past scientific studies have often failed to address theproblem of latency in evaluating the incidence of disease(such as asbestosis). In order to develop a clear picture ofdiseases which appear many years after exposure,researchers must study not only the current workforce(including many workers who have worked in a particularenvironment for less than twenty years), but also thoseworkers who had exposure in the past.Finally, a workplace free of disease is not necessarily aworkplace free of hazards. The diseases of todaygenerally reflect the working conditions of severaldecades ago. Similarly, the workplace hazards of todaymay produce the health problems of the future.

Acute and chronic effects ofworkplace hazardsWorkplace hazards may have both immediate and long-term effects on the body. These are termed acute andchronic effects. The sudden collapse of a worker who hasbeen exposed to massive doses of carbon monoxide, orthe headaches of a backhoe operator working in a poorlyventilated cab, are examples of acute effects.The acute effects of toxic substances occur immediatelyor very soon after the worker’s exposure, and aregenerally caused by high levels of exposure. They maycause death, but are often treatable if caught quickly.Sudden and dramatic, they result from the directaction of the hazardous material on the cellsof the body.Often more serious, however, are the chronic effects oftoxic substances. Chronic effects become apparent onlyafter many years. By and large, they are not treatable.They often result from the body’s attempts to repair itselfor to compensate for the acute effects of a substance. Forexample, cancer is a chronic effect, as is the lung scarringcaused by silica dust or the hearing damage caused byexcessive noise. Chronic disease becomes evident onlyafter severe damage has occurred.The acute effects of hazardous material are usually verydifferent from the chronic effects. Table 7 illustrates thedifference between the acute and chronic effects of someof the hazards discussed earlier.

Factors influencing toxic effect

Factors related tothe substancea) Chemical compositionDifferent chemicals produce different effects, but changesin composition may influence the toxic effect. For example,pressure-treated wood presents very little problem whendry. However, when the wood is burned the preservativedecomposes, producing more toxic chemicals.In some instances exposure to more than one chemicalmay change the toxic effect. For example, a person whoworks with solvents and then has a drink after work willget drunk faster and may have an increased risk of liverdamage than from either factor alone.b) Physical propertiesWith respiratory hazards, the two main concerns areparticle size and vapour pressure.Particles greater than 10 micrometers in diameter areremoved from inhaled air in the nose and upper respiratory

OCCUPATIONAL HEALTH

Acute and Chronic Effects of SomeCommon Workplace Hazards

Table 7

Acute Chronic

Acid Mists Irritation of the eyes andthroat, watering of the eyes,cough, sore throat, chestpain

Chronic bronchitis andemphysema

Asbestos Mild respiratory irritation,cough, sneezing

Asbestosis; cancerof the lung, pleura,larynx, stomach, andintestines

Carbon Monoxide Drowsiness, headache,confusion; in very highamounts, unconsciousnessand death

May contribute to heartattacks

Dust (containingsilica)

Cough, irritation, bronchitis,asthma

Silicosis, cancer,bronchitis

Noise Temporary threshold shift,tinnitus, pain

Noise-induced hearingloss, tinnitus

Trichloroethylene Lightheadedness, euphoria,“drunken” feeling, numbness

Liver and kidneydamage; possiblyliver cancer

Vibration Tingling and stiffness in thejoints

Arthritis, tendonitis

Exposure limits have been developed for varioushazardous materials to protect workers, but they shouldnot be treated as a fine line between safe and unsafeworkplaces. Not all individuals react in the same mannerto the same amount of a harmful material. The levels ofworkers’ exposures should be reduced to the lowestpractical level achievable. Efforts to reduce workers’exposures should start at half the exposure limit. This isknown as the “action level.”

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system. As particle size decreases, the system’s ability toremove particles also decreases until it is unable to filterout the substance.Vapour pressure measures the potential of a liquid tovaporize. The higher the vapour pressure, the greater thehazard. If, for example, two solvents of equal toxicity areavailable for use, the one with the lower vapour pressurewill present less of a vapour hazard and will therefore bethe safer choice.c) Solubility in body fluidsCertain chemicals are more soluble in body fluids thanothers. Chemicals termed lipid soluble are soluble in cellmembranes. They can very easily penetrate the body andare more mobile once inside. By being lipid soluble theymay also remain longer in the body before beingexcreted. Organic solvents such as toluene, xylene,acetone, and methanol are considered lipid soluble.

Factors related toexposure situationa) DoseWith most chemicals, the frequency and severity of toxiceffect is directly related to how much of the hazard theindividual is exposed to and for how long. This iscommonly referred to as the dose/effect or dose/responserelationship. With ethyl alcohol, for example, there is noadverse effect if the dose is within the body’s ability tocontrol it. However, if the dose exceeds that capacity, theeffect increases with the amount consumed.By examining the past use of toxic materials in theworkplace, by conducting animal studies, and bycomparison with other substances, it is possible to assign“safe working levels” of exposure for many materials. The“threshold” is the level up to which no significant adverseeffect is likely to occur in most people.With some substances, mainly carcinogens, the safeworking levels are difficult to define or may not exist. Forthis reason, exposures to known or suspected cancer-causing substances must be very closely controlled.b) Co-factorsMost of the standards that are set for “safe working levels”are based upon exposure to one chemical at a time. Inmany cases this does not occur. For example, exposure toasbestos increases the risk of lung cancer five times, whilesmoking increases the risk 10 times. A smoker exposed toasbestos, however, is 50 times more likely to develop lungcancer than a person who does not smoke and is notexposed to asbestos. The concept of multiple exposureshas not been extensively studied. As a result, exposures tocomplex mixtures should be kept as low as possible.

Factors related to the individualCertain individuals are more susceptible to chemicalexposure than others. These are some factors which mayinfluence toxic effect.a) Genetic statusIndividual susceptibility may be explained by geneticmake-up. It is suspected that the sites where toxic agentsreact is determined by genes that differ from person toperson. This theory may help to explain why only somepeople exposed to a particular substance develop anillness while others do not.b) Allergic statusIn people allergic to certain substances, antibodies causethe body to overproduce its own chemical defences,leading to symptoms such as asthma and dermatitis.For example, when a person is first exposed to epoxies orisocyanates a number of antibodies are produced. Onsubsequent exposure, the reaction is much more severebecause of this store of antibodies. With repeatedexposure, the allergic reaction can be triggered by smallerand smaller doses. This process is called “sensitization.”c) Presence of predisposing diseaseDisease may make a person more susceptible to certaintoxic agents as the body is already in a weakenedcondition.For example, a person with a heart ailment such asangina may have a heart attack if exposed to levels ofcarbon monoxide which would have little effect on normalhealthy people. Similarly, people who suffer from a lungailment such as emphysema will have a much moresevere reaction to lung irritants than a healthy person.d) AgeBe aware that chemicals may have a greater effect onboth older and younger workers.

OCCUPATIONAL HEALTH

8 – 1

8 BACK CARE ANDMATERIALS HANDLING

Nearly 25% of the lost-time injuries in construction arerelated to the back. More than half of these injuries resultfrom lifting excessive weight or lifting incorrectly.To prevent injuries, you need1. proper posture2. correct lifting techniques3. regular exercise.

PostureCorrect posture is not an erect, military pose. It meansmaintaining the naturally occurring curves in your spine.You have two inward curves — at the neck and low back— and one outward curve — at the upper back.Keeping your spine aligned in this manner reduceseveryday stresses on your back and minimizes the effectsof the normal aging process on the spine.When working in a crouched, bent, or stooping positionfor a prolonged period, take regular breaks by standing upand bending backwards three times.

Materials HandlingProper Lifting

1. Plan your move.• Size up the load and make sure your pathway isclear.

• Get help as needed.• Use a dolly or other device if necessary.

2. Use a wide-balanced stance with one foot slightlyahead of the other.

3. Get as close to the load as possible.4. Tighten your stomach muscles as the lift begins.5. When lifting, keep your lower back in its normal

arched position and use your legs to lift.6. Pick up your feet and pivot to turn — don't twist your

back.7. Lower the load slowly, maintaining the curve in your

lower back.Your back can manage most lifts — if you lift correctly.Avoid lifting above shoulder height. This causes the back toarch, placing heavy stress on the small joints of the spine.

BACK CARE AND MATERIALS HANDLING

Cervical Lordosis

Thoracic Kyphosis

Lumbar Lordosis

Correct Posture

You have two inwardcurves (lordosis), oneeach at the neck and lowback, and one outwardcurve (kyphosis) at theupper back.

Precision work

Light work

Heavy work

For long-term work overheador at heights, use scaffolds,scissor lifts, or other workplatforms rather than ladders.Remember — take regularstretch breaks to relievemuscle tension.

Common Posture

NormalProlonged standingoften causes anincreased curve inyour back. Elevatingone foot on a stoolor any other object(a phone book orbrick will do) willtake stress off thelower spine.

Sway BackAn increased curvein your lower backwill jam the vertebraetogether (sway back).If held too long, theposition will causelower back musclesand ligaments totighten and lead tolower back pain.

Flat BackToo little curve(flat back) willput extrapressure on thefront of yourdiscs. This maycontribute todisc problemsand pain.

Bending over to work can contribute to backpain and injury.Wherever possible, put workon a bench or other elevatedsurface.Ideally, the workshould be keptbetween waistand shoulderheight.

8 – 2

Do not catch falling objects. Your muscles may not havetime to coordinate properly to protect the spine.Push rather than pull. Pushing allows you to maintainthe normal curves in your back.

Weight TransferPull the object toward you while transferring your weightto the lift side.Lift only to the level required.Shift your weight to your other leg while pushing theobject into position.

Two-Person LiftLifters should be of similarheight. Before starting,they should decide on alifting strategy and whowill take charge.For a two-person lift of along load, the lifter whotakes charge must seethat the load is carried onthe same side, with aclear line of vision. Beginby lifting the load from ground to waist height.Then lift the load from waist to shoulder.

Carrying on StairsUse your stomach muscles tohelp support and protect yourback. If possible, the tallestand/or strongest person shouldbe at the bottom of the load.


Lifting Pipe

Pipe carts are ideal for transportinga load of pipe.

Lifting with SupportSupporting yourself byplacing one hand on asecure object or on yourthigh can reduce stress onyour spine and knees.

Balancing a LoadAny activity that unevenlyloads the spine mayaggravate your back. Avoidone-handed carrying ifpossible. Try to distribute theweight evenly on each side.If you can't avoid one-handed carrying, such aswith a single pail, hold thefree arm straight out as acounterbalance.

Rolling framescaffolds withtube-and-clampcomponents can beused to move pipe andother material.

Scaffold frames combinedwith tube-and-clamp

components,casters, and asmall boatwinch havemany uses inmoving andlifting.

Lift pipe atone end Walk to mid-

point

Balance onshoulder

A small rolling scaffold can be used totransport tools and materials

Loose fittings and shortlengths of pipe can beefficiently stored andtransported in metalbaskets equipped forlifting and moving byforklifts.

8 – 3

In addition to the equipment mentioned so far, there are anumber of inexpensive hand-operated devices which makematerials handling safer, more efficient, and less of a pain inthe back.

ExerciseConstruction work strengthens some muscles while othersbecome shorter and weaker, creating a muscleimbalance. A regular exercise program can help toprevent this from happening.A good exercise program should consist of four basic parts:

• warm-up• main workout• strength and stretch• cool-down.

Warm-UpThis is a general exercise program only. Before startingany exercise program, consult your doctor first.If you have any concerns or experience any painwhile doing the exercises, stop and consult yourdoctor.

1. March in PlaceStart: Stand in position.Action: Pump arms and legs in opposite directions.

Make sure heels contact ground. Continue3 to 5 minutes.

2. Arm CirclesStart: Stand with arms raised

horizontally and slightly infront of shoulders, palms down,and feet shoulder-width apart.

Action: Rotate arms in forward circularmotion for 15-30 seconds. Relax.Repeat 3-5 times.

Stretching ProgramThe following stretching exercises are of greatest valuebefore work starts. They may, however, be done at anyconvenient time. Whenever they are done, a brief warm-up(walking briskly or jogging on the spot) is most beneficial.

The exercises should be performed in a slow, controlledmanner and held in a sustained stretch. Avoid bouncy,jerky movements which may tear muscle fibres.

3. Knees to ChestStart: Support yourself securely with one hand.Action: Pull your knee toward your chest and

grasp around your knee with your freehand. Hold the stretch for 30 seconds.Lower your leg to the ground and repeatwith the other leg. Repeat three times foreach leg.

4. Hip StretchStart: Stand with one foot in front of the other.

Place hands above the knee of the frontleg.

Action: Gently bend front knee, keeping backfoot flat on the floor. Hold 20-30seconds. Repeat with other leg.Repeat three times for eachleg.

5. Thigh StretchStart: Support yourself with one hand on

something secure.Action: Bend your leg back and grasp your

ankle with your free hand. Gentlypull your ankle toward your body,keeping your trunk straight. Hold 20 to30 seconds; repeat with other leg.Repeat three times for each leg.

6. Calf StretchStart: Stand slightly away from a solid

support and lean on it withyour outstretched hands.Bend the forward leg and placethe other leg straight behind you.

Action: Slowly move your hips forward,keeping the heel of the back leg onthe ground. Hold 30 seconds, relax,and repeat with other leg. Repeatthree times for each leg.

7. Hamstring StretchStart: Place the back of your heel on a platform

at a comfortable height. Bend yoursupporting leg slightly.

Action: Looking straight ahead, slowlybend forward at the hips untilyou feel a good stretch at theback of the raised leg. Hold 30seconds and repeat with otherleg. Repeat three times foreach leg.


Chainfall

Mechanical Derrick

Chain Hoist

Pipe Cart

Lift

Contents continued on the next page

ASBESTOS

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9 ASBESTOS:CONTROLS FORCONSTRUCTION,RENOVATION, ANDDEMOLITION

CONTENTS (Numbers refer to sections in this chapter, not pages)

1 INTRODUCTION

1.1 Types of asbestos

1.2 History

2 HEALTH EFFECTS OF ASBESTOS

2.1 Disease statistics

2.2 Pre-employment medical examination

3 LOCATION OF ASBESTOS

3.1 Typical locations – friable materials

3.1.1 Sprayed-on fireproofing

3.1.2 Pipe and boiler insulation

3.1.3 Loose fill insulation

3.1.4 Vermiculite

3.2 Typical locations – non-friable materials

3.2.1 Asbestos cement products

3.2.2 Acoustical plaster

3.2.3 Acoustical tiles

3.2.4 Vinyl asbestos products

3.2.5 Roofing felts/shingles

3.2.6 Asphalt/asbestos limpet spray

3.2.7 Drywall joint-filling compound

3.2.8 Coatings and mastics

3.2.9 Gaskets and packings

3.2.10 Refractory brick

3.3 Summary: Typical locations

4 IDENTIFYING ASBESTOS-CONTAINING MATERIAL(ACM)

4.1 The age of the building or equipment

4.2 The type of construction

4.3 The nature of the equipment

4.4 The appearance of the material

5 OVERVIEW OF THE NON-ASBESTOS LEGISLATIONAND POLICIES THAT APPLY TO ASBESTOS WORK INONTARIO

5.1 Occupational Health and Safety Act (OHSA)

5.1.1 Specific non-asbestos regulations made underthe OHSA

5.1.1.1 Construction Regulation (OntarioRegulation 213/91)

5.1.1.2 WHMIS (Workplace HazardousMaterials Information System)

5.1.1.3 Critical Injury Definition Regulation

5.2 Workplace Safety and Insurance Act

5.3 Environmental Protection Act

5.4 Transportation of Dangerous Goods Act

5.5 Company policies

6 OVERVIEW OF THE ASBESTOS LEGISLATION THATAPPLIES TO ASBESTOS WORK IN ONTARIO

6.1 Application

6.2 Restriction of sprayed material and thermal insulation

6.3 Classification of Type 1, Type 2, and Type 3operations

6.4 Demolition, alteration, and repair—Owner’s report

6.5 Training and certification requirements

6.5.1 General asbestos awareness trainingrequirement

6.5.2 Certification requirements for Type 3operations

6.5.2.1 Steps to get certified

6.5.2.2 Exemption from exams

6.6 Notifying the Ministry of Labour (MOL)

6.6.1 Informing the Ministry of Labour of Type 3operations and Type 2 glove-bag operations

6.6.2 Discovery of material that may be asbestos

6.7 Enclosures

6.8 Clearance air sampling

6.9 Asbestos work report

6.10 Asbestos work registry

6.11 Use of equivalent measure or procedure

6.12 Enforcement of OHSA and its regulations

6.12.1 Powers of the Ministry of Labour Inspectors.

7 NON-ASBESTOS HAZARDS ASSOCIATED WITHASBESTOS OPERATIONS

7.1 Electrical hazards

7.1.1 Electrical power distribution

7.1.2 Temporary power distribution systems

7.1.3 Electrical cords and tools

7.2 Slips, trips, and falls

7.3 Ladders and scaffolds

7.4 Heat stress

7.5 Cold stress

7.6 Mechanical hazards

7.7 Explosive atmospheres

7.8 Atmospheric hazards

7.9 Carbon monoxide

7.10 Noise

8 IDENTIFY EMERGENCY RESPONSE PROCEDURES

9 TYPE 1 ASBESTOS OPERATIONS

9.1 What are Type 1 operations?

9.2 Controls for Type 1 operations

10 TYPE 2 OPERATIONS



10.3 Glove Bag Operations




11.3 Worker protection

11.3.1 Protective clothing

11.3.2 Respiratory protection

11.3.3 Types of respirators

11.3.3.1 Air-supplying respirators

11.3.3.1.1 Modes of operation

11.3.3.1.1.1 Negative-pressure(demand) mode

11.3.3.1.1.2 Continuous-flow mode

11.3.3.1.1.3 Positive-pressure orpressure-demand mode

11.3.3.2 Air-purifying respirators

11.3.3.2.1 Non-powered air-purifying respirators

11.3.3.2.2 Powered air-purifyingrespirators (PAPR)

11.3.4 Proper fit

11.3.4.1 Fit testing

11.3.4.2 Seal checking

11.3.5 Inspection and maintenance

11.3.6 Cleaning and sanitizing

11.3.7 Storage

11.3.8 Limitations of respirators

11.3.8.1 Some major limitations of air-purifying respirators

11.3.8.2 Some major limitations of poweredair-purifying respirators (PAPR)

11.3.8.3 Some major limitations of supplied-air respirators

11.4 Site preparation—indoor projects

11.5 Entry/decontamination facility

11.5.1 Procedures for entry and decontamination

11.5.1.1 Entry

11.5.1.2 Decontamination

11.6 Removal

11.7 Clean-up and storage

11.8 Visual inspection

11.9 Lockdown/gluedown

11.10 Clearance air testing

11.11 Teardown

11.12 Disposal of asbestos-containing material

11.13 Outdoor operations

11.14 Demolition

11.15 Disturbing non-friable asbestos with power tools notequipped with HEPA filters

12 ASBESTOS WASTE MANAGEMENT

APPENDIX A: Respirator chart

APPENDIX B: Reference chart for asbestos operations

APPENDIX C: Clearance air testing

APPENDIX D: Inspecting respirators

APPENDIX E: Cleaning and storage of respirators

APPENDIX F: Putting on and seal checking respirators

APPENDIX G: Fit testing respirators

APPENDIX H: Respirator policy

APPENDIX I: HEPA filters

APPENDIX J: Negative air units and HEPA filters:troubleshooting

9 – 2

ASBESTOS

amphibole

1 INTRODUCTION“Asbestos” refers to a group of naturallyoccurring minerals once used widely in theconstruction industry.

Its strength, insulation properties, ability towithstand high temperatures, and resistance tomany chemicals made asbestos useful inhundreds of applications in the constructionindustry.

1.1 Types of asbestos

There are two general categories of asbestos:serpentine (long and flexible fibres) andamphibole (brittle and sharp fibres). There aresix types of asbestos generally recognized:

• chrysotile (serpentine)

• crocidolite

• amosite

• actinolite

• anthophyllite

• tremolite

Chrysotile asbestos is characterized by longwavy fibres that are white or off-white. Amositeis often called “brown” asbestos and has muchstraighter, shorter and sharper fibres thanchrysotile. Crocidolite is referred to as “blue”asbestos and has long straight fibres much likeamosite.

Chrysotile is by far the most common type ofasbestos found in Ontario. Within the amphibolefamily, only amosite and crocidolite have hadsignificant commercial use.

Some studies show that fibres such as amositeand crocidolite (amphiboles) stay in the lungslonger than chrysotile fibres (serpentine). Thistendency may account for the greater toxicity(harmfulness) of amphibole fibres.

1.2 History

Major use of asbestos products in constructionbegan in the 1930s and escalated during thepost-war building boom. During the 1950s andup to 1970 approximately 30 to 80 thousandtons were used annually in Canada.

In the early 1970s, the use of such products inCanada declined sharply because of increasingconcern over the health effects of asbestos. Inthe mid-1970s specific prohibition and theavailability of safer substitutes put an end to theuse of many asbestos products. But the earlywidespread use of asbestos has left a potentiallydangerous legacy. The thousands of tons ofasbestos installed over the past eighty years canpose serious risk to workers in the renovation,maintenance, repair, and demolition sectors ofthe construction industry.

2 HEALTH EFFECTS OF ASBESTOSAsbestos fibres don’t break in half across theirdiameter (width), but rather split into thinnerand thinner needle-like fibres along their length.

An asbestos fibre can remain airborne for a longtime and can easily become airborne again afterit has settled if there is any air movement.

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Asbestos fibres

ASBESTOS

Asbestos fibres usually need to be less than 3micrometres in diameter before they can beinhaled deep into the lungs. (A micrometre isone millionth of a metre, which is onethousandth of a millimetre, and its abbreviationis µm.) The fibres can remain in the lungs formany years—even decades.

The average diameter of an airborne asbestosfibre ranges from 0.11 to 0.24 µm, depending onthe type of asbestos and are invisible to the eye.You can see fibres that are greater than 100 µmin diameter. Human hair is approximately100 µm in diameter—more than 300 timesthicker than asbestos fibre.

Inhalation of the airborne asbestos fibres thatyou cannot see is what causes asbestos-relateddiseases.

Inhaling asbestos fibres has been shown tocause the following diseases:

• Mesothelioma

• Lung cancer

• Asbestosis

• Other illnesses.

A person exposed to asbestos may feel no illeffects at the time of exposure. The time periodbetween exposure to asbestos fibres and the

development of disease can range from 15 to55 years. This is known as the latency period.The asbestos-related diseases workers get todayare the result of exposures during the 1960s,1970s, and 1980s.

Mesothelioma is a rare and fatal cancer of thelining of the chest and/or abdomen. While thisdisease is seldom observed in the generalpopulation, it appears frequently in workersexposed to asbestos.

Because of past exposures, mesothelioma isthe #1 cause of occupation-related death inconstruction.

Lung cancer appears quite frequently inpeople exposed to asbestos dust. While scienceand medicine have not yet been able to explainprecisely why or how asbestos causes lungcancer, it is clear that exposure to asbestos dustcan increase the risk of this disease. Studieshave shown that the risk to asbestos workers isroughly five times greater than for people whoare not exposed to asbestos.

Cigarette smoking, another cause of lung cancer,multiplies the risk. Cigarette smoking andasbestos combine to produce a synergistic effect.Research has shown that the risk of developinglung cancer was fifty times higher for asbestosworkers who smoked than for workers whoneither smoked nor worked with asbestos.

Asbestosis is a disease of the lungs caused byscar tissue forming around very small asbestosfibres deposited deep in the lungs. As theamount of scar tissue increases, the ability oflungs to expand and contract decreases, causingshortness of breath and a heavier workload onthe heart. Ultimately, asbestosis can be fatal.

Other illnesses – There is some evidence ofan increased risk of cancers of thegastrointestinal tract and larynx. However, thelink between asbestos exposure and thedevelopment of these illnesses is not as clear aswith lung cancer or mesothelioma.

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ASBESTOS

The diseases described above do not respondwell to current medical treatment and, as aresult, are often fatal.

Asbestos may cause skin irritation and a wart-like condition which can be prevented bywearing normal clothing. Asbestos does notcause skin cancer.

Significant exposure to asbestos puts you at riskfor developing pleural plaques (scarring of thepleura—the lining of the lung). Pleural plaquesare an indicator of previous exposure toasbestos and can make breathing difficult. Someresearchers believe that there is evidence thatworkers with pleural plaques are at risk ofdeveloping other asbestos-related diseases suchas lung cancer or mesothelioma. If you developpleural plaques you should inform yourphysician about your exposure to asbestos.

2.1 Disease statistics

From 1997 to 2006, Ontario’s Workplace Safetyand Insurance Board (WSIB) approved 300occupational disease fatality claims – the vastmajority of them (approximately 85%) due toasbestos exposure. Trades at particular riskinclude plumbers/pipe fitters, insulators,labourers, and electricians.

2.2 Pre-employment medical examination

Before starting as an asbestos worker, it isrecommended that the prospective worker gothrough a pre-employment medical examination.The examination is to see if the worker has apre-existing respiratory disease (such as asthmaor evidence of impaired lung function) that mayprevent the worker from using respiratoryprotection.

3 LOCATIONS OF ASBESTOSTwo classes of asbestos products were widelyused. The first includes materials easily crumbledor loose in composition such as spray-fireproofing. These are referred to as “friable.”The second type includes materials that are

much more durable because they are heldtogether by a binder such as cement, vinyl, orasphalt. These products are termed “non-friable.”

FRIABLE means easily crumbled into dust

NON-FRIABLE means difficult to crumbleinto dust.

3.1 Typical locations – friable materials

3.1.1 Sprayed-on fireproofing

This material was widely used to fireproof steelstructures. It can be found on beams, columns,trusses, joists, and steel pan floors. Sprayedmaterial was also used as a decorative finishand as acoustical insulation on ceilings. Thematerial can be loose, fluffy, and lumpy intexture or, if more gypsum or cement was used,it may be quite hard and durable.

3.1.2 Pipe and boiler insulation

Much of the insulation on older heating systemsand industrial processes was asbestos. Sometypes were pre-formed blocks or sections whileothers (commonly called “air cell” insulation)were corrugated and resemble cardboard. Oftenthese materials are covered by painted canvasor sheet material.

Site-mixed asbestos cement was often used toinsulate valves and elbows on piping and on therounded ends of boilers and pressure vessels.

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ASBESTOS

Sprayed-on fireproofing

3.1.3 Loose fill insulation

This application was relatively rare and usuallylimited to tank insulation where the asbestos isheld in place by light gauge wire mesh andthen covered with sheet metal.

3.1.4 Vermiculite

Vermiculite is a mineral. It has been used ininsulation and many commercial and consumerproducts for well over 50 years. Vermiculiteitself is not asbestos and has not been shown topose a health problem. Vermiculite, however,can be contaminated with asbestos sincemineral deposits of the two substances canoccur togetherunderground. Forexample,vermiculite orefrom the LibbyMine in Montanafrom the 1920s to1990 wascontaminated withasbestos. Insulationmade from thisvermiculite wassold in Canadaduring that timeunder various trade names such as “Zonolite.”

Not all vermiculite contains asbestos fibres. It isrecommended that buildings with vermiculite-based insulation be tested to determine ifasbestos is present. If you don’t test thematerial, assume that it contains some asbestos.

Boiler

Pipe and boiler insulation

Air cell insulation

Loose fill insulation

Vermiculite

ASBESTOS

9 – 6

3.2 Typical locations – non-friablematerials

Note: Certain conditions (such as chemicalexposure, thermal degradation, and waterdamage) may cause non-friable asbestos-containing material to deteriorate and becomefriable.

3.2.1 Asbestos cement products

This type of material contains cement to bindthe asbestos fibres together and was used inpipe form for sewers and water supply. In sheetform it was used for roofing and siding, as wellas some types of firewall construction—forexample, behind stoves and fireplaces and inhigh-rise construction.

3.2.2 Acoustical plaster

Acoustical plaster may be friable – it dependson the exact mixture. This material was mixedon site and applied like conventional plaster. Itwas used in schools, auditoriums, hospitals, andcommercial buildings where acousticalproperties were required.

3.2.3 Acoustical tiles

Some of the older acoustical tiles may containsignificant amounts of asbestos. Some tiles werestapled or glued in place whereas others weresuspended on T-bar. Some tiles can beconsidered friable because they can becrumbled by hand pressure. They are generallyconsidered to be non-friable, however, sincethey are usually intact when they’re handled.

3.2.4 Vinyl asbestos products

These products were widely used in flooring asboth tiles and sheets. The vinyl served to lockin the asbestos fibres.

3.2.5 Roofing felts/shingles

Some roofing felts used in built-up asphalt orpitch roofing contained asbestos. Asphalt orpitch was used to saturate the felts and bind thefibres in place.

3.2.6 Asphalt/asbestos limpet spray

This black tarry mixture was sprayed onto tanksand other equipment primarily in petrochemicalplants and heavy industry. The application wasvery similar to sprayed-on fireproofing except

Acoustical tile

Vinyl asbestos flooring

Asbestos concrete

ASBESTOS

9 – 7

that asphalt was used as the binder. In someapplications a surface coat of asphalt was usedto cover asbestos insulation on tanks, hoppers,and other storage or process equipment.

Asbestos was added to asphalt and used forroad construction.

3.2.7 Drywall joint-

filling compound

Early drywall joint-fillingcompounds containedsignificant amounts ofasbestos fibre. This particularuse was specificallyprohibited in 1980 by theHazardous Products Act.Still, it may be found inbuildings constructed severalyears afterwards.

3.2.8 Coatings and mastics

Since asbestos was relatively inexpensive andwithstood weathering, it was widely used as afiller in many coatings and mastic products suchas roofing cement, caulking materials, andflooring adhesives.

3.2.9 Gaskets and packings

Several different types of gasket materialcontained asbestos. One common type wasa rubber/vinyl/asbestos mixture whichcould be cut to size or came in standardsizes and patterns. Woven or pressedasbestos material was also widely used ondoors and other openings on boilers,furnaces, and kilns (see image a). A thirdtype consisted of a metal outer ring and anasbestos inner ring (see image b) and wasused on high pressure steam lines andsimilar processes (see image c). A fourthtype was often used as packing for pumpsand valves (see image d).

3.2.10 Refractory brick

High temperature refractory brick andmortar containing asbestos material were

previously used in the construction of structuresrequired to withstand high temperatures such asin boiler rooms and furnace rooms.

3.3 Summary: Typical locations

Table 1 summarizes where asbestos productshave been generally used. The images on thefollowing pages indicate typical locations ofasbestos materials in various types ofconstruction.

Drywall joint-filling compound

a b

c d

Gaskets and packings

Product Residential IndustrialCommercial/Institutional

TABLE 1 — ASBESTOS PRODUCTS IN CONSTRUCTION

*Extensive use

Sprayed-On Fireproofing XX*

Pipe and Boiler Insulation X X XX

Loose Fill Insulation X X

Vermiculite Insulation X

Asbestos Cement Products X X X

Acoustical Plaster X X

Acoustical Tiles X XX

Vinyl Asbestos Tiles X X

Gaskets X XX

Roofing Felts X X X

Asphalt/Asbestos Limpet Spray X

Drywall Joint-Filling Compound X X

Coatings and Mastics X X X

ASBESTOS

9 – 8

Asbestos Products in Residential Buildings

ASBESTOS

9 – 9

ASBESTOS

9 – 10

ASBESTOS

9 – 11

4 IDENTIFYING ASBESTOS-CONTAINING MATERIAL (ACM)

Although the only true method of identifyingasbestos is by microscopic analysis of samples,several rules of thumb indicate whether it’slikely that asbestos is present.

4.1 The age of the building or equipment

Asbestos pipe and boiler insulation was usedextensively in all sectors of the industry until the1970s, when substitutes such as fibreglass,mineral wool, rock wool, and refractory ceramicfibre became more economical and lesshazardous. Buildings and installations datingfrom before that period may contain asbestos indifferent forms.

Since the late 1970s, many owners of processeshave upgraded their insulation. The originalasbestos insulation may have been covered bysome other material (e.g., fiberglass or refractoryceramic fibre) and a surface inspection may notreveal any underlying asbestos.

In the case of fireproofing, 1974 marks the lastmajor use of asbestos for this application.

4.2 The type of construction

Structural steel frame buildings requirefireproofing to protect the integrity of thestructure until occupants can be evacuated. Thisresulted in widespread use of sprayed-on ortrowelled-on fireproof coatings, most of whichcontained chrysotile asbestos.

Reinforced concrete structures do not normallyrequire additional fireproofing since theconcrete protects the reinforcing steel whichprovides the critical structural support. However,composite steel pan/concrete floor constructionwas often fireproofed with asbestos.

In low-rise residential construction, the use offriable asbestos material is usually limited topipe and boiler insulation as described above.

4.3 The nature of the equipment

Asbestos insulation materials were used onequipment exposed to extreme conditions suchas high temperatures and corrosiveenvironments. As a result, asbestos can beanticipated on high pressure steam lines, “hot”process piping, and refractory linings infurnaces and kilns.

Asbestos cement sheeting was often used inindustrial settings for roofing, siding, and splashprotection from corrosive material.

4.4 The appearance of the material

While mineral wool, calcium silicate, andasbestos are quite similar in appearance, othermaterials such as fibreglass are noticeablydifferent. This fact can be used to eliminatecertain materials from consideration andanalysis.

In the case of pipe insulation, the corrugatedtype of material commonly called “air-cell”insulation was almost exclusively made with asignificant amount of asbestos.

The factors in section 4.1 and 4.4 (above), alongwith a review of original plans andspecifications, can be used by the client or theclient’s representative in conducting aninspection and preparing the required report.Any suspect materials which cannot bedetermined to be asbestos or are not treated asasbestos-containing material (ACM) must besampled and microscopically analyzed (U.S. EPATest method EPA/600/R-93/116) to determine:

• whether the material is ACM

• the type of asbestos

• the percentage of asbestos present.

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5 OVERVIEW OF THE NON-ASBESTOSLEGISLATION AND POLICIES THATAPPLY TO ASBESTOS WORK INONTARIO

5.1 Occupational Health and Safety Act(OHSA)

The Occupational Health and Safety Act

1. sets out the rights and duties of all partiesin the workplace. Its main purpose is toprotect workers against health and safetyhazards on the job.

2. establishes procedures for dealing withworkplace hazards, and it provides forenforcement of the law where compliancehas not been achieved voluntarily throughthe internal responsibility system.

5.1.1 Specific non-asbestos regulations

made under the OHSA

5.1.1.1 Construction Regulation

(Ontario Regulation 213/91)

Asbestos removal falls under the ConstructionRegulation which regulates health and safetyissues such as:

• housekeeping

• electrical hazards

• fire safety

• ladders

• scaffolds and work platforms

• elevating work platforms

• confined spaces

• demolition.

5.1.1.2 WHMIS (Workplace Hazardous

Materials Information System)

WHMIS applies to all work sites wherecontrolled products are used. Under the WHMISregulation, employers must

• provide material safety data sheets(MSDSs) for the products,

• ensure that controlled products haveWHMIS labels applied to the containers,

• ensure that workers receive WHMIStraining.

5.1.1.3 Critical Injury Definition

Regulation (Regulation 834)

For the purposes of the Occupational Healthand Safety Act and the regulations, “criticallyinjured” means an injury of a serious naturethat,

• places life in jeopardy;

• produces unconsciousness;

• results in substantial loss of blood;

• involves the fracture of a leg or arm butnot a finger or toe;

• involves the amputation of a leg, arm,hand or foot but not a finger or toe;

• consists of burns to a major portion of thebody; or

• causes the loss of sight in an eye.

All critical injuries must be reported to theMinistry of Labour (MOL) for furtherinvestigation.

5.2 Workplace Safety and Insurance Act

Through the Workplace Safety and InsuranceAct, the Workplace Safety and Insurance Board(WSIB) oversees the compensation of thoseinjured or made ill due to work-related causes.The WSIB provides disability benefits, monitorsthe quality of health care, and assists in early,safe return to work for workers who wereinjured on the job or who developed anoccupational disease.

The Workplace Safety and Insurance Act alsooutlines first aid requirements for companies.

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5.3 Environmental Protection Act

The disposal of asbestos is strictly regulated bythe Environmental Protection Act. Asbestos wastemust be disposed of at a landfill specificallyapproved and equipped to handle asbestos waste.

5.4 Transportation of Dangerous Goods Act

The transportation of asbestos-containing wastefrom the site of the asbestos abatement projectto the landfill is regulated by the Transport ofDangerous Goods (TDG) Regulation andrequires that

• any person transporting or handlingdangerous goods has a TDG certificate

• the contractor transporting asbestos wastemust have correct

TDG placarding on vehicles

manifest

• friable asbestos waste is transported onlyin vehicles equipped with emergency spillclean-up equipment.

5.5 Company policies

Companies may establish additional safe workpractices and procedures (policies) that go beyondthe requirement set out in the OHSA and itsregulations. Company supervisors are responsiblefor ensuring compliance and enforcement of thesework practices and procedures.

6 OVERVIEW OF THE ASBESTOSLEGISLATION THAT APPLIES TOASBESTOS WORK IN ONTARIO

Ontario Regulation 278/05 (DesignatedSubstance—Asbestos on Construction Projectsand in Buildings and Repair Operations) underthe Occupational Health and Safety Act (OHSA)outlines safe work measures and proceduresand respiratory protection for workers who mayencounter asbestos-containing material (ACM) inthe course of their work.

ACM (asbestos-containing material) isdefined as material containing 0.5% or moreasbestos.

6.1 Application

The regulation applies to all work on ACM, orwork which is likely to disturb ACM, with themajor exception being residential buildingscontaining four dwelling units or less, whereone of the units is occupied by the owner orthe owner’s family. However, Section 30 of theOccupational Health and Safety Act states thathomeowners are required to inform contractorsabout the presence of asbestos in their homesso that they can protect workers.

6.2 Restriction of sprayed material andthermal insulation

Spraying material containing more than 0.1%asbestos or the use of thermal insulationcontaining more than 0.1% asbestos isprohibited.

6.3 Classification of Type 1, Type 2, andType 3 operations

The Ministry of Labour uses the following fivefactors to categorize the asbestos-related activityinto one of three types: Type 1, Type 2, or Type3. Think of Types 1, 2, and 3 as describing low-,medium-, and high-risk work.

1) Nature of material

FRIABLE versus NON-FRIABLE

Friable means easy-to-crumble with handpressure into dust.

Non-friable means difficult-to-crumble withhand pressure into dust.

• Friable products such as fireproofing andthermal insulation can release fibres veryeasily, whereas non-friable products willgenerally release fibres only when they are

cut

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shaped

otherwise worked with power tools

deliberately crumbled or pulverized.

• Compared to chrysotile, amphiboles suchas amosite are not as easily controlled bywater and thus tend to generate more dustduring removal.

• Some studies show that amphibole fibres(crocidolite, amosite, tremolite) stay in thelungs longer than serpentine (chrysotile)fibres. This tendency may account for thegreater toxicity (harmfulness) of amphibolefibres.

2) Nature of activity

This can greatly affect the degree of hazard. Forexample, cutting asbestos cement products witha power tool creates much more dust thanscribing and breaking.

3) Application of water

Using water to prevent the creation and spreadof dust is a practical control in many cases. It isnot practical, however, in areas where wettingwould create a hazard or cause damage. In suchcircumstances, dry removal is allowed.

4) Size of the project or duration of

exposure

Asbestos diseases are dose-related: the greaterthe exposure in duration and/or intensity, thegreater the risk. Short exposures to any givenamount of asbestos will usually be lesssignificant than longer exposures.

5) Risk to bystanders

The hazards of exposure must be considered forboth workers and other people not directlyinvolved in the asbestos project. For instance,handling asbestos outdoors or pre-demolitiondoes not pose the same risk to bystanders ashandling it in an occupied building where thedust may recirculate.

The classification and control procedures forcarrying out Type 1, 2, and 3 operations areoutlined in sections 9, 10, and 11 of thismanual.

6.4 Demolition, alteration, andrepair–Owner’s report

For any demolition, alteration, or repair projectsthe owner must complete a report indicatingwhether any material that is likely to be handled,dealt with, disturbed, or removed is

• friable or non-friable asbestos-containingmaterial (ACM), or

• to be treated as ACM, and, in the case ofsprayed-on friable material, treated asthough it contained a type of asbestosother than chrysotile.

The report (including drawings, plans, andspecifications as appropriate) must show thelocation of the ACM and must be provided to allcontractors bidding on the job and must bereviewed before contract arrangements arefinalized.

6.5 Training and certification requirements

6.5.1 General asbestos awareness

training requirement

Anybody who works in a Type 1, Type 2, orType 3 asbestos operation must be trained by acompetent person on the following:

• the hazards of asbestos exposure

• the purpose, inspection, maintenance, use,fitting, cleaning, disinfecting, andlimitations of respirators

• personal hygiene and correct proceduresfor work with asbestos

• how to use, clean, and dispose ofprotective clothing.

This requirement includes workers such aselectricians, plumbers and pipe fitters, gas fitters,

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painters, drywallers, demolition workers, heatingand ventilation workers, and computer installersperforming work in the area of a Type 1, Type2, or Type 3 operation, but not involved in anactual removal operation.

Workers performing Type 3 operations andsupervisors in these operations must also becertified to do so, as described below.

6.5.2 Certification requirements for

Type 3 operations

As of November 1, 2007, workers andsupervisors must be certified before they cando Type-3 asbestos work or supervise Type-3work. Certification is not required for

• workers in Type 1 or Type 2 operations

• workers entering Type 1, 2, or 3 workareas to perform work not related to theasbestos removal operation.

The workers that do not require certificationare, however, required to have asbestosawareness training.

There are two asbestos abatement certificationprograms: one for workers (Asbestos AbatementWorker) and one for supervisors (AsbestosAbatement Supervisor). Before becoming acertified asbestos abatement supervisor youmust

• be certified as an asbestos abatementworker

• have taken a 16-hour training course onbeing a supervisor in construction

• take the Asbestos Abatement Supervisorprogram and pass the test.

Workers and supervisors must have theiroriginal certification cards available at the worksite when they are working. Ministry of LabourInspectors may ask a worker to produce theiroriginal card plus appropriate identification.

6.5.2.1 Steps to get certified

1. One of the following groups must registeryou for an in-school training programapproved by the Ministry of Training,Colleges, and Universities (MTCU):

• employers engaged in Type 3 asbestoswork

• joint local union/employer trainingcommittees.

Note: The employer must apply to theMTCU for “signing authority” before it canenroll you in an approved training program.

2. Take the training that you need.

3. Once you have completed the in-schoolpart, you are eligible to write the asbestosabatement worker or supervisor test. Eachtest is administered by the MTCU (not thetraining provider) and consists of 40multiple-choice questions.

4. If you pass the test, the “signing authority”(the employer) sends the requiredpaperwork to the MTCU. This confirms thatyou have successfully completed the in-school training program and have passed thetest. The MTCU will then issue you aCertificate of Completion.

6.5.2.2 Exemption from exams

Until November 1, 2008, experienced Type 3workers and supervisors can take the testswithout having to take the in-school trainingprograms. If you fail the test, however, you willbe required to take an in-school trainingprogram approved by the MTCU.

Experienced workers and supervisors fromoutside Ontario can take the tests withouthaving to take the in-school training. If they failthe test, however, they will be required to takean in-school training program approved by theMTCU.

You are considered experienced if you have atleast 1,000 hours of experience performing Type 3work before November 1, 2007. You must provethis with an Asbestos Work Report Form 1 (orequivalent document for those from outsideOntario) or a letter on official company letterhead.

6.6 Notifying the Ministry of Labour (MOL)

6.6.1 Informing the Ministry of Labour

of Type 3 operations and Type 2

glove-bag operations

You must notify the Ministry of Labour (MOL),orally and in writing, before beginning a Type 3operation, or before beginning a Type 2operation in which one square metre or more of

insulation is to be removed using a glove bag.The written notice must include

• the name and address of the person givingthe notice

• the name and address of the owner of theplace where the work will be done

• the exact address and location where thework will be done

• a description of the work that will be done

• the starting date and expected duration ofthe work

• the name and address of the supervisor incharge of the work.

TORONTO-BASED ENERGY COMPANY FINED FOR HEALTH AND SAFETY VIOLATIONS

SARNIA, Ont. - A Toronto-based energy company that operates an ethanol refinery in Sarnia, wasfined $125,000 for two violations of the Occupational Health and Safety Act, and a London, Ont.-based insulation contractor, was fined $50,000 for one violation, both on May 14, 2007, inconnection with asbestos infractions.

Between March 9 and 12, 2005, workers removed insulation and other materials from heatexchangers and from a “stripper change drum” (large chemical vessel). On the morning of March11, 2005, a concern was raised that material on the stripper change drum contained asbestos. Theconstructor of the insulation-removal project sent the materials for testing to a facility in London andreceived confirmation at 4 p.m. from that facility that the materials contained asbestos. The energycompany failed to notify the Ministry of Labour of the asbestos, both orally and by submitting arequired written report in a timely fashion. Both the energy company and the insulation contractor,which employed the workers who were removing the materials, also failed to ensure workers woreappropriate personal protective equipment when removing the materials both after the suspectedasbestos was discovered and after it was confirmed.

The energy company pleaded guilty, as a constructor, to:

1. failing to ensure friable material discovered during the work, that was not referred to in apreviously-prepared asbestos report, was reported to the Ministry of Labour, both orally and ina written report, as required by Section 7(6) of the Regulations for Asbestos on ConstructionProjects and in Buildings and Repair Operations. This was contrary to Section 23(1) of the act;and

2. failing to ensure workers were provided with protective equipment that included a supplied-air, positive-pressure full-face-piece respirator for a Type 3 asbestos removal, as required bySection 14(5)(viii) of the Regulations for Asbestos on Construction Projects and in Buildingsand Repair Operations. This was contrary to Section 23(1)(b) of the act.

The Justice of the Peace fined the company $25,000 on the first count and $100,000 on the second count.

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6.6.2 Discovery of material that may be

asbestos

If during work, suspicious material that was notreferred to in the asbestos report (see section6.4) is discovered, then the constructor mustimmediately report the discovery to the Ministryof Labour, both orally and in a written report.The owner, contractors and the joint health andsafety committee must also be informed bothorally and in writing by the constructor.

No work is allowed until the material is testedfor the presence of asbestos unless the materialis treated as ACM and, in the case of sprayed-onfriable material, as though it contained a type ofasbestos other than chrysotile.

6.7 Enclosures

Where there is a significant risk ofcontamination (certain Type 2 and Type 3operations) there is a requirement to enclose thework area. The purpose of the enclosure is tocontain ACM within the enclosure, thuspreventing exposure of people outside of thecontainment area. Additionally, by enclosing thework area you prevent unauthorized access tothe work area.

For indoor Type 3 operations the enclosuremust be kept under negative pressure(0.02 inches of water).

For more information about enclosures, seesections 10.2, 11.4, and 11.5 in this manual.

6.8 Clearance air sampling

For certain Type 3 operations, once asbestosremoval has been completed a visual inspectionand clearance air testing must be performed(see sections 11.8, 11.10, and Appendix C in thismanual for more details).

6.9 Asbestos work report

The employer must complete and submit to theMinistry of Labour an asbestos work report form(available from the Ministry of Labour) for each

person working in a Type 2 or Type 3operation. The employer must do this at leastonce a year and immediately on termination ofa worker’s employment.

6.10 Asbestos work registry

The Ministry of Labour maintains an AsbestosWorkers Register based on asbestos work reportforms. Workers listed in the Register may beasked by the Ministry’s Provincial Physician ortheir own physicians to voluntarily have amedical examination to determine if they aresuffering from a condition resulting fromasbestos exposure.

6.11 Use of equivalent measure orprocedure

If you wish to use other equivalent methods orprocedures than those required by OntarioRegulation 278/05, you must submit a proposalin writing to the joint health and safetycommittee or the health and safetyrepresentative. The equivalent method mustprovide protection equal to the protectionprovided in the regulation. Workers must betrained on the equivalent measure or procedure.

Poor work practices

Poor work practices such as not wettingACM, or dry sweeping of waste ACM, canlead to high fibre levels. By not followingproper work practices you will not onlyendanger yourselves but also your family,co-workers, and building occupants.

6.12 Enforcement of OHSA and itsregulations

The Ministry of Labour Inspectors areresponsible for enforcing the provisions of theOHSA and the regulations made under it.

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6.12.1 Powers of the Ministry of Labour

Inspectors.

An inspector can visit a site at any time andexercise fairly broad powers to inspect, test,look at documents/records, take photographs,ask questions, and give orders. If the inspectorapproaches a worker or supervisor directly, theworker must answer questions and cooperate.The supervisor must be informed of any ordersgiven or recommendations made.

7 NON-ASBESTOS HAZARDSASSOCIATED WITH ASBESTOSOPERATIONS

7.1 Electrical hazards

Due to the presence of water used in asbestosabatement procedures, one of the most dangeroushazards is contact with electricity. The employermust develop and implement specific safetyprocedures for preventing electric shock and burn.

Sometimes, work on energized equipment isunavoidable, such as when transformers orcontrol boxes must remain energized during theabatement project. In such circumstances, dryremoval is allowed provided that theappropriated precautions are taken.

7.1.1 Electrical power distribution

• Ensure all electrical panels, exposedelectrical conductors, or equipment (suchas transformers, switches, capacitors) arelocked out and tagged before any workbegins. All wiring should be treated asenergized unless tested and proven to bede-energized.

• If power cannot be disconnected, allexposed electrical equipment must becovered to prevent moisture from enteringinto the equipment.

• Electrical power connections to permanentfixtures must be disconnected buttemporary connections may be made for

lighting purposes or the operation of toolsor equipment.

• Every precaution must be taken to avoidelectrical shock. Use ground fault circuitprotection.

• Ensure that all permanent circuits areprovided with a grounding system. Thiscan be determined with a portable groundtester.

• Ensure that electrical outlets are tightlysealed and taped to avoid water spray.

• Determine what equipment must remainenergized during the abatement process.

• Insulate or guard energized equipment andwiring from employee contact and otherconductive objects.

• Avoid damaging permanent building wiringduring the work.

7.1.2 Temporary power distribution

systems

• All temporary circuits provided by theabatement contractor must be providedwith a grounding system and protected byground fault circuit interrupters (GFCIs).

• Avoid stringing temporary wiring acrossfloors and through door openings.

• Elevated wiring should not be fastenedwith staples, nails, or wire.

• Use care not to damage the wiring insulationduring installation or abatement work.

• Temporary lights are to be installedaccording to the Ontario Electrical Code.You must use inline or circuit breaker/receptacle type GFCIs at all times.

GFCI – A Ground Fault CircuitInterrupter provides additionalprotection from shocks by shutting offthe current to equipment when theGFCI senses an electrical fault.

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7.1.3 Electrical cords and tools

• Provide heavy-duty extension cords with aground conductor.

• Ensure that cords are not damaged,contain no splices, and that grounding pinson the male plugs are intact.

• Position extension cords to eliminatetripping hazards and to protect them frombeing damaged by moving scaffolds.

• Provide electrical tools which are eithergrounded or double-insulated.

• Use shatterproof, guarded bulbs and heavyduty wiring for temporary lighting.

• Where plugs enter receptacles, ensure thatthe connection is protected and secured inplace.

• Provide mechanical protection to protectall temporary power cords.

• Before using them, inspect all power toolsfor damaged components and power cordconnections.

7.2 Slips, trips, and falls

Using water to control the spread of asbestosfibres can make polyethylene sheeting veryslippery. Rubber boots with non-skid soles arerecommended. Post signs in conspicuouslocations warning workers of the slip hazard.

Poor lighting makes it difficult to see and canlead to trips and falls. Lighting needs to besufficiently bright to minimize shadow and toilluminate objects on the work surface.

Poor housekeeping is a cause of trips and falls.ACM or other rubbish—such as ceiling tile, t-bar,metal hangers, wood, nails and screws, anddrywall—should be bagged as often as necessaryto keep the work area free of slipping andtripping hazards.

Electrical cords, vacuum hoses, and water hosesshould be organized and moved away fromwhere workers could trip over them.

Wherever there is a danger of falling from aheight, you must install guardrails or useappropriate fall protection equipment. Workersmust receive fall protection training inaccordance with the Construction Regulation.

Unguarded openings in the work area must beadequately protected by installing a securetemporary cover or by guardrails with toe boards.Covers must be capable of supporting all verticalloads imposed upon them. A large conspicuoussign should warn people about the opening.

Running and horseplay in work areas isprohibited.

7.3 Ladders and scaffolds

Asbestos abatement work often requiresworking at heights, leading to the use of laddersand scaffolds. Improper use or inadequatemaintenance of this equipment can cause injury.

• Inspect ladders regularly for damage.Repair or replace them when damaged.

• Workers must be instructed on how to useladders correctly.

• Maintain 3-point contact.

• Ladders must not be used as a workplatform or walk board.

• Stepladders should be used only whenthey are completely open.

• If extension ladders are used, the baselocation should be 1 m away from thepoint below the upper contact point forevery 3 or 4 m of elevation. (One metreout for every three or four metres up.)

Many projects require the use of scaffolds.Correct set-up, regular inspection, and basicmaintenance are essential. If a scaffold is rented,the contractor should inspect all componentsbefore accepting them. Scaffolding must beerected and dismantled properly. To reduce therisk of a mobile scaffold tipping over, the heightmust not exceed three times the smallest

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dimension of its base. The wheels of thescaffold must operate properly. The scaffoldplatforms must be fully planked or “decked.”Guardrails should always be installed onscaffolds to prevent falls. Toe boards should beinstalled to prevent tools and other objects fromdropping on workers below. The scaffold mustnot be overloaded. The rolling scaffold must notbe moved with workers on it unless the workersare each tied off to a separate fixed anchor.

7.4 Heat stress

Heat-related disorders are common in asbestosabatement work. Heat stress takes place whenyour body’s cooling system is overwhelmed andyour temperature starts to increase. Heat stresscan be a hazard when working around boilers,hot pipe, tanks or furnaces, or structures heatedby the sun.

Heat stress can occur when heat combines withother factors such as

• protective clothing that restricts theevaporation of sweat

• hard physical work

• high humidity

• dehydration (loss of fluids)

• certain medical conditions

• lack of acclimatization:

When exposed to heat for a number ofconsecutive days, the body will adaptand become more efficient in dealingwith heat. This is called acclimatization.

Acclimatization usually takes six toseven days but may be lost in as little asthree days away from work. Peoplereturning to work after a holiday or along weekend must understand this —and so should their supervisors.

Heat stress can lead to illness or even death.

• Heat cramps: painful muscle cramps.

• Heat exhaustion: high bodytemperature; weakness or feeling faint;headache, confusion or irrationalbehaviour; nausea or vomiting.

• Heat stroke: no sweating (hot, dry skin),high body temperature, confusion, orconvulsions. Get immediate medical help.

Controls for heat stress hazards:

• Provide cool drinking water near workersand remind them to drink a cup every1/2 hour.

• Increase the frequency and length of restbreaks.

• Cool break areas should be provided ifpossible.

• Caution workers about working in directsunlight.

• Train workers to recognize the signs andsymptoms of heat stress. Start a “buddysystem” because it’s unlikely that peoplewill notice their own symptoms.

• Allow workers time to get acclimatized.

Note: Employers have a duty under Section25 (2) (h) of the Occupational Health andSafety Act to take every precaution reasonablein the circumstances to protect the worker. Thisincludes developing policies and procedures forhot environments. For more information, see thechapter on Heat Stress in CSAO’s ConstructionHealth and Safety Manual.

7.5 Cold stress

Exposure to the cold can be an importantconsideration for workers if work must be doneoutdoors in the winter or indoors if a building’sheating system must be shut down. Exposure tothe cold can cause frostbite or hypothermia. Forwork performed continuously in the cold, allowrest and warm-up breaks. Heated shelters such

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as trailers should be available nearby. For moreinformation, see the chapter on Cold Stress inCSAO’s Construction Health and Safety Manual.

7.6 Mechanical hazards

A work site hazard assessment should beconducted to identify mechanical hazards thatcan cause injury. Injury can occur when aworker’s body comes in-between a componentof a moving object and a stationary object. Anymechanically-operated part of a machine towhich a worker has access must be guarded orfenced so that it will not endanger a worker.Guards prevent contact between the worker andthat part of the machine which may present ahazard.

Workers must wear properly fitting hand, arm,leg, or body protective equipment, appropriate tothe work being done and the hazards involved.

Hard hats, eye protection, and safety boots, asappropriate, must be worn at all times whenthere is potential for workers to be exposed tofalling objects, debris entering the eyes, ormaterials falling on feet.

7.7 Explosive atmospheres

Before spraying highly flammable liquids suchas spray glue, eliminate sources of ignition suchas static electricity, unprotected electricalequipment, cigarettes, and open flames.

7.8 Atmospheric hazards

Chemicals used during asbestos abatement suchas spray glue, lock down sealants, and propanemay build up and lead to adverse health effects.Ensure that the material safety data sheets(MSDSs) are available at the workplace, andprovide information about protective measuresto be followed.

7.9 Carbon monoxide

Carbon monoxide (CO) has no odour or tasteand is clear and colourless.

CO poisoning can be very subtle and may causedrowsiness and collapse followed by death.

The major sources of CO include the internalcombustion engines powering saws, scissor lifts,generators, compressors, and forklift trucks.Another source of CO can be the internalcombustion engine powering the compressorwhich supplies air to your respiratory protectiveequipment.

Adequate ventilation is absolutely essentialwhen you cannot avoid using combustionengines indoors or in confined spaces.

7.10 Noise

Power tools or compressors can generate highlevels of noise. Workers exposed to high noiselevels must be given adequate hearingprotection and trained on how to use it.

8 IDENTIFY EMERGENCY RESPONSEPROCEDURES

Potential emergency situations that can beencountered in an asbestos Type 3 operationinclude

• fire and smoke

• hazardous material release (e.g., spills, gas,liquids, vapour)

• an electrical failure resulting in a loss ofnegative air pressure

• respirator failure

• a critical injury that requires immediateattention.

Combustion engines produce carbon monoxide

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An emergency plan must be in place for eachindividual jobsite and workers must be informedof the procedures to follow. Workers must betrained on how to respond in the event of anemergency.

There must be a means of communicationbetween workers inside the enclosure andpersons outside the enclosure (e.g., two-wayradios, cell phones, etc.) The method ofcommunication must be determined by theemployer and set out in the emergency plan.Before any Type-3 work begins, workers mustknow the location of emergency equipmentincluding fire extinguishers, first aid kits, spill kits,and jobsite fire alarms. They must also know theemergency exit routes (clearly marked), where tofind the map to the nearest hospital, theemergency phone numbers, and the materialsafety data sheets. Workers must also know whothe health and safety representative and first aidattendants are.

A serious injury or life-threatening hazard is amore immediate health concern than short-termasbestos exposure. Therefore standard protectivemeasures may be temporarily suspended if theywould result in an immediate threat to life. Ifperforming CPR, the respirator should be

removed from an ill or injured worker sincebreathing through a respirator can place extrastress on the heart.

The ill or injured worker should be removedfrom the contaminated area to the clean roomunless the worker has sustained a head, neck,or back injury. Moving the worker minimizesexposing emergency response personnel andtheir equipment to asbestos. Non-injuredworkers responding to the ill or injured workermust decide if there is time to decontaminatethe worker. When first aid, ambulance, oremergency personnel have to enter thecontaminated area they must be

• warned of the hazard

• provided with appropriate personalprotective equipment

• told how to use the protective equipment

• told about the limitations of the protectiveequipment.

Emergency exit

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9 TYPE 1 ASBESTOS OPERATIONS


Type 1 operations include the following:

1. Installing or removing less than 7.5 squaremetres of ceiling tile containing asbestos(81 square feet, or ten 4-foot x 2-footceiling tiles) without it being broken, cut,drilled, abraded, ground, sanded, orvibrated.

2. Installing or removing non-friable asbestos-containing material, other than ceiling tiles,without it being broken, cut, drilled,abraded, ground, sanded, or vibrated.

3. Breaking, cutting, drilling, abrading,grinding, sanding, or vibrating non-friableasbestos-containing material if a) you wetthe material, and b) you use only non-powered hand-held tools.

4. Removing less than one square metre ofdrywall where asbestos joint-fillingcompound was used.

DRYWALL JOINT-FILLING COMPOUND

Early drywall joint-filling compoundscontained significant amounts of asbestosfibre. This particular use was specificallyprohibited in 1980. Still, it may be found inbuildings constructed several yearsafterwards.

If these operations are done properly, it isunlikely that exposure will exceed acceptable

limits. This is why the use of respirators isoptional for Type 1 work.


1. Eating, drinking, smoking, and chewinggum are prohibited.

2. If a worker requests a respirator andprotective clothing for Type 1 operations,the employer must provide them. Therespirators must be the proper type (seerespirator chart, Appendix A) with filterssuitable for asbestos. Once workersrequest respirators, they must wear them.Protective clothing must be impervious toasbestos fibres. Once workers requestprotective clothing, they must wear it.

Refer to section 11.3 of this manual formore information on the use, care, anddisposal of respirators and protectiveequipment.

Protective clothing is used for two reasons:

• to prevent transfer of dust and wasteinto clean areas

• to guard unprotected workers, theirfamilies, and the public from secondaryexposures to asbestos.

Members of asbestos workers’ familieshave developed illnesses from the dustbrought home in work clothes. (See articleon the next page.)

3. Before beginning work, visible dust mustbe removed by wiping with a damp clothor by vacuuming with a special HEPA*-filtered vacuum.

* HEPA (High Efficiency ParticulateAerosol) vacuums are specially designedto trap very small particles. They catchat least 99.97% of all particles 0.3microns or larger. See “HEPA Filters,”Appendix I.

Continued after the article on the next page.

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SUFFERING FROM A FATHER’S JOBMARTIN MITTELSTAEDT

GLOBE AND MAIL, April 2006

[What follows is a partial excerpt from the article.]

CAMPBELLFORD, ONT. — The expression “like father, like son,” has tragic poignancy for TomO’Donnell.

His father died nine years ago at age 76 from lung cancer caused by asbestos.

The cause of death was not entirely surprising. He had worked for nearly 25 years at a nowdefunct Johns-Manville plant in eastern Toronto that was called a “world-class occupational healthdisaster” by a 1980s royal commission investigating the plant’s use of asbestos.

Now the son, who is only 48, is dying of mesothelioma, a painful cancer whose only known causeis contact with asbestos.

Mr. O’Donnell’s diagnosis might seem unusual, given that he never worked with the substance. Buthe is not the only one in his family to have been afflicted since his father died. An older sister andolder brother succumbed to the same cancer, which affects the lining of the chest wall, in their 50s.

Medical authorities suspect Mr. O’Donnell and his siblings are victims of a seemingly innocuousasbestos exposure: traces of asbestos dust carried unknowingly home on their father’s work clothes.

Those traces, a testament to the killing power of the mineral, provided enough of a dose to placehis children in mortal peril decades later.

Mr. O’Donnell said his father was a loving man for whom “the kids came first” and he remembershim with fondness as “such a nice guy all around. There is not a bad thing you could say aboutthat guy.”

His father had no inkling that the asbestos he worked with was hazardous, and that unknowinglyhe had started a nightmare for his six children.

“He’s up there,” Mr. O’Donnell said, referring to heaven, “thinking all this work he did and raisingthe kids and we’re dying because of what was on his clothes.”

Cases such as Mr. O’Donnell’s, once thought to be extremely rare, are starting to crop up morefrequently in Canada. There are enough cases that they have been given the formal name of“bystanders,” people who never worked with asbestos yet are at risk of its illnesses.

They are falling ill now because they were exposed during the 1960s and 1970s — the peak yearsin Canada of asbestos use — as children and spouses of asbestos workers. Because certain cancershave a decades-long latency period, the bystanders are only now starting to be seen in significantnumbers.

The bystander cases hold a special cruelty. Many of those exposed to asbestos as children aredying young, robbed of far more years than were their fathers, who were exposed as adults andhad a crack at reaching old age because of the latency period.

4. Never use compressed air to cleanasbestos dust off surfaces. This just blowsthe fibres into the air.

5. When you wish to cut, shape, or drill thenon-friable materials as mentioned inSection 9.1 #3 (above), you must wet thework (water plus wetting agent—see boxbelow) and use only hand tools such asnibblers, rasps, files, shears, knives, handdrills, or hand saws. Using hand tools maycreate some dust, but wetting the materialwill prevent the dust particles frombecoming airborne.

WETTING AGENT

Water alone is not sufficient to control dustand fibres. You must add a “wetting agent”to reduce the water’s surface tension. Thisincreases the water’s ability to penetratematerial and get into nooks and crannies.To make this “amended water,” you can useordinary dishwashing detergent: 1 cupdetergent for every 20 litres of water.

The US Environmental Protection Agency(EPA), in its Guidance for ControllingAsbestos-Containing Materials in Buildings,EPA-560/5-85-024 (Purple Book), recommendsthe use of a 50:50 mixture of polyoxyethyleneester and polyoxyethylene ether.

6. You must use a dropsheet (typically 6-milpolyethylene) below the work area to helpcontrol dust.

7. All asbestos dust and waste must becleaned up regularly and frequently(before it dries out) using a HEPA vacuumor by damp-mopping or wet-sweeping.

8. Before leaving the work area, workersmust damp-wipe or HEPA-vacuum theirprotective clothing to remove any surfacecontamination. Workers must damp-wipetheir respirators before taking them off.

9. Asbestos waste and disposable coverallsmust be placed in dust-tight containers andlabeled with warning signs (see sections11.7, 11.12, and 12 for more informationon clean-up and disposal).

10. You must never reuse dropsheets. Afterthe work is done, dropsheets must be

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Vacuum with HEPA filter

wetted or damp-wiped and then foldedso that any residual dust or scrap iscontained inside the folds. Dispose ofdropsheets as asbestos waste.

11. Barriers and portable enclosures that arerigid and will be reused must be cleanedby damp-wiping or HEPA-vacuuming.Barriers and enclosures that are not rigidor cannot be cleaned must not bereused.

12. Containers must be cleaned by dampwiping or HEPA-vacuuming before beingremoved from the work area.

13. You must dispose of waste at a landfillsite that will accept asbestos (seesections 11.12 and 12).

14. A washbasin, soap, water, and towels—or a similarly-equipped clean-upfacility—must be provided for workers sothat they can wash their hands and facesupon leaving the work area. Workersmust also wash before eating, drinking,smoking, or any such activities. This willhelp reduce secondary exposure toasbestos.



Exposure to asbestos is likely in Type 2operations. You need controls to protectworkers and others nearby. Type 2 operationsinclude the following:

1. Removing all or part of a false ceiling inbuildings containing sprayed asbestosfireproofing if it is likely that asbestosfibres are resting on top of the ceiling. Thisis likely when fireproofing is deterioratingor damaged.

2. Removing or disturbing less than 1 squaremetre of friable asbestos materials—forexample, repairing an insulated pipe joint

or removing some fireproofing to fasten anew pipe hanger.

3. Enclosing friable asbestos insulation toprevent further damage or deterioration.

4. Applying tape, sealant, or other covering(by means other than spraying) to pipe orboiler insulation.

5. Installing or removing more than7.5 square metres of ceiling tile containingasbestos, without it being broken, cut,drilled, abraded, ground, sanded, orvibrated.

6. Breaking, cutting, drilling, abrading,grinding, sanding, or vibrating non-friableasbestos-containing material if the materialis not wetted and the work is done onlywith non-powered hand-held tools.

7. Removing one square metre or more ofdrywall where the joint-filling compoundcontains asbestos.

8. Working on non-friable asbestos withpower tools that are attached to dustcollecting devices equipped with HEPAfilters. If you need to power-grind ormachine the asbestos product and yourtools are not equipped with HEPA-filtereddust collectors, refer to Section 11.15.

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To prevent electric shock, any power toolsused around water must be equipped with aground fault circuit interrupter (GFCI) andbe maintained properly. GFCIs constantlymonitor for any current leaking to ground. Ifleaking current is detected, the GFCIimmediately switches off power to thatcircuit to prevent a lethal dose of electricity.

9. Using a glove bag to remove asbestos-containing insulation.

10. Cleaning or removing filters used in air-handling equipment in a building withsprayed asbestos fireproofing.

11. Any other operation that is not Type 1 orType 3, but one that may cause exposureto asbestos.


1. Workers involved in Type 2 operationsmust wear a NIOSH-approved respirator asidentified in the respirator chart, AppendixA. The employer must provide workerswith training on the individual respiratorsthey will be using. The training must cover

• selection of respirator

• fitting

• inspection

• use

• care and maintenance

• cleaning and disinfecting

• limitations of the respirator.

The equipment must be maintainedaccording to the employer’s writtenprocedures and must be consistent withthe manufacturer’s instructions. Themanufacturer can provide cleaning anddisinfecting products which will notdamage the respirators. Any damaged orworn parts must be replaced before aworker uses the equipment.

Wherever possible, the respirators shouldbe assigned to individual workers for theirexclusive use. Otherwise, the respiratorsmust be properly cleaned and disinfectedbefore being used by someone else.

Refer to section 11.3 of this manual formore information on the use, care, anddisposal of respirators and protectiveequipment.

2. Workers must wear protective clothingimpervious to asbestos with tight-fittingcuffs at the wrists, ankles, and neck, aswell as a hood or head cover. This usuallymeans one-piece disposable coveralls—ones which are easy to clean of surfacecontamination before you throw them

away. Torn or damaged clothing must berepaired or replaced. We recommend youuse laceless, pull-on rubber boots. Theycan be washed off later or disposed of ascontaminated waste.

Refer to section 11.3 of this manual formore information on the use, care, anddisposal of protective equipment.

Protective clothing is required for tworeasons:

a) to prevent transfer of dust and wasteinto clean areas

b) to guard unprotected workers, theirfamilies, and the public from secondary

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Protective clothingLaceless, pull-on

rubber boots

exposures to asbestos. Members ofasbestos workers’ families havedeveloped illnesses from the dustbrought home in work clothes.(See article in section 9.2.)

3. Only those workers wearing the requiredrespirators and protective clothing arepermitted in the work area.

4. You must never eat, drink, smoke, or chewgum in the work area.

5. Never use compressed air to removeasbestos dust from a surface.

6. You must wet asbestos-containing materialbefore you remove it to lessen the chanceof creating dust—unless wetting wouldcause a hazard or damage.

7. You must add a wetting agent to the water.See section 9.2 number 5.

8. Any dust on exposed surfaces must becleaned by damp-wiping or HEPAvacuuming before starting work whichmay disturb the dust.

9. Warning signs are required for all Type 2activities.

10. For ceiling removal (to gain access to awork area) and for removal of less than

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Warning sign

1 square metre of friable asbestos-containing material indoors, an enclosuremust be erected around the area toprevent the spread of asbestos dust. Ifyour enclosure is opaque, it must have atransparent window to allow observationof the work. The ventilation system mustbe disabled and sealed off if the inlets orexhausts are within the enclosed area.For other Type 2 operations, 6-milpolyethylene dropsheets should beadequate.

11. You must put waste asbestos, disposableclothing, the enclosure and barriermaterials (such as polyethylene sheeting),and any other contaminated items intodust-tight containers labeled with warningsigns. The containers must be damp-wiped or HEPA-vacuumed to remove anysurface contamination before you takethe containers out of the work area. Referto Sections 11.7, 11.12, and 12 in thismanual for information on clean-up andwaste disposal.

12. Any dust or waste must be cleaned up bydamp-wiping or HEPA-vacuuming beforeit can dry out and pose a hazard. Youmust never reuse dropsheets. Dropsheetsand enclosures must be decontaminatedand wetted before disposal.

13. After the work is completed, barriers andportable enclosures that are rigid and thatwill be reused must be cleaned by dampwiping or HEPA-vacuuming. Barriers andportable enclosures must not be reusedunless they are rigid and can be cleaned.

14. Before leaving the work area, workersmust damp-wipe or HEPA-vacuum theirprotective clothing to remove any surfacecontamination. Workers must damp-wipetheir respirators before taking them off.

15. A washbasin, water, soap, and towelsmust be provided for workers to wash

their hands and faces before leaving thework area. Workers must also washbefore eating, drinking, smoking, or anysuch activities.

10.3 Glove Bag Operations

All the procedures that apply to Type 2operations also apply to glove bag operations.In addition, you must do the following.

1. Separate the work area from the rest of theworkplace by walls, barricades, fencing, orother suitable means.

2. Disable the mechanical ventilation systemserving the work area and seal allopenings or voids, including ventilationducts and windows to and from the workarea.

3. Place polyethylene dropsheets below thework area.

4. The glove bag must be strong and largeenough to hold the material you’reremoving.

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5. You must not use a glove bag if you can’tmake a proper seal because of thecondition of the insulation, the temperatureof the surface, or the type of jacketing.

6. Check the glove bag for damage ordefects.

7. Be careful not to puncture the glove bag.

8. When you’ve finished removing theasbestos,

• damp-wipe and HEPA-vacuum the tools

• wet down the inside walls of the glovebag

• thoroughly wet the material inside theglove bag

• wipe down the pipe (or whatever theasbestos was removed from) and seal itwith a suitable encapsulant

• evacuate air from the bag using a HEPA-vacuum and place the glove bag, withthe waste inside, in a suitable dust-tightcontainer

• clean up the work area by damp-wipingor HEPA-vacuuming.



Type 3 operations include the following:

1. Removing or disturbing more than 1square metre of friable asbestos-containingmaterial.

2. Spraying a sealant onto friable asbestosmaterial.

3. Cleaning or removing air-handlingequipment in buildings with sprayedasbestos fireproofing.

4. Repair, alteration, or demolition of kilns,metallurgical furnaces, and other

installations with asbestos refractorymaterials.

5. Disturbing non-friable asbestos material inany way with power tools not attached todust collectors equipped with HEPAvacuums.

6. Repair, alteration, or demolition ofbuildings which are or were used tomanufacture asbestos products unless theasbestos was cleaned up and removedbefore March 16, 1986.


Type 3 operations require the most precautionsbecause they can release substantial amounts ofasbestos dust. Controls for Type 3 operationsinclude requirements for

• worker protection including protectiveclothing, respiratory protection, anddecontamination facilities

• site preparation including enclosure andisolation of the work area and negative airunits

• removal, clean-up, and disposal of wasteincluding dust-suppression techniques.

The following sections provide details.

11.3 Worker protection

11.3.1 Protective Clothing

Protective clothing is required for two reasons:

a) to prevent transfer of dust and waste intoclean areas

b) to guard unprotected workers, theirfamilies, and the public from secondaryexposures to asbestos.

Members of asbestos workers’ families havedeveloped illnesses from the dust brought homein work clothes. (See article in section 9.2.)

Continued on the next page.

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Protective clothing must

• fit the worker

• not readily retain asbestos dust or allow itto penetrate. Although it is not a regulatoryrequirement, we recommend one-piecedisposable coveralls with hood for Type 3operations.

• have tight-fitting cuffs at the wrists andankles and on the hoods of overalls

• cover the head and feet. Although it is nota regulatory requirement, we recommendlaceless rubber boots because they areeasy to clean when leaving the work area.Footwear with laces will trap asbestosfibres between the laces and should not beused.

• be immediately repaired or replaced iftorn.

Head coverings should be close-fitting andcover the parts of the head and neck notcovered by the respirator. The head straps ofrespiratory protective equipment should beworn under the head covering.

Street clothes must not be worn under coveralls.

Any protective clothing (including rubber boots,reusable coveralls, and disposable coveralls)exposed to the work area must be cleanedeither by damp-wiping or HEPA-vacuumingbefore leaving the work area. If contaminatedreusable coveralls are to be laundered, theyshould first be placed in dust-tight bags whichare soluble in hot water and can be loaded,unopened, into a washing machine. These innerbags should then be placed inside a second bagwhich is sealed and labeled prior to being sentto laundry facilities that specialize in cleaningasbestos-contaminated clothing.

Disposable coveralls that will not be reused mustbe disposed of as described in section 11.7.

IT CAN GET HOT IN THERE!

Protective clothing can contribute to aworker’s heat stress, especially in summer.See the chapter on Heat Stress in CSAO’sConstruction Health and Safety Manual.

11.3.2 Respiratory Protection

The primary means of exposure to asbestosfibres is inhalation. Despite the use of othercontrol measures such as wet removal, workersinvolved in Type 3 operations will stillencounter airborne asbestos. For this reason,respirators are an important control method.

The respirator requirements for Type 3operations vary according to:

• the size of the operation

• whether the ACM is friable or non-friable

• the type of asbestos present (chrysotile, orasbestos other than chrysotile)

• whether the ACM is wet or dry

• whether power tools or non-power toolsare used for the removal

• whether the power tool is attached to adust-collecting device equipped with aHEPA filter or not.

The types of respirators required for variousType 3 operations are identified in OntarioRegulation 278/05, Table 2. CSAO hassummarized this table in the form of charts (seeAppendices A and B).

The employer must develop written procedureson the selection, use, and care of respirators.The employer must give a copy of theprocedures to each worker required to wear arespirator, and review the contents with them.

Wherever possible, the respirators should beassigned to individual workers for theirexclusive use. Otherwise the respiratorsmust be properly sanitized before beingused by someone else.

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Workers cannot be assigned to an asbestos workoperation unless they are physically able toperform the operation while wearing therespirator (See Appendix E — “HealthSurveillance Guidelines” — of CSA StandardCSA-Z94.4-02.)

The employer must provide workers withtraining on the individual respirators they willbe using. The training must cover

• proper fit

• inspection and maintenance

• cleaning and disinfecting

• limitations of the respirator.

11.3.3 Types of respirators

There are two main categories of respiratorsused to protect workers in an asbestos Type-3environment:

• air- (atmosphere-) supplying respirators(respirators that are attached to a supply ofnew, clean air)

• air-purifying respirators (respirators thatclean the air around you before youbreathe it in).

11.3.3.1 Air-supplying respirators

Air-supplying respirators provide clean airthrough a hose called an airline, which isattached to a freestanding tank of compressedair, an air compressor, or an ambient air blower.

11.3.3.1.1 Modes of operation

Air-supplying respirators can operate in thefollowing modes:

• “negative pressure” or “demand”

• “continuous-flow”

• “positive pressure” or “pressure-demand.”

11.3.3.1.1.1 Negative-pressure (demand)

mode

Air is delivered only when the wearer inhales.Because contaminated air may leak inwardaround the facepiece if the breather inhalesstrongly, these devices have limited use in high-exposure conditions.

11.3.3.1.1.2 Continuous-flow mode

As the name implies, these devices deliver aconstant flow of air to the wearer. Inwardleakage of contaminated air is still possible ifthe breather inhales more air than the devicecan supply. Minimum flow rates must bemaintained to minimize inward leakage.Continuous-flow mode offers better protectionthan the negative pressure (demand) mode.

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Air-supplying respirator

11.3.3.1.1.3 Positive-pressure or

pressure-demand mode

Since the previous modes may permit inwardleakage, a system was developed whichmaintains a positive pressure inside thefacepiece at all times, and also supplies more airas demanded. This class of device is used forhigh-exposure conditions and offers the bestprotection of the three modes.

11.3.3.2 Air-purifying respirators

Air-purifying respirators used for protectionduring a Type-3 asbestos operation must beequipped with N-100, R-100, or P-100 (HEPA)filters.

The “100” (actually 99.97%) refers to theefficiency of the filters.

Oil has been found to ruin the filtering ability ofsome filter material. Therefore, to ensure that asuitable filter is being used, particulate filtershave an N, R, or P designation:

N – Not resistant to oil – must not be used at allin an environment where solvent or oil ispresent.

R – Resistant to oil - can be used for a singleshift in an environment where solvent or oil ispresent.

P – Oil-Proof – can be used for an extendedperiod of time in an environment where solventor oil is present.

Air-purifying respirators can be powered or non-powered.

11.3.3.2.1 Non-powered air-purifying

respirators

Air is drawn through the filter by the wearerbreathing in. Non-powered respirators dependentirely on the wearer breathing in (inhaling)and breathing out (exhaling) to deliver anadequate supply of purified breathing air.

For asbestos Type 3 removals, only full-facepiece respirators are allowed whenusing a non-powered air-purifying respirator.

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Full-facepiece non-poweredair-purifying respirator

11.3.3.2.2 Powered air-purifying

respirators (PAPR)

These respirators use a battery-powered blowerto continuously draw air through HEPA filtersand into the tight-fitting facepiece (full or halffacepiece)

11.3.4 Proper fit

The performance of a respirator with a tight-fitting facepiece depends on good contactbetween the wearer’s skin and the respirator. Agood face seal can only be achieved if thewearer is clean-shaven in the region of the sealand the facepiece is of the correct size andshape to fit the wearer’s face. Eyeglasses cannotbe worn with a full-facepiece respirator as the

side arms will break the seal. An alternativesuch as eyeglass inserts in the respiratorfacepiece or contact lenses (check with youremployer to see if the use of contact lenses isallowed) should be considered for those whorequire prescription glasses.

Employers should ensure that the selectedfacepiece is the right size (small, medium, large)and can correctly fit each wearer.

11.3.4.1 Fit testing

For a tight-fitting facepiece the initial selectionshould include fit-testing to ensure the wearerhas the correct device. The test will assess thefit by determining the degree of face-sealleakage using a test agent while the user iswearing the respirator (see Appendix G formore details).

You need to fit test again when

• changing to a different model of respirator

• changing to a different-sized facepiece

• there have been significant changes to thefacial characteristics of the individualwearer (e.g., as a result of significantweight gain or weight loss, or a dentalprocedure).

Fit testing and seal checking aredifferent.

Fit testing (described above) detects if therespirator fits the wearer correctly in the firstplace. A user seal check (described below)is when the user makes sure the straps arecorrectly adjusted and the respirator isproperly seated on the face before each use.

11.3.4.2 Seal checking

Before each use, the wearer should conduct aseal check. The manufacturer’s instructions willgive information on simple seal checks, such asthose involving blocking the filters and inhalingto create suction inside the mask (negative seal

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Powered air-purifying respirator

check), or blocking the exhalation valve andexhaling (positive seal check) so that anyleakage can be detected. (See the followingimages and Appendix F for more details.)

11.3.5 Inspection and maintenance

The equipment must be maintained andinspected according to the employer’s writtenprocedures which must be consistent with themanufacturer’s instructions.

A respirator should be checked by the wearerbefore and after it is used to make sure that it isin good working order (see Appendix D formore details). Any damaged or worn parts mustbe replaced before a worker uses the equipment.

11.3.6 Cleaning and sanitizing

Respirators must be cleaned after each useaccording to the manufacturer’s instructions. Ifshared by different workers, respirators must beproperly sanitized before they can be used byanother person.

The manufacturer can provide cleaning andsanitizing products which will not damage therespirators.

Strong detergents, hot water, or householdcleaners or solvents must not be used becausethey may cause the rubber parts to deteriorate.Use a neutral detergent.

The respirator should be thoroughly cleaned andrinsed with warm water to avoid skin irritation(for more details see Appendix E). After rinsing,respirators should be hung up to dry.

Positive seal check

Clean your respirator with a neutral detergentNegative seal check

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11.3.7 Storage

Respirators should be stored in a clean location(away from sunlight, chemicals, excessive heator cold, and excessive moisture), preferably in aplastic bag in a locker. Respirators must not beleft in a car or out where they can gather dustand dirt or be damaged.

11.3.8 Limitations of respirators

11.3.8.1 Some major limitations of air-

purifying respirators

• They are not suitable for confined spaces,or atmospheres with less than 19.5%oxygen.

• They are not suitable for gases or vapoursunless equipped with proper cartridges.

• As the filter becomes clogged with dust, airflow resistance increases and the filters willhave to be changed.

• Proper fit is essential for protection —workers must be clean shaven.

11.3.8.2 Some major limitations of

powered air-purifying

respirators (PAPR)

• Requires the battery power pack to berecharged frequently.

• The power pack can fail during userequiring the worker to immediately leavethe asbestos work area.

• Proper functioning requires a minimumrate of air flow into the respirator mask.Consult the manufacturer’s specificinstructions concerning the required flowrate and how this should be checked.

11.3.8.3 Some major limitations of

supplied-air respirators

• When using supplied-air respirators, the airmust be tested to ensure that the it meetsthe requirements set out in the CanadianStandards Association’s CompressedBreathing Air (CSA Z180.1-00). Thisstandard limits the amount of carbonmonoxide, oil mist, water vapour, andother contaminants permissible in suchsystems.

• Oil-lubricated compressors can producecarbon monoxide. A continuous carbonmonoxide monitor equipped with an alarmmust be provided.

Carbon monoxide monitor

After rinsing it, hang your respirator up to dry

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11.4 Site preparation—indoor projects

Indoor Type-3 operations require strict controlsto prevent asbestos dust from contaminatingother areas. The work area must be completelyenclosed and isolated from the rest of thelocation in order to

• prevent and contain the spread of asbestosdust

• prevent other people in the rest of thebuilding from being exposed to asbestos

• restrict access of unauthorized personnel.

Requirements for site preparation:

1. Polyethylene sheeting or other suitablematerial that is impervious to asbestos,held in place with appropriate tape andadhesive, is normally used to build theenclosure. Typically, 6-mil polyethylene isused on the walls and heavierpolyethylene is used on the floor (it mustwithstand foot traffic).

When existing walls aren’t appropriate forthe enclosure, it may be necessary to erecttemporary walls to which the plasticbarrier can be attached.

All joints must overlap and be taped toensure the area is completely sealed off.Regulation 278/05 requires you to have

one or more transparent observationalwindows when you’re using opaque,Type-3 enclosures for operations wherenon-friable asbestos is disturbed in anyway with power tools not attached to dustcollectors equipped with HEPA vacuums.However, CSAO recommends that all Type3 enclosures have a transparent window ifthe enclosure is opaque. Collectively, thewindows should allow as much of thework area as possible to be viewed fromoutside the enclosure. Keep the windowsclean and unobstructed.

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Temporary walls

Transparent observation window

Polyethylene sheeting

2. During the construction of the enclosure,asbestos materials should not be disturbeduntil the enclosure is complete andnegative air is in place. In situations whereasbestos debris or dust is lying on anysurface of the work area and will bedisturbed during the construction of theenclosure then the area must beprecleaned using a damp cloth, or byusing a vacuum equipped with a HEPAfilter, before the enclosure is built. Suitablepersonal protective equipment, includingrespirators, should be worn duringprecleaning and during all work whichdisturbs or could disturb asbestos duringthe building of enclosures.

Wet wiping procedures

• Wet wipe with clean water and papertowels to remove any residue.

• Dispose of paper towels as asbestoswaste.

HEPA vacuum procedures

• vacuum the contaminated area in parallelpasses with each pass overlapping theprevious one.

• Vacuum the area a second time, in thesame manner, in passes at right angles tothe first passes.

Never use compressed air to clean asbestosdust off surfaces – it is prohibited. It justblows the fibres into the air.

3. The ventilation system serving the workarea must be shut down and sealed off.

4. Any furnishings that can be removed mustbe damp-wiped or HEPA-vacuumed ifdusty and taken out of the enclosurebefore other work begins. Items whichcannot be moved must be cleaned andsealed with polyethylene sheeting.

5. If scaffolding is used during the asbestosremoval operation the open ends of thescaffold tubing must be sealed.

6. Any openings such as stairways, doors(including elevator doors), windows, and

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Sealing the ventilation system

Covered and sealed furniture

Sealed pipe

pipe/conduit penetrations must also besealed off.

7. If asbestos is being removed from anentire floor, the elevators must beprevented from stopping at that floor.

8. With two exceptions (see box below), allType 3 operations require a negativepressure of 0.02 inches of water inside theenclosure relative to the area outside theenclosure. You can do this by

• running negative air units equipped withHEPA filters inside the enclosure andventing them outside, and

• making sure that the enclosure is sealedfrom the surrounding area. The betterthe area is sealed, the easier it will be tomaintain negative air pressure.

Type 3 operations require a negativepressure of 0.02 inches of water inside theenclosure relative to the area outside theenclosure, unless

• the building will be entirely demolishedfollowing the asbestos removal work

• the asbestos removal is done outdoors.

Air always moves from positive pressure tonegative pressure. By maintaining negativeair pressure, air will always move from the

non-contaminated or “clean” area into theenclosure, instead of the other way.Without negative air pressure, dust couldget out of the enclosure through cracks,tears, ducting, or even through the door tothe enclosure.

A competent worker must measure thepressure difference between the inside andoutside of the enclosure at regularintervals. A digital pressure monometerwill measure the differential pressure.Because air pressure can vary within alarge enclosure it is recommended that thedifferential pressure be measured in avariety of locations.

Here are some clues that there is negativeair pressure inside the enclosure:

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HEPA-filtered negative air unit Monometer

• Plastic barriers and sheeting will moveinwards toward the work area.

• There will be noticeable air movementthrough the decontamination units. Youcan use smoke tubes to see if air movesfrom the clean room through the showerroom and equipment room to the workarea. This must be done with thenegative air units on.

A competent worker must inspect andmaintain the negative air units before eachuse to make sure that air isn’t leaking andthat the HEPA filter isn’t damaged ordefective (See Appendix I and Appendix Jfor more details on negative air units andHEPA filters). The negative air units mustbe in proper working order before youcan use them. Clean replacement air mustbe taken from outside the enclosure toreplace air being exhausted.

9. Warning signs mustbe posted outsideand at everyentrance to thework area.

10. If you plan to usewet removalmethods, theelectrical powersupply in thearea should beshut down,isolated, locked,and tagged to prevent electric shock.

11. Any temporary power supply for tools orequipment should have a ground faultcircuit interrupter (GFCI).

12. A competent worker must inspect the workarea for defects in the enclosure at thebeginning and end of each shift. Anydefect must be repaired immediately – Nowork is allowed until the defect is repaired.

11.5 Entry/decontamination facility

1. You must set up an entry/decontaminationfacility that keeps airborne asbestoswithin the “dirty” area and provides aplace for workers to decontaminatethemselves as well as their tools,materials, and equipment. A typicalentry/decontamination facility is shownon the next page.

The facilities will need to have a separate“dirty” changing room for contaminatedwork clothing, and a separate “clean”changing room for clean or personalclothing. The showers should be locatedbetween the two changing rooms so that itis necessary to pass through them whengoing from one changing facility to theother. The ‘clean’ and ‘dirty’ ends shouldbe fitted with adequate seating and be ofsufficient size for changing purposes.

2. The doorways should be fitted withoverlapping polyethylene curtains on eachside so that they will close behind workerspassing through. This “airlock” will helpprevent the spread of dust.

3. There must be a temporary shower withhot and cold running water so workers canwash off residual asbestos before theyleave the contaminated area.

4. A competent worker must inspect thework area for defects in the

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ASBESTOS

Warning sign

Isolated electrical panel

decontamination facility at the beginningand end of each shift. Any defect must berepaired immediately – No work is alloweduntil the defect is repaired.

11.5.1 Procedures for entry and

decontamination

These entry and decontamination proceduresmust be followed every time workers enter orexit the work area.

11.5.1.1 Entry

1. Workers enter the clean change room and

• remove street clothes

• put on disposable coveralls

• inspect their respirators

• replace filters and perform othermaintenance (e.g., change power packson powered air-purifying respirators)

• put on and seal-check respirators

• go to the curtained doorway.

2. They enter the shower room and go(without showering) into the equipmentroom.

3. Here, they put on their boots, hardhats, andother equipment from the previous shift.

4. They enter the dirty work area through thelast curtained doorway.

Equipment (“dirty”) roomNote lockers and airlock/curtained doorway

ASBESTOS

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11.5.1.2 Decontamination

1. Workers enter the dirty change room andremove any visible dust from theirprotective clothing by damp-wiping orHEPA vacuuming.

2. Workers remove and discard disposablecoveralls (see Section 11.7 for disposalinformation) and store any other personalprotective equipment (PPE), tools, andequipment to be reused. They continue towear their respirators.

3. Workers enter the shower area via thecurtained doorway and shower with theirrespirator on, rinsing off the respirator.They then remove the respirator and

continue showering. With most respirators,the filters, blowers, and battery pack mustbe kept out of the shower water toprevent damage. Damp-wipe them beforetaking them off.

4. Workers exit to the clean side, and enterthe change room via the curtaineddoorway, and change into their streetclothes.

Used towels should be treated as asbestos wasteand put into a sealable container.

Any tools or equipment used in the work areashould be decontaminated by damp-wiping orHEPA-vacuuming before being taken out ofthe area.

Leaving Enclosure

Shower thoroughly with soap. Exit showerand move to clean room. Dry with towel.

HEPA vacuum or damp wipe allvisible dust and fibres from PPE.

Remove respirator.

Dry and store respirator.Dress and drink water to hydrate.

Leave work area and enter dirty change room

Protect filter port from water. Enter showerwith respirator on, rinsing respirator.

Remove and place contaminated clothing inasbestos disposal bags. Store equipment, footwear,

and underwear. Keep respirator on.

Entering Enclosure

Enter the clean change room of thedecontamination unit through

the clean end door

Put on disposable coveralls

Inspect and replace respirator filtersbefore putting on respirator

Carry out negative and positive seal-check

Pass through shower area intodirty room and put on boots,

hardhats, and other equipment

Enter work area

ASBESTOS

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If necessary, arrangements must be made so thatfemale workers can decontaminate themselvesseparately from male workers.

11.6 Removal

1. Wherever possible, asbestos-containingmaterial (ACM) should be wetted beforeremoval starts. Unless wetting creates ahazard, it is not recommended to removeACM when the material is dry. To improvepenetration of the water and reduce runoffand dry patches, a “wetting agent” must beadded to the water (see section 9.2). Youmay need to spray this “amended water”repeatedly to penetrate the ACM and tokeep it wet. A portable pressurized vesselsuch as a pump-up garden sprayer can beused to apply the amended water.Constant water pressure is desirable. Highpressure water spray should not be used.

2. Any electric tools and equipment used inwet removal operations must be equippedwith ground fault circuit interrupters(GFCIs) to prevent electric shock.

11.7 Clean-up and storage

1. Asbestos waste must be cleaned upfrequently and regularly by HEPA-vacuuming, damp-mopping, or wet-sweeping before it dries out. It might benecessary to spray down asbestos debriswith amended water to keep it damp afterit is removed.

2. Asbestos waste and protective clothing thatwill not be reused must be placed in asuitable container for disposal. Dropsheets,polyethylene sheets, and enclosurematerials must be wetted before they areplaced in a suitable container for disposal.

3. A suitable container is

• dust-tight

• suitable for the type of waste (e.g., if thewaste is sharp, such as floor tiles, the

container must be rigid and puncture-proof)

• impervious to asbestos

• properly marked that it contains asbestoswaste (see label below).

Examples ofsuitablecontainers are6-milpolyethylenebags (alwaysdouble-bagthem) orpolyethylenedrums.

4. You must always damp-wipe or HEPAvacuum the surface of the container toremove asbestos dust before taking it outof the work area. Containers must beremoved from the workplace frequentlyand at regular intervals.

5. Before sealing the first 6-mil polyethylenebag, use a HEPA vacuum to suck anyexcess air out of it. Seal the bag bytwisting the top tightly, folding it over, andsealing it with duct tape. Damp-wipe orHEPA-vacuum the outside of the bagbefore it is moved from the work area tothe decontamination area. Once in thedecontamination area, place the bag into asecond 6-mil polyethylene bag and seal it.

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ASBESTOS

Double-bagged

Although not required by regulation it isgood practice to remove waste bags fromthe enclosure via a separate “bag lock,”which is a separate passageway for thewaste bags. The bags should be vacuumedall over before being passed into the nextcompartment of the bag lock where thebags are put into second, outer bags. Thebags are then passed to the outside or to anadditional storage compartment before beingpassed to the outside.

6. Don’t place waste materials with sharpedges—such as floor, wall, or ceilingtiles—into a bag. These items should beneatly stacked together. Wrap each stack in2 layers of 6-mil or thicker polyethylene.Then place in a suitable container forasbestos waste.

7. After cleaning up and removing theasbestos waste, the work area must bethoroughly washed down with amendedwater if it’s possible to do so.

8. Once all the asbestos has been removed,tools and equipment—includingscaffolding, ladders, etc.—must be

thoroughly cleaned by damp-wiping orHEPA-vacuuming to remove any settledasbestos dust. The negative air units mustkeep operating during this time.

11.8 Visual inspection

1. A competent worker must conduct a visualinspection to ensure that the enclosure andthe work area inside the enclosure are freefrom visible asbestos-containing material(ACM). A thorough visual inspectionconsists of verifying that there is no debrisor residue from removed ACM and that allvisible dust or debris in the work area hasbeen cleaned up. If visible residue, dust,or debris remain, it must be cleaned upusing wet wiping and/or HEPA vacuumingbefore lockdown (gluedown) is appliedand clearance sampling is started.

2. The visual inspection should be performedusing procedures outlined in the AmericanSociety for Testing and Materials (ASTM)’sStandard Practice for Visual Inspection ofAsbestos Abatement Projects (ASTM E 1368).

11.9 Lockdown/gluedown

Although it is not a regulated requirement, it isa standard industry practice to apply a lock-down sealant throughout the containment areato seal down any invisible dust and fibresundetected during the visual inspection after theremoval activities.

• The lockdown sealant needs to becompatible with any materials that will beinstalled over the sealant such asfireproofing material. (The supervisor mustverify this with the manufacturer.)

• The sealant should be applied inaccordance with the manufacturer’srecommendations.

• There are a variety of lockdown sealantsavailable and the one you choose must beappropriate for the intended use. For

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ASBESTOS

example, if the area requires a certain fireprotection rating, the sealant must havethat rating.

• Lockdown sealants are available in clearand colour mixtures. They will requiredifferent drying times, depending on themanufacturer. Follow the manufacturer’sinstructions.

• Take care to avoid getting sealant on or inHVAC units, HEPA vacuums, and negative-pressure machines.

• After the first coat, an inspection should beconducted to see if a second coat might benecessary

• If applying two coats, consider using adifferent colour to ensure completecoverage. You will be able to see the areaswhere only one coat has been applied.

• Certain lockdown sealants can pose ahealth risk if used in an enclosed space.

• Review the MSDS for hazards, requiredpersonal protective equipment (e.g.,respiratory protection requirements), andcontrol measures to use when applying thesealant.

• Follow the manufacturer’s instructions.

11.10 Clearance air testing

1. Clearance air testing must be performedupon completion of Type 3 removal orrepair operations except under any of thefollowing conditions:

• the operation involves work only onnon-friable ACM using a power tool notequipped with a HEPA-filtered vacuum

• the work is done outdoors

• the work is done in a building that willbe demolished and only the asbestosremoval and demolition workers willenter the building.

2. Only a competent worker can conductclearance air testing after an acceptablevisual inspection and after the work areainside the enclosure is dry. For moreinformation, see “Clearance Air Testing,”Appendix C. You must keep the barriers,enclosure, decontamination facility, andnegative air pressure units operating untilthe work area inside the enclosure passesthe clearance air test (less than 0.01fibres/cubic centimetre). If the work areadoes not pass the test, cleaning,decontamination, inspection and lock-down measures inside the enclosure mustbe repeated before retesting.

3. Within 24 hours after receiving theclearance air testing results, the owner andthe employer must post a copy of theresults and provide a copy to the jointhealth and safety committee or the healthand safety representative.

Lockdown

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11.11 Teardown

1. All polyethylene used for lining and inenclosures must be wetted, disposed of asasbestos waste, and not be reused.Dropsheets must be wetted and thenfolded so that any residual dust or scrap iscontained inside the folds. Dispose ofdropsheets as asbestos waste.

2. After the work is completed, barriers andportable enclosures that are rigid and thatwill be reused must be cleaned by damp-wiping or HEPA-vacuuming. Barriers andportable enclosures must not be reusedunless they are rigid and can be cleaned.

3. After the work area has passed both thevisual inspection and air-clearance test,you can shut down the negative airfiltration units. The negative-air systemmust be completely decontaminated. Allpre-filters must be removed and disposed

of as asbestos waste. Seal the inlet andoutlet with 2 layers of 6-mil polyethylene.

4. Teardown should be done as a Type 2operation and workers must be adequatelyprotected.

11.12 Disposal of asbestos-containingmaterial

Regulation 347 under Ontario’s EnvironmentalProtection Act covers the off-site handling anddisposal of asbestos waste. The regulationdescribes types of containers, labelling, anddisposal procedures. There are also regulationsconcerning the transportation of dangerousgoods, enforced by either the Ontario Ministryof Transportation or Transport Canada.

Some municipalities may not accept asbestoswaste at their landfills. Check with your localauthorities or the Ministry of Environment tofind the nearest disposal site.

11.13 Outdoor operations

Outdoor operations can be simpler than indooroperations. You can often use large quantities ofwater to thoroughly soak the material andreduce the amount of airborne dust. There’s lessrisk to bystanders because of this increasedwetting and the natural dispersion of asbestosdust in the air.

For these reasons, there are some differentrequirements for outdoor Type-3 operations:

• No final visual inspection or clearance airtest is required after removal.

• An enclosure is required only whenremoving non-friable asbestos-containingmaterial using power tools without HEPA-filtered vacuums. A transparent windowarea to allow observation of the entirework area is required if the enclosurematerial is opaque.

• Full decontamination facilities are requiredfor outdoor Type-3 operations except for

Air sampling

ASBESTOS

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outdoor operations on non-friableasbestos-containing material involvingpower tools without dust-collecting devicesequipped with HEPA filters (only wash-upfacilities are required for this exception).

• Dust and waste must not be allowed to fallfreely from one work level to another.

• All the other requirements as for indoorType-3 operations apply.

Weather conditions may influence theperformance of work. Heat, cold, or highwinds can make working unsafe. Exposure tothe cold can be an important considerationfor workers if work must be done outdoorsin the winter or indoors if a building’sheating system must be shut down.

For outdoor operations it will generally not bepossible to connect a decontamination facilitydirectly to the work area. In such situations,

portable decontamination units will have to beprovided. When leaving the work area, workersshould thoroughly vacuum their personalprotective equipment and respirators, and washtheir footwear, but DO NOT REMOVERESPIRATORS. Workers should immediately puton another set of disposable coveralls (transitcoveralls having a different colour from thoseworn inside the work area) before making theirway to the portable decontamination unit. Alltransit routes should be clearly marked to keepout other workers and members of the public.

11.14 Demolition

Before any building is demolished, all asbestos-containing material (ACM) that may be disturbedduring the work has to be removed if possible,including material that is hidden:

• Asbestos can be hidden in shafts, betweenwalls, or above false ceilings.

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ASBESTOS

• You may have to look behind thesehidden places to identify suspected ACM.Care must be taken when sampling thematerial to see if it is ACM.

• All pipes should be traced along theirwhole length and all the ACM removed.

Demolition involving Type 3 operations isexempt from

• creating and maintaining a negative airpressure of 0.02 inches of water within theenclosed area

• a final visual inspection and clearance airtesting.

All the other requirements as for indoor Type-3operations apply.

No one must enter the building that is to bedemolished except for the workers involved inthe demolition.

11.15 Disturbing non-friable asbestos withpower tools not equipped with HEPAfilters

If you use power tools without HEPA-equippeddust-collecting devices, then all Type-3requirements for indoor projects apply, withthree exceptions:

• If the work is outdoors or you’redemolishing a building, you do not needto maintain a negative pressure of 0.02inches of water inside the enclosure.

• You do not need full decontaminationfacilities. You must, however,decontaminate protective clothing andhave facilities for workers to wash theirhands and faces.

• You do not need a final visual inspectionor clearance air testing.

Power tools should not be used forremoving ACM because they generate highlevels of airborne dust. If possible, use non-powered tools or power tools with HEPA-equipped dust-collecting devices. Also, useamended water to control the dust.

To prevent electric shock, all power toolsused around water must be equipped with aground fault circuit interrupter (GFCI) andbe maintained properly.

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ASBESTOS

12 ASBESTOS WASTE MANAGEMENTOntario’s Environmental Protection Act coversthe disposal of asbestos waste and is enforcedby the Ministry of Environment.

There are also regulations concerning thetransportation of dangerous goods, enforced byTransport Canada.

Some municipalities may not accept asbestoswaste at their landfills so check with your localauthority or the Ministry of Environment to findthe nearest disposal site.

INDIVIDUAL FINED $45,000 FORILLEGAL TRANSPORT OF ASBESTOSWASTE

SARNIA – A person was fined $45,000 foroperating a waste management systemwithout Ministry of the Environment (MOE)approval under the Environmental ProtectionAct (EPA). In the fall of 2002, the personwas awarded a demolition contract requiringthe removal and disposal of asbestos wasteat a long-term care facility for seniorcitizens.

The contract clearly set out the requirementsfor the disposal of the waste in accordancewith Ontario Regulation 347 made under theEPA. At the time, the individual bagged someof the asbestos waste and transported it toasbestos waste bins owned by a disposalcompany in London without notifying thatcompany. In July 2003, the ministry wasadvised that some asbestos waste from thesenior citizen’s home had not been handledin accordance with the regulations. Aninvestigation by the ministry’s Investigationand Enforcement Branch confirmed that aquantity of asbestos waste was transportedwithout a Certificate of Approval for a wastemanagement system. The individual wascharged accordingly.

On June 21, 2005, the individual wasconvicted on one count under the EPA. Fortransporting waste without a Certificate ofApproval contrary to Section 27(1) (a) of theact, the person received a $45,000 fine plusvictim fine surcharge.

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ASBESTOS

APPENDIX A: RESPIRATOR CHART

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RESPIRATORS

Disposable respirators or dust masks are not recommended for avoiding exposure to asbestos fibres because it’s difficult to performnegative-pressure and positive-pressure seal checks. For more information on seal checks, see Appendix F of CSAO’s Asbestos:Controls for Construction, Renovation, and Demolition (DS037), available on www.csao.org

* For any Type 2 operation in which you will not wet the asbestos-containing material, CSAO recommends that you use a *category B respirator.

CHART FOR ASBESTOS OPERATIONS

How to use the chart Use this chart with CSAO’s data sheet Asbestos: Controls for Construction,

Renovation, and Demolition (DS037). It will clarify any details. You canorder the data sheet from CSAO or download it free from www.csao.org.(You can also download a colour version of this chart).

Start in the middle of the chart and work outwards.

Your goal is to reach the boxes that will tell you the “Type” of removal(Type 1, 2, or 3) and the respirator you require.

The outside circle of the chart tells you what kind of respirator you need.We’ve used A, B, C, and D to represent different kinds of respirators. Therespirator table below explains what each of the letters means.

For two categories of operations, the chart asks you to determine the sizeof the material you’re working with. Once you choose the size (area inm2), you have to stay within the colour (shading) of the size until you getto the “Type” ring. For example, if you’re removing ceiling tiles, and the area is greater than 7.5 m2, you have tostay within the area of the chart that is coloured the same dark grey as the “Greater than 7.5 m2” cell (thisincludes the striped area) until you get to the “Type” ring. You must not move into to the light-grey areas whichare for operations of less than 7.5 m2.

See the third page of this chart for another example of how to use the chart.

When you know the “Type” of removal, you need to implement the required controls. The controls foreach type of operation are listed in the asbestos regulation (Ontario Regulation 278/05, DesignatedSubstance—Asbestos on Construction Projects and in Buildings and Repair Operations). To help you understandthe regulation’s requirements, CSAO has produced a guide called Asbestos: Controls for Construction, Renovation,and Demolition (DS037). You can order both of these publications from CSAO or download them free fromwww.csao.org.

Use this chart to determine the “Type” of asbestos procedure and required respirator.

LEGENDACM means asbestos-containingmaterial.

HEPA or No HEPA refers to whetheryour tool is attached to a dust-collecting device equipped with aHigh-Efficiency Particulate Aerosol(HEPA) filter.

Wetted or not wetted refers to thepractice of wetting the asbestos-containing material with “amendedwater,” (such as a mixture of 1 cupdishwashing detergent for every 20litres of water).

APPENDIX B: REFERENCE CHART

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A* B C D

Air-purifying half-mask respirator withN-100, R-100, orP-100 particulatefilter. The workermust wear therespirator if theyrequest it from theemployer.

Choose any of the following:

Air-purifying full-facepiece respirator with N-100, R-100, or P-100 particulatefilter.

Powered air-purifying respirator with a tight-fitting facepiece (either full orhalf facepiece) and a high-efficiency filter.

Negative-pressure (demand) supplied-air respirator with a full facepiece.

Continuous-flow supplied-air respirator with a tight-fitting facepiece (full orhalf facepiece).

Pressure-demandsupplied-airrespiratorwith a halffacepiece.

Pressure-demandsupplied-airrespiratorwith a fullfacepiece.


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© Construction SafetyAssociation of Ontario

February 2008, DS037,greyscale


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1. Let’s say you want to remove drywall where thejoint-filling compound contains asbestos.The firstthing you do is find the slice of the pie that saysthis. (To the right and a bit below“START”.)

2. You then move outward and see what decisionyou need to make. In this case, you need todecide how much drywall you will be removing(greater than 1 m2 or less than 1 m2). Let’s say thatyou will be removing less than 1 m2.

Notice that the “colour” of the box is light grey.

3. Staying within the light grey colour,moveoutward and see what decision you need tomake.You need to decide if you will use a powertool or not. (“Power tool” is an option despite thedark stripes because the area still contains somelight grey.) Let’s say you will be using a powertool for the removal.

4. The next step asks if your power tool is attachedto a dust-collecting device equipped with a HEPAfilter. If it doesn’t have a HEPA filter, then yourproject is a Type 3 asbestos operation.

5. Now that you know the “Type”of youroperation, you need to learn your legalrequirements and the controls you must use.Refer to the documents listed on the pageopposite the chart (under “When you knowthe “Type” of removal”).

6. To determine what respirator you require,move one step further in the circular chart,and decide whether you will wet thematerial with “amended water” (see the pageopposite the chart). If you’re performing adry removal, the respirator type will be C.

7. Look at the respirator table on the pageopposite the circular chart, and see whatrespirator “C” represents. It is a pressure-demand supplied-air respiratorequipped with a half facepiece.This is thekind of respirator you need.

Example of how to use the chart

1

2

3

4

5

7

6

APPENDIX CCLEARANCE AIR TESTINGThe asbestos regulation for construction(Ontario Reg. 278/05) requires clearance airtesting upon completion of Type-3 removal orrepair operations. (There are some exceptions tothis rule. See the regulation for details.)

Clearance air testing involves collecting airsamples from inside the work area andanalyzing them. This will determine if the clean-up and decontamination measures haveeliminated the asbestos dust hazard. Clearanceair testing is done only after the work area haspassed the visual inspection, the area insideenclosure is dry, and “lockdown/gluedown” hasbeen applied.

Clearance air testing reference: M.1.5,Appendix M of Guidance forControlling Asbestos-ContainingMaterials in Buildings, publicationnumber EPA 560/5-85-024, 1995, by theU.S. Environmental Protection Agency.

Barriers, enclosures, decontaminationfacilities, and negative air units must bemaintained until the work area inside theenclosure passes the clearance air test.

Only a competent worker can perform clearancesampling.

Before and during sampling, “forced” air usingleaf blowers or similar equipment is used todisturb settled dust from all surfaces in the workarea, including enclosure surfaces. Thisdisturbance displaces any settled dust to ensure“worst case” air concentrations of asbestos dust.Airborne dust is then sampled using an air pumpwhich draws air through a filter. Samples aresent to an accredited laboratory for analysis.Laboratory turn-around times are anywhere from24 to 72 hours.

There are two methods of analysis:

• Phase Contrast Microscopy (PCM). Atechnician uses an optical microscope.

• Transmission Electron Microscopy (TEM).A technician uses an electron microscope.

Phase Contrast Microscopy generally costs less,but it can be less accurate than TransmissionElectron Microscopy. In Phase ContrastMicroscopy, all fibres including non-asbestosfibres are counted, while in TransmissionElectron Microscopy, only asbestos fibres arecounted. Also, the number of samples requiredfor analysis is different.

There are 3 clearance test analysis options:

1. Clearance test using PCM analysis alone

2. Clearance test using TEM analysis after theclearance test fails using PCM analysis.

3. Clearance test using TEM alone.

The clearance test passes if

• using PCM alone; all samples are less than0.01 fibres per cubic centimeter inconcentration

• using TEM after the clearance test usingPCM analysis fails, all samples are less than0.01 fibres per cubic centimeter inconcentration. (The 0.01 refers to allfibres for PCM, and asbestos fibres forTEM.)

• using TEM alone, the average asbestosfibre concentration level inside theenclosure is statistically the same or lessthan the average asbestos fibreconcentration outside the enclosure.

Consequences of failure of clearance test:If the work area does not pass the test,cleaning, decontamination, inspection, and lock-down measures inside the enclosure must berepeated before retesting. This adds to the costand duration of project. It’s crucial that the

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APPENDIX C: CLEARANCE AIR TESTING

project owner or general contractor ensures thatthe asbestos work is done properly and that theclearance sampling is done only by a competentworker.

Clearance air testing is not required for

• Type 1 operations

• Type 2 operations

• Type 3 operations when

• the operation involves work only onnon-friable ACM using a power tool notequipped with a HEPA-filtered vacuum

• the work is done outdoors, or

• the work is done in a building that willbe demolished and only the asbestos-removal and demolition workers willenter the building.

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APPENDIX C: CLEARANCE AIR TESTING

APPENDIX DINSPECTING RESPIRATORSBefore each use, respirators must be inspectedto make sure that they are in good workingorder. The pre-use inspection should includechecking

1. the facepiece and face-seal area for cracks,tears, dirt, or warping

2. the inhalation valves for warping, cracking,or tearing

3. the head straps for cracks — ensure thatthey have good elasticity

4. all plastic parts for signs of cracking —ensure that filter gaskets or seal areas arein good condition

5. the exhalation valve and valve seat forsigns of dirt, warping, cracking, or tearing

6. the viewing area of the full facepiece forany damage that might restrict vision

7. the type and condition of the filter

8. the battery charge/condition and theairflow rate for powered air-purifyingrespirators (PAPR).

9. the regulators, alarms, and other warningsystems.

A respirator with any damaged ordeteriorated components must be repairedor discarded.

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APPENDIX D: INSPECTING RESPIRATORS

APPENDIX ECLEANING AND STORAGE OFRESPIRATORSRespiratory protective equipment should becleaned after each use. It must be disinfectedwhenever the equipment is transferred from oneperson to another. Maintenance and cleaningprocedures need to be appropriate for the typeof respiratory protective equipment being used.Follow the manufacturer’s instructions.

The following is based on Appendix F(Guidelines for cleaning, disinfecting and storingof respirators) of CSA Z94.4-02:

1. Remove cartridges and filters.

2. Rinse respirator in warm water.

3. Immerse facepiece (excluding filters andcartridges) in warm water (50° C) with amild detergent.

4. Clean with soft brush or sponge. Do notuse cleaners containing solvents, becausethey will damage the respiratorcomponents.

5. Rinse in fresh, warm water.

6. If the respirator is shared, disinfect thefacepiece by soaking in a solution ofquaternary ammonia disinfectant or sodiumhypochlorite (30 ml of household bleachin 7.5 litres of water).

7. Rinse in fresh, warm water, and air dry.

8. The cleaned respirator must be stored ina clean area away from dust, chemicals,sunlight, heat, extreme cold, and excessivemoisture.

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APPENDIX E: RESPIRATOR CLEANING AND STORAGE

APPENDIX FPUTTING ON AND SEAL CHECKINGRESPIRATORS

Putting on the respirator

1. Fully loosen all head straps. Pull hair backwith one hand. Bring facepiece up to facewith other hand.

2. While holding the facepiece in place, pullthe straps over your head.

3. Tighten the straps starting from the bottomand going to the top.

Seal checking

Respirators must be seal checked (negative andpositive) before each use.

Negative pressure test

• Wearer puts on respirator and adjusts itappropriately.

• Inlets to the filters are blocked with handsor covers.

• Wearer inhales gently and holds for 5seconds.

• Mask should collapse slightly and notpermit air into the facepiece.

• If a leak is detected, readjust the mask andrepeat the test.

Positive pressure test

• Perform only once wearer is satisfied withnegative pressure test.

• Cover or block exhaust port of respirator.

• Wearer exhales gently for 5-10 seconds.

• Mask should expand outward slightly

• If a leak is detected, inspect and/orreadjust mask and repeat the test.

If you cannot achieve a proper seal, donot enter the work area. See yoursupervisor.

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APPENDIX F: SEAL CHECKING RESPIRATORS

Negative-pressure seal check

Positive-pressure seal check

APPENDIX GFIT TESTING RESPIRATORSFit testing is required

• for each user when they use a new type ormodel of respirator

• to ensure user can achieve an acceptableseal.

Accurate records should be kept of whoperformed the fit test, when it was performed,on whom it was performed, the method of fittesting performed, and the results of the fit test.

There are two methods of fit testing: qualitativeand quantitative. Fit testing should be performedaccording to CSA standard Z94.4-02.

Qualitative

In qualitative fit testing, the worker wears therespirator. A chemical agent which can normallybe noticed by smell, taste, or the irritation that itcauses, is introduced to determine if a proper fithas been achieved. A negative result (theworker does not smell, taste, or becomeirritated) indicates a good fit, while a positiveresult (the worker smells, tastes, or is irritated)indicates a poor fit.

Qualitative fit testing is uncomplicated, fast, andcan be done in the field. The drawback is that itdepends on the wearer’s subjective response tothe testing agent.

When testing half masks, irritant smoke orother substances can irritate the eyes.Wearers should close their eyes during thetest.

Quantitative

Quantitative fit testing is a procedure in which atest substance (aerosol, vapour, or smoke) isreleased outside the respirator. A probe andspecialized equipment measure theconcentration of the test substance both outside

and inside the respirator. The test passes if theconcentration inside the respirator passes a fitfactor (based on an assigned NIOSH rating).

Quantitative fit testing does not depend on thewearer’s subjective response, but it is expensive,and it requires a competent person to conductthe test. Quantitative fit test equipment must bemaintained, calibrated, and used according tothe manufacturer’s instructions.

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APPENDIX G: FIT TESTING RESPIRATORS

APPENDIX HRESPIRATOR POLICYEach company is required to have a writtenrespirator policy and a program forimplementing that policy.

The CSA Z94.4-02 standard outlines the contentrequirements for a respiratory program whichincludes:

• Roles and responsibilities

• Hazard assessment

• Selection of the appropriate respirator

• Respirator fit testing

• Training

• Use of respirators

• Cleaning, inspection, maintenance, andstorage of respirators

• Health surveillance of respirator users

• Program evaluation

• Record-keeping.

A qualified person should administer andoversee the respiratory protection program.

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APPENDIX H: RESPIRATOR POLICY

To qualify as a HEPA filter, the filter must becertified by the Institute of EnvironmentalSciences and Technology to ensure that it cancapture 99.97% of particles greater than orequal to 0.3 microns in diameter. A filterpassing the certification test is given a numberand the test results are recorded on the label.So read the label carefully.

APPENDIX I: HEPA FILTERS

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APPENDIX IHEPA FILTERSHEPA stands for High-Efficiency ParticulateAerosol, and refers to filters used in a varietyof industries and workplaces.

In construction, there are two main uses forHEPA filters:

1. industrial HEPA vacuum cleaners

2. negative air filtration units.

Vacuum cleaners with HEPA filters trap toxicparticles such as asbestos and keep themfrom returning to the air where people caninhale them.

Negative air filtration maintains air pressureinside an enclosure at a lower level thanoutside. The filtration unit drawscontaminated air from within the enclosurethrough a HEPA filter and blows the airoutside.

Efficiency

By definition, a HEPA filter is able to removea minimum 99.97% of all particles 0.3 micronsin diameter or larger. A human hair, bycomparison, is about 100 microns in diameter.

Ordinary filters cannot trap such microscopicparticles. Instead, the particles are blown backinto the air where workers can inhale them.HEPA filters prevent this from happening.

HEPA vacuums and negative air units havepre-filters to remove large particles beforethey can reach the HEPA filter itself. Withoutpre-filters, costly HEPA filters would have tobe replaced much more often.

Guidelines

To ensure that HEPA filters are workingefficiently, take the following steps.

• Read and follow the manufacturer’sinstruction manual.

• Filters are contaminated with toxicsubstances. When inspecting or replacingfilters, do it in a safe, well-controlled placeand wear personal protective clothing andequipment. Personal protective equipmentwill vary according to the hazard but mayinclude an N-100, R-100, or P-100 NIOSH-approved air-purifying respirator, dust-resistant safety goggles, disposablecoveralls, and impervious gloves.

• When renting HEPA vacuums or negativeair units with HEPA filters, make sure thefilters are real HEPA filters and not “HEPA-like” filters.

• Test HEPA filters by means of a Dispersed OilParticulate (DOP) test when the filters arefirst installed to see if they’re mountedcorrectly. The purpose is to ensure that airflows through the filter and doesn’t leakaround the seals of the filter housing.

We recommend that after the test iscomplete, you put a sticker on the unitstating when the test was completed andthe result. After the work is finished andbefore the next use, perform a new testand place a new sticker on the unit.

• Make sure the filter is not installedbackwards, is properly seated in itshousing, and is tightly secured.

• Inspect the filter housing for signs of dustindicating that dust is bypassing the filter.A HEPA filter is useless if the housingleaks.

• Dust in the exhaust airflow means theHEPA filter has ruptured or failed and mustbe replaced.

• If the fan is not drawing the amount of airrequired to keep the area under negative

pressure, the unit filters may have becomeloaded or clogged with dust. This can beconfirmed by measuring the pressurechange across the filters (most units haveeither a differential pressure gauge or a“change filter” indicator). If the filter isclogged, the pre-filter should be changedfirst. If the pressure change does notdecrease, the intermediate filter should bechanged. If changing both the pre-filterand the intermediate filter does not solvethe problem, the HEPA filter may need tobe changed.

• When changing the HEPA filter, make surethe fan is off. Always use themanufacturer’s recommended replacementfilter. Other filters may not fit and thereforethey may leak.

• After the filter has been replaced, arrangefor a Dispersed Oil Particulate (DOP) testto ensure that

- the new filter’s integrity is good

- air flows through the filter

- air doesn’t leak around the seals of thefilter housing.

A new test certificate sticker should beplaced on the unit.

• All used filters must be placed in sealableplastic bags, labeled, and disposed of asasbestos waste.

• Pre-filters and HEPA filters cannot becleaned. They must be replaced with newfilters approved by the manufacturer.

• Don’t use compressed air to clean oldfilters or bang old filters to removeaccumulated dust.

• Don’t punch holes in HEPA filters or pre-filters when they get clogged.

• Follow the manufacturer’s instructions onwhen and how to change the filter.

• To replace old filters, use only new filtersapproved by the manufacturer.

• Don’t use another manufacturer’s filter oralter it to fit your vacuum or air filtrationunit.

• Dispose of old filters as contaminatedwaste.

See Appendix J for information on“Negative Air Units and HEPA Filters:Troubleshooting.”

APPENDIX I: HEPA FILTERS

As the HEPA filter becomes coated with moreand more particles, the air flow through thevacuum or negative air unit will decrease.Change the filter.

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APPENDIX JNEGATIVE AIR UNITS AND HEPAFILTERS: TROUBLESHOOTINGHow do I know if the HEPA filter isleaking dust?

• There are two specific purposes for testingthe HEPA filters:

1. to check the filter, and

2. to ensure that air flows through the filterand doesn’t leak around the seals or thefilter housing.

• Before each use it is the supervisor’sresponsibility to have the negative airunit’s HEPA filter tested.

• Testing must be done by means of a DOP(Dispersed Oil Particulate) test. During aDOP test, a competent worker willintroduce small amounts of aerosol or“smoke” upstream of the HEPA filter. Whilethe aerosol or “smoke” is being pulledthrough the unit, the competent workerdoing the testing will then use a meter tocheck for particles downstream of the HEPAfilter to determine if any aerosol or “smoke”has passed through or around the filter.

• After the test is complete, the tester willplace a sticker on the unit stating whenthe test was completed, the serial numberof the unit, and whether the result was apass or fail.

• The test certificate is only valid for thatspecific “job” or “setup.” Once the work hasbeen completed and before the next use,your supervisor must arrange for a new test.

Take extra care when handling a negativeair unit.

• Any jarring movement to the unit or eventhe slightest damage to the unit can causethe seal to fail or even the HEPA filter tobreak.

• If you notice any damage to the unit, or ifyou know that the unit has been hit orjarred, you should notify your supervisorimmediately.

How do I know when there is a problemand what do I check for?

• It is a requirement to maintain theenclosure pressure at 0.02 inches of waternegative to the surrounding area. If the airpressure in the enclosure goes below 0.02inches of water, immediate action isrequired.

• The first thing you need to do is checkif the negative air unit is still running.

• If the unit is running then there couldbe an opening in the enclosuresomewhere. Even a small opening cancause a substantial drop in the negativeair pressure.

• If you have checked the enclosure andeverything is okay then the problem

APPENDIX J: NEGATIVE AIR UNITS & HEPA FILTERS

HEPA test sticker

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could be that the negative air unit’sfilters have become clogged with dustwhich restricts the air flow through theunit. If this is the case the first thing youcan do is vacuum some of the dust offof the pre-filter. You may be able toremove enough dust to substantiallyincrease the air flow through the unit. Ifthis doesn’t work, the negative air unit’sfilters need to be changed.

How do I change the filters?

• When the fan is not drawing the amountof air required to keep the containmentarea under negative pressure, the unitfilters may have become loaded or cloggedwith dust.

• This can be confirmed by measuring thepressure difference across the filters. Mostunits have either a differential pressuregauge or a “change filter” indicator as partof the unit.

• If the filters have become clogged, the pre-filter should be changed first.

• All filters must be changed within theType-3 enclosure and in accordance withthe manufacturer’s instructions.

• If changing the pre-filter does not increasethe air flow then the intermediate filtershould be changed as well.

• If changing both the pre-filter andintermediate filter does not solve theproblem, the HEPA filter may requirechanging.

When changing the HEPA filter, makesure the fan is off.

Always use the manufacturer’srecommended replacement HEPA filter.Other filters may not fit and thereforethey may leak.

After the filter has been replaced,arrange for a DOP (Dispersed OilParticulate) test to ensure the new filter

integrity is good and that air flowsthrough the filter and doesn’t leakaround the seals or the filter housing.

All used filters must be placed insealable plastic bags, labeled, anddisposed of as asbestos waste.

Where do I position the negative air unitand the exhaust?

• When preparing for a Type 3 removal thelocation of the negative air unit and thelocation of the unit’s exhaust duct areimportant.

• Try to position the negative air unit awayfrom the demolition or in a location thatwill have the least amount of airbornedust.

• Lower dust levels will minimize thelikelihood of having to replace the filterswhich means

the unit will operate for longer durations

the unit will operate more efficiently

there will be less change in pressurewithin the enclosure

• Whenever possible, the exhaust ordischarge duct should be placed so that itdischarges outside.

• Never have the exhaust duct discharge tothe building’s return air system. If theunit’s HEPA filter fails, asbestos fiberscould be spread throughout the building.

• Negative air pressure within the enclosuremust be established before any work isperformed.

• Negative air pressure must be maintainedat all times during Type-3 removal.

What will happen if there is a powerfailure?

• In the event of a power failure, thenegative air unit will stop running. This

means that the enclosure will no longer beunder negative air pressure.

• If this happens, do the following:

Stop working immediately.

Leave the work area through thedesignated exit.

After you leave the enclosure seal theentrance way, exits or any otheropening in the enclosure with plasticand tape.

Do not open the door to the enclosure.Remember, without negative airpressure, dust could get out of theenclosure and contaminate adjacentareas with asbestos.

Leave the negative air unit in the onposition even though it is not running.When the power is reestablished, theenclosure will again be under negativepressure without anyone having to opena door.

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10 – 1

10 RADIATION

This chapter provides essential information about therecognition, assessment, and control of radiation.

What is Radiation?Radiation is energy that travels through space in the formof electromagnetic waves or sub-atomic particles. Thereare two main types of radiation: IONIZING and NON-IONIZING.

IONIZING RADIATION produces electrically chargedparticles or ions when it interacts with material. Ionizationis the result of a collision between ionizing radiation andmatter.NON-IONIZING RADIATION produces changes in thehuman body mainly through thermal effects.

What is Ionizing Radiation?Ionizing radiation can be found anywhere in the naturalenvironment. It comes from space, from the sun, and fromnaturally occurring radioactive elements in the earth.Ionizing radiation can also come from manmade sourcessuch as nuclear power plants and x-ray machines. Themain sources of ionizing radiation are x-rays, gammarays, alpha particles, beta particles, and neutrons.

X-raysX-radiation is electromagnetic radiation produced by x-raymachines. X-rays can penetrate deep into the humanbody.

Gamma RaysLike x-rays, gamma rays are electromagnetic. They canpass right through the human body, interact with tissue,and cause severe damage.

Alpha ParticlesAlpha particles are emitted from the nucleus of atoms.Because of their large size, a piece of paper or theoutermost, dead layer of the skin can stop alpha particles.Alpha particles are produced by elements such asuranium and radon gas. Alpha particles are hazardouswhen taken into the body through inhalation or ingestion.Uranium miners exposed to radon gas have a muchhigher incidence of lung cancer when compared to thegeneral population.

Beta ParticlesLike alpha particles, beta particles are emitted from thenucleus of atoms. However, unlike alpha particles, theyare extremely small and move at nearly the speed of light.Beta particles can penetrate up to 2 centimetres of tissue

depending on their energy. This type of radiation is usedfor light-emitting sources, medical procedures, andbiological research.

NeutronsNeutrons can penetrate deep into the body. Neutrons areproduced by nuclear reactors and particle accelerators. Athick layer of plastic or water slows neutrons.

Exposure to Ionizing RadiationWorkers can be exposed to radiation in two ways:1) Internal exposure — radioactive substances are

ingested, inhaled, or absorbed through the skin.Some can be eliminated within a few hours via urineand feces while others are stored in the body andeliminated slowly over many years.

2) External exposure — x-rays, gamma rays, andneutrons represent the main health hazard becauseof their ability to penetrate the human body.

The extent of radiation damage varies with the type ofradiation. For a given dose, alpha radiation producesgreater damage than beta, gamma, or x-rays. The degreeof harm depends on the specific organ or tissue exposedto the radiation. The same dose may result in differentdamage to various organs. Reproductive organs, forexample, are particularly sensitive to radiation.Two kinds of health effects result from exposure toionizing radiation:Immediate effects— High doses of radiation delivered ina short period to the whole body or particular organs canproduce various health effects including death within afew weeks after exposure. Death is usually a result of thebody's inability to cope with the large quantity of deadcells within various tissues and/or organs. The severity ofsymptoms depends on• the total radiation dose• how quickly the dose was delivered• the type of radiation and the part of the body exposed.

Delayed effects— Workers exposed to low doses ofradiation are at increased risk of developing cancer laterin life and of passing on damaged genetic material to theiroffspring. Cancers observed in populations exposed tolow levels of radiation include leukemia, thyroid, breast,lung, and bone.

Sources of Ionizing RadiationConstruction workers can be exposed to ionizing radiationfrom both natural and manmade souces.

RADIATION

NON-IONIZING IONIZINGLow Radio- Microwave Infrared Visible UV UV AlphaFrequency Frequency Beta

A B C GammaX-ray

Large wavelength Small wavelengthLow frequency High frequency

Figure 18.1

Job type Radiation typeNatural Sources Radon in soil Tunnelling, highway Alpha

and road constructionManmade Industrial GammaSources Radiography

Nuclear Power Beta, Gamma,Plants NeutronsX-ray X-raysMachines

Figure 18.2

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Natural SourcesRadon— Rock and soil rich in uranium decays to radongas which produces alpha particles. Alpha particles canbe inhaled with air and deposited in the lungs, therebyincreasing the risk of lung cancer. Radon can accumulatein poorly ventilated areas such as crawlspaces,basements, mines, and tunnels.

Manmade SourcesIndustrial Radiography— Industrial radiography is a non-destructive method of inspecting materials or findingobjects underground using ionizing radiation to form animage of the object. Industrial radiography employinghighly radioactive materials such as cobalt-60 is usedcommonly on construction sites. Exposure is possiblewithout adequate shielding.Nuclear Power Plants— Contractors working in a nuclearpower plant can potentially be exposed to beta, gamma,and neutron radiation.

MonitorsVarious monitors are available to measure radiation. Theycan be divided into two main types:1. personal monitoring for measuring a worker's

cumulative exposure2. survey instruments for measuring exposure at a given

time and place.

Personal MonitoringFilm Badge — The film badge, worn on the outer layer ofclothing, is used for monitoring x-ray, gamma rays, andhigh-energy beta particles. Radiation interacts with thefilm causing it to lighten (develop). After a specific periodof time the film is compared to a control film to determinethe amount of exposure the person has sustained.

Thermoluminescence Detector (TLD) — TLDs aredosimeters widely used to detect x-rays, gamma rays,and beta particles. They are usually pinned to the outerlayer of clothing or worn as finger rings. TLDs are mostcommonly composed of lithium fluoride. Lithium fluorideabsorbs radiation and releases it as light when heated.The amount of light emitted is directly related to theindividual's radiation exposure.

Pocket Dosimeter— The pocket dosimeter is a directreading instrument shaped like a pen with a pocket clip. Itis used for monitoring x-rays and gamma rays. The barrelcontains a quartz fibre and a charged piece of wire. Whenthe wire is exposed to radiation, it causes the fibre tomove. The amount of movement is read off a scale and isdirectly proportional to the amount of radiation present.

Survey Instruments— The most common surveyinstruments used for detecting radiation are the ionizationchamber, Geiger Müeller (GM) counter, and proportionalcounter.

Ionization Chambers— When radiation interacts with air,ions are produced. Radiation can be accurately quantifiedto determine the amount of ions produced. This is theprinciple behind the ionization chamber. These units canmeasure gamma, x-rays, beta, and alpha radiation butcannot discriminate between them.

Geiger Müeller Counters— The Geiger Müeller Counteris used for gamma, x-ray, and beta radiation surveymeasurements. This instrument cannot distinguishdifferent types of radiation but is sensitive to smallamounts.

Proportional Counters— Proportional counters are similarto ionization chambers except that they are able todifferentiate between alpha and beta particles.

Scintillation Counters— Scintillation counters use theprinciple that when ionizing radiation strikes certainmaterials, visible light is created. The amount of lightgenerated is directly proportional to the amount ofradiation. Scintillators can differentiate between varioustypes of ionizing radiation.

Body Monitoring InstrumentsFrisker MonitorWorkers exiting radiation areas should be frisked forcontamination. This does not apply to workers exitingareas containing only radionuclides, such as tritium, thatcannot be detected using hand-held whole body orautomatic frisking equipment.Frisker monitors are used at nuclear power stations toscan the body and clothing for radioactive contamination(Figure 18.3). The instruments click when they detectradiation. The greater the number of clicks the greater thelevel of contamination.

Foot and Frisker MonitorsThese are used at boundaries where there is a fairly lowprobability of your hands being contaminated (Figure18.4). To use the monitor, simply centre your feet on thefoot grills and wait for the green "clean" signal on thedisplay panel. If you suspect that hands, clothing, oranything else may be contaminated, survey them with thefrisker provided.

Hand, Foot, and Frisker MonitorsThese are placed at zone boundaries where traffic flow ishighest (Figure 18.5) To check for contamination, centreyour feet on the foot grills, insert your hands in the slots,and press the plates at the back. If your hands and feetare not contaminated, the panel will display a green"clean." If you are contaminated, an alarm will sound, the

RADIATION

Figure 18.3

10 – 3

word “contaminated” will flash in red, and a symbolindicating which extremity is contaminated will light up. Ifyou move off the monitor before it has finished counting,an alarm will sound and the words "removed too soon"will flash. Remonitor and wait for the "clean" signal. If yoususpect that hands, clothing, or anything else may becontaminated, survey them with the frisker provided.

Portal MonitorPortal monitors (Figure 18.6) check not only your hands andfeet for contamination but also your skin, clothing, and hair.

Bioassay SamplesA bioassay program is set up to measure radioactivematerial within the body so that internal dose may becalculated. The main contributor to internal dose is tritium,a radioactive form of heavy water. Tritium in the body caneasily be measured by determining concentration in aurine sample.

Radiation Control ProgramsBasic Safety FactorsFor external radiation exposure, the basic protectionmeasures are reducing time of exposure, increasingdistance from the source, and shielding the source withappropriate material.

TimeThe longer a person is exposed to radiation, the greaterthe chance of injury. Reducing exposure time by one-halfreduces exposure by one-half. A common control methodis therefore to reduce exposure time and thus exposure.

DistanceDoubling the distance from the source reduces theradiation exposure by one fourth of the original amount.Workers working around radiation-producing machinesthat are not adequately shielded must maintain a safedistance.

ShieldingRadiation can be blocked by placing a barrier betweensource and worker. The greater the mass of the barrierthe less radiation the worker will receive. Shielding cantake many forms depending on type of radiation. Thetable below outlines the appropriate shielding for varioustypes of radiation.

Radiation type Shielding materialNeutrons WaterAlpha PaperBeta PlasticGamma Lead, concrete

Figure 18.7

Controlling Radiation ExposureTo minimize exposure, the following measures arerecommended.1. Engineering controls, such as properly enclosing the

source, are the primary means of control.2. Administrative controls, such as restricting access and

maintaining a safe distance, should be used as asecondary means of control.

3. Training and educating workers is an essentialelement in any control program.

4. Personnel should not smoke, eat, drink, or chew incontaminated areas.

5. The selection of personal protective equipmentdepends on the contamination level in the work area.Workers should inspect protective equipment andclothing before using it.

6. Workers must wear personal monitoring deviceswhere required.

7. Workers must keep track of radiation exposure status.8. Potentially contaminated clothing should be removed

without spreading contamination to the skin anddisposed of in the dirty clothes hamper.

9. A shower is required to ensure that contamination isnot taken home.

Control for Industrial Radiography MachinesBecause of potential high radiation exposure to operatorsof industrial radiography machines and to workers inadjacent areas, strict controls are necessary duringoperation.The following measures are recomended by HealthCanada.1. Portable cameras should be properly shielded to

prevent excessive radiation from escaping.2. The device should be locked to prevent unauthorized

use.3. The camera should be designed so that the radiation

source cannot be removed.4. The camera should be designed so that it cannot be

unlocked unless it is fully shielded.

RADIATION

Figure 18.4

Figure 18.6

Figure 18.5

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5. The control device should be designed so that itcannot be removed unless the radiation source is inthe stored position.

6. A radiation warning sign should be placed in thevicinity of the instrument.

7. The control device should be designed so that theoperator can work the device without being exposedto the emergent beam.

8. The camera must be transported in accordance withregulations for transporting dangerous goods.

9. Operators must be certified to operate the machine.10. Operators should have a yearly medical exam.

What is Non-Ionizing Radiation?Non-ionizing radiation does not have enough energy toionize atoms, but it vibrates and rotates molecules,causing heating. Non-ionizing radiation is classified byfrequency and stated in units of hertz (Hz).The following types of non-ionizing radiation may bepresent in construction; ultraviolet (UV), lasers, radio-frequency, and RF/microwave.

Ultraviolet Light RadiationUltraviolet (UV) radiation occupies the range betweenvisible rays and x-rays on the electromagnetic spectrum.UV rays can be divided into three categories according towavelength:• UVA 320 nm• UVB 290-320 nm• UVC 100-290 nm

Wavelengths are measured in nanometers (nm). Ananometer is one billionth of a metre.UVC from the sun is usually not a concern becausewavelengths below 290nm are filtered out by the earth'satmosphere.Construction personnel working outdoors are exposed toinvisible UV radiation from the sun during spring andsummer. Another source of UV radiation is the intenselight generated by welding. Overexposure to UV radiationcan lead to skin and eye damage.

Skin Damage — Overexposure to UV radiation leads tothe painful reddening, blistering, and peeling of skincommonly known as sunburn. The skin may "tan" byproducing melanin to protect itself against UV light.Although this dark pigment blocks some of the damagingrays (mostly UVB), the protection is far from adequate.Skin damage still occurs.Damage done to the skin by excessive exposure to UVrays is cumulative. Chronic or long-term exposure to UVradiation has been related to a number of health effects,including skin cancer, premature aging or wrinkling of theskin, and eye problems.Note the following points about UV exposure and skincancer.• UV exposure from the sun has been established as a

major cause of melanoma — a deadly form of skincancer in people with light skin colour.

• People who experience multiple sunburns early in lifeare more likely to develop skin cancer than peoplewho experience no sunburns.

• People who work outdoors as teenagers are at anincreased risk of developing skin cancers.

• People with chronic exposure to the sun are at anincreased risk of developing skin cancer.

Eye Damage — UV radiation can damage the eyes.Conditions include cataracts (clouding of the lens) andcorneal injuries (involving the outer membane of the eye).

Welders’ flash, also known as arc eye and snowblindness, is a painful irritation of the cornea andconjunctiva (the membrane connecting the eyeball andthe inner eyelid). Symptoms include sensitivity to light andthe sensation of sand in the eye.

Control Measures— To protect yourself from UV radiationwhile working outdoors, take the following precautions.• If possible, work in the shade when the sun is most

intense (late morning and early afternoon).• Wear sunglasses or safety glasses that protect

against UVA and UVB.• Use sunscreen with a Sun Protection Factor (SPF) of

at least 15. Apply sunsreen generously to all exposedskin, including lips and nose.

• Wear clothing that covers arms and legs. The tighterthe weave the better.

LasersLasers are increasingly used in construction for lineguides and levellers. Lasers can cause serious injuries,especially to your eyes and skin. Lasers are identified byclass, ranging from Class 1 (low-power lasers incapableof damaging the eye and therefore exempt from controlmeasures) to Class 4 (high-powered lasers capable ofcausing severe eye damage in less than 0.25 seconds).

Control Measures— The degree of hazard associatedwith low-power lasers used in construction is relativelylow. However, everyone in the work area should beadvised of possible laser hazards and the followingprecautions should be taken.1. The lasers should have a power output of less than

5 milliwatts (mW) and a power intensity (density) ofless than 2.5mW per square centimetre.

2. Operators of laser equipment should be trained insafety procedures, set-up, operation, andmaintenance of the specific devices being used.

3. Where possible, the laser beam should be set up wellabove eye level.

4. The laser device should be shut off when not in use.5. All employees working near the laser should be

advised not to look directly at the laser or itsreflection.

6. Lasers should not be pointed at reflective surfaces.7. A sign should be placed in the vicinity warning people

not to stare at the instrument or beam.8. Each laser should be labelled to indicate maximum

output and power intensity.9. Workers who regularly work in the laser vicinity

should have a yearly eye exam.10. For the safety of the general public, the beam should

be confined within the construction area.11. Optical instruments such as transits and levels should

not be pointed at the laser beam or its reflection.

RADIATION

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12. The laser instrument should be stored in a locked boxwhen not in use.

Radio-Frequency Heat SealersRadio-frequency sealers commonly operate at afrequency of 27.12 megahertz. These devices are alsoknown as heat sealers or welders. Heat sealers generatehigh-energy radio-frequency (RF) radiation between twoconductive plates. When two or more pieces of non-conductive material such as PVC plastic are placedbetween the energized plates, the material is fusedtogether. RF sealers are used in construction to weld rooftarps and PVC pipe. RF sealers provide a very strongseal and require no toxic solvents.The National Institute for Occupational Health and Safety(NIOSH) has found that in certain situations the hands ofworkers operating RF sealers have been exposed to highlevels of radiation.

Control Measures1. The RF sealer should be properly shielded to prevent

excessive radiation from escaping.2. The device should be designed so that it cannot be

operated unless it is fully shielded.3. The control device should be designed so that the

operator can work the device without being exposedto RF radiation.

4. Operators of the RF sealer should have a yearlymedical exam.

Radio and Television AntennasRadio and television broadcast stations transmit theirsignals via radio-frequency (RF) radiation. In urban areas,broadcast antennas are usually located on rooftops whereconstruction workers may unknowingly be exposed to RFradiation as they complete maintenance, repair, and otherwork.

Control Measures1. Temporarily lower power levels while work is being

performed on or around antennas.2. Transmit from another antenna while work is being

performed.3. Perform repairs or other work while the antenna is not

operational.4. Maintain a safe distance from the antenna while it is

operating.

RADIATION

11 – 1

11 HEAT STRESS

The Construction Safety Association of Ontario thanks thefollowing for their help in developing this chapter:• American Conference of Governmental Industrial

Hygienists (ACGIH)• Sarnia Regional Labour-Management Health and

Safety Committee.

WHERE DOES HEAT STRESS OCCUR INCONSTRUCTION?Construction operations involving heavy physical work inhot, humid environments can put considerable heat stresson workers. Hot and humid conditions can occur eitherindoors or outdoors.Indoors• steel mills and foundries• boiler rooms• pulp and paper mills• electrical utilities• petrochemical plants• smelters• furnace operations• oil and chemical refineries• electrical vaults• interior construction and renovation.Outdoors• roadbuilding• homebuilding• work on bridges• trenching• pouring and spreading tar or asphalt• working on flat or shingle roofs• excavation and grading.Asbestos removal, work with hazardous wastes, and otheroperations that require workers to wear semi-permeable orimpermeable protective clothing can contribute significantlyto heat stress. Heat stress causes the body’s coretemperature to rise.

WHAT HAPPENS WHEN THE BODY’SCORE TEMPERATURE RISES?The human body functions best within a narrow range ofinternal temperature. This “core” temperature varies from36°C to 38°C. A construction worker performing heavywork in a hot environment builds up body heat. To get ridof excess heat and keep internal temperature below 38°C,the body uses two cooling mechanisms:1) The heart rate increases to move blood—and heat—

from heart, lungs, and other vital organs to the skin.2) Sweating increases to help cool blood and body.

Evaporation of sweat is the most important way thebody gets rid of excess heat.

When the body’s cooling mechanisms work well, coretemperature drops or stabilizes at a safe level (around37°C). But when too much sweat is lost through heavylabour or working under hot, humid conditions, the body

doesn’t have enough water left to cool itself. The result isdehydration. Core temperature rises above 38°C. A seriesof heat-related illnesses, or heat stress disorders, canthen develop.

HOW CAN WE RECOGNIZE HEATSTRESS DISORDERS?Heat stress disorders range from minor discomforts to life-threatening conditions:• heat rash• heat cramps• heat exhaustion• heat stroke.

Heat rashHeat rash—also known as prickly heat—is the most commonproblem in hot work environments. Symptoms include• red blotches and extreme itchiness in areas

persistently damp with sweat• prickling sensation on the skin where sweating occurs.Treatment—cool environment, cool shower, thoroughdrying. In most cases, heat rashes disappear a few daysafter heat exposure ceases. If the skin is not cleanedfrequently enough the rash may become infected.Heat crampsUnder extreme conditions, such as removing asbestosfrom hot water pipes for several hours in heavy protectivegear, the body may lose salt through excessive sweating.Heat cramps can result. These are spasms in largermuscles—usually back, leg, and arm. Cramping createshard painful lumps within the muscles.Treatment—stretch and massage muscles; replace salt bydrinking commercially available carbohydrate/electrolytereplacement fluids.Heat exhaustionHeat exhaustion occurs when the body can no longerkeep blood flowing to supply vital organs and send bloodto the skin to reduce body temperature at the same time.Signs and symptoms of heat exhaustion include• weakness• difficulty continuing work• headache• breathlessness• nausea or vomiting• feeling faint or actually fainting.Workers fainting from heat exhaustion while operatingmachinery, vehicles, or equipment can injure themselvesand others. Here’s one example from an injury descriptionfiled with the Workplace Safety and Insurance Board:High temperature and humidity in the building contributedto employee collapsing. When he fell, his head struck theconcrete floor, causing him to receive stitches above theright eye.

Treatment—heat exhaustion casualties respond quickly toprompt first aid. If not treated promptly, however, heatexhaustion can lead to heat stroke—a medicalemergency.

HEAT STRESS

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• Call 911.• Help the casualty to cool off by

• resting in a cool place• drinking cool water• removing unnecessary clothing• loosening clothing• showering or sponging with cool water.

It takes 30 minutes at least to cool the body down once aworker becomes overheated and suffers heat exhaustion.Heat strokeHeat stroke occurs when the body can no longer coolitself and body temperature rises to critical levels.WARNING: Heat stroke requires immediate medicalattention.The following case is taken from a coroner’s report.On June 17, 1994, a rodworker was part of a crewinstalling rebar on a new bridge. During the lunch break,his co-workers observed him in the hot sun on thebulkhead of the bridge; the recorded temperature byEnvironment Canada for that day was 31ºC with 51%humidity. Shortly thereafter the rodworker was foundlying unconscious on the scaffold, apparently overcomeby the intense heat. He was taken to a local hospital, thentransferred to a Toronto hospital. However, despiteaggressive treatment by numerous specialists, he died.Cause of death: heat stroke.

The primary signs and symptoms of heat stroke are• confusion• irrational behaviour• loss of consciousness• convulsions• lack of sweating• hot, dry skin• abnormally high body temperature—for example, 41°C.TreatmentFor any worker showing signs or symptoms of heat stroke,• Call 911.• Provide immediate, aggressive, general cooling.

- Immerse casualty in tub of cool water or- place in cool shower or- spray with cool water from a hose.- Wrap casualty in cool, wet sheets and fan rapidly.

• Transport casualty to hospital.• Do not give anything by mouth to an unconscious

casualty.

WARNING

• Heat stroke can be fatal even after first aid isadministered. Anyone suspected of suffering fromheat stroke should not be sent home or leftunattended unless that action has been approved bya physician.

• If in doubt as to what type of heat-related disorder theworker is suffering from, call for medical assistance.

HEAT STRESS

Heat Stress DisordersCause Symptoms Treatment

Heat rashHot humid environment;plugged sweat glands. Red bumpy rash with severe itching. Change into dry clothes and avoid hot

environments. Rinse skin with cool water.

SunburnToo much exposure tothe sun.

Red, painful, or blistering and peelingskin.

If the skin blisters, seek medical aid. Use skin lotions(avoid topical anaesthetics) and work in the shade.

Heatcramps

Heavy sweating drains aperson’s body of salt,which cannot bereplaced just by drinkingwater.

Painful cramps in arms, legs or stomachwhich occur suddenly at work or later athome. Heat cramps are serious becausethey can be a warning of other moredangerous heat-induced illnesses.

Move to a cool area; loosen clothing and drink coolsalted water (1 tsp. salt per gallon of water) orcommercial fluid replacement beverage. If thecramps are severe or don't go away, seekmedical aid.

FaintingFluid loss andinadequate water intake.

Sudden fainting after at least two hoursof work; cool moist skin; weak pulse

GET MEDICAL ATTENTION. Assess need for CPR.Move to a cool area; loosen clothing; make person liedown; and if the person is conscious, offer sips of coolwater. Fainting may also be due to other illnesses.

Heatexhaustion

Fluid loss andinadequate salt andwater intake causes abody’s cooling systemto start to break down.

Heavy sweating; cool moist skin; bodytemperature over 38°C; weak pulse;normal or low blood pressure; tired andweak; nausea and vomiting; very thirsty;panting or breathing rapidly; vision maybe blurred.

GET MEDICAL AID. This condition can lead to heatstroke, which can kill. Move the person to a coolshaded area; loosen or remove excess clothing;provide cool water to drink; fan and spray with coolwater.

Heatstroke

If a person’s body hasused up all its water andsalt reserves, it will stopsweating. This cancause body temperatureto rise. Heat stroke maydevelop suddenly ormay follow from heatexhaustion.

High body temperature (over 41°C) andany one of the following: the person isweak, confused, upset or actingstrangely; has hot, dry, red skin; a fastpulse; headache or dizziness. In laterstages, a person may pass out and haveconvulsions. AN IMMEDIATE MEDICALEMERGENCY. PROMPT ACTION MAYSAVE THE CASUALTY’S LIFE.

CALL AMBULANCE. This condition can kill a personquickly. Remove excess clothing; fan and spray theperson with cool water; offer sips of cool water ifthe person is conscious.

Table courtesy of the Ontario Ministry of Labour: www.labour.gov.on.ca/english/hs/guidelines/gl_heat.html

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WHAT FACTORS ARE USED TO ASSESSHEAT STRESS RISK?Factors that should be considered in assessing heatstress include• personal risk factors• environmental factors• job factors.

Personal risk factorsIt is difficult to predict just who will be affected by heatstress and when, because individual susceptibility varies.There are, however, certain physical conditions that canreduce the body’s natural ability to withstand hightemperatures:• Weight

Workers who are overweight are less efficient atlosing heat.

• Poor physical conditionBeing physically fit aids your ability to cope with theincreased demands that heat places on your body.

• Previous heat illnessesWorkers are more sensitive to heat if they haveexperienced a previous heat-related illness.

• AgeAs the body ages, its sweat glands become lessefficient. Workers over the age of 40 may thereforehave trouble with hot environments. Acclimatization tothe heat and physical fitness can offset some age-related problems.

• Heart disease or high blood pressureIn order to pump blood to the skin and cool the body, theheart rate increases. This can cause stress on the heart.

• Recent illnessWorkers with recent illnesses involving diarrhea,vomiting, or fever have an increased risk ofdehydration and heat stress because their bodieshave lost salt and water.

• Alcohol consumptionAlcohol consumption during the previous 24 hoursleads to dehydration and increased risk of heat stress.

• MedicationCertain drugs may cause heat intolerance by reducingsweating or increasing urination. People who work ina hot environment should consult their physician orpharmacist before taking medications.

• Lack of acclimatizationWhen exposed to heat for a few days, the body willadapt and become more efficient in dealing withraised environmental temperatures. This process iscalled acclimatization. Acclimatization usually takes 6to 7 days. Benefits include- lower pulse rate and more stable blood pressure- more efficient sweating (causing better evaporativecooling)

- improved ability to maintain normal bodytemperatures.

Acclimatization may be lost in as little as three daysaway from work. People returning to work after aholiday or long weekend—and their supervisors—should understand this. Workers should be allowed togradually re-acclimatize to work conditions.

Environmental factorsEnvironmental factors such as ambient air temperature,air movement, and relative humidity can all affect anindividual’s response to heat. The body exchanges heatwith its surroundings mainly through radiation and sweatevaporation. The rate of evaporation is influenced byhumidity and air movement.Radiant HeatRadiation is the transfer of heat from hot objects through airto the body. Working around heat sources such as kilns orfurnaces will increase heat stress. Additionally, working indirect sunlight can substantially increase heat stress. Aworker is far more comfortable working at 24°C undercloudy skies than working at 24°C under sunny skies.HumidityHumidity is the amount of moisture in the air. Heat loss byevaporation is hindered by high humidity but helped bylow humidity. As humidity rises, sweat tends to evaporateless. As a result, body cooling decreases and bodytemperature increases.Air MovementAir movement affects the exchange of heat between thebody and the environment. As long as the air temperatureis less than the worker’s skin temperature, increasing airspeed can help workers stay cooler by increasing both therate of evaporation and the heat exchange between theskin surface and the surrounding air.

Job factorsClothing and Personal Protective Equipment (PPE)Heat stress can be caused or aggravated by wearing PPEsuch as fire- or chemical-retardant clothing. Coated andnon-woven materials used in protective garments blockthe evaporation of sweat and can lead to substantial heatstress. The more clothing worn or the heavier the clothing,the longer it takes evaporation to cool the skin.Remember too that darker-coloured clothing absorbsmore radiant heat than lighter-coloured clothing.

WorkloadThe body generates more heat during heavy physicalwork. For example, construction workers shoveling sandor laying brick in hot weather generate a tremendousamount of heat and are at risk of developing heat stresswithout proper precautions. Heavy physical work requires

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careful evaluation even at temperatures as low as 23°C toprevent heat disorders. This is especially true for workerswho are not acclimatized to the heat.

ARE THERE MEASURES FOREVALUATING HEAT STRESS RISK?To prevent heat stress, scientists from the World HealthOrganization (WHO) have determined that workers shouldnot be exposed to environments that would cause theirinternal body temperature to exceed 38°C. The only trueway of measuring internal body temperature is rectally(oral or inner ear measurements are not as accurate). Asan alternative, the American Conference of GovernmentalIndustrial Hygienists (ACGIH) has developed a method ofassessing heat stress risk based on a wet bulb globetemperature (WBGT) threshold (Table 2).This method of assessment involves the three maincomponents of the heat burden experienced by workers:1) thermal environment2) type of work3) type of clothing.

Thermal environmentThe first factor in assessing heat stress is the thermalenvironment as measured by WBGT index. WBGT iscalculated in degrees Celsius using a formula whichincorporates the following three environmental factors:• air temperature• radiant heat (heat transmitted to the body through the

air from hot objects such as boilers or shingles heatedby the sun)

• cooling effects of evaporation caused by airmovement (humidity).

To measure WBGT, a heat stress monitor consisting ofthree types of thermometers is required:

1) A normal thermometer called a dry bulb thermometeris used to measure air temperature.

2) Radiant heat is measured by a black bulb globethermometer. This consists of a hollow, 6-inchdiameter copper ball painted flat black and placedover the bulb of a normal thermometer.

3) A wet bulb thermometermeasures the cooling effectof evaporation caused by air movement (wind or fan).It consists of a normal thermometer wrapped in a wickkept moist at all times. As air moves through the wetwick, water evaporates and cools the thermometer inmuch the same way that sweat evaporates and coolsthe body.

Heat stress monitors currently available calculate WBGTautomatically. The equipment required and the method ofmeasuring WBGT can be found in the ACGIH bookletTLVs® and BEIs®: Threshold Limit Values…BiologicalExposure Indices. The booklet also outlines permissibleexposure limits for heat stress. Older instruments,however, require calculation by the operator.Calculation depends on whether sunlight is direct(outdoors) or not (indoors).Working outdoors in direct sunlightFor work in direct sunlight WBGT is calculated by taking70% of the wet bulb temperature, adding 20% of the blackbulb temperature, and 10% of the dry bulb temperature.WBGT (out) = [70% (0.7) x wet bulb temperature] +[20% (0.2) x black bulb globe temperature] +[10% (0.1) x dry bulb temperature]

Working indoors (no sunlight)

For work indoors or without direct sunlight, WBGT iscalculated by taking 70% of the wet bulb temperature andadding 30% of the black bulb temperature.WBGT (in)= [70% (0.7) x wet bulb temperature] +[30% (0.3) x black bulb globe temperature]

ExampleSuppose it’s a bright sunny day and a crew of roofers isworking 20 feet above ground. Our assessment yields thefollowing readings:Wet bulb temperature(cooling effects of evaporation) = 20°CBlack bulb globe temperature (radiant heat) = 36°CDry bulb temperature (air temperature) = 33°C

Using the formula for work in direct sunlight, we calculateas follows:

WBGT = (0.7 x wet bulb temperature) + (0.2 x blackbulb globe temperature) + (0.1 x dry bulb temperature)

= (0.7 x 20) + (0.2 x 36) + (0.1 x 33)= 14 + 7.2 + 3.3

WBGT (outdoors) = 24.5 °C

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Type of workThe second factor in assessing heat stress is the type ofwork being performed. Following are the four categories,with some examples of each:Light work • Using a table saw

• Some walking about• Operating a crane, truck,or other vehicle

• WeldingModerate work • Laying brick

• Walking with moderate liftingor pushing

• Hammering nails• Tying rebar• Raking asphalt• Sanding drywall

Heavy work • Carpenter sawing by hand• Shoveling dry sand• Laying block• Ripping out asbestos• Scraping asbestosfireproofing material

Very Heavy Work • Shoveling wet sand• Lifting heavy objects

Type of clothingFree movement of cool, dry air over the skin maximizesheat removal. Evaporation of sweat from the skin isusually the major method of heat removal. WBGT-basedheat exposure assessments are based on a traditionalsummer work uniform of long-sleeved shirt and longpants. With regard to clothing, the measured WBGT valuecan be adjusted according to Table 1.TABLE 1: Additions to measured WBGT values for sometypes of clothingClothing Type Addition to WBGTSummer work uniform 0Cloth (woven material) overalls +3.5Double-cloth overalls +5

Note: These additions do not apply to encapsulatingsuits, thermal-insulated clothing, or clothingimpermeable or highly resistant to water vapour orair movement. Special garments such as these, andmultiple layers of clothing, severely restrict sweatevaporation and heat removal. As a result, body heatmay produce life-threatening heat stress even whenenvironmental conditions are considered cool.

Determine work/rest schedulesThe WBGT can be used to determine work/rest schedulesfor personnel under various conditions. Knowing that theWBGT is 24.5°C in the example above, you can refer toTable 2 and determine that workers accustomed to theheat (“acclimatized”), wearing summer clothes, and doing“heavy” work can perform continuous work (100% work).Suppose work is being performed indoors at a pulp andpaper mill under the following conditions:• Workers are wearing cloth coveralls.• Boilers are operational.

• Work load is moderate.• General ventilation is present.

Our assessment yields the following readings:Wet bulb temperature(cooling effects of evaporation) = 23°CBlack bulb globe temperature (radiant heat) = 37°CDry bulb temperature (air temperature) = 34°C

Using the formula for work indoors, we calculate asfollows:WBGT = (0.7 x wet bulb temperature)+ (0.3 x black bulb globe temperature)= (0.7 x 23) + (0.3 x 37) = 27.2°CAddition for cloth overalls(Table 1) = 3.5WBGT (indoors) = 30.7°C

Referring to Table 2, we determine that workersaccustomed to the heat (acclimatized), wearing clothoveralls, and performing “moderate” work can work 15minutes per hour (25% work; 75% rest).The WBGT must never be used as an indicator of safe orunsafe conditions. It is only an aid in recognizing heatstress. The ultimate assessment and determination ofheat stress must lie with the individual worker or co-worker trained to detect its symptoms. Supervisors mustallow individual workers to determine if they are capableof working in heat.Table 2 is intended for use as a screening step only.Detailed methods of analysis are fully described in varioustechnical and reference works. Contact CSAO for furtherinformation.TABLE 2: Screening Criteria for Heat Stress Exposureusing WBGT(Values are WBGTs in °C. These are NOT air temperatures.)

Acclimatized UnacclimatizedWork Very VeryDemands Light Moderate Heavy Heavy Light Moderate Heavy Heavy100% Work 29.5 27.5 26 27.5 25 22.575% Work; 30.5 28.5 27.5 29 26.5 24.525% Rest50% Work; 31.5 29.5 28.5 27.5 30 28 26.5 2550% Rest25% Work; 32.5 31 30 29.5 31 29 28 26.575% Rest

Notes• WBGT values are expressed in °C. WBGT is NOT air

temperature.• WBGT-based heat exposure assessments are based

on a traditional summer work uniform of long-sleevedshirt and long pants.

• If work and rest environments are different, hourlytime-weighted averages (TWA) should be calculatedand used. TWAs for work rates should also be usedwhen the demands of work vary within the hour.

• Because of the physiological strain produced by veryheavy work among less fit workers, the table does notprovide WBGT values for very heavy work in thecategories 100% Work and 75% Work; 25% Rest.

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Use of the WBGT is not recommended in these cases.Detailed and/or physiological monitoring should be usedinstead.

• Consult the latest issue of TLVs® and BEIs®: ThresholdLimit Values® and Biological Exposure Indices®,published by the American Conference of GovernmentalIndustrial Hygienists, for guidance on how to properlymeasure, interpret, and apply the WBGT.

Because of the variable and transient nature of constructionsites it may not be practical to measure the WBGT. It’stherefore reasonable to ask if there are other ways toevaluate heat stress risk.

IS IT POSSIBLE TO USE THE HUMIDEXTO EVALUATE HEAT STRESS RISK?The humidex is a measure of discomfort based on thecombined effect of excessive humidity and hightemperature. As noted already, heat-related disordersinvolve more than air temperature and humidity. Otherfactors—air movement, workload, radiant heat sources,acclimatization—must also be considered in assessingheat stress. But humidex readings can signal the need toimplement procedures for controlling heat stress in theworkplace.Environment Canada provides the following humidexguidelines.• Where humidex levels are less than 29°C, most

people are comfortable.• Where humidex levels range from 30°C to 39°C,

people experience some discomfort.• Where humidex levels range from 40°C to 45°C,

people are uncomfortable.• Where humidex levels are over 45°C, many types of

labour must be restricted.

In the hazard alert Heat Stress and Heat Stroke in OutdoorWork, the Ontario Ministry of Labour recommends using theWBGT to evaluate heat stress. However, the humidex canbe permissible instead if equivalency is demonstrated.In the absence of any heat-related incidents, a Ministry ofLabour inspector is not likely to issue orders against anyemployer with a comprehensive heat stress program basedon the humidex.If the humidex rather than the WBGT is being used tomonitor conditions, the employer should have• documentation describing the heat stress policy• training that emphasizes recognition of heat stress

symptoms• thorough investigation of any heat stress incidents to

determine whether the heat stress policy is deficient.

Because humidex readings can vary substantially from pointto point it is important that a reading be taken at the actualworkplace.See the Appendix for a five-step approach for using thehumidex.

HOWCAN HEAT STRESS BE CONTROLLED?Heat stress can be controlled through education,engineering, and work procedures. Controls will

• Protect healthIllness can be prevented or treated while symptomsare still mild.

• Improve safetyWorkers are less liable to develop a heat-relatedillness and have an accident. Heat stress often creepsup without warning. Many heat-induced accidents arecaused by sudden loss of consciousness.

• Increase productivityWorkers feel more comfortable and are likely to bemore productive as a result.

Training and educationAccording to the U.S. National Institute of OccupationalSafety and Health (NIOSH), heat stress training shouldcover the following components:• knowledge of heat stress hazards• recognition of risk factors, danger signs, and symptoms• awareness of first-aid procedures for, and potential

health effects of, heat stroke• employee responsibilities in avoiding heat stress• dangers of using alcohol and/or drugs (including

prescription drugs) in hot work environments.

Engineering controlsEngineering controls are the most effective means ofpreventing heat stress disorders and should be the firstmethod of control. Engineering controls seek to provide amore comfortable workplace by using• reflective shields to reduce radiant heat• fans and other means to increase airflow in work areas• mechanical devices to reduce the amount of physical

work.

Given the constantly changing nature of constructionsites, engineering controls are not usually feasible. Properwork procedures are therefore required to prevent heatstress disorders.

Work proceduresThe risks of working in hot construction environments canbe diminished if labour and management cooperate tohelp control heat stress.Management• Give workers frequent breaks in a cool area away

from heat. The area should not be so cool that itcauses cold shock—around 25°C is ideal.

• Increase air movement by using fans where possible.This encourages body cooling through theevaporation of sweat.

• Provide unlimited amounts of cool (not cold) drinkingwater conveniently located.

• Allow sufficient time for workers to become acclimatized.A properly designed and applied acclimatization programdecreases the risk of heat-related illnesses. Such aprogram exposes employees to work in a hotenvironment for progressively longer periods. NIOSHrecommends that for workers who have had previousexperience in hot jobs, the regimen should be- 50% exposure on day one- 60% on day two

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- 80% on day three- 100% on day four.For new workers in a hot environment, the regimenshould be 20% on day one, with a 20% increase inexposure each additional day.

• Make allowances for workers who must wearpersonal protective clothing and equipment thatretains heat and restricts the evaporation of sweat.

• Schedule hot jobs for the cooler part of the day;schedule routine maintenance and repair work in hotareas for the cooler seasons of the year.

• Consider the use of cooling vests containing icepacks or ice water to help rid bodies of excess heat.

Labour• Wear light, loose clothing that permits the evaporation

of sweat.• Drink small amounts of water—8 ounces (250 ml)—

every half hour or so. Don’t wait until you’re thirsty.• Avoid beverages such as tea, coffee, or beer that

make you pass urine more frequently.• Where personal PPE must be worn,

- use the lightest weight clothing and respiratorsavailable- wear light-colored garments that absorb less heat fromthe sun- use PPE that allows sweat to evaporate.

• Avoid eating hot, heavy meals. They tend to increaseinternal body temperature by redirecting blood flowaway from the skin to the digestive system.

• Don’t take salt tablets unless a physician prescribesthem. Natural body salts lost through sweating areeasily replaced by a normal diet.

WHAT ARE THE RESPONSIBILITIES OFWORKPLACE PARTIES REGARDINGHEAT STRESS?EmployersThe Occupational Health and Safety Act and its regulationsdo not specifically cover worker exposure to heat. However,under the Occupational Health and Safety Act employershave a general obligation to protect workers exposed to hotenvironments. Employers should develop a written healthand safety policy outlining how workers in hot environmentswill be protected from heat stress. As a minimum, thefollowing points should be addressed.• Adjust work practices as necessary when workers

complain of heat stress.• Make controlling exposures through engineering controls

the primary means of control wherever possible.• Oversee heat stress training and acclimatization for new

workers, workers who have been off the job for a while,and workers with medical conditions.

• Provide worker education and training, including periodicsafety talks on heat stress during hot weather or duringwork in hot environments.

• Monitor the workplace to determine when hot conditionsarise.

• Determine whether workers are drinking enough water.• Determine a proper work/rest regime for workers.• Arrange first-aid training for workers.

When working in a manufacturing plant, for instance, acontractor may wish to adopt the plant’s heat stressprogram if one exists.

Workers• Follow instructions and training for controlling heat

stress.• Be alert to symptoms in yourself and others.• Avoid consumption of alcohol, illegal drugs, and

excessive caffeine.• Find out whether any prescription medications you’re

required to take can increase heat stress.• Get adequate rest and sleep.• Drink small amounts of water regularly to maintain fluid

levels and avoid dehydration.

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APPENDIXASSESSING HEAT STRESS HAZARDSUSING THE HUMIDEXWBGT is the most common and useful index for settingheat stress limits, especially when sources of radiant heatare present. It has proven to be adequate when used aspart of a program to prevent adverse health effects inmost hot environments.However, taking WBGT measurements properly is quitecomplicated.This section provides a simplified version of the WBGT byconverting the WBGT into humidex. The method wasdeveloped by the Occupational Health Clinics for OntarioWorkers, Inc. It allows workplace parties to measure heatstress using only workplace temperature and humidity. Thefollowing five steps are designed to help workplacesdetermine whether conditions require action to reduce heatstress.

Step 1: Clothing• The humidex plan assumes workers are wearing

regular summer clothes (light shirt and pants,underwear, and socks and shoes).

• If workers wear cotton overalls on top of summerclothes, add 5°C humidex to the workplace humidexmeasurement.

• Estimate correction factor for other kinds of clothing bycomparing them with cotton overalls (e.g., gloves, hardhat, apron, and protective sleeves might be equivalentto a little less than half the evaporation resistance ofoveralls, so add 1°C or 2°C humidex).

Step 2: Training• Measurements by themselves cannot guarantee

workers protection from heat stress. It is essential thatworkers learn to recognize the early signs andsymptoms of heat stress and know how to preventthem.

• If it’s possible, workers need to be able to alter theirpace of work, take rest breaks, and drink in response toearly symptoms (a cup of water every 20 minutes). Theideal heat stress response plan would let workersregulate their own pace by “listening to their body.”

Step 3: Select a measurement location• Divide the workplace into zones which have similar heat

exposures.• Select a representative location in each zone where you

can take measurements. Note: the Humidex HeatStress Response (Table B) is based on workplacemeasurements, not weather station/media reports(temperatures inside buildings do not necessarilycorrespond with outside temperatures).

Step 4: Measure workplace humidex• A thermal hygrometer (usually $20–$60 at hardware or

office supply stores) is a simple way to measure thetemperature and relative humidity in your workplace.Avoid placing the thermal hygrometer in direct sunlightor in contact with a hot surface. Once you have thetemperature and humidity, use Table A (or the humidex

calculator located at:http://www.ohcow.on.ca/menuweb/heat_stress_calculator.htm)to determine the corresponding humidex value.

• From Table B select Humidex 1 or Humidex 2 accordingto the amount of physical activity involved with the workand the level of acclimatization. This helps youdetermine what steps should be taken to reduce theheat stress. Humidex 1 is for moderate unacclimatizedand heavy acclimatized work; Humidex 2 is for lightunacclimatized work (sitting/standing doing light armwork).

Step 5: Adjust for radiant heat• For outdoor work in direct sunlight between the hours of

10 am and 5 pm, add 1–2°C (pro-rate according topercentage cloud cover) to your humidex measurement.

• For indoor radiant heat exposures (such as boilers orfurnaces), use common sense to judge whether theexposure involves more or less radiant heat than directsunlight and adjust the 1–2°C correction factorappropriately.

See Table A and Table B on the followingpages.

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HEAT STRESS

Table A: Humidex Table

Humidex 1(moderate unacclimatizedand heavy acclimatized

work)

ResponseNever ignore someone’s symptoms no matter

what you measure!

Humidex 2light unacclimatized work (sitting/standing

doing light arm work)

30-37 Low• Alert workers to potential for heat stress.• Ensure access to water.

34-41

38-39 Medium• Reduce physical activity (e.g., slower pace,double up, breaks).

• Drink a cup of water every 20-30 minutes.

42-43

40-42 Moderate• Reduce physical activity further.• Drink a cup of water every 15-20 minutes.

44-45

43-44 High• Ensure sufficient rest and recovery time.Severely curtail physical activity.

• Drink a cup of water every 10-15 minutes.

46-48

45or over

Extreme• It is hazardous to continue physical activity.

49or over

Table B: Response

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12 – 1

12 COLD STRESS

Contents- Core temperature- Wind chill- Hypothermia- Frostbite- Risk factors- Controls- Exposure limits

Cold stress or hypothermia can affect constructionworkers who are not protected against cold. The cold mayresult naturally from weather conditions or be createdartificially, as in refrigerated environments.Cold is a physical hazard in many constructionworkplaces. When the body is unable to warm itself,serious cold-related illnesses and injuries may occur,leading to permanent tissue damage and even death.Construction workplaces exposed to cold, wet, and/orwindy conditions include- roofs- open or unheated cabs- bridges or other projects near large bodies of water- large steel structures that retain cold or are exposedto cold

- high buildings open to the wind- refrigerated rooms, vessels, and containers.

This section provides information on- effects of overexposure to cold- factors that can worsen these effects- control measures.

Knowing this information can help construction workersavoid hypothermia and frostbite.

CORE TEMPERATUREThe body tries to maintain an internal (core) temperatureof approximately 37°C (98.6°F). This is done by reducingheat loss and increasing heat production.Under cold conditions, blood vessels in skin, arms, andlegs constrict, decreasing blood flow to extremities. Thisminimizes cooling of the blood and keeps critical internalorgans warm. At very low temperatures, however,reducing blood flow to the extremities can result in lowerskin temperature and higher risk of frostbite.

WIND CHILLWind chill involves the combined effect of air temperatureand air movement. The wind-chill cooling rate is defined

as heat loss (expressed in watts per metre squared)resulting from the effects of air temperature and windvelocity upon exposed skin.The higher the wind speed and the lower the temperaturein the work environment, the greater the insulation valueof the protective clothing required.Chart 1 provides equivalents between air temperatureswith and without wind. For example, -12.2°C with a windof 48 km/h is equivalent to -45°C with no wind. When airspeed and temperature produce an equivalent chilltemperature of -32°C (-25.6°F), continuous skin exposureshould not be permitted. Unprotected skin will freeze onlyat temperatures below -1°C (30.2°F), regardless of windspeed.When weather information is not available, the followingsigns may help to estimate wind speeds in the field:- 8 km/h (5 mph) light flag just moves- 16 km/h (10 mph) light flag is fully extended by thewind

- 24 km/h (15 mph) raises a newspaper sheet offthe ground

- 32 km/h (20 mph) wind capable of blowing snow.

COLD STRESS

Chart 1: Equivalent chill temperaturesAdapted from TLVs® and BEIs®: Threshold LimitValues® for Chemical Substances and Physical Agentsand Biological Exposure Indices®, American Conferenceof Governmental Industrial Hygienists, 1999.

12 – 2

Exposure to cold causes two major health problems:frostbite and hypothermia.

HYPOTHERMIA—signs and symptomsWhen the body can no longer maintain core temperatureby constricting blood vessels, it shivers to increase heatproduction. Maximum severe shivering develops when thebody temperature has fallen to 35°C (95°F).The most critical aspect of hypothermia is the body’sfailure to maintain its deep core temperature. Lower bodytemperatures present the following signs and symptoms:

- persistent shivering—usually starts when coretemperature reaches 35°C (95°F)

- irrational or confused behaviour- reduced mental alertness- poor coordination, with obvious effects on safety- reduction in rational decision-making.

In addition, acute exertion in cold can constrict bloodvessels in the heart. This is particularly important for olderworkers or workers with coronary disease who may havean increased risk of heart attack.

HYPOTHERMIA—stagesMildEarly signs of hypothermia include- shivering- blue lips and fingers- poor coordination.

ModerateThe next stage includes- mental impairment- confusion- poor decision-making- disorientation- inability to take precautions from the cold- heart slowdown- slow breathing.

SevereIn severe cases, hypothermia resembles death. Patientsmust be treated as though they are alive.Symptoms of severe hypothermia include- unconsciousness- heart slowdown to the point where pulse isirregular or difficult to find

- no shivering- no detectable breathing.

HYPOTHERMIA—first aidStop further cooling of the body and provide heat to beginrewarming.- Carefully remove casualty to shelter. Suddenmovement or rough handling can upset heart rhythm.

- Keep casualty awake.- Remove wet clothing and wrap casualty in warmcovers.

- Rewarm neck, chest, abdomen, and groin—but notextremities.

- Apply direct body heat or use safe heating devices.- Give warm, sweet drinks, but only if casualty isconscious.

- Monitor breathing. Administer artificial respiration ifnecessary.

- Call for medical help or transport casualty carefullyto nearest medical facility.

FROSTBITE—signs and symptomsFrostbite is a common injury caused by exposure tosevere cold or by contact with extremely cold objects.Frostbite occurs more readily from touching cold metalobjects than from exposure to cold air. That’s becauseheat is rapidly transferred from skin to metal.The body parts most commonly affected by frostbite areface, ears, fingers, and toes. When tissue freezes, bloodvessels are damaged. This reduces blood flow and maycause gangrene.Frostbite symptoms vary, are not always painful, but ofteninclude a sharp, prickling sensation.The first indication of frostbite is skin that looks waxy andfeels numb. Once tissues become hard, the case is asevere medical emergency. Severe frostbite results inblistering that usually takes about ten days to subside.Once damaged, tissues will always be more susceptibleto frostbite in future.

FROSTBITE—first aid- Warm frostbitten area gradually with body heat.Do not rub.

- Don’t thaw hands or feet unless medical aid isdistant and there is no chance of refreezing. Partsare better thawed at a hospital.

- Apply sterile dressings to blisters to preventbreaking. Get medical attention.

RISK FACTORSVarious medical conditions can increase the risk of coldinjury:- heart disease

COLD STRESS

12 – 3

- asthma/bronchitis- diabetes- vibration/white finger disease.

Check with your health practitioner to learn whethermedications you are taking may have adverse effects in acold environment.

CONTROLSThe best protection against cold-related health risks is tobe aware and be prepared. Workers should recognize thesigns and symptoms of overexposure in themselves andothers. Pain in the extremities may be the first warningsign. Any worker shivering severely should come in out ofthe cold.

General- Ensure that the wind-chill factor is understood byworkers, especially those working on bridges or outin the open on high buildings.

- Ensure that workers are medically fit to work inexcessive cold, especially those subject to the riskfactors highlighted in the previous section.

- Make sure that workers understand the importanceof high-caloric foods when working in the cold. Warmsweet drinks and soups should be arranged at thework site to maintain caloric intake and fluid volume.Coffee should be discouraged because it increaseswater loss and blood flow to extremities.

- Personnel working in isolated cold environments,whether indoors or outdoors, should have backup.

- Provide hot drinks and regular breaks underextremely cold working conditions.

ClothingSelect protective clothing to suit the cold, the job, and thelevel of physical activity.- Wear several layers of clothing rather than one thicklayer. The air captured between layers is an insulator.

- Wear synthetic fabrics such as polypropylene nextto the skin because these wick away sweat.Clothing should not restrict flexibility.

- If conditions are wet as well as cold, ensure thatthe outer clothing worn is waterproof or at leastwater-repellent. Wind-resistant fabrics may also berequired under some conditions.

- At air temperatures of 2°C (35.6°F) or less,workers whose clothing gets wet for any reason mustbe immediately given a change of clothing and betreated for hypothermia.

- Encourage the use of hats and hoods to preventheat loss from the head and to protect ears.Balaclavas or other face covers may also benecessary under certain conditions.

- Tight-fitting footwear restricts blood flow. Footwearshould be large enough to allow wearing either one

thick or two thin pairs of socks. Wearing too manysocks can tighten the fit of footwear and harm ratherthan help.

- Workers who get hot while working should opentheir jackets but keep hats and gloves on.

ShelterFor work performed continuously in the cold, allow restand warm-up breaks (see table on the next page). Heatedshelters such as trailers should be available nearby.Encourage workers to use these shelters at regularintervals depending on the wind-chill factor.Workers showing signs of shivering, frostbite, fatigue,drowsiness, irritability, or euphoria should immediatelyreturn to the shelter.Workers entering the shelter should remove their outerlayer of clothing and loosen other clothing to let sweatevaporate. In some cases, a change of clothing may benecessary.

TrainingBefore working in extreme cold, workers should beinstructed in safety and health procedures.Training should cover- proper clothing and equipment- safe work practices- guidelines for eating and drinking- risk factors that increase the health effects of coldexposure

COLD STRESS

Hand ProtectionManual dexterity is essential to safety and production.- Fine work performed with bare hands for more

than 10-20 minutes in an environment below16°C (60.8°F) requires special measures to keepworkers’ hands warm. These measures may includewarm air jets, radiant heaters (fuel burning orelectric), or contact warm plates.

- Metal handles of tools and control bars should becovered by thermal insulating material fortemperatures below -1°C (30.2°F).

- Workers should wear gloves where fine manualdexterity is not required and the air temperaturefalls below 16°C (60.8°F) for sedentary, 4°C(39.2°F) for light, and -7°C (19.4°F) for moderatework.

- To prevent contact frostbite, workers should wearinsulated gloves when surfaces within reach(especially metallic surfaces) are colder than -7°C(19.4°F). Warn workers to avoid skin contact withthese surfaces.

- Tools and machine controls to be used in coldconditions should be designed for operation bygloved hands.

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- how to recognize signs and symptoms of frostbite- how to recognize signs and symptoms ofhypothermia

- appropriate first aid treatment, including rewarmingprocedures.

EXPOSURE LIMITSOntario has no legislated exposure limits for work in coldenvironments. The table below was developed by theSaskatchewan Department of Labour and adopted by theAmerican Conference of Governmental IndustrialHygienists (ACGIH). It indicates Threshold Limit Valuesfor properly clothed personnel working at temperaturesbelow freezing.

COLD STRESS

Air temperature(sunny sky)

No noticeablewind

8 km/h wind(5 mph)

16km/h wind(10 mph)

24 km/h wind(15mph)

32 km/h wind(20 mph)

°C(approx.)

°F(approx.)

Maxworkperiod

No.of

breaks

Maxworkperiod

No.of

breaks

Maxworkperiod

No.of

breaks

Maxworkperiod

No.of

breaks

Maxworkperiod

No.of

breaks

-26° to-28°

-15° to-19°

Normalbreaks

1 Normalbreaks

1 75minutes

2 55minutes

3 40minutes

4

-29° to-30°

-20° to-24°

Normalbreaks

1 75minutes

2 55minutes

3 40minutes

4 30minutes

5

-32° to-34°

-25° to-29°

75minutes

2 55minutes

3 40minutes

4 30minutes

5 Non-emergencywork should

stop-35° to-37°

-30° to-34°

55minutes

3 40minutes

4 30minutes


stop-38° to-39°

-35° to-39°

40minutes

4 30minutes


stop-40° to-42°

-40° to-44°

30minutes


stop-43° andbelow

-45° andbelow

Non-emergencywork should

stop

Work/Warm-up Schedule for a Four-Hour Shift

a) This table applies to any 4-hour work period of moderate-to-heavy work with warm-up periods of ten minutesin a warm location and with an extended break (e.g., lunch) at the end of the 4-hour work period in a warmlocation. For light-to-moderate work (limited physical movement) apply the schedule one step lower. For example,at -35°C (-30°F) with no noticeable wind (row 4), a worker at a job with little physical movement should have amaximum work period of 40 minutes with 4 breaks in a 4-hour period (row 5).

b) Here is a rough guideline for using the chart if only the wind-chill cooling rate is available: 1) initiate specialwarm-up breaks at a wind chill cooling rate of about 1750 W/m2; 2) cease all non-emergency work at or before awind chill of 2250 W/m2. In general, the warm-up schedule slightly undercompensates for the wind at the warmertemperatures, assuming acclimatization and clothing appropriate for winter work. On the other hand, the chartslightly overcompensates for the actual temperatures in the colder ranges because windy conditions rarelyprevail at extremely low temperatures.

c) The chart applies only to workers in dry clothing.

Source: Occupational Health and Safety Division, Saskatchewan Department of Labour

Notes

13 – 1

13 MOULDSMore and more construction firms are involved inremoving toxic moulds from contaminated buildings. Thissection explains• what moulds are• where they are found• why they are of concern• what health effects they may cause• how they can be identified• how they can be safely removed.

This section also covers the obligations of employers andothers under Ontario’s Occupational Health and SafetyAct.

What are moulds?Moulds are microorganisms that produce thousands oftiny particles called spores as part of their reproductivecycle. Mould colonies are usually visible as colourful,woolly growths. They can be virtually any colour – red,blue, brown, green, white, or black. When disturbed by airmovement or handling, moulds release their spores intothe air. Given the right environmental conditions, thesespores can go on to form other mould colonies.Where are moulds found?Moulds can be found almost anywhere outdoors andindoors. Indoor moulds usually originate from outsidesources such as soil and vegetation. Moulds love dark,moist environments and can grow at room temperature onvarious construction materials including wallpaper,particleboard, ceiling tiles, drywall, and plywood.Construction workers can be exposed to toxic sporeswhen working on buildings with some sort of waterdamage from flooding, plumbing leaks, or leaks in thestructure itself.Why are moulds of concern?In buildings with water damage or ongoing moistureproblems, certain types of “water-loving” moulds mayreproduce to higher than normal levels and potentiallycause adverse health effects. Stachybotrys chartarum(formerly known as Stachybotrys atra) is of particularconcern because it can be found in large colonies andcan cause adverse health effects.Stachybotrys has gained special attention because it hasbeen discovered in portable classrooms with ongoingmoisture problems. It appears as small black patches andgrows well on water-soaked cellulose material such aswallpaper, ceiling tiles, drywall, and insulation containingpaper.In addition to Stachybotrys, construction personnelworking in water-damaged buildings may be exposed toother types of toxic moulds such as Fusarium, Aspergillus,and Penicillium.What health effects can moulds cause?Air movement and the handling of contaminated materialcan release toxic spores into the atmosphere. Thesespores cause adverse health effects by producing toxicsubstances known as mycotoxins. Once released, toxicspores must come into contact with the skin or be inhaled

before symptoms can develop. Not all exposedconstruction workers will develop symptoms.• Exposure to toxic moulds may irritate skin, eyes,

nose, and throat, resulting in allergy-like symptomssuch as difficulty in breathing, runny nose, and wateryeyes.

• Other symptoms such as fatigue and headache havealso been reported.

• Workers who are allergic to moulds could experienceasthmatic attacks.

• Workers exposed to Stachybotrys have alsoexperienced burning in the nose, nose bleeds, severecoughing, and impairment of the immune system.Stachybotrys does not cause infection and is notspread from person to person.

• People with weakened immune systems areparticularly susceptible to mould-related illness andshould not work in mould-contaminated areas.

How are moulds identified?Owners of buildings that may be mould-contaminatedshould conduct, at their own expense, an assessment todetermine whether or not the buildings are indeedcontaminated. The assessment should include buildinginspection and analysis of bulk samples.Mould on visible surfaces may be just the tip of theiceberg. Since they thrive in dark, moist environments,moulds may be hidden from view. Thorough inspections ofwater-damaged areas must be conducted. This involveslooking into wall cavities, behind drywall, under carpets,and above ceiling tiles.Not all mounds are toxic. The type of mould identified andthe extent of the contamination will determine theprecautions to be taken.Bulk sampling and laboratory analysis are used todocument the type of mould growing on surfaces. Theprocedure involves scraping surface material into asealable plastic bag and sending it by overnight deliveryto an accredited laboratory.An accredited laboratory is one that participates in theAmerican Industrial Hygiene Association's EnvironmentalMicrobiology Proficiency Analytical Testing Program. Thechosen laboratory should have a competent mycologist (aperson that studies moulds) who can analyze the sampleand determine whether the mould is likely to pose ahealth risk.Based on the presence of visible mould, evidence ofwater damage, and symptoms that are consistent withallergic or toxic response to mould, it may be justified toskip bulk sampling and go straight to remediation(removal).The person taking bulk samples or performing inspectionsmust be suitably protected for Level 1 work (see chart onthe next page) and must be careful not to unduly disturbthe mould.How can moulds be safely removed?Toxic moulds must be removed. However, special controlmeasures must first be implemented to prevent workerexposure and the spread of moulds from the constructionarea to adjacent areas. This is especially true for

MOULDS

13 – 2

MOULDS

13 – 3

Stachybotrys because of its potentially severe health effects.The extent of contamination governs what remediationmeasures need to be taken in order to prevent the spread oftoxic moulds.Note: The cause of moisture problems should be correctedbefore any mould remediation takes place.A follow-up inspection should be conducted 3–6 monthsafter remediation to ensure that the mould has not returned.Obligations under the ActAlthough there are no Ontario regulations specificallyaddressing moulds, an employer must, under theOccupational Health and Safety Act, take everyprecaution reasonable in the circumtances for theprotection of a worker. Work practices set out by HealthCanada in Fungal Contamination of Public Buildings: AGuide to Recognition and Management provide areasonable standard.Employers have a duty to instruct workers in the saferemoval and handling of mould-contaminated material.Workers in turn have the duty to follow these instructions.Building owners must ensure that trade contractors followproper remediation procedures.

The chart on the opposite page summarizes mould controlprocedures recommended by the Environmental ProtectionAgency in the United States.For various kinds of material, the chart indicates how mouldgrowth can be prevented within 24–48 hours of waterdamage and also provides general advice on remediation.This information is intended only as a summary of basicprocedures and is not intended, nor should it be used, as adetailed guide to mould remediation.Although the chart may look complicated, it becomes clearand useful when taken one step, or one ring, at a time.1) Start at the centre.2) In the first ring, identify the material you are

concerned about.3) In the next ring, find out what actions to take within the

first 24-48 hours of CLEAN water damage. Actions arenumbered 1, 2, 3, 4 and so on. Each is spelled outunder the Action within 24–48 hrs column at right.

4) Proceed to the next ring if mould growth is apparentand more than 48 hours have elapsed since waterdamage. Determine whether the contaminated area isless than 10 square feet, between 10 and 100 squarefeet, or greater than 100 square feet.

5) Proceed to the next ring and follow the clean-upmethod indicated for the size of the contaminatedarea. Methods are lettered A, B, C, and D. Each isspelled out under the Clean-up Methods column.

6) In the next ring, determine the level of personalprotective equipment required. This is indicated by M,L, or F under the PPE column.

7) Finally, in the outermost ring, determine whethercontainment is necessary and, if so, whether it mustbe L (limited) or F (full). These requirements areexplained in the Containment column.

Action within 24–48 hrsActions are for damage caused by clean water. If youknow or suspect that water is contaminated by sewage orchemical or biological pollutants, consult a professional.Do not use fans unless the water is clean or sanitary. Ifmould has grown or materials have been wet for morethan 48 hours, consult Clean-up Method in the chart.1. Discard non-valuable items.2. Photocopy valuable items, then discard.3. Freeze (in frost-free freezer or meat locker) orfreeze-dry.

4. Remove water with water-extraction vacuum.5. Reduce humidity levels with dehumidifiers.6. Accelerate drying process with fans and/or heaters.• Don’t use heat to dry carpet.• Use caution applying heat to hardwood floors.

7. Discard and replace.8. May be dried in place, if there is no swelling and theseams are intact. If not, then discard and replace.

9. Ventilate wall cavity.10. For all treated or finished woods, porous (linoleum,

ceramic tile, vinyl) and non-porous (metal, plastic)hard surfaces, vacuum or damp-wipe with water orwater and mild detergent and allow to dry; scrub ifnecessary.

11. For porous flooring and carpets, make sure thatsubfloor is dry. If necessary clean and dry subfloormaterial according to chart.

12. Wet paneling should be pried away from walls fordrying.

MOULDS

Mould remediation chart

13 – 4

Clean-up MethodsMethods are for damage caused by clean water. If youknow or suspect that water is contaminated by sewage orchemical or biological pollutants, consult a professional.These are guidelines only. Other cleaning methods maybe preferred by some professionals. Consult Actionwithin 24–48 hrs in the chart if materials have been wetfor less than 48 hours and mould growth is not apparent.If mould growth is not addressed promptly, some itemsmay be damaged beyond repair. If necessary, consulta restoration specialist.A. Wet-vacuum the material. (In porous material, some

mould spores/fragments will remain but will not grow ifmaterial is completely dried.) Steam cleaning may bean alternative for carpets and some upholsteredfurniture.

B. Damp-wipe surfaces with water or with water anddetergent solution (except wood – use wood floorcleaner); scrub as needed.

C. Use a high-efficiency particulate air (HEPA) vacuumonce the material has been thoroughly dried. Disposeof HEPA-vacuum contents in well-sealed plastic bags.

D. Remove water-damaged materials and seal in plasticbags inside containment area, if there is one.Dispose of as normal waste. HEPA-vacuum areaonce it is dried.

PPE (Personal Protective Equipment)Use professional judgment to determine PPE for eachsituation, particularly as the size of the remediation siteand the potential for exposure and health effects increase.Be prepared to raise PPE requirements if contamination ismore extensive than expected.M Minimum – Gloves, N-95 respirator, goggles/eye

protection.L Limited – Gloves, N-95 respirator or half-face

respirator with HEPA filter, disposable overalls,goggles/eye protection.

F Full – Gloves, disposable full-body clothing, headgear, foot coverings, full-face respirator withHEPA filter.

ContainmentUse professional judgment to determine containment foreach situation, particularly as the size of the remediationsite, and the potential for exposure and health effects,increase.NR None RequiredL Limited – From floor to ceiling, enclose affected area

in polyethylene sheeting with slit entry and coveringflap. Maintain area under negative pressure withHEPA-filtered fan. Block supply and return air ventsin containment area.

F Full – Use two layers of fire-retardant polyethylenesheeting with one airlock chamber. Maintain areaunder negative pressure with HEPA-filtered fanexhausted outside of building. Block supply andreturn air vents in containment area.

Endnotesa) Upholstery may be difficult to dry within 48 hours. For

items with monetary or sentimental value, consult arestoration specialist.

b) Follow manufacturer’s laundering instructions.

MOULDS

Equipment,Techniques,and Hazards

14 – 1

14 PERSONAL PROTECTIVEEQUIPMENT

INTRODUCTIONPersonal protective equipment (PPE) is something allconstruction workers have in common.PPE is designed to protect against safety and/or healthhazards. Hard hats, safety glasses, and safety boots, forinstance, are designed to prevent or reduce the severityof injury if an accident occurs.Other PPE, such as hearing and respiratory protection, isdesigned to prevent illnesses and unwanted healtheffects.It is important to remember that PPE only providesprotection. It reduces the risk but does not eliminate thehazard.This manual’s chapters on particular kinds of PPE willenable users to• assess hazards and select a suitable control method• locate and interpret legislation related to PPE• effectively use and maintain PPE.

Legal RequirementsWhile common to all trades, PPE varies according toindividual, job, and site conditions.Legal requirements for personal protective equipment alsovary and the appropriate sections of the constructionregulation (O. Reg. 213/91) under the OccupationalHealth and Safety Act should be consulted.The Occupational Health and Safety Act makes employersand supervisors responsible for ensuring that required PPEis worn. This does not mean that the employer must providePPE but only ensure that it is provided by someone.Workers, meanwhile, have a duty under the Act to wear oruse PPE required by the employer. This addressessituations where the regulations may not require PPE butthe employer has set additional health and safetystandards, such as mandatory eye protection.The construction regulation (O. Reg. 213/91) broadlyrequires that such protective clothing, equipment, ordevices be worn “as are necessary to protect the workeragainst the hazards to which the worker may beexposed.” It also requires that the worker be trained in theuse and care of this equipment.

Control StrategiesPersonal protective equipment should be the last resort indefence. Better alternatives lie in engineering controls thateliminate as much of the risk as possible. Engineeringcontrols fall into five categories:• substitution• alternative work methods• isolation• enclosure• ventilation.

SubstitutionThis control substitutes a less toxic chemical that can dothe same job. A common example is the substitution ofcalcium silicate or fibreglass insulation for asbestosinsulation. Substitution is an effective control as long asthe substitute is less hazardous.Alternative Work MethodsThis simply means doing the job in a way which is lesshazardous. For example, brushing or rolling paintproduces much lower vapour levels than spray painting.Similarly, wet removal of asbestos releases up to 100times less dust than dry removal. The change should bechecked to ensure that it is safer.IsolationIsolation isolates the worker from the hazard. In a quarry,for example, the operator of a crusher can be isolatedfrom dust by a filtered, air-conditioned cab.EnclosureA substance or procedure may be enclosed to containtoxic emissions. It may be as simple as putting a lid on anopen solvent tank or enclosing asbestos removal projectswith polyethylenesheeting (Figure1). Enclosureshave also beenbuilt aroundcompressors toreduce the noiselevel. Enclosuresmust not restrictaccess whenmaintenance isrequired.VentilationA commonengineering controlis to dilute the contaminant in the air by using generalventilation. Local ventilation is better because it removesthe contaminant. General ventilation may employ fans tomove large volumes of air and increase air exchange.This is not suitable, however, for highly toxic materials.

Localventilationcaptures andremovescontaminants attheir source. Ata shop bench,a fume hoodcan beconstructed toremove dustsand fumes. Onsites, portablefume extractors(Figure 2) can

be used. Remember: many filtering systems can onlyremove fumes—not gases or vapours.

PERSONAL PROTECTIVE EQUIPMENT

Figure 1Enclosure

Figure 2Fume Extractor

14 – 2

Personal Protective EquipmentWhen it is not possible to apply any of the five engineeringcontrols, personal protective equipment may be the lastresort.Regulations often refer to CanadianStandards Association (CSA) or otherequipment standards as a convenientway to identify equipment which meetsrequirements and is acceptable. CSA-certified equipment can be identified bythe CSA logo. For instance, there areCSA standards for• Head Protection - CSAZ94.1M1992• Eye Protection - CSAZ94.3-99• Foot Protection - CSAZ195-M1992

For respiratory protection, National Institute for OccupationalSafety and Health (NIOSH) standards and approvals areusually referenced throughout North America.For life jackets, Transport Canada certification is thestandard reference.See the following chapters on particular kinds of PPE.

PERSONAL PROTECTIVE EQUIPMENT

CSA logo

15 – 1

15 EYE PROTECTIONWith the permission of the Canadian Standards Association, some informationin this chapter is reproduced from CSA Standard CAN/CSA-Z94.3-99, IndustrialEye and Face Protectors, which is copyrighted by Canadian StandardsAssociation, 178 Rexdale Boulevard, Toronto, Ontario M9W 1R3.While use ofthis material has been authorized, CSA shall not be responsible for the mannerin which the information is presented, nor for any interpretations thereof.

IntroductionEye protection is not the total answer to preventing eyeinjuries. Education regarding proper tools, workprocedures, hazard awareness, and the limitations of eyeprotection is also very important. Like any othermanufactured product, eye protection has material,engineering, and design limitations. But proper eyeprotection, selected to match the specific constructionhazard, combined with safe work procedures, can help tominimize the number and severity of eye injuries.When we consider that one out of every two constructionworkers may suffer a serious eye injury during theircareer, the importance of wearing proper eye protectioncannot be over-emphasized. In the hazardousenvironment of the construction industry, wearing propereye protection should be considered a labour-management policy, not a matter of individual preference.

Classes of Eye ProtectorsBefore outlining the type(s) of eye protectors recommendedfor a particular work hazard, it is necessary to explain thevarious types of eye protectors available. Eye protectorsare designed to provide protection against three types ofhazards — impact, splash, and radiation (visible andinvisible light rays) — and, for purposes of this manual, aregrouped into seven classifications based on the CSAStandard Z94.3-99, Industrial Eye and Face Protectors.The seven basic classes of eye protectors are:spectacles, goggles, welding helmets, welding handshields, hoods, face shields, and respirator facepieces.Class 1 – Spectacles (Figure 3)CSA Standard Z94.3-99 requires that Class 1 spectaclesincorporate side protection. Most side shields arepermanently attached to the eyewear, but some may bedetachable.

Class 2 – GogglesThere are two types of goggles — eyecup and cover. Bothmust meet the CSA Z94.3-99 Standard.Eyecup goggles (Figure 4) completely cover the eye socketto give all-round protection. They have adjustable orelasticized headbands and are equipped with ventilationports to allow passage of air and prevent fogging. Somehave direct ventilation ports which prevent the directpassage of large particles, but do not exclude dust orliquids. Others have indirect ventilation ports which preventthe passage of particles, dust, and liquids. There are alsomodels available with an adjustable chain bridge.

Cover goggles (Figure 5, below) are designed to be wornover spectacles. They have adjustable or elasticizedheadbands and are equipped with direct or indirectventilation ports to allow passage of air and prevent fogging.

EYE PROTECTION

Examples of Class 1 - Spectacles

Class 1ASpectacles with side protection

Figure 3

Class 1BSpectacles with side and radiation protection

Class 2A– Direct ventilated goggles for impact protectionEyecup goggles with direct ventilation openings or ports. These openingsexclude direct passage of large particles. They do not exclude dust andsplash. a) headband; b) lens; c) direct ventilation port; d) bridge.

Figure 4 – Eyecup Goggles

Class 2B – Non-ventilated and indirect ventilated goggles for impact,dust, and splash protectionEyecup goggles with indirect ventilation ports to exclude direct passage ofdust or liquids. These goggles are identical to class 2A except for the typeof ventilation ports. a) indirect ventilation port

Class 2C – Radiation protectionEyecup goggles for radiation protection with indirect ventilation ports not only toallow passage of air and prevent fogging, but also to exclude light. The lensesin these goggles are filter lenses. a) indirect ventilation port; b) filter lens.

15 – 2

Class 3 – Welding Helmets (Figure 6)This class provides radiation and impact protection for faceand eyes. There are two types of welding helmets available— the stationary plate helmet and the lift-front or flip-upplate helmet. There are also special models incorporatingearmuff sound arrestors and air purification systems.Special magnifying lens plates manufactured to fixedpowers are available for workers requiring corrective lenses.

The filter or shaded plate is the radiation barrier. Arcwelding produces both visible light intensity and invisibleultraviolet and infra-red radiation. These ultraviolet rays arethe same type of invisible rays that cause skin burning andeye damage from overexposure to the sun. However,ultraviolet rays from arc welding are considerably moresevere because of the closeness of the eyes to the arc andlack of atmospheric protection. In arc welding, therefore, itis necessary to use a filter plate of the proper lens shadenumber to act as a barrier to these dangerous light raysand to reduce them to the required safe degree of intensity.For proper welding shade numbers, see Table 2.In addition to common green filters, many special filtersare also available. Some improve visibility by reducingyellow or red flare; others make the colour judgment oftemperature easier. A special gold coating on the filterlens provides additional protection by reflecting radiation.Class 4 – Welding Hand Shields (Figure 7)Welding hand shields are designed to give radiation andimpact protection for the face and eyes.NOTE: With welding helmets and hand shields, the useris continually lifting and lowering the visor. To protect theeyes when the visor is lifted, Class 1 spectacles shouldbe worn underneath.

Class 5 – Hoods (Figure 8)Non-rigid helmets or hoods come with impact-resistantwindows usually made of plastic. An air-supply systemmay also be incorporated. Hoods may be made of non-rigid material for use in confined spaces and of collapsibleconstruction for convenience in carrying and storing.Hood types include5A with impact-resistant window5B for dust, splash, and abrasive materials protection5C with radiation protection5D for high-heat applications.

EYE PROTECTION

Hand-held shields or inspectors’ shields aresimilar to Class 3 welding helmets exceptthat there are no lift-front type models. a)stationary plate; b) handle.

Figure 7 – Hand Shields

Class 2A– Direct ventilated goggles for impact protectionCover goggles with direct ventilation ports. (This type normallyincorporates a soft-frame goggle.) As in class 2A eyecup goggles, theseopenings or ports exclude direct passage of large particles. They do notexclude dust and splash. a) headband; b) direct ventilation port; c) lens.

Class 2B – Non-ventilated and indirect ventilated goggles for impact, dust,and splash protectionCover goggles for dust and splash with indirect ventilation ports to excludedirect passage of dust or liquid. a) indirect ventilation port.

Class 2C – Radiation ProtectionCover goggles for radiation protection. a) filter lens; b) indirect ventilation port.

Figure 5 – Cover Goggles

Figure 6 – Welding Helmets

Lift-front helmets or shields have threeplates or lenses – a filter or shaded platemade of glass or plastic in the flip-upcover, along with a clear thin glass orplastic outer lens to keep it clean, and aclear, impact-resistant plastic or glass lensmounted in the helmet itself. a) hard hatattachment; b) flip-up lens holder.Stationary plate helmets are similar to lift-front helmets except for the fact that theyhave a single filter lens plate, normally51mm x 108mm (2” x 4-1/4”) in size, or alarger plate 114mm x 113mm(4-1/2” x 5-1/4”) in size which is moresuitable for spectacle wearers.

Figure 8 – Hoods

15 – 3

Class 6 – Face Shields (Figure 9)Face shields are just what the name implies—a devicethat includes a transparent window or visor to shield theface and eyes from impact, splash, heat, or glare. Withface shields, as with welding helmets and hand shields,the user is continually lifting and lowering the visor. Toprotect the eyes when the visor is lifted, Class 1spectacles should be worn underneath. Face shields mayalso be equipped with an adjustable spark deflector orbrow guard that fits on the worker’s hard hat. Shadedwindows are also available to provide various degrees ofglare reduction; however, they do not meet therequirements of CSA Standard Z94.3-99 Industrial Eyeand Face Protectors for ultraviolet and total heat pro-tection and should not be used in situations where anyhazard is present from ultraviolet or infra-red radiation.Class 6This class includes6A for impact and splash protection6B for radiation protection6C for high-heat applications.

Class 7 – Respirator Facepieces (Figure 10)This class includes7A for impact and splash protection7B for radiation protection7C with loose-fitting hoods or helmets7D with loose-fitting hoods or helmets for radiation protection.

Hazards and Recommended ProtectorsReprinted from CSA Standard Z94.3-99 Industrial Eye andFace Protectors, Table 1 classifies the main eye hazardsand outlines the types of protectors recommended foreach. Each situation requires that all hazards beconsidered in selecting the appropriate protector orcombination of protectors.The practice of requiring all personnel to wear spectaclesis strongly recommended. Spectacles should be wornunderneath Classes 3, 4, 5, 6, or 7 protectors, where thehazard necessitates the use of spectacles.The following classifications provide a general overview ofeye protectors for each hazard group. For specifichazards, refer to Table 1. Note that the best eyeprotection results from a combination of different classesof eye protectors.Group A: Flying Objects (Figure 11)Minimum eye protection recommended:

Class 1 spectaclesOptimum eye protection recommended:

Goggles worn with face shields to provide eyeand face protection.

Group B: Flying Particles, Dust, Wind, etc. (Figure 12)Minimum eye protection recommended:

Class 1 spectaclesOptimum eye protection recommended:

Goggles (for dust and splash) worn with faceshields to provide eye and face protection.

Group C: Heat, Glare, Sparks, and Splash from MoltenMetal (Figure 13)Minimum eye protection recommended:

Class 1 spectacles with filter lenses for radiationprotection. Side shields must have filteringcapability equal to or greater than the front lenses.

Optimum eye protection recommended:Eyecup or cover goggles with filter lenses forradiation protection, worn with face shields toprovide eye and face protection.

EYE PROTECTION

Class 6AFace shield for impact, piercing, splash,head, and glare protection.a) hard hat attachment; b) face shield(window).

Class 6BFace shield for light non-piercingimpact, splash, low heat, and glareprotection. The major differencebetween 6A and 6B is the degree ofthickness in the shield.

Class 6CFace shield for light non-piercing impactand high heat protection only (usuallywire screen windows). a) hard hatattachment; b) wire screen.

Figure 9 – Face Shields

Figure 10 – Respirator Facepieces

7A 7B

7C

7D

15 – 4

EYE PROTECTION

Note: Shaded areas are recommendations for protectors. Class 1 and Class 2 protectors shall be used in conjunction with recommendations for Class 3, 4, 5, and 6protectors.The possibility of multiple and simultaneous exposure to a variety of hazards shall be considered in assessing the needed protection.Adequate protection againstthe highest level of each of the hazards should be provided.This Table cannot encompass all of the various hazards that may be encountered. In each particular situation,thorough consideration should be given to the severity of all the hazards in selecting the appropriate protector or combination of protectors.The practice of wearing protectivespectacles (Class 1B) with filter lenses under welding helmets or hand shields is strongly recommended to ensure impact and flash protection to the wearer when thehelmet or lift front is raised or the shield is not in use. Protectors that meet the requirements for ignition and flame resistance are not intended to provide protection inenvironments that expose the user to open flames or high-energy arcs. Courtesy Canadian Standards Association

Table 1Hazards and Recommended Protectors

Hazardgroups

Chipping, scaling,stonework, drilling;grinding, buffing,polishing, etc.;hammer mills, crushing;heavy sawing, planing;wire and strip handling;hammering, unpacking,nailing; punch press,lathework, etc.

Woodworking, sanding;light metal working andmachining; exposure todust and wind; resistancewelding (no radiationexposure); sand, cement,aggregate handling;painting; concrete work,plastering; materialbatching and mixing

Nature ofhazard

Hazardous activitiesinvolving but notlimited to

WeldinghelmetClass 3

Weldinghand shieldClass 4A B A B C

SpectaclesClass 1

GogglesClass 2

Face shieldsClass 6

Non-rigid hoodsClass 5

A B C A B C D

A Flyingobjects

Flyingparticles,dust,wind,etc.

B

C Heat,sparks, andsplash frommoltenmaterials

Babbiting, casting, pouringmolten metal; brazing, soldering;spot welding, stud welding; hotdipping operations

D Acid splash;chemicalburns

Acid and alkali handling;degreasing, pickling andplating operations; glassbreakage; chemical spray;liquid bitumen handling

E Abrasiveblastingmaterials

Sand blasting; shotblasting; shotcreting

F Glare, straylight (wherereduction ofvisibleradiation isrequired)

Reflection, bright sun andlights; reflected weldingflash; photographic copying

G Injuriousopticalradiation(wheremoderatereduction ofopticalradiation isrequired)

Torch cutting, welding,brazing, furnace work;metal pouring, spotwelding, photographiccopying

H Injuriousopticalradiation(where largereduction ofopticalradiation isrequired)

Electric arc welding;heavy gas cutting;plasma spraying andcutting; inert gas shieldedarc welding; atomichydrogen welding

15 – 5

EYE PROTECTION

Figure 11

GroupA: Flying Objects(Chipping)

Figure 12

Group B: Flying Particles, Dust,Wind, etc. (Sawing)

Figure 13

Group C: Heat, Glare, Sparks,and Splash (Brazing)

Notes:(1) For other welding processes (e.g., laser, electron beam welding), consult the manufacturer for eye

protection recommendations.

(2) For pulsed GMAW (MIG), use peak current for selecting the appropriate shade number.

(3) For underwater welding, the minimum shade number shown may not necessarily apply.

Courtesy Canadian Standards Association

Table 2

Recommended Shade Numbers for Arc Welding and Cutting

15 – 6

Group D: Acid Splash, Chemical Burns, etc. (Figure 14)Only eye protection recommended:

Eyecup or cover goggles (for dust and splash)worn with face shields to provide eye and faceprotection.Hoods may also be required for certain hazardousactivities such as chemical spraying.

Group E:Abrasive Blasting Materials (Figure 15)Minimum eye protection recommended:

Eyecup or cover goggles for dust and splash.Optimum eye protection recommended:

Hoods with an air line.Group F: Glare, Stray Light (Figure 16)These are situations where only slight reduction of visiblelight is required, e.g., against reflected welding flash. Straylight would result from passing by a welding operation andreceiving a flash from the side without looking directly at theoperation.Minimum eye protection recommended:

Filter lenses for radiation protection. Side shieldsmust have filtering capability equal to or greaterthan the front lenses.

Optimum eye protection recommended:Goggles with filter lenses for radiation protection.See Table 2 for recommended shade numbers.

Group G: Injurious Radiation (Figure 17)These are situations where only moderate reduction ofvisible light is required: for example, gas welding.Injurious radiation would result from looking directly at thewelding operation.Only eye protection recommended:

Goggles with filter lenses for radiation protection.

EYE PROTECTION

Figure 16

Group F: Glare, Stray Light

Figure 15

Group E:Abrasive Blasting

Figure 14

Group D:Acid Splash, ChemicalBurns, etc. (Roofing)

Figure 17

Group G: Injurious Radiation(Gas Cutting)

15 – 7

Note: The intensity of the flame and arc is lower in GroupG than in Group H. For this reason, required filter shadenumbers for this group are also lower. See Table 2.Group H: Injurious Radiation (Figure 18)These are situations where a large reduction in visible lightis essential, e.g., in electric arc welding.Only eye protection recommended:

Class 1 spectacles worn with full weldinghelmets or welding hand shields. Thesespectacles should incorporate suitable filterlenses if additional protection is required whenthe welding helmet is in the raised position: forexample, when working near other weldingoperations. See Table 2.

Injuries Associatedwith Construction HazardsThe cornea is the front layer of the eye and the first pointat which light enters the eye; if light rays cannot passthrough the cornea, vision is prevented. Injuries to thecornea that cause scarring, scratching, or inflammationcan impair sight.1. Flying Objects

A piece of metal can pierce the cornea and eyeballand possibly cause the loss of an eye.

2. DustDust, sawdust, etc. can cause irritation resulting in acorneal ulcer which is a breakdown of corneal tissuecausing a red, watery, or pussy eye.

3. HeatHeat can burn and severely damage the cornea.

4. Acid SplashAcid splash and chemicals can burn the cornea,conjunctiva (white coat on the eye), and eyelid andpossibly cause loss of sight.

5. AbrasiveSand can cause a corneal abrasion which can resultin loss of sight.

6. GlareGlare can make it difficult to see and can causeextreme fatigue to the eye.

7. RadiationUltraviolet light from a welding arc can damage thecornea.

Correct eye protection, when matched to the hazard, canprevent or reduce the degree of any eye injury. However,once an eye injury has occurred, it is critical that the injury, nomatter how small, be given immediate attention and first aid.Eye protection can only protect against injury if it is worncontinuously on-site.It is often the time when a worker removes eye protectionwhile working near or passing by other hazardous activitieson the job that an eye injury results. When it is necessaryto remove eye protection, do so only in a location that iscompletely away from hazardous work areas.The inconvenience of wearing eye protection is faroutweighed by the risk of being blinded in one or both eyes.

Purchase of Protective SpectaclesProtective spectacles are available with “plano” or non-prescription lenses and with prescription lenses.The polycarbonate materials used in safety glassesprovide the best protection, while regular plastic CR-39lenses in industrial thickness provide a substitute wherepolycarbonate is not available. Anti-scratch coatings areapplied to the lens surface to extend useful lens life.Glass lenses, even when thermally or chemicallyhardened, are not acceptable for the workplace. Currentglass lenses do not meet the impact requirements of CSAStandard Z94.3-99.When purchasing safety glasses, specify industrialprotection lenses and frames. This term indicates that theeye protection meets specific test requirements.Industrial protection safety glasses can be identified bythe manufacturer’s or supplier’s logo or monogram whichis located on the lens and frame (Figure 19).

This mark must appear on both the frame and the lens. Itdistinguishes industrial quality lenses and frames fromstreetwear lenses and frames.

EYE PROTECTION

Figure 18

Group H: Injurious Radiation(Electric Arc Welding)

Figure 19 – Where to Locate IdentificationMarks or Symbols

On non-prescription eye protectors, look also for the CSA logo.

IdentificationMark on Frames

IdentificationMark on Lenses

Identification Markon PrescriptionLenses

15 – 8

The Canadian Standards Association (CSA) certificationprogram for non-prescription (plano) industrial eye andface protection covers complete protectors only. It doesnot cover separate components such as lenses, frames,or shields.In addition to the manufacturer’s logo or I.D.mark which appears on the eye protector,the CSA logo will appear to indicate the eyeprotection meets the requirements of theCSA Z94.3-99 standard. Certification ofindustrial prescription safety glasses is notyet available.Until such a program is available, the user should look forthe manufacturer’s or supplier’s logo or I.D. mark on theframe and lens which indicates adherence to theAmerican National Standards Institute (ANSI) StandardZ87.1-1989.

FittingImproper fit is the most common reason for resistance towearing eye protection. A worker who wears non-prescription (plano) lenses and continues to complainabout blurred vision after the fit has been checked by acompetent person may require prescription lenses.Prescription lenses must be fitted by an optician oroptometrist. Plano eye protection should be fittedindividually by a trained person.Here are some general guidelines to follow when fittingthe various classes of eye protectors.Class 1 – Spectacles require that the proper eye size,bridge size, and temple length be measured for eachindividual. The wearer should be able to lower his headwithout the spectacles slipping.Class 2 – Goggles with adjustable headbands should fitsnugly over the wearer’s spectacles when worn.Class 3 – Welding helmets are equipped with adjustableattachments to provide a comfortable fit over the headand face. Attachments are also available to fit on hardhats.Class 4 – Hand-held shields require no adjustment.Class 5 – Hoods Adjustments are located on the topinside of the hood. A tie is located around the neck tosecure the hood and to prevent the entry of dust.Class 6 – Face shields are equipped with adjustableattachments to provide a comfortable fit over the headand face. Attachments are also available to fit on hardhats.Class 7 – Respirator facepieces should fit snugly withoutgaps to make an effective seal against airbornecontaminants.

CareEye protectors in construction are subjected to manydamage-causing hazards. Therefore, care is veryimportant.1. Lenses should be inspected regularly for pitting and

scratches that can impair visibility.

2. Scratched or pitted lenses and loose frames ortemples should be replaced or repaired as soon aspossible with components from the originalmanufacturer.

3. Lenses should be cleaned with clear water to removeabrasive dust—cleaning dry lenses can scratch thesurface.

4. Anti-fog solutions can be used on glass or plasticlenses.

5. Frames should be handled with care and checkeddaily for cracks and scratches.

6. Eye protectors should never be thrown into tool boxeswhere they can become scratched or damaged.

7. Cases should be provided and used to protectspectacle lenses when not being worn.

Contact LensesIn the construction industry, contact lenses are not asubstitute for protective eyewear. Dust and dirt can getbehind the contact lenses causing sudden discomfort andimpairment of vision.Contact lenses are also difficult to keep clean when theyhave to be removed or inserted since there are seldomsuitable washing-up facilities on a jobsite.It is recommended that contact lenses not be worn onconstruction sites.However, in cases where contact lenses must be worn tocorrect certain eye defects, workers should obtain fromtheir ophthalmologist or optometrist written permissionindicating the necessity of wearing contact lenses in orderto function safely at work. In these cases eye protection,preferably cover goggles, must be worn with the contactlenses.

EYE PROTECTION

16 – 1

16 HEAD PROTECTIONStandardsRequirements for head protection are specified in the currentedition of the construction regulation (O. Reg. 213/91).Under this regulation, hard hats are mandatory for allconstruction workers on the job in Ontario. The hard hatmust protect the wearer’s head against impact andagainst small flying or falling objects, and must be able towithstand an electrical contact equal to 20,000 voltsphase to ground.At the present time, the Ministry of Labour (MOL)considers the following classes of hard hats to be incompliance with the regulation.Class B– manufactured and tested in accordance with CSA

Standard Z94.1-1977Class B– manufactured and tested in accordance with ANSI

Z89.1-1986Type I, Class E– manufactured and tested in accordance with ANSI

Z89.1-1997.Class E– manufactured and tested in accordance with CSA

Standard Z94.1-1992Type II, Class E– manufactured and tested in accordance with ANSI

Z89.1-1997."Type" and "Class" of hard hat can be identified by theCSA or ANSI label. Some manufacturers also stamp theCSA or ANSI classification into the shell of the hard hatunder the brim.

StylesNew Class E hard hats come in three basic styles:1) standard design with front brim, rain gutter, and

attachment points for accessories such as hearingprotection

2) standard design with front brim and attachment pointsfor accessories but without a rain gutter

3) full-brim design with attachment points for accessoriesand brim that extends completely around the hat forgreater protection from the sun.

HEAD PROTECTION

CSA label, stamped into the shell, indicating Class E hard hat

Figure 20

17 – 1

17 FOOT PROTECTIONAnkle injuries represent 50% of all foot injuries in Ontarioconstruction. Properly worn, a CSA-certified Grade 1workboot meets the requirements of the currentconstruction regulation (O. Reg. 213/91) and helps protectagainst ankle and other injuries.One of three CSA grades, Grade 1 offers the highestprotection and is the only one allowed in construction. In aGrade 1 boot, a steel toe protects against falling objects whilea steel insole prevents punctures to the bottom of the foot.Grade 1 boots can be identified by• a green triangular patch imprinted with the CSA logo

on the outside of the boot and• a green label indicating Grade 1 protection on the

inside of the boot.

Grade 1 boots are also available withmetatarsal and dielectric protection. Awhite label with the Greek letterOmega in orange indicates protectionagainst electric shock under dryconditions.

Selection and FitGrade 1 boots are available in various styles and solematerials for different types of work. For example, Grade1 rubber boots may be better suited than leather boots forsewer and watermain or concrete work.Boots should provide ample “toe room” (toes about 1/2inch back from the front of steel box toe cap whenstanding with boots laced).When fitting boots, allow for heavy work socks. If extrasock liners or special arch supports are to be worn in theboots, insert these when fitting boots.

Care and UseLacing boots military style permits rapid removal. In anemergency, the surface lace points can be cut, quicklyreleasing the boot.In winter, feet can be kept warm by wearing a pair of lightsocks covered by a pair of wool socks. Feet should bechecked periodically for frostbite.Use high-cut (260 mm or 9 in) or medium-cut (150 mm or6 in) CSA Grade 1 workboots. The higher cut helpssupport the ankle and provides protection from cuts orpunctures to the ankle.

FOOT PROTECTION

Greek Omega Label

Properly laced safety bootswith CSA labels

Figure 21

18 HEARING PROTECTIONIntroductionConstruction generally produces noise. Typicalconstruction work may involve equipment driven by largeand small engines, metal fabrication, power drilling andsawing, air hammering, and blasting — all of which canproduce noise at harmful levels.Depending on the noise level, duration of exposure, andother factors, a temporary or permanent hearing loss mayresult. Temporary hearing losses will usually be restoredby the body within a few hours after the exposure hasceased. Hearing losses which cannot be restored by thebody over any length of time are termed permanent.A person suffering a hearing loss will frequently notrealize it. Noise may be harmful at levels that an exposedperson does not consider irritating or annoying. Therefore,despite individual preferences, prevention and controlprocedures must be based on the general potential forhearing loss.Waiting for personal discomfort before taking preventivemeasures may be too late to avoid a permanent noise-induced hearing loss.

Noise MeasurementMeasuring sound levels can determine• whether or not a noise hazard is present

• noise exposures of workers• which workers require hearing protection, hearing

tests, education, and training.

Measurements are performed with a sound level meter(SLM). The unit used to measure the intensity of sound isthe decibel (dB). Intensity is perceived as loudness.Noise levels can’t be added directly like other numbers. Forexample, two noise sources producing 90 dB each wouldhave a combined output of 93 dB, not 180 dB. Thecombined output of 93 dB is actually a doubling of intensity.In many construction situations several different sourceseach contribute to the overall noise. This means that aworker’s exposure may be much higher than it would be ifonly one of the sources was present (Figure 22).In addition to intensity, the SLM can detect a wide range offrequencies. Since the human ear tends to filter out thelower frequencies and slightly accentuate the higher ones,SLMs are engineered to do the same. They feature aninternal mechanism called "A-weighting." The resulting noiselevel is expressed as decibels (dB) on the "A" scale or dBA.Two types of noise measurements can be performed: areaand personal.An area noise measurement is taken in a specific workarea. The measurement is generally used as a preliminarystep to determine whether more detailed evaluationinvolving personal noise measurement is necessary. Area

noise readings should not be used todetermine what hearing protection isrequired or who needs a hearing test.Personal exposure measurement shouldbe used for these purposes.Personal noise measurement involves asmall device called a noise dosimeter.Workers can wear the device to determinetheir average noise exposure over a wholeshift. Usually worn around the waist, thedosimeter has a microphone that is placedas close to the worker’s ear as possible.Noise measurements should be carried outin accordance with acceptable standards.Canadian Standards Association (CSA)Standard Z107, Procedures for theMeasurements of Occupational NoiseExposure, provides guidance on the typeof equipment to use, which workers to test,and how to test.Noise evaluation must be done by aknowledgeable person trained andexperienced in conducting noise surveys.

Hearing ProcessThe hearing process begins when theouter ear directs sound waves into the earcanal (Figure 23). The eardrum vibratesas sound waves strike it. This vibration isthen transmitted through the middle earwhere it is amplified on a membranecalled the oval window. The oval windowseparates the middle ear from the inner

HEARING PROTECTION

The backhoe is producing 90 dB of noise. The worker standing nearby is therefore exposed to 90 dB.

The backhoe is producing 90 dB. The compressor is also producing 90 dB. The worker standingbetween the two pieces of equipment is therefore exposed to their combined output. This doubleintensity is 93 dB.

Figure 22

18 – 1

18 – 2

ear where the sensitive hearing organs are located.Attached to the other side of the oval window is a tiny,snail-shaped structure called the cochlea. The cochleacontains fluid and hair cells. These thousands of small buthighly sensitive hair cells feel the vibration. Responding tothe cells are microscopic nerve endings that sendmessages to the brain, where the signals are interpretedas varieties of sound.

Hearing LossAny reduction in the normal ability to hear is referred to asa loss of hearing. A hearing loss can be either temporaryor permanent.Temporary Threshold ShiftWith a temporary hearing loss, normal hearing will usuallyreturn after a rest period away from all sources of intense orloud noise. The recovery period may be minutes, hours, aday or perhaps even longer. It is believed that a temporaryhearing loss occurs when hair cells in the inner ear havebeen bent by vibrations and need time to bounce back.Most of the temporary hearing loss occurs during the firsttwo hours of exposure and recovery takes place usuallywithin the first two hours after exposure stops. However,the length of time needed for recovery depends primarilyon how great the initial loss was. The greater the initialloss the longer the time needed to recuperate. Thistemporary decrease in hearing ability is called atemporary threshold shift (TTS) because the threshold orlevel at which sound can be heard has been raised.For instance, to listen to your favourite music at thevolume you like, you would have to turn it up a few morenotches than usual. This phenomenon explains why somepeople, particularly those who suffer from some form ofhearing loss, claim that they “get used to the noise.”If these previous exposures are allowed to continue underthe same conditions and without the proper interval of rest,then a certain degree of permanent hearing loss is possible.Permanent Threshold ShiftPermanent hearing loss is the result of hair cell or nervedestruction within the cochlea. Once these important parts

of the hearing process are destroyed, they can never berestored or regenerated. The resulting permanent hearingloss, also referred to as permanent threshold shift (PTS),can range from slight impairment to nearly total deafness.A symptom of PTS is the inability to pick up sounds withhigher frequencies. As damage increases, the reception ofspeech becomes more difficult.Unfortunately, the damage builds up gradually. Workersmay not notice changes from one day to another. Butonce the damage is done there is no cure. Effects mayinclude the following.• Sounds and speech become muffled so that it’s hard

to tell similar-sounding words apart or to pick out avoice in a crowd.

• Sufferers ask people to speak up, then complain thatthey are shouting.

• There’s a permanent ringing in the ears (tinnitus).• Sufferers need to turn the volume on the radio or

television way up or find it hard to use the telephone.

Determining FactorsThe following factors determine the degree and extent ofhearing loss:• Type of Noise

(continuous, intermittent, impact, high or lowfrequency)

• Intensity of Noise(level of loudness)

• Duration of Exposure(length of time worker subjected to noise — forexample, during day, on specific shifts)

• Employment Duration(years worker subjected to noise)

• Type of Noise Environment(character of surroundings – for example, enclosed,open, reflective surfaces)

• Source Distance(s)(distance of worker from noise source)

• Workerʼs Position(position of worker relative to noise source)

• Workerʼs Age(for instance, a 20-year-old apprentice versus a 50-year-old journeyperson)

• Individual Susceptibility(sensitivity difference, physical impairments)

• Workerʼs Present Health(whether a worker has any detectable losses or eardiseases)

• Workerʼs Home and Leisure Activities(exposures to noise other than occupational, such ashunting, skeet shooting, earphone music,snowmobiling, etc.)

Other prime causes of permanent hearing loss are age,traumatic injuries (such as from explosions or gunfire), andinfection.Noise, however, is the major identifiable cause of hearingloss. Therefore, it is important that controls are exercisedwherever possible so that such losses can be prevented.

HEARING PROTECTION

Figure 23

Sound travelling through ear canal

Hammer

Ear DrumEar Canal

AnvilStirrup

CochleaMessagesto Brain

OvalWindow

18 – 3

Hearing ProtectionOne form of controlling noise hazards isthrough the proper use of hearingprotection devices (HPDs). Hearingprotectors should be provided whenengineering controls cannot beimplemented or while such controls arebeing initiated.Hearing protective devices are barriersthat reduce the amount of noisereaching the sensitive inner ear. Fit,comfort, and sound reduction or“attenuation” are importantconsiderations in choosing HPDs.Commonly used hearing protectiondevices are either earplugs or earmuffs.Earplugs attenuate noise by pluggingthe ear canal (Figure 24). The muff-typeprotector is designed to cover theexternal part of the ear providing an“acoustical seal” (Figure 25). Table 1 describes some ofthe characteristics of these different types of hearingprotectors.

EffectivenessObviously, the effectiveness of an HPD depends on theamount of time it is worn. What is not obvious to mostwearers is the drastic reduction in protection if HPDs arenot worn in noisy environments even for short periods oftime.The reduction in effectiveness can be as great as 95% ormore if the protectors are not worn for as little as three orfour minutes. It is therefore important to wear HPDsduring the entire noise exposure period in order toachieve the maximum protection available.The effectiveness of HPDs also depends on the mannerin which noise is transmitted through or around theprotector. The following points should be noted.• Even relatively small openings or air leaks in the seal

between the hearing protector and the skin cantypically reduce attenuation by 5 to 15 dB or more.

• Constant movement of the head or body vibration canlead to air leaks, therefore making periodicadjustments necessary to ensure a proper seal.

• Hair, especially long hair and facial hair, can cause apoor fit.

• Proper fitting is crucial to obtaining a reasonabledegree of protection from an HPD.

• Earmuff effectiveness is greatly influenced byheadband tension. If tension decreases throughroutine usage or alteration by the user, earmuffeffectiveness is reduced.

• Modifying the earmuff by drilling holes in the earcupsrenders the protection useless.

• Anatomical differences such as ear canal size, jawsize, and heads of different shape and size may affectthe fit of earmuffs and earplugs. To accommodatethese differences, HPDs should be made available tousers in various shapes and sizes.

• Recreational headsets such as those used with radiosand CD players are not to be used as hearingprotection.

HEARING PROTECTION

Figure 24

Disposable Permanent

Plug-type Hearing Protectors

Muff-type Hearing Protectors

Figure 25 Standard Muffwith Band

AttachableMuff

Two-way Communicator

One-wayCommunicator

18 – 4

HEARING PROTECTION

EARMUFFS

STYLEand

COMFORT

Consist ofcompressibleplastic foam. Comein many shapes.Often described as“disposable plugs.”Elasticity lets themadapt easily tochanges in earcanal.

Usually made ofplastic or siliconerubber attached toa flexible stem forhandling andinsertion. Come inmany shapes andsizes to suitdifferent earcanals.

Consist of twoinsulated plasticcups attached tometal or plasticband. Cupsequipped with softcushions for sealand comfort. Headband tensionensures good seal.

INTENDEDUSE

Most brands canbe reused a fewtimes before beingdiscarded.

To be used morethan once.

To be usedregularly. Can beworn with orwithout plugs.Easily attached tohard hats.

HYGIENEPRACTICES

Clean handsrequired each timefresh plugsinserted.

Plugs should becleaned regularlywith warm soapywater, preferablyafter each removalfrom ear.

Generalmaintenancerequired. Head bandmust be maintained.Cushions must bereplaced whensoiled or brittle.

ADVANTAGES Low risk ofirritation. One sizefits most workers.

Reusable. Less likely to causeirritation. Whenattached to hardhat, alwaysavailable for use.

DISADVANTAGES Use requires cleanhands. Largesupply required forfrequent removalsand usage.

Plugs must be keptclean to preventirritation. Mayproduce somediscomfort withpressure. Thoughreusable, plugsdegrade over time.Inspect and replaceas necessary.

Bands may wearout and tensiondecrease. Eyewearand hair mayinterfere with fitand reduceprotection.

FOAMEARPLUGS

PREMOULDEDEARPLUGS

Table 3: Types of Hearing Protectors

FORMABLEEARPLUGS

CUSTOM-MOULDEDEARPLUGS

SEMI-INSERTEARPLUGS

• Single-use formineral woolproducts.• Multi-use forcotton/waxproducts.• Semi-permanentfor silicone puttyproducts.

Permanent use To be used morethan once.

Made from pliablematerial such ascotton/waxmixture, siliconeputty, and mineralwool.

Custom made to fita particular ear bytaking animpression of theear, making amould, and castinga plug.

Commonly knownas banded earplugsor canal caps. Theyconsist of smallcaps or pods thatare held in placeover the ear canalby spring-loadedbands.

Clean handsrequired forshaping andinsertion.

Wash with hotwater and soap,preferably afterremoval.

Wash with hotwater and soap,preferably afterremoval.

Relatively cheap Good fit only if aproper impressionof the ear is taken.

Good for whenfrequent removal isrequired.

Not recommendedfor the noise levelsfound onconstructionprojects.

If the wearer’sweight changesdrastically, newplugs should bemade. Plugs can belost, shrink,harden, or crackover time, andmust be replaced.

Proper seal isnecessary for goodattenuation.

18 – 5

Selection CriteriaIn addition to attenuation characteristics, the followingfactors should be considered when selecting hearingprotectors:– noise exposure levels and standards– comfort– appearance– communication requirements– work environment or work procedures– overprotection.

Noise Exposure Levels and StandardsIdentifying the noise level(s) to which an individual may beexposed throughout an entire working day determines theclass of hearing protector needed.Evaluation is based on eight-hour noise exposure, not aspot or area measurement. For example, a quick-cut sawoperated by a mason may produce a noise level of 110dBA. But the mason may only be exposed to an averageof 92 dBA over the full eight-hour shift. The reason is thatthe saw is not operated continuously during that period.There will be times when the worker is laying brick, takinga coffee break, or eating lunch.

CSA Standard Z94.2, Hearing Protectors, identifiesclasses of hearing protectors as A, B, and C. Protectorsare classed by attenuation ability under laboratoryconditions modified by certain practical fieldconsiderations. Class A protectors offer the highest abilityto attenuate, followed by B and C.Table 4 provides guidelines for proper selection. Table 5lists typical noise levels for various kinds of constructionequipment. The upper limits of the noise levels can beused as a guide in selecting a specific class of hearingprotectors.ComfortComfort is an important consideration in selection. AnHPD that isn’t comfortable will simply not be worn or willbe worn improperly.

With earplugs several factors affect comfort. Since someplugs are relatively non-porous they can often create apressure build-up within the ear and cause discomfort.Dirty plugs may irritate the ear canal. The shape of anindividual’s ear canals may not allow certain plugs to fitproperly.Earmuffs should be made of materials which do notabsorb sweat and which are easy to maintain and clean.The earmuff cup should be adjustable to conform tovarious head sizes and shapes. Headband tension andearcup pressure should be adjusted so that they areeffective without being uncomfortable. Weight may also bea factor.Workers should be allowed to try out various HPDs todetermine which are most comfortable.AppearanceHPD appearance may influence selection. Those that lookbulky or uncomfortable may discourage potential users.Allowing workers to select from various HPDs, or variousmakes of the same HPD, can help overcome this problem.Speech RequirementsConsider the level of the noise hazard and the risks ofimpaired communication (Table 6). The potential forspeech interference is greatest when background noise —meaning all noises generated in the surrounding area —is low. In this case HPD wearers with impaired hearingmay have difficulty understanding speech because theymust contend not only with their hearing loss but with theattenuation of their protector as well. In other cases, theuse of HPDs by workers with normal hearing may actually

HEARING PROTECTION

Table 4

MAXIMUM NOISE LEVEL(dBA)

RECOMMENDED CLASS OFHEARING PROTECTOR

Less than 85 dBA No protection required

Up to 89 dBA Class C

Up to 95 dBA Class B

Up to 105 dBA Class A

Up to 110 dBA Class A plug + Class A orClass B muff

More than 110 dBA Class A plug + Class A orClass B muff and limitedexposure

Recommended criteria for selecting a class of hearing protector, based on a daily 8-

hour exposure to noise levels in dBA. Adapted from CSA Standard Z94.2-M1984.

Table 5

TYPICAL NOISE LEVEL MEASUREMENTSFOR CONSTRUCTION

NOISE LEVEL (dBA)* EQUIPMENT AT OPERATOR’S POSITION

Cranes 78 – 103Backhoes 85 – 104Loaders 77 – 106Dozers 86 – 106Scrapers 97 – 112Trenchers 95 – 199

+ PIle drivers 119 – 125Compactors 90 – 112

+ Explosive-actuated tools 120 – 140Grinders 106 – 110Chainsaws 100 – 115Concrete saw 97 – 103Sand blasting nozzle 111 – 117Jackhammers 100 – 115Compressors 85 – 104

* Generally, newer equipment is quieter than older equipment. (Fornoise levels of specific equipment, contact the ConstructionSafety Association of Ontario.)

+ Pile drivers and explosive-actuated tools generate intermittent or“impulse” sound.

18 – 6

improve their understanding of speech in noisyenvironments.In other words, wearing HPDs doesn’t always reduce theability to communicate. Factors to consider include theuser’s hearing ability, noise levels, and the type of HPD.Where two-way communication is vital, radio-equippedhearing protectors can be worn (Figure 25).Work Environment/ProceduresChoosing an HPD is sometimes dictated by the constraintsof the work area or work procedures. For example, largevolume earmuffs may not be practical in confined worksituations with little head room or clearance.In this case, flat-cup muffs or earplugs may be morepractical. Where work is necessary near electrical hazards,it may be desirable to use non-conductive suspension-typemuffs. The type of protector may also be determined by thenature of work, as in welding where certain types ofearmuffs may interfere with the welder’s helmet.The attenuation of the muff-type hearing protector may beconsiderably reduced when worn with spectacle-type safetyglasses. (The head configuration of the wearer and the typeof glasses worn will determine the reduction in attenuation.)Where safety glasses must be worn, cable-type templesshould be used in order to allow the smallest possible openingbetween the seal of the protector and the head. Otherwiseearplugs should be worn, provided they are adequate.Consideration should be given to hearing protectors whichcan be attached to hard hats where exposures to noisemay be high but intermittent and where hard hats must beworn at all times. Periodic adjustments may be necessarybecause movement of the hard hat may break the seal ofthe HPD.Consideration should also be given to work involving oils,grease, and other products which may soil hands. Earinfections may occur when earplugs are inserted by soiledhands.OverprotectionWorkers wearing HPDs that provide too much attenuationmay feel isolated from their surroundings. Sounds may beheard as muffled. Speech or warning sounds may beunrecognizable. Overprotection can lead workers to resistwearing HPDs. Protectors should be chosen to providesufficient, but not excessive, attenuation. The objectiveshould be to reduce noise levels to or below therecommended maximum eight-hour exposure of 85 dBA,but not below 70 dBA.

Fit, Care, and UseWorkers should be instructed in the proper fitting of HPDsas recommended by the manufacturer. Training shouldinclude a demonstration. Workers should then practiceusing the HPDs under close supervision. Checks areneeded to ensure the best possible protection. Many ofthese checks relate to fit.Earmuffs1) Earmuffs should conform to the latest issue of CSA

Standard Z94.2.2) The cup part of the earmuff should fit snugly over the

entire ear and be held firmly in place by a tensionband.

3) The cup and band should not be so tight as to causediscomfort.

4) Cup, cushion, and band should be checked forpossible defects such as cracks, holes, or leakingseals before each use of the HPD.

5) Because band tension can be reduced over a periodof time, the band may require repair or replacement.

6) Defective or damaged parts should be repaired orreplaced as needed. Tension band, cushions, andcups are readily replaceable.

Earplugs1) Earplugs should conform to the latest issue of CSA

Standard Z94.2.2) For maximum attenuation the method of insertion

illustrated in Figure 26 should be used. Because theear canal is slightly S-shaped, the ear must be pulledback to straighten the canal for the plug to fit properly.

3) Earplugs must be fitted snugly in the ear canal. Thiswill cause some discomfort initially. However, in time(usually a period of two weeks) the discomfortvanishes. Should there be severe discomfort initiallyor mild discomfort for more than a few weeks, seekprofessional advice. In most instances it will only be amatter of re-sizing, although some ear canals cannotbe fitted with plugs because of obstructions, uniqueshapes, or deformities. In fact, the shape of one earcanal may be entirely different from the other.

HEARING PROTECTION

Table 6Effects of Hearing Protectors on Understanding Speech

HEARINGABILITY

OF WEARER Lessthan 75 75 to 85 Greater than 85

BACKGROUND / SURROUNDING NOISE LEVELS IN dBA

Normal Little No Improveshearing effect effect communication

Impaired Moderate Little No effecthearing effect effect

Figure 26

Proper Technique for Inserting Earplugs

Reach one hand around backof head, pull ear upwards tostraighten S-shaped ear canal,then insert plug with other handaccording to manufacturer’sinstructions.

18 – 7

4) Reusable earplugs should be washed with warmsoapy water daily to prevent the remote possibility ofinfection or other discomfort. When not in use, theyshould be kept in a clean container.

5) Earplugs with torn or otherwise damaged flangesshould be replaced.

WARNING: Cotton batten does not provide adequateprotection from construction noise.

TrainingWorkers who wear HPDs should be trained to fit, use, andmaintain the protectors properly. Workers should understand• that there is risk of hearing loss if HPDs are not worn

in noisy environments (eight-hour exposure of 85 dBA)• that wearing HPDs is required in all situations where

noise exposure may damage hearing• that to be effective an HPD must not be removed

even for short periods• that various HPDs are available to accommodate

differences in ear canal size, jaw size, head size andshape, comfort level, compatibility with other forms ofPPE, etc.

• that proper fit is essential to achieve maximumprotection.

AudiometryAnyone who works with noisy equipment on a regularbasis should take a periodic audiometric or hearingcapability test for the following reasons:1) To determine whether or not a hearing loss exists.

Even if no hearing loss is detected, workers exposedto noise levels in excess of 90 dBA should wearhearing protectors. Workers who have some hearingloss should wear HPDs to minimize any further loss.

2) To determine the type of hearing loss. Certainhearing losses can be reversed. Some individualshave suffered for years only to find out that theirhearing problem could have been corrected surgically.These situations usually occur as a result of birthdefects and are known as “conductive losses.”

3) To determine the effectiveness of programs fornoise control and hearing protection. Earlyidentification is important so that prevention practicescan be implemented, maintained, and revised whennecessary.

SummaryControl of noise in construction is of growing importanceas a result of increasing hearing loss claims.Most noise problems can be analyzed in terms of source,transmission path, and receiver. This allows a convenientunderstanding of the overall problem and a usefulapproach to remedial measures. The three componentscan usually be treated in isolation, although sometimes allthree must be considered together in order to controlunacceptable noise levels.At source, remedial measures are aimed at reducing thenoise being generated.Along the transmission path, barriers can be introduced toreduce or eliminate noise reaching the ears.

For the receiver, remedial measures involve personalprotective equipment properly selected, fitted, and worn.The equipment must be used in high noise environmentsall the time.Failure to provide preventive or control measures will resultin temporary and ultimately permanent hearing losses.The Construction Safety Association of Ontario can assistmanagement and labour in the industry by providinguseful information, research, and training.

HEARING PROTECTION

19 – 1

19 RESPIRATORY PROTECTIONIntroductionIn the course of their work, construction personnel areoften exposed to respiratory hazards in the form ofdangerous dusts, gases, fumes, mists, and vapours.In some cases careful selection of materials and workpractices can virtually eliminate respiratory hazards.Where that is not possible, the next best choice isengineering controls such as fume exhaust systems thatdeal with the hazard at the source.Respirators are the least preferred method of protectionfrom respiratory hazards because they• do not deal with the hazard at the source• can be unreliable if not properly fitted and maintained• may be uncomfortable to wear.In spite of these drawbacks, in many constructionoperations respiratory protective equipment is the onlypractical control.

Respiratory HazardsRespiratory hazards may be present as• gases• vapours• fumes• mist• dusts.

Gases — consist of individual molecules of substances,and at room temperature and pressure, they are alwaysin the gaseous state. Common toxic gases found inconstruction are carbon monoxide from engine exhaustand hydrogen sulphide produced by decaying matterfound in sewers and other places.Vapours — are similar to gases except that they areformed by the evaporation of liquids (e.g., water vapour).Common vapours found in construction are produced bysolvents such as xylene, toluene, and mineral spirits usedin paints, coatings, and degreasers.Fumes — are quite different from gases or vapours,although the terms are often used interchangeably.Technically, fumes consist of small particles formed by thecondensation of materials which have been subjected tohigh temperatures. Welding fume is the most commontype of fume in construction. Other examples include pitchfume from coal tar used in built-up roofing and fume fromdiesel engines.Mists — are small droplets of liquid suspended in air. Thespraying of paint, form oils, and other materials generatesmists of varying composition.Dusts — are particles which are usually many timeslarger than fume particles. Dusts are generated bycrushing, grinding, sanding, or cutting and by work suchas demolition. Two kinds of hazardous dust common inconstruction are fibrous dust from insulation materials(such as asbestos, mineral wool, and glass fibre) andnon-fibrous silica dust from sandblasting, concrete cutting,or rock drilling.In construction settings, respiratory hazards may becompounded, depending on the number and variety of

jobs under way. For example, both mist and vapours maybe present from paint spraying or both gases and fumesfrom welding.Health EffectsRespiratory hazards can be divided into the followingclasses based on the type of effects they cause.Irritants are materials that irritate the eyes, nose, throat,or lungs. This group includes fibreglass dust, hydrogenchloride gas, ozone, and many solvent vapours. Withsome materials (e.g., cadmium fume produced by weldingor oxyacetylene cutting of metals coated with cadmium)the irritation leads to a pneumonia-like condition calledpulmonary edema. This effect may not be apparentuntil several hours after exposure has stopped.Asphyxiants are substances which result in inadequateoxygen in the body. They can be classified as eithersimple asphyxiants or chemical asphyxiants.Simple asphyxiants are other gases or vapours whichcause oxygen to be displaced, creating an oxygen-deficient atmosphere. Oxygen content of 18% may leadto some fatigue during exertion. Oxygen concentrationslower than 15% can cause loss of consciousness andmay be fatal. For example, nitrogen used to purge tankscan displace oxygen, resulting in unconsciousness andeven death for those who enter. Oxygen may also beconsumed by chemical or biological activity such asrusting or bacteria digesting sewage.Chemical asphyxiants interfere with the body’s ability totransport or use oxygen. Two examples are carbonmonoxide and hydrogen sulphide.Central nervous system depressants interfere withnerve function and cause symptoms such as headache,drowsiness, nausea, and fatigue. Most solvents arecentral nervous system depressants.Fibrotic materials cause “fibrosis” or scarring of lungtissue in the air sacs. Common fibrotic materials found inconstruction include asbestos and silica.Carcinogens cause or promote cancer in specific bodyorgans. Asbestos is the most common carcinogen inconstruction.Nuisance dusts do not cause significant effects unlessexposure is of high concentration and/or long duration.Excessive exposure to these substances can be adverse initself or can aggravate existing conditions such asemphysema, asthma, or bronchitis. Examples includeplaster dust, cellulose from some insulation, and limestonedust.

Respiratory Protective EquipmentA wide variety of equipment can be used to protectworkers from respiratory hazards. Devices range fromsimple, inexpensive dust masks to sophisticated self-contained breathing apparatus. Generally, the equipmentcan be divided into two distinct classes — air-purifyingrespirators and supplied-air respirators.Air-Purifying RespiratorsAs their name indicates, these devices purify the airdrawn through them. There are two main types of air-purifying respirators:

RESPIRATORY PROTECTION

19 – 2

1) Non-poweredAir is drawn through the air-purifying filter by thewearer breathing in and creating a negative pressurein the facepiece. Non-powered respirators dependentirely on the wearer breathing in (inhaling) andbreathing out (exhaling) to deliver an adequate supplyof purified breathing air.

2) PoweredThese respirators have a blower that blows purifiedair into the facepiece. (Figure 31).

Air-purifying respirators have limitations and should not beused where• there is insufficient oxygen• very high concentrations of contaminant are present• the contaminant cannot be detected by odour or taste

at safe levels.

Warning: Air-purifying respirators simply removecertain airborne hazards. They do not increase orreplenish the oxygen content of the air and shouldnever be worn in atmospheres containing less than19.5% oxygen.

Although many different filters have been designed forspecific hazards, there are three basic types used withair-purifying respirators:

• particulate filters• gas/vapour cartridge filters• combination particulate/gas/vapour filters. See Figure 27.

Particulate FilterThis type removes solid particles such as dusts, fumes, ormists and operates like the air filter in a car engine. Thedevices may be filtering facepiece respirators or respiratorswith replaceable filters. Different grades of filters areavailable, depending on the size of particles to be removed.When particulate filters fill up with dust or fume, theybecome harder to breathe through but are more efficient,since air is being filtered through the layer of trappedparticles as well as the filter itself.While particulate filters can provide good protectionagainst particles such as dusts, mists, or fumes, theycannot filter out gases or vapours because of the verysmall size of gas and vapour molecules.Particulate filters for non-powered air-purifying respiratorsare divided into three levels of filter efficiency: 95%, 99%,and 99.97%. These numbers refer to the percentage ofparticles the filter can remove, based on the particle sizemost difficult to trap. Filters rated to these efficienciesoutperform the dust/mist and dust/fume/mist filters of thepast. For workers removing asbestos insulation or leadpaint, for instance, the 99.97% efficiency cartridge wouldbe the best choice. This is known as the 100 efficiencyclass, previously identified as the HEPA filter.Oil has been found to ruin the filtering ability of some filtermaterial. Oil coats the filter fibres, preventing the electrostaticcharge on the fibres from attracting and removingparticulates. Therefore, to ensure that a suitable filter is beingused, particulate filters have an N, R, or P designation:N – Not resistant to oilR – Resistant to oilP – oil-Proof.

The N series of filters is suitable for airborne particlessuch as wood dust, when there are no oil-based particlesalso in the air. For example, an N series filter would berecommended during the removal of old lead paint.However, when spraying form oil or putting down hotasphalt—operations that involve airborne oil particles—thecorrect filter would have an R or P designation.The R series—resistant to oil—should only be used for asingle shift when solvent or oil mist is present in the air.This filter resists oil but may lose its filtering ability whenin contact with oil over a long time.When using P series filters, check the manufacturer’sinstructions to determine how long the filter can be usedwhen airborne oil particles are present. P series filters wereoriginally thought to be oil-proof but tests show there maybe some loss of filtering ability with long-term oil exposure.Warning: N, R, and P series filters by themselves donot provide protection against organic vapours.


Figure 27

Filter Types

Particulate Filter

Gas/Vapour Cartridge Filter

Combination Particulate/Gas/Vapour Cartridge Filter

Gas/Vapour Cartridge FilterThis type uses substances which absorb or neutralizegases and vapours. Unlike particulate filters, gas/vapourcartridge filters become less efficient the longer they areused. They act like sponges and, when full, allow gas orvapour to pass through without being absorbed. This iscalled “breakthrough.”Common gas/vapour cartridge filters include the following:• “Organic Vapour Cartridges” usually contain activated

charcoal to remove vapours such as toluene, xylene,and mineral spirits found in paints, adhesives, andcleaners.

• “Acid Gas Cartridges” contain materials which absorbacids and may be used for protection against limitedconcentrations of hydrogen chloride, sulphur dioxide,and chlorine.

• “Ammonia Cartridges” contain an absorbent designedspecifically to remove only ammonia gases.

NoteFor respirators equipped with gas or vapourcartridges to be used safely, the contaminant musthave good warning properties (odour, taste, orbreathing irritation) that let the user know thecartridge is no longer working. When the user sensescontaminant starting to penetrate the cartridge, it’stime to change the cartridge.When users depend on odour as a warning, theodour threshold of the contaminant must be below itsexposure limit.Certain cartridges are available with an end-of-service-life indicator. These cartridges have beendeveloped for a few contaminants with poor warningproperties. The end-of-service-life indicator changescolour to warn the user to change the cartridge.Cartridges must not be used for contaminants withpoor warning properties unless the respiratormanufacturer can offer cartridges with end-of-service-life indicators.

Combination Particulate/Gas/VapourCartridge with FilterThis type removes particulate matter, vapours, and gasesfrom the air. It is used where more than one type ofhazard is present or may develop.Supplied-Air RespiratorsSupplied-air respirators provide clean breathing air froman uncontaminated source, usually a special compressorlocated in a clean environment, or from cylinderscontaining compressed breathing air. The quality of the airsupplied should meet the requirements of CSA StandardZ180.1, Compressed Breathing Air and Systems.The moisture content of supplied air should be limited toprevent fogging, corrosion, and freezing of regulators andvalves and to prolong the service life of filters used toremove other contaminants.The “pressure dew point” is important in relation tomoisture. The term refers to the temperature at which

moisture in compressed air, at a given pressure, willcondense out as droplets or “dew.” It must be kept at least5°C below the lowest expected ambient temperature.For example, if you are working where the temperature is-10°C, the dew point should be at least -15°C. Watervapour can be removed from compressed air with adrying system or water-absorbing materials.Types of Supplied-Air RespiratorsThe three basic types of supplied-air respirators areairline unit, ambient air blower, and self-containedbreathing apparatus (SCBA).The airline unit depends on a hose connecting therespirator to cylinders of compressed breathing air. Anabrasive-blaster’s hood is one example (Figure 28).The ambient air blower draws air through an inlet hose(positioned where the air is clean) and pumps the airunder fairly low pressure to the worker’s hood, helmet, orfacepiece.The self-contained breathing apparatus (SCBA) uses acylinder of air carried by the wearer (Figure 29). SCBAs areawkward, heavy, and require frequent cylinder changes.Combination airline/SCBA units are available for work inconfined spaces and other high-risk assignments wherereserve protection is required (Figure 30).With these devices or with simple airline units, thewearer’s mobility is understandably restricted by thetrailing hose and the length of line available. In addition,airlines may get crimped or may snag on equipment.If an atmosphere is immediately dangerous to life orhealth, a combination airline/SCBA unit is required.Both airline and SCBA units are more expensive than air-purifying systems, but they generally provide muchgreater protection.Modes of OperationRespirators can operate in the following modes:• “negative pressure” or “demand”• “constant-flow”• “positive pressure” or “pressure-demand.”Negative Pressure or Demand ModeAir is delivered only when the wearer inhales. Pressureinside the facepiece is then lower than pressure outsidethe facepiece. This allows air to pass through the filters inthe case of air-purifying respirators, or actuates a valvethat allows air into the facepiece in the case of supplied-air respirators. Because contaminated air may leak inwardaround the facepiece, these devices have limited use inhigh exposure conditions.Constant-Flow ModeAs the name implies, these devices deliver a constantflow of air to the wearer. Powered air-purifying respirators(PAPRs) use a battery-powered fan to draw air throughthe filter and then blow it into the facepiece (Figure 31).Constant-flow supplied-air respirators such assandblasters’ hoods use a simple valve to control the flowof “clean” air from the compressor. Minimum flow rates of170 litres per minute (6 cubic ft/min) for loose-fitting hoods

19 – 3


19 – 4

or helmets and 115 litres per minute (4 cubic ft/min) fortight-fitting facepieces must be maintained to minimizeinward leakage of contaminated air and still provideadequate breathing air.Positive Pressure or Pressure-Demand ModeSince the previous modes may permit significant inwardleakage, a system which maintains a positive pressureinside the facepiece at all times, as well as supplyingmore air as demanded, was developed.If leakage occurs, the high pressure inside the facepiecedirects the leakage away from the facepiece rather thanallowing it in.This class of device is only available with supplied-airrespirators.Styles of FacepiecesIn addition to the type of respirator and mode ofoperation, the style of facepiece is used to classifyrespirators. Different styles are available (Figure 32).

Protection FactorsThe protection factor (PF) is a measure of theeffectiveness of a respirator. PFs are determined bydividing the concentration of a contaminant outside therespirator by the concentration inside the respirator. PFsare used in the selection process to determine themaximum use concentration (MUC) for the respirator. TheMUC is determined by multiplying the legislated orrecommended exposure limit by the PF.For example, the exposure limit for chrysotile asbestos inOntario is 0.1 fibre/cm3 of air. If we are using a half-maskrespirator with N100 filters (PF=10), the MUC is 1fibre/cm3. This is obtained by multiplying the PF (10) by

the exposure limit (0.1 fibre/cm3). If the concentration ofasbestos becomes greater than 1 fibre/cm3 during thecourse of work, a respirator with a greater protectionfactor must be used.The Canadian Standards Association (CSA), the USNational Institute for Occupational Safety and Health(NIOSH), and the American National Standards Institute(ANSI) have each published slightly different protectionfactors. In this manual, NIOSH-assigned protection factorsare used.The degree of protection depends on the type ofrespirator, style of facepiece, and principle of operation.Generally, supplied-air respirators provide betterprotection than air-purifying respirators; full-face masksprovide better protection than half-face masks; andpositive-pressure devices provide more protection thannegative-pressure types.Table 7 lists protection factors for the respirators describedso far. The information can be used to select the mostappropriate device for any given situation.The protection factors listed in Table 7 were determinedby testing a wide variety of devices worn by a largenumber of people and represent the average degree ofprotection achieved. Protection factors for individualwearers may differ significantly from the values listed.

Respirator SelectionIn order to select the proper respirator for a particular job,it is necessary to know and understand• the characteristics of the contaminant(s)• the anticipated exposure conditions• the performance limitations of the equipment• any legislation that applies.


Abrasive–Blaster’s Supplied-Air Hood

Type CE abrasive-blast supplied-air respirators arethe only respirators suitable for abrasive-blast(sandblasting) operations. As a minimum, NIOSHrecommends a type CE, positive pressure, with tight-fitting half-mask facepiece respirator.

Figure 28

Self-Contained Breathing Apparatus(SCBA)

Figure 29

Combination Airline/SCBA Unit

Figure 30

19 – 5

It is also important to realize that facial hair and deepfacial scars can interfere with the seal between respiratorand face. Respirators should only be selected bysomeone who understands all of these factors.Before using or handling a controlled product, consult thematerial safety data sheet (MSDS). The MSDS will identifyany respiratory protection required. Under the WorkplaceHazardous Materials Information System (WHMIS), MSDSsmust be available to users of control-led products. TheMSDS should specify the type of respirator to be worn.The chart at the end of this section is a guide to respiratorselection. It is intended as a guide only and may not beapplicable to every case.For activities not listed, information regarding type ofwork, nature of material(s) involved, and workingconditions is required and expert advice should beobtained.If there is any doubt about the correct type of protectionfor a specific material and operation, consult themanufacturer of the product, a supplier or manufacturer ofrespirators, or CSAO. When seeking information on thetype of respirator for use in specific situations, provide asmuch of the following information as possible:a) Name and form of the material (oil or non-oil). If the

form is unknown, consider it an oil.

b) Type of work to be done (e.g.,painting, welding).

c) Description of worksite conditions(e.g., inside a tank, outdoors).

d) Exposure concentration, if known(e.g., 150 ppm of toluene).

e) Whether the material will beheated, sprayed, etc.

f) Other materials being used in thevicinity.The respiratory protectionspecialist will evaluate thisinformation and compare it withthe following additional data:

g) The permissible exposure limit ofthe dust, gas, or vapour, oftenreferred to as the TLV® orThreshold Limit Value*. Thesevalues are used in conjunctionwith the protection factors listed inTable 1 to determine themaximum use concentration.*TLV is a term copyrighted by the AmericanConference of Governmental IndustrialHygienists.

h) The physical properties of thecontaminant:• Vapour Pressure — Themaximum amount of vapourwhich can be generated undergiven conditions.

• Warning Properties (e.g.,irritation, odour, taste) — If thematerial has poor warningproperties (for example, whenthe lowest concentration thatcan be detected by odour is

greater than the permissible exposureconcentration), air-purifying respirators are usuallynot permitted.

• Types of Effects — With cancer-causing materialsa higher degree of protection is usually specified.

• Performance of Filters — With some gases andvapours the filter can become overloaded in just afew minutes. Therefore, knowledge of the filteringmaterial and its performance against specificgases and vapours is necessary.

i) The concentration considered to be ImmediatelyDangerous to Life or Health (IDLH). IDLHatmospheres pose an immediate threat to life orhealth or the threat of a serious but delayed effect onhealth (e.g., radioactive dust exposures). Oneexample of an IDLH situation is the repair of achlorine leak where a worker could be overcome bythe gas very quickly. IDLH atmospheres should onlybe entered by persons wearing SCBA or SCBA/airlinerespirators as shown in Figures 29 and 30.

j) Possibility of skin absorption. With some chemicalsthe amount of material which can be absorbedthrough the skin is of equal or greater concern thanthe amount of gas or vapour which can be inhaled.For these situations supplied-air protective suits maybe necessary.


Figure 31

A powered air-purifying respirator(PAPR) blows a continuous supplyof filtered air over the face. Whenworking conditions are hot andhumid, it provides more comfortthan non-powered air-purifyingrespirators.

Remember: PAPRs are air-purifyingand should never be used underoxygen-deficient conditions.

Powered Air-Purifying Respirators (PAPRs)

Battery Pack, Blower and Filter Housing

19 – 6

k) Eye irritation — some contaminants will cause eyeirritation, making it difficult to see. For thesecontaminants, a full-face mask must be worn.

As shown by points a) to k), many factors must beconsidered to ensure that the proper respirator is selectedfor a specific situation.

NoteFacial hair and eye protection can adversely affectthe respirator seal. Facial hair between the face and atight-fitting respirator can cause a great deal ofleakage and reduce the effectiveness of protectionsignificantly. Respirator wearers should be clean-shaven to achieve the best possible seal. Where eyeprotection with temple bars or straps passing betweenface and respirator is necessary, consider wearing afull-face mask.

Fit Testing and Seal ChecksOnce a respirator has been selected, the next critical stepis ensuring that it fits properly. One size does not fit all.With every respirator except hoods or helmets, a tightseal is required between facepiece and face.With negative-pressure respirators (e.g., non-powered air-purifying respirators and demand supplied-air respirators)gaps in the seal will permit contaminated air to enter thebreathing zone.With positive-pressure respirators (e.g., powered air-purifying respirators and pressure-demand supplied-airrespirators) a lot of air will be wasted through outward


Filtering Facepiecefor Particulates

Filtering Facepiecewith Exhalation Valves

Filtering Half-FacepiecesMost of these devices are designed tobe worn only once. They fit over themouth and nose, rest on the chin, andare held in place by two straps. Someof the more sophisticated versions withadjustable straps and exhalation valvescan be worn more than once, providedthey are not damaged.

Figure 32

Full-Face MaskThis style covers the entire faceand consists of a mouldedrubber or plastic frame and aclear visor. Since it fits againstthe relatively smooth rim of theface, it provides more protectionthan other face masks. Full-facemasks can be used with air-purifying, powered air-purifying,and supplied-air respirators.

Half-Face MaskThis style is widely used as an air-purifying respirator with oneor more filters or cartridges attached to the facepiece. Thesilicone, thermoplastic, or rubber facepiece covers the mouthand nose, cups under the chin, and is usually held in place bytwo straps. It generally provides better protection than quarter-face masks because the chin cup affords a more secure fit.

Facepiece

Strap

Exhalation Valve

Inhalation Valve

ReplaceableFilter/Cartridge

Hoods and HelmetsUnlike the previous styles, thesedevices do not rely on tight sealsto prevent inward leakage ofcontaminated air. Instead theydepend on the continuous flow oflarge volumes of air. Hoods andhelmets can be usedwith powered air-purifyingand supplied-air systems.

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leakage and the degree of protection provided to thewearer could be reduced. Also, “venturi effects” may allowair to escape in one area and draw contaminated air intothe facepiece around the escaping air.For these and other reasons, the fit of respirators must becarefully tested. Generally there are two types of fit testing— qualitative and quantitative.Qualitative Fit Tests1) Irritant Smoke Test — The wearer puts on the

respirator with “high efficiency or fume filters” in place.A cloud of irritant smoke is created around the wearer.If leakage is detected the respirator should beadjusted.Caution: Most of the smoke clouds used in this testare very irritating to the eyes, nose, and throat.Workers are advised to keep their eyes closed duringthe test and to back out of the smoke as soon as theynotice any leakage or irritation.

2) Iso Amyl Acetate (Banana Oil) Test — The wearerputs on the respirator with “organic vapour” cartridgefilters in place. A cotton swab dipped in iso amylacetate solution is passed along the outline of thefacepiece (iso amyl acetate smells like very ripebananas). If the wearer smells the solution, therespirator should be adjusted.Note: Some people cannot smell iso amyl acetate.Before starting the test, check to ensure that theperson can detect the odour. Use two small jars, onecontaining water, the other containing the testsolution. Ask the person whether one smells differentand what it smells like.

3) Saccharin Test — This test is similar to the iso amylacetate test except that it uses saccharin as the testmaterial and a dust/mist or high efficiency respirator. Ifthe sweet taste or smell of saccharin is detected, thefit must be adjusted.

4) Bitrex Solution Aerosol Test — In this test thewearer puts on the respirator with any particulatefilter. A hood or test enclosure is put over the wearer’shead and shoulders. Bitrex is then sprayed into thehood or enclosure. Bitrex is a very bitter solution andcan easily be detected if it leaks through the faceseal. If the wearer cannot taste the Bitrex, then therespirator fits properly.


Table 7: Protection Factors (according to NIOSH)

Type of Respirator Facepiece Style FacepiecePressure

CartridgeType Hazard Form Protection

Factor

Air-purifying Filtering half-facepiece N N/A Particle 10 ‡

Half-face mask N 1 Particle, gas, vapour 10 ‡

Full-face mask N 1 Particle 10Full-face mask N 2 Particle 50Full-face mask N 3 Gas, vapour 50 ‡

Powered air-purifying Loose hood helmet C 1 Particle, gas, vapour 25 ‡

Tight-fitting facepiece C 3 Gas, vapour 50 ‡

Tight-fitting facepiece C 2 Particle 50

Airline Half-face mask N N/A Particle, gas, vapour 10Half-face mask P N/A Particle, gas, vapour 1,000Full-face mask N N/A Particle, gas, vapour 50Full-face mask P N/A Particle, gas, vapour 2,000Hood or helmet C N/A Particle, gas, vapour 25

SCBA * Half-face mask P N/A Particle, gas, vapour 1,000SCBA * Full-face mask N N/A Particle, gas, vapour 50SCBA * Full-face mask P N/A Particle, gas, vapour 10,000

* SCBA or airline with emergency air bottle adequate forescape from the hazardous environment

‡ Protection factor may be limited by the cartridge. Checkwith manufacturer.

N NegativeC Constant flowP PositiveN/A Not applicable

1 Any appropriate NIOSH-approved2 High efficiency particulate aerosol (HEPA)3 Appropriate NIOSH-approved gas or vapour

19 – 8

Quantitative Fit TestsIn these tests the wearer puts on a special respirator whichhas a probe mounted inside the facepiece. The wearer thengoes into a test chamber or booth which contains a knownconcentration of a specific gas, vapour, or aerosol. Theamount of leakage is determined by sampling the air insidethe facepiece through the probe. This method is not wellsuited for use on most construction projects.User Seal ChecksEvery time you put a respirator on, check the seal using thenegative-pressure and positive-pressure method.

1) Negative Pressure Test—The wearer puts on therespirator and adjusts it so that it feels relativelycomfortable. Then the air inlets are blocked off with thehands or a plastic cover, and the wearer inhales gently(Figure 33). If the respirator is properly fitted, it shouldcollapse slightly and not permit any air into the facepiece.If leakage is detected, the mask should be readjustedand the test repeated until the fit is satisfactory.

2) Positive Pressure Test — The wearer puts on therespirator and adjusts it so that it feels relativelycomfortable. Then the exhaust port of the respirator iscovered and the wearer tries to exhale gently (Figure34). The facepiece should puff away from the wearer,but no leakage should occur.

Respirator MaintenanceLike any equipment, respirators require maintenance. Thefollowing instructions cover the major points.1) Filters should be changed as follows:

• Dust/mist/fume filters should be changed whenthere is noticeable resistance to normal breathing.

• Chemical cartridge respirators should be changedwhen the gas or vapour can be tasted or smelled.

• Any filter should be changed at the intervalspecified by the manufacturer or when damagedin any way.

2) Inhalation and exhalation valves should be checkedbefore the respirator is used.

3) Damaged facepiece, straps, filters, valves, or other partsshould be replaced with “original equipment” parts.

4) Facepieces should be washed with mild soapy water asoften as necessary to keep them clean and wearable.

5) Respirators should be assigned to the exclusive useof individual workers.

6) Where a respirator must be assigned to more thanone worker, it should be disinfected after each use(check with the manufacturer regarding acceptable

sanitizers/disinfectants).7) Check all supply hoses, valves, and regulators on

supplied-air respirators as specified by the manufacturer.8) SCBA units and high-pressure cylinders of

compressed breathing air should be used andmaintained in accordance with current CanadianStandards Association Z180.1 Compressed BreathingAir and Systems, and Z94.4 Selection, Care and Useof Respirators.

9) Compressors and filtration systems used withsupplied-air respirators must be maintained inaccordance with the manufacturers’recommendations.

10) Consult manufacturer for information on respiratorcartridge change-out.

Approvals and StandardsThe most commonly referenced standards for respiratoryprotection in North America are the test criteria used by theNational Institute for Occupational Safety and Health (NIOSH).NIOSH is a U.S. government agency which tests andapproves respiratory protective equipment as one of itsmajor activities and publishes a list of approved devicesannually.The Construction Safety Association of Ontariorecommends that only NIOSH-approved equipment beused for protection against respiratory hazards.Unapproved devices should be evaluated carefully by acompetent respiratory protection specialist before use.The Canadian Standards Association has issued twostandards pertaining to respiratory protection whichshould be reviewed by the person responsible for therespirator program:• Z180.1 Compressed Breathing Air and Systems lists

the criteria for air purity and delivery systems• Z94.4 Selection, Care and Use of Respirators offers

recommendations on these three aspects of the subject.These standards are copyrighted by CSA. Copies can bepurchased fromCanadian Standards Association178 Rexdale BoulevardRexdale, OntarioM9W 1R3(416) 747-4000 www.csa.ca


Cover inletsand try toinhale.

Figure 33

Negative-Pressure Seal Check

Coverexhalationvalve and tryto exhale.

Figure 34

Positive-Pressure Seal Check

19 – 9

ReviewThe following section lists common claims about respirators and explains why the statements are true or false. Theinformation provides a convenient review of major points in this chapter.1) All respirators are the same. (False) Most respirators, especially air-purifying types, are limited to

certain types of hazards. For instance, dust masks may besuitable for dusts, but do not provide protection against gasesand vapours.

2) One size fits all. (False) Most manufacturers offer three sizes of facepieces (small,medium and large) to ensure a proper fit. In some cases, nosize from one manufacturer may fit an individual and adifferent brand may be necessary.

3) Respirators make breathing (True) With air-purifying respirators the air is beingmore difficult. inhaled through a filter so some additional effort is required.

With most pressure/demand supplied-air respirators additionaleffort is required to activate the inhalation and exhalationvalves.

4) Air-purifying respirators supply (False) These devices simply filter out specific gases,oxygen. vapours, dust, mists, or fumes, but do not increase the

oxygen content of the air.5) Most respirators require (True) With the exception of disposable and single-use

maintenance. respirators, some maintenance is required.6) Any source of compressed air (False) Compressed breathing air must be “clean” and

will be adequate for supplied-air free from carbon monoxide, oil mist, and otherrespirators. contaminants.

7) Protection factors are the same (False) The protection factors listed in Table 7for everyone. are averages obtained by testing a large number or wearers.

Individual protection factors can be considerably different fromthose listed.

8) Respirators are the best way to (False) Good ventilation is the best way of controllingcontrol respiratory hazards. respiratory hazards, though it is not always practical in many

construction applications.9) The moisture content of (True) If the moisture content of the air in a pressurized

compressed air is important. breathing air system is too high, the regulators can freezeshut and cut off the supply of air. Moisture can also causedeterioration of storage cylinders.

10) Parts can be interchanged from (False) Using improperly fitted or matched componentsone manufacturer to another. voids the NIOSH approval and can cause failure of the

respirator posing serious risk to the wearer.11) Fitting of respirators is not (False) No matter how effective its protection against

important. specific hazards, the respirator must be properly fitted toprevent inward leakage of contaminated air. The onlyexceptions are hoods and helmets, and even these dependon fit to a certain degree.

12) Self-Contained Breathing (True) They also have disadvantages which makeApparatus (SCBA) and air-line their use impractical in some situations.respirators provide the best protection.

13) Respirators should be checked (True) Damaged straps, missing or ill-fitting valves, andeach time they are used. other problems can make the device useless.

14) Only one respiratory hazard is (False) Often there are two or more hazards present.present in a particular job. For instance, spray painting produces mists and vapours

while welding can produce fume and gases.15) Respirators can be fitted with (True) Many manufacturers offer filters which will

filters suitable for more than one remove selected dusts, fumes, gases, andhazard. vapours all at the same time.

16) Single-use dust masks should (True) These inexpensive respirators are meant to be put on oncenot be worn more than once. only. They may not provide adequate protection once the

straps have been stretched.


19 – 10

17) Respirators provide absolute (False) Every respirator has limitations which the wearerprotection. must understand. Protection is ensured not only by the

respirator but also by its proper use.18) Respirators are simple to select (False) In many cases even the respiratory protection

for any job. specialists have problems in selecting the right device.19) Respirators interfere with eye (True) Protective goggles and glasses may not fit properly with

protection. many respirators. Full-face masks may be necessary.20) NIOSH approvals are important. (True) NIOSH approvals indicate that the device has passed a set of

minimum design and performance standards. Unapprovedrespirators may provide similar protection but this can only beevaluated by expert review of the manufacturer’s claims.

21) Beards and mustaches do not (False) With the exception of hoods and some helmets,affect respiratory protection. beards and mustaches cause a great deal of leakage and

reduce the effectiveness of respirators significantly. Respiratorwearers should be clean shaven to obtain the best possibleprotection.

SummaryRespiratory protective equipment can prevent illness, disease, and death from breathing hazards. But the equipmentmust be properly selected, fitted, worn, and maintained to ensure maximum protection.The Construction Safety Association of Ontario can provide assistance in selecting respiratory protection and trainingworkers in its use, care, and maintenance. For additional information, contact CSAO.


19 – 11


Asbestos: see Asbestos chapter in this manual.

Filter efficiency and type 95 100 95 100 Organicvapour

95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA

Assigned Protection Factor*(NIOSH 1987) 10 10 10 10 10 10 10 10 50 50 50 1000 10,000

Air purifying Supplied air

Half facepiece Full facepiece PoweredAir-

PurifyingRespirator(PAPR),tight-fitting

Hood orHelmet

NIOSHtype CEpressuredemand

Half-facepiecepressuredemand

SCBA orSCBA +airline,

fullfacepiece

andpositivepressure

Filtering facepiece Elastomeric facepiece

Respirator Selection Guide forCommon Construction Activities

Lead

Application of lead-containingcoatings with a brush or roller

Optional

N, R, or P

Spray application of lead-containing coatings

Hood orhelmet

Removal of lead-containingcoatings or materials by scrapingor sanding using non-poweredhand tools

N, R, or P

Removal of lead-containingcoatings or materials using non-powered hand tools—other thanmanual scraping or sanding

Optional

N, R, or P

Removal of lead-containingcoatings with a chemical gel orpaste and fibrous laminated clothwrap

Optional

N, R, or P

Removal of lead-containingcoatings or materials using apower tool without a dustcollection system equipped with aHEPA filter(airborne dust ≥ 0.05 mg/m3)

Full

facepiece

Continued on next page . . .

N = Not resistant to oil R = Oil-resistant P = Oil-proof OV = Organic vapour cartridge indicates suitable protection. If oil mist is present, use R or P filters.

* Assigned protection factor: The protection factor assigned by NIOSH, the US National Institute for Occupational Safety and Health. It’s ameasure of the effectiveness of a type of respirator and suitable filter. Higher numbers mean greater protection. You may use a respirator witha greater protection factor than the one recommended for your task. Never use a respirator with a smaller protection factor.

These recommendations will provide adequate protection in most circumstances. Factors such as ventilation, duration of exposure, and usercharacteristics can affect how well a respirator protects you. If unsure about the respirator required for a task, contact the manufacturer or CSAOat 1-800-781-2726, www.csao.org.

19 – 12


Respirator Selection Guide for Common Construction Activities

Lead cont’d

Removal of lead-containingcoatings or materials using apower tool with a dust collectionsystem equipped with a HEPA filter(airborne dust must be controlledto < 0.05 mg/m3)

Optional

N, R, or P

Abrasive blasting of lead-containing coatings or materials

Type CEblasting;positive

pressure;tight-fittinghalf-

facepiece

Dry removal of lead-containingmortar using an electric orpneumatic cutting device

Tight-

fitting fullfacepiece

Welding or high-temperaturecutting of lead-containing coatingsor materials indoors or in aconfined space

Tight-


Welding or high-temperaturecutting of lead-containing coatingsor materials outdoors—long-termoperations or if material not pre-stripped

Tight-


Welding or high-temperaturecutting of previously stripped lead-containing coatings or materialsoutdoors—short term only

N, R, or P

Burning of a surface containinglead

Tight-


SolderingOptional

N, R, or P

Installation or removal of lead-containing sheet metal

Optional

N, R, or P

Installation or removal of lead-containing packing, babbit, orsimilar material

Optional

N, R, or P


N = Not resistant to oil R = Oil-resistant P = Oil-proof OV = Organic vapour cartridge


95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure


19 – 13




Lead cont’d

Demolition or cleanup of a facilitywhere lead-containing productswere manufactured

Tight-


Manual demolition of lead-paintedplaster walls or buildingcomponents using asledgehammer or similar tool

N, R, or P

Removal of lead-containing dustusing an air-mist extraction system

Pressuredemand;

fullfacepiece

Removal or repair of a ventilationsystem used for controlling leadexxposure

Tight-


An operation that may expose aworker to lead dust, fume, or mist,that is not a Type 1, Type 2, orType 3b operation

Tight-


Painting

Spraying latex paint

N, R, or P(small-scale)

N, R, or P(small-scale)

N, R, or P

(large-scale)

Alkyds, enamels, and sealers:brush and roller applicationindoors but well-ventilated

R or P

Alkyds and enamels: spray paintingin well-ventilated area

R or P

Alkyds and enamels: painting in aconfined space

Epoxy or polyurethane spraypainting

Spraying lead paint N, R, or P

Spraying stucco R or P


95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure


19 – 14



Roofing

Removal of roofing material (built-up roofing, no asbestos)

R or P

R or P

R or P

Heat welding roofing membrane N, R, or P

N, R, or P

Adhesive welding roofingmembrane

N,R, or P

Roofing kettle operators (asphalt) N, R, or P

+OV

Silica

Breaking concrete outdoors N, R, or P

N, R, or P

Crushing rock and gravel N, R, or P

N, R, or P

Blasting rock N, R, or P

N, R, or P

Abrasive blasting—either ≥ 1%silica in the abrasive blastingmedia or ≥ 1% silica in the targetmaterial being blasted

Drywall sandingFor short-term

applications,

a filtering

facepiece

respirator

may be

appropriate

N, R, or P

N, R, or P

Machine mixing concrete or mortar N, R, or P

N, R, or P

Drilling holes in concrete or rockthat is not part of a tunnellingoperation or road construction

N, R, or P

N, R, or P

Milling of asphalt from concretehighway pavement

N, R, or P

N, R, or P

Charging mixers and hoppers withsilica sand (sand consisting of atleast 95% silica) or silica flour(finely ground sand consisting ofat least 95% silica)

N, R, or P

N, R, or P

Any other operation at a projectthat requires the handling of silica-containing material in a way that aworker may be exposed toairborne silica

N, R, or P

N, R, or P



95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure



19 – 15




Silica cont’d

Entry—for less than 15 minutes—into a dry mortar-removal orabrasive-blasting area forinspection or sampling whereairborne dust is visible

For short-termapplications,a filteringfacepiecerespiratormay beappropriate

N, R, or P

N, R, or P

Entry into an area where abrasiveblasting is being carried out formore than 15 minutes

For short-term applications

or applications involving tools

or equipment with adequate controls

(local exhaust ventilation or water),

a half-facepiece respirator

may be appropriate

N, R, or P

Dry method dust clean-up fromabrasive blasting operations

N, R, or P

Removal of silica-containingrefractory materials with ajackhammer

N, R, or P

Drilling holes in concrete or rockas part of a tunnelling operation orroad construction

N, R, or P

Using a power tool to cut, grind, orpolish concrete, masonry, terrazzo,or refractory materials

N, R, or P

Using a power tool to removesilica-containing materials

N, R, or P

Using a power tool indoors to chipor break and remove concrete,masonry, stone, terrazzo, orrefractory materials

N, R, or P

Tunnelling (operation of tunnelboring machine, tunnel drilling,tunnel mesh insulation)

N, R, or P

Tuckpointing and surface grinding N, R, or P

Dry-mortar removal with anelectric or pneumatic cuttingdevice

N, R, or P

Using compressed air outdoors toremove silica dust

N, R, or P


95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure


19 – 16




Other dust and fibre exposure

Removal of roofing material (built-up roofing, no asbestos)

R or P

R or P

R or P

Dry method dust clean-up fromabrasive blasting operations

For short-term applications orapplications involving tools or

equipment with adequate controls(local exhaust ventilation or water)

a half-facepiece respiratormay be appropriate.

N, R, or P

Wood dust, including pressure-treated wood dust

N, R, or P

N, R, or P

Vinyl or laminate floor sanding

N, R, or P

N, R, or P

Synthetic Vitreous Fibres (Man-made mineral fibres)

Installation, removal, or blowingcellulose, fiberglass, mineral wool,or calcium silicate

N, R, or P

N, R, or P

N, R, or P

N, R, or P

Installation of refractory ceramicfibres (silica may be present)

N, R, or P

Removal of refractory ceramicfibres (silica may be present)

N, R, or P


95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure


19 – 17


** Protection from ozone may be required in some circumstances. Contact the respirator manufacturer.

Miscellaneous

Epoxy adhesive (large-scale use)

Solvents, adhesives, and epoxy(small scale)

R or P

Caulking compounds, solvent-based, large-scale use

R or P

Form oil spraying R or P

Paving R or P



Welding and flame-cutting

Any welding in confined spaceswhen the atmosphere is notmonitored

Aluminum** N,R, or P

N,R, or P

Mild steel N, R, or P

N, R, or P

Stainless steel N, R, or P

N, R, or P

Galvanized or plated metals N,R, or P

N,R, or P

Lead-painted steel: flame cutting orwelding, short-term, not repeated,material stripped before work

N,R, or P

N,R, or P

Welding or high-temperaturecutting of lead-containing coatingsor materials indoors or in aconfined space

N, R, or P


95+organicvapour

100+organicvapour

95 100100+

organicvapour

HEPA





Hood orHelmet




fullfacepiece

andpositivepressure


20 – 1

HAND / SKIN PROTECTION

20 HAND/SKIN PROTECTIONIn construction, exposed hands and skin are susceptibleto physical, chemical, and radiation hazards. Personalhand/skin protection is often the only practical means ofpreventing injury from• physical hazards—sharp or jagged edges on

materials and tools; heat; vibration• corrosive or toxic chemicals• ultraviolet radiation.

Physical HazardsFor physical hazards such as sharp edges, splinters, andheat, leather gloves are the preferred protection. Cottonor other materials do not stand up well and arerecommended only for light-duty jobs.Vibration transferred from tools and equipment can affecthands and arms. One result may be hand/arm vibrationsyndrome (HAVS). This disease causes the followingchanges in fingers and hands:• circulation problems such as whitening or bluish

discoloration, especially after exposure to cold• sensory problems such as numbness

and tingling• musculoskeletal problems such as difficulty with fine

motor movements—for instance, picking up smallobjects.

Workers who use vibrating tools such as jackhammers,grinders, riveters, and compactors on a daily basis maydevelop HAVS. Preventing this disease requirescooperation between employers and workers.Employers• Provide power tools with built-in vibration-reducing

components.• Review exposure times and allow rest breaks away

from vibrating tools.• Ensure proper tool maintenance (worn grinding wheels

or tool bearings can lead to higher vibration levels).• Train exposed workers in prevention techniques.• Provide anti-vibration gloves.

Workers• Wear appropriate clothing in cooler weather to

maintain core body temperature.• Wear gloves whenever possible.• Wear anti-vibration gloves when using power tools

and equipment.• Avoid smoking (smoking contributes to circulatory

problems).• Report any poorly functioning tools immediately.

Chemical HazardsFor protection against chemical hazards, the materialsafety data sheet (MSDS) for the product being usedshould identify whether gloves are needed and what theyshould be made of. MSDSs must be available on site forall controlled products being used.

Table 8: Glove Selection Chart

Table 8 identifies glove materials to be worn for protectionagainst chemicals that may injure the skin. Thisinformation can be used when the MSDS does not specifythe type of glove to be worn.

CAUTION: Common glove materials have limitedprotective properties and do not protect against allhazards. Some solvents, degreasers, and otherliquids can penetrate and/or dissolve rubber,neoprene, or PVC.

Ultraviolet RadiationIn recent years there has been growing concern over thehealth risks of exposure to the sun’s ultraviolet (UV)radiation. Construction workers are particularly at riskbecause they often work outdoors.Long-term health risks of UV exposure include skincancer. Every year there has been an alarming increasein the incidence of skin cancer. Sunlight is the mainsource of UV radiation known to damage the skin andcause skin cancer. Exposure to the sun’s UV radiation iswidely recognized as a highly preventable cause of skincancer.Melanoma is the least common but most dangerous typeof skin cancer. The incidence of melanoma in men isrising faster than all other cancers. According to theCanadian Dermatology Association (CDA), the mortalityrate from malignant melanoma is increasing, particularlyin middle-aged males.Melanomas most often appear on the upper back, head,and neck. The CDA also notes that there is generally alag time of 10 to 30 years for the clinical appearance ofskin cancer to occur. Consequently, it is critical for youngworkers to beware of the cumulative effect of unprotected

Chemical Name Glove Selection

Acetone Butyl RubberCellosolve PVA, PVC, NeopreneCellosolve Acetate PVA, PVCCyclohexane NBR, Viton®

Hexane Neoprene, NBR, PVAMethyl Alcohol Neoprene, Rubber, NBRMethyl Chloroform PVA, VitonMethylene Chloride PVA, VitonMethyl Ethyl Ketone Butyl RubberMethyl Isobutyl Ketone Butyl Rubber, PVAMineral Spirits NeopreneNaphtha NBR, PVAPerchloroethylene NBR, PVA, VitonStoddard Solvent PVA, NBR, RubberToluene PVA, VitonTurpentine PVA, NBRTrichloroethylene PVA, Viton1, 1, 1 Trichloroethane PVA, Viton1, 1, 2 Trichloroethane PVA, VitonXylene PVA, Viton

PVA – Polyvinyl AlcoholPVC – Polyvinyl ChlorideNBR – Nitrite Butyl RubberViton® – Dupont tradename product

sun exposure. The more time they spend unprotected inthe sun, the higher the risk of developing skin cancer.Although most construction workers generally cover uptheir arms, legs, and torso on site, their faces and necksare still exposed to the sun’s harmful rays. In addition,areas like the tips of the ears and the lips are oftenoverlooked when it comes to sun protection.The type of skin cancer that develops on the ear or the liphas a high chance of spreading to other parts of the bodyand causing death. Melanoma may also occur on the sun-exposed parts of the head and neck.In fact the majority of skin cancers (2 out of 3) occur onthe head and neck, followed by the forearm and back ofthe hand. Workers too often leave these critical areasexposed to the harmful effects of UV radiation.Individual risk factors for developing skin cancer include- fair skin that burns easily- blistering sunburns in childhood

and adolescence- family history of melanoma- many freckles and moles.In addition to the harmful effects of the sun’s direct rays,some workers may be exposed to indirect UV radiation.Workers can receive additional radiation if they are on ornear a surface that reflects sunlight. Reflective surfacessuch as concrete, water, unpainted corrugated steel,building glass, and aluminum can increase the amount ofultraviolet radiation to which a worker is exposed.Another source of indirect UV radiation is from the hardhat itself. UV rays can reflect off the hard hat onto aworker’s face, magnifying the amount of UV exposure.Although all construction workers are at risk, those who don’thave ready access to shade and/or work at heights are at ahigher risk for UV overexposure. These trades include- concrete finishing workers- roofers- rodworkers- formworkers on high-rise and

residential sites- roadworkers- traffic signallers- ironworkers.In addition, working at sites with southern exposuredecreases the daytime shade available and increasesUV exposure.Remember—even on cloudy or hazy days, UVradiation can penetrate the atmosphere and burnyour skin.

What Workers Can Do Apply a broad-spectrum sunscreen with a sun protection

factor (SPF) of 15 or greater to all exposed skin areas.Be sure to cover your ears and the back of your neck.Apply sunscreen 20 to 30 minutes before you go out inthe sun. Reapply sunscreen every 2 hours.

Use an SPF 15 or higher sunscreen lip balm andreapply every two hours. Skin cancers can develop onlips.

You may add UV protection to the back of your neck byusing fabric to block the sun’s rays. Neck protectors thatclip onto your hardhat are available.

Wear UV-absorbent safety glasses (CSA-approvedpolycarbonate glasses incorporate this feature).

Wear clothing that covers as much of the skin aspossible. Tightly woven material will offer greaterprotection as a physical block to UV rays.

If you sweat heavily, you may need to reapplysunscreen more often. Additionally, when clothing iswet, it loses some of its ability to block out the sun’srays. Ensure you have additional dry clothing ifnecessary.

Try to find a shaded area for your breaks and lunch. Wear a wide-brim hard hat designed to protect your

face and neck from the sun. Adding a glare guardunder the peak of your hard hat will help reducereflective UV rays.

Examine your skin regularly for any unusual changes.The most important warning sign for skin cancer is aspot on the skin that is changing in size, shape, orcolour. The danger signs include any wound or skinpatch that doesn’t heal properly or scales. Beparticularly attentive to any mole that grows orbecomes irregular in shape, especially if it is multi-coloured. If anything looks unusual, see your doctor assoon as possible. Skin cancers detected early canalmost always be cured.

What Employers Can Do Supply workers with a broad-spectrum sunscreen with

an SPF of 15 or higher. Ensure adequate shaded areas for workers on breaks

and lunch. If possible, rotate workers to shaded areas of the

jobsite. Educate workers on the hazards of UV radiation. Ensure that workers use UV-absorbent safety glasses.The majority of skin cancers are preventable. Takingbasic precautions can significantly reduce the healtheffects of chronic sun exposure.

20 – 2

HAND / SKIN PROTECTION

21 – 1

HIGH-VISIBILITY CLOTHING

21 HIGH-VISIBILITY CLOTHINGThe construction regulation (O. Reg. 213/91) requires thatany worker who may be endangered by vehicular trafficon a project must wear a garment that provides a highlevel of visibility.There are two distinct features to high-visibility clothing.Background MaterialThis is the fabric from which the garment is made. It mustbe fluorescent orange or bright orange in colour andafford increased daytime visibility to the wearer.Fluorescent orange provides a higher level of daytimevisibility and is recommended.Retroreflective Stripes or BandsThe stripes or bands must be fluorescent andretroreflective and be arranged on the garment with twovertical stripes down the front and forming an X on theback. The stripes must be yellow and 50 mm wide.Retroreflective stripes are to afford the worker both low-light and night-time visibility.

For night-time work, additional stripes or bands arerequired on the arms and legs. One way to meet thisrequirement is to dress workers in fluorescent orangecoveralls with retroreflective bands or stripes attached.Risk AssessmentBefore selecting high-visibility garments, assess the risksto be controlled. Workers who require greater visibility,such as roadway construction workers, should wearclothing that is highly conspicuous under theconditions expected.For further recommendations on high-visibility clothing,consult CSA's standard Z96-02.

22 – 1

22 GUARDRAILSA worker at risk of falling certain distances (see below) mustbe protected by a guardrail system or, if guardrails are notpractical, by a travel-restraint system, fall-restricting system,fall-arrest system, or safety net. In many cases, guardrailsare the most reliable and convenient means of fall protectionand they must be your first consideration.Guardrails or, if guardrails are impractical, other appropriatemethods of fall protection must be used when• a worker could fall more than 3 metres (10 feet) from

any location• there is a fall hazard of more than 1.2 metres, if the

work area is used as a path for a wheelbarrow orsimilar equipment

• a worker could have access to the unprotected edgeof any of the following work surfaces and is exposedto a fall of 2.4 metres (8 feet) or more:• a floor, including the floor of a mezzanine or

balcony• the surface of a bridge• a roof while formwork is in place• a scaffold platform or other work platform,

runway, or ramp.• there are openings in floors, roofs, and other working

surfaces not otherwise covered or protected• there are open edges of slab formwork for floors and

roofs• a worker may fall into water, operating machinery, or

hazardous substances.Basic requirements for wood guardrails (Figure 33) include• top rail, mid rail, and toeboard secured to vertical

supports• top rail between 0.9 m (3 feet) and 1.1 m (3 feet 7

inches) high

• toeboard at least 100 mm (4 inches) high – 89 mm(3 1/2 inches) high if made of wood – and installedflush with the surface

• posts no more than 2.4 metres (8 feet) apart.Other systems are acceptable (Figure 34) if they are asstrong and durable as wood guardrails with the sameminimum dimensions.

Guardrails must be installed no farther than 300 mm froman edge.A guardrail must be capable of resisting – anywhere alongits length and without exceeding the allowable unit stress foreach material used – the following loads when appliedseparately:• a point load of 675 newtons (150 lb) applied laterally to

the top rail• a point load of 450 newtons (100 lb) applied in a vertical

downward direction to the top rail• a point load of 450 newtons (100 lb) applied in a lateral

or vertical downward direction to the mid-rail• a point load of 225 newtons (50 lb) applied laterally to

the toeboard.

SupportTypical methods of supporting wood guardrails are shownin Figure 33. Posts extending to top rail height must bebraced and solidly fastened to the floor or slab.Shoring jacks used as posts should be fitted with plywoodsoftener plates top and bottom. Snug up and check theposts regularly for tightness.

GUARDRAILS

Wire Rope Guardrail System

Manufactured Safety Fences

Figure 34

Figure 33

22 – 2

For slabs and the end of flying slab forms, manufacturedposts can be attached to the concrete with either clamps orinset anchors (Figure 35).Maximum StrengthTo strengthen guardrails, reduce the spacing of posts tobetween 1 and 2 metres (3 feet and 4 inches and 6 feet and8 inches) and double the 2 x 4 top tail. Posts on woodenguardrails must not be further apart than 2.4 metres (8 feet).Where guardrails must be removed, open edges shouldbe roped off and marked with warning signs. Workers inthe area must use a fall-arrest or travel-restraint system(Figure 36).Floor OpeningsGuardrails are the preferred method for protecting workersnear floor openings but may not always be practical.Narrow access routes, for example, may rule them out. Insuch cases, securely fastened covers – planks, plywood, orsteel plates – may be the best alternative.Use 48 mm x 248 mm (1 7/8" x 9 3/4") full-sized No. 1spruce planks.Make opening covers stand out with bright paint. Include awarning sign – DANGER! OPENING – DO NOT REMOVE!DO NOT LOAD!Fasten the cover securely to the floor to prevent workersfrom removing it and falling through the opening.StairsThe open edges of stairs requireguardrail protection. Specificationsfor a wooden arrangement areshown in Figure 37.

GUARDRAILS

VerticalShore Jack

Screw-clamp Posts

Stand-up Post

Cast Sleeve

ClampBindingPosts

Figure 35

Figure 37Guardrails on Stairs

2.4 m(8'0") max

Clip angles tosecure posts

Top rail –Double 2" x 4"

850m

m(34")

Fall Arrest

Travelrestraint

6 feet, 6 inches

6 feet, 6 inches

23 PERSONAL FALL PROTECTIONA worker at risk of falling certain distances (see chapteron Guardrails in this manual) must be protected byguardrails or, if guardrails are not practical, by a travel-restraint system, fall-restricting system, fall-arrest system,or safety net. This chapter describes travel-restraintsystems and fall-arrest systems.Personal fall protection equipment consists of thecomponents shown in the following illustration.This equipment can be used for travel restraint or fallarrest.

Travel-Restraint SystemsA travel-restraint system lets a worker travel just farenough to reach the edge but not far enough to fall over.

The basic travel-restraint system consists of• CSA-approved full body harness• lanyard• lifeline• rope grab to attach harness or lanyard to lifeline• adequate anchorage (capable of supporting a static

load of 2 kilonewtons—450 pounds—with a

recommended safety factor of at least 2, that is, 4kilonewtons or 900 pounds).

Travel-restraint arrangements must be thoroughlyplanned, with careful consideration given to- selection of appropriate components- location of adequate anchor points- identification of every fall hazard in the proposed work

area.

Try to select an anchor point that is as close as possibleto being- perpendicular to the unprotected edge, and- at the centre of the work area.

All fall hazards in the work area must be identified. Payspecial attention to work areas with irregular shapedperimeters, floor openings, or locations near corners.A fully extended lifeline and/or lanyard that adequatelyrestrains a worker from a fall hazard in one section of thework area may be too long to provide the same protectionin another section.Two methods of travel restraint are commonly used inconstruction.1) Connecting an adequately anchored lifeline directly to

the D-ring of the worker’s full body harness. It’sabsolutely critical that the length of the lifeline,measured from the anchor point, is short enough torestrain the worker from any fall hazard.

2) Attaching a lanyard from the D-ring of the worker’s fullbody harness to a rope grab on an adequatelyanchored lifeline. There must be some means—suchas a knot in the lifeline—to prevent the rope grab fromsliding along the lifeline to a point where the worker isno longer restrained from falling.

Whether method 1 or 2 is used, the system must beadjusted so that the fully extended lifeline and/or lanyardprevents the worker from reaching any point where theworker may fall. The system must also be securelyanchored.

Fall-Arrest SystemsWhere workers cannot be protected from falls byguardrails or travel restraint, they must be protected by atleast one of the following methods:- fall-restricting system- safety net- fall-arrest system.

In the event of a fall, these systems must keep a workerfrom hitting the ground, the next level below, or any otherobjects below.A fall-restricting system is designed to limit a worker’s free falldistance to 0.6 metres (2 feet). One type uses a belt grab orbelly hook that attaches to a safety rail on a fixed ladder.A safety net system must be designed by a professionalengineer. The system is installed below a work surfacewhere a fall hazard exists.A fall-arrest system• must include a CSA-approved full body harness

LockingSnapHooks

RopeGrab

To adequateanchor point

WebLanyard

Lifeline

FullBody

Harness

ShockAbsorber

PERSONAL FALL PROTECTION

23 – 1

• must include a lanyard equipped with a shockabsorber unless the shock absorber could cause afalling worker to hit the ground or an object or a levelbelow the work

• must include an adequate fixed support; the harnessmust be connected to it via a lifeline, or via a lanyardand a lifeline

• must prevent a falling worker from hitting the groundor any object or level below the work

• must not subject a falling worker to a peak fall-arrestforce greater than 8 kilonewtons.

The construction regulation (O. Reg. 213/91) requires that• all fall protection equipment must be inspected for

damage, wear, and obvious defects by a competentworker before each use

• any worker required to use fall protection must betrained in its safe use and proper maintenance.

Any defective component should be replaced by one thatmeets or exceeds the manufacturer’s minimumperformance standards for that particular system.The regulation also requires that any fall-arrest systeminvolved in a fall be removed from service until themanufacturer certifies all components safe for reuse.For any worker receiving instruction in fall protection, themanufacturer’s instructions for each piece of equipmentshould be carefully reviewed, with particular attention towarnings and limitations.ComponentsThe Canadian Standards Association (CSA) providesminimum standards for most components of personal fallprotection equipment:- CAN/CSA-Z259.1-M99 – Safety Belts and Lanyards- CAN/CSA-Z259.2.1-M98 – Fall Arresters, Vertical

Lifelines, and Rails- CAN/CSA-Z259.2.2-M98 – Self-Retracting Devices for

Personal Fall-Arrest Systems- CAN/CSA-Z259.2.3-M98 – Descent Control Devices- CAN/CSA-Z259.10-M90 – Full Body Harnesses- CAN/CSA-Z259.111-M92 – Shock Absorbers for

Personal Fall-Arrest Systems- CAN/CSA-Z259.12-01 – Connecting Components for

Personal Fall-Arrest Systems.For any component not covered by these standards,confirm with the manufacturer that the component issuitable for the particular system being considered.The minimum strength of fall-arrest components dependson whether or not the system uses a shock absorber.• In systems without shock absorbers, all components,

including lifeline and lifeline anchorage, must be ableto support a static load of at least 8 kilonewtons (1800pounds) without exceeding the allowable unit stress ofthe materials used for each component.

• In systems with shock absorbers, all components,including lifeline and lifeline anchorage, must be ableto support a static load of 6 kilonewtons (1350pounds) without exceeding the allowable unit stress ofthe materials used for each component.

In designing both systems, it is recommended that asafety factor of at least two be applied to the stated

minimum load capacity. In practical terms, anchorageshould be strong enough to support the weight of a smallcar (about 3600 pounds).LifelinesThere are three basic types of lifelines:1) vertical2) horizontal3) retractable.All lifelines must be inspected daily to ensure that they arefree of cuts, burns, frayed strands, abrasions, and

other defects or signs of damage- free of discolouration and brittleness indicating heat or

chemical exposure.

1) Vertical LifelinesVertical lifelines must comply with the current edition ofthe applicable CSA standard and the following minimumrequirements:- Only one person at a time may use a vertical lifeline.- A vertical lifeline must reach the ground or a level

above ground where the worker can safely exit.- A vertical lifeline must have a positive stop to prevent

the rope grab from running off the end of the lifeline.

Vertical lifelines are typically 16-millimetre (5/8-inch)synthetic rope (polypropylene blends).2) Horizontal LifelinesThe following requirements apply to any horizontal lifelinesystem:- The system must be designed by a professional

engineer according to good engineering practice.- The design can be a standard design or specifically

engineered for the site.

The design for a horizontal lifeline system must clearly indicate how the system is to be arranged,

including how and where it is to be anchored list and specify all required components clearly state the number of workers that can safely be

attached to the lifeline at one time spell out instructions for installation, inspection, and

maintenance


23 – 2

specify all of the design loads used to design thesystem.

The system must be installed, inspected, and maintainedin accordance with the professional engineer’s design.Before each use, the system must be inspected by aprofessional engineer or competent worker designated bya supervisor. A complete and current copy of the designmust be kept on site as long as the system is in use.CAUTION: The construction regulation requires that "ahorizontal or vertical lifeline shall be kept free from splicesor knots, except knots used to connect it to a fixedsupport." Knots along the length of either a horizontal orvertical lifeline can reduce its strength by as much as 40%.3) Retractable LifelinesRetractable lifelines consist of a lifeline spooled on aretracting device attached to adequate anchorage.Retractable lifelines must comply with CAN/CSA-Z259.2.2-M98.In general, retractable lifelines- are usually designed to be anchored above the worker- employ a locking mechanism that lets line unwind off

the drum under the slight tension caused by a user’snormal movements

- automatically retract when tension is removed,thereby preventing slack in the line

- lock up when a quick movement, such as that causedby a fall, is applied

- are designed to minimize fall distance and the forcesexerted on a worker’s body by fall arrest.

Always refer to the manufacturer’s instructions regardinguse, including whether a shock absorber is recommendedwith the system.Any retractable lifeline involved in a fall arrest must beremoved from service until the manufacturer or a qualifiedtesting company has certified it for reuse.

Lifeline HazardsUltraviolet light – Exposure to the sun may damage orweaken synthetic lifelines. Ensure that material beingconsidered for lifelines is UV-resistant.

Temperature – Extreme heat can weaken or damagesome lifelines while extreme cold can make others brittle.Ensure that material being considered for lifelines canstand up to the most extreme conditions expected.Friction and abrasion – Normal movement may wear,abrade, or otherwise damage lifelines in contact withsharp or rough surfaces. Protection such as woodsofteners or rubber mats can be used at contact points toprevent wear and tear.Sparks or flame – Hot work such as welding or flamecutting can burn, melt, cut, or otherwise damage a lifeline.Ensure that material being considered for lifelines isflame-resistant or provide appropriate protection wheresparks or flame may be encountered.Chemicals – Chemical exposure can burn or degrade alifeline very quickly. Ensure that material being consideredfor lifelines will resist any chemicals encountered on the job.Storage – Always store lifelines separately. Never storethem where they may contact hazards such as sharpobjects, chemicals, or gasoline.

Anchor SystemsThere are three basic types of anchor systems for fallprotection:1) designed fixed support – load-rated anchors

specifically designed and permanently installed for fallprotection purposes as an integral part of the buildingor structure (for example, roof anchors on high-risebuildings)

2) temporary fixed support – anchor systems designedto be connected to the structure using specificinstallation instructions (for example, nail-on anchorsused by shinglers)

3) existing structural features or equipment notintended as anchor points but verified by aprofessional engineer or competent person as havingadequate capacity to serve as anchor points (forexample, rooftop mechanical rooms, structural steel,or reinforced concrete columns).

Designed fixed support can be used to anchor a fall-arrestsystem, fall-restricting system, or travel-restraint system ifthe support has been installed according to the BuildingCode and is safe and practical to use.

23 – 3


23 – 4

Temporary fixed support can be used as anchorage if itmeets the following conditions: it can support at least 8 kilonewtons

(1800 pounds) without exceeding the allowable unitstress for each material used;

when used with a fall-arrest system incorporating ashock absorber, it can support at least 6 kilonewtons(1350 pounds) without exceeding the allowable unitstress for each material used; or

when used with a travel-restraint system,it can support at least 2 kilonewtons(450 pounds) without exceeding the allowable unitstress for each material used.

In all cases, a safety factor of at least two should beapplied when determining the minimum load that ananchor point must support.As a general rule with fall-arrest systems, choose ananchor capable of supporting the weight of a small car(about 3600 pounds).When existing structural features or equipment are usedas anchor points, avoid corners or edges that could cut,chafe, or abrade fall protection components.Where necessary, use softeners such as wood blocking toprotect connecting devices, lifelines, or lanyards from damage.Never anchor to- roof vents or stink pipes- roof hatches- small pipes and ducts- metal chimneys- TV antennas- stair or balcony railings.

Full Body Harness- Chest strap should be adjusted so that it’s snug and

located near the middle of the chest. In a headfirst falla properly adjusted chest strap will prevent the workerfrom coming out of the harness.

- Leg straps should be adjusted so the user’s fist can fitsnugly between strap and leg.

- Harness straps should be adjusted to put the D-ringbetween the shoulder blades. A properly positioned D-ring will keep a worker upright after fall arrest.

Inspect harness for burns, cuts, or signs of

chemical damage loose or broken stitching frayed web material D-ring and keeper pads free

from distortion and signs ofundue wear or damage

grommets and buckles freeof damage, distortion, orsharp edges.

Lanyards- Use manufactured lanyards

only. They can be made ofwire rope, synthetic fibre rope, or synthetic webbing.

- Lanyards are manufactured to specific lengths. Nevertry to shorten a lanyard by tying knots in it. Knots canseriously reduce its rated strength.

- Never store lanyards around chemicals, sharpobjects, or in wet places. Never leave them exposedfor long periods to direct sunlight.

- Inspect lanyards for


Examples of adequate anchorage

Examples of inadequate anchorage

23 – 5

burns, cuts, or signs of chemical damage loose or broken stitching frayed web material.

Shock Absorbers- Shock absorbers absorb some of the force generated

by fall arrest. Shock absorbers can be purchased asseparate equipment or built into lanyards.

- One end of the shock absorber must be connected tothe D-ring on the full body harness.

- In most cases the shock-absorbing component isenclosed in a snug-fitting jacket to protect it from theuser’s day-to-day activities. In a fall, the jacket tearsopen as the shock absorber deploys.

- Check the cover jacket for stress or tearing (manyshock absorbers have a tag on the jacket that tears ifthe unit is exposed to a shock load—make sure thistag is intact).

- Ensure that a shock absorber built into a lanyard hasa constant cross-section or diameter.

Connecting DevicesLocking Snap Hook – has a spring-loaded keeper acrossthe opening of the hook that cannot be opened unless thelocking mechanism is depressed.Karabiner (D-Clip) – designed not to open under twistloads. To open the gate or keeper requires two separateactions: 1) twisting the locking mechanism and (2) pullingthe locking mechanism back. When released, the spring-loaded locking mechanism flicks back into the lockedposition.Rope Grab – used to connect lanyard to lifeline. Thesedevices can be moved up and down the lifeline when asteady force is applied but will lock when a sharp tug orpull is applied. They will remain locked on the lifeline untilthe applied force is released.Each rope grab is designed and manufactured for usewith a specific diameter and type of lifeline. Rope graband lifeline must be compatible. Specifications are usuallylisted on the housing.The rope grab must also be attached to the lifeline in thecorrect direction—not upside down. On most rope grabsan arrow indicates the direction in which to orient thedevice. In addition, each rope grab is designed for usewith a specific length of lanyard, normally two or threefeet maximum.

Check all connecting devices for damage, cracking, dents, bends, or signs of deformation connecting rings centred—not bent to one side or

otherwise deformed rust moving parts working smoothly signs of wear or metal fatigue.

Fall-Arrest PlanningBefore deciding on a fall-arrest system, assess thehazards a worker may be exposed to in case of a fall.Before the fall is arrested, will the worker "bottom out,"that is, hit ground, material, equipment, or a lower level ofthe structure? Will the pendulum effect cause the workerto swing from side to side, possibly striking equipment,material, or structure? In the event of fall arrest, how willthe suspended worker be rescued? Planning must takeinto account these and other concerns.Total Fall Distance is the distance required to fully arrest afall. It consists of- Free Fall Distance, which should be kept to 1.5

metres (5 feet) or less, plus- Fall Stopping Distance, which includes stretch in the

lanyard (minimal) and lifeline, slack in the harness(maximum 30 cm or 1 foot due to allowableadjustments for user’s comfort), and deployment ofthe shock absorber (maximum 1.1 metres—or 42inches).

Free Fall Distance is measured from the D-ring of aworker standing on the work surface down to the pointwhere either the lanyard or the shock absorber begins toarrest the fall. It is strongly recommended that thisdistance be kept as short as possible.To minimize free fall, workers should tie off to an anchoroverhead and use as short a lanyard as the work will allow.Where a worker isconnected to a verticallifeline by a rope grab,the rope grab shouldbe positioned as highabove the D-ring asthe work will allow. Bydoing this, the workerminimizes not only theFree Fall Distance butalso the Fall StoppingDistance required tocompletely arrest a fall.Bottoming OutBottoming out occurswhen a falling workerhits a lower level, theground, or some otherhazard before the fallis fully arrested.This occurs whenTotal Fall Distance isgreater than thedistance from the work


Bottoming Out

23 – 6

surface to the next level, the ground, or some other hazardbelow.Fall-arrest systems must be planned, designed, andinstalled to prevent any risk of bottoming out.Pendulum EffectThe farther you move sideways from your anchor point,the greater the chance of swinging if you fall. This isknown as the "pendulum effect." And the more you swing,the greater the force with which you’ll strike columns,walls, frames, or other objects in your path.Swinging may even cause your taut lanyard or lifeline tobreak where it runs over rough or sharp edges.

Swing Fall or Pendulum Effect

To minimize pendulum effect, workers should keeplanyard or lifeline perpendicular from edge to anchor.Where work extends along an open edge, anchor pointscan be changed to keep lanyard or lifeline perpendicularas work progresses.Another solution is to run a horizontal lifeline parallel tothe edge. The worker attaches lanyard to lifeline, movesalong the edge, and the lanyard travels at the same pace,remaining close to perpendicular at all times.

Emergency RescueThe construction regulation (O. Reg. 213/91) requires thatbefore workers use any fall-arrest system or safety net ona project, the employer must develop written rescueprocedures. It’s important that a worker involved in a fallarrest be brought to a safe area as quickly as possiblewithout causing injury or putting rescuers at risk.In many cases, the rescue plan can be simple. A ladder orelevating work platform can be used to reach suspendedworkers and get them down safely. Other workers may behauled back up to the level from which they fell or pulledin through a nearby window or other opening.In other cases, procedures may be more complicated. Forinstance, workers trapped on a failed swingstage, orhanging from it, may need to be rescued by speciallytrained and equipped personnel from the local fire

department. Aerial ladder trucks or other high-reachequipment may be necessary. In extreme cases, the firedepartment may use rappelling techniques to reachtrapped workers and lift or lower them to a safe level.Plans should cover the on-site equipment, personnel, andprocedures for different types of rescue. Any off-siterescue services that might be required should becontacted and arranged in advance to familiarize themwith the project. CSAO’s Emergency Response poster(P103) can be used to indicate the nearest hospital andthe phone numbers of fire, ambulance, and policeservices.Site management must ensure that- everyone on site is aware of the rescue plan- equipment and other resources are available- designated personnel are properly trained.

Workers must receive training from their employerregarding the specific fall protection equipment andprocedures they will use. Products differ not onlybetween manufacturers but also between productlines in a single company. Training must thereforecover the exact harness, lanyard, shock absorber,rope grab, lifeline, and anchorage each worker willrely on, as well as the applications to be encountered.

ConclusionEmployers, supervisors, and workers all have responsibilitiesin reducing or eliminating falls in construction.This section has provided guidelines for fall protection,including both fall prevention and fall arrest. But theinformation means nothing unless employers, supervisors,and workers apply it on the job.Workers who have any questions about fall hazards or fallprotection should ask their supervisor. When it comes tofall protection, make sure you know how the equipmentworks and how to use it. Your life depends on it.


24 – 1

24 LADDERS

INTRODUCTIONEvery year in the Ontario construction industry more than800 lost-time injuries are caused by ladder accidents.Many of these accidents involve falls resulting in seriousinjuries and fatalities. Falls from ladders are common toall trades and pose one of the most serious safetyproblems in construction. The following are major causesof accidents.— Ladders are not held, tied off, or otherwise secured.— Slippery surfaces and unfavourable weather

conditions cause workers to lose footing on rungs orsteps.

— Workers fail to grip ladders adequately when climbingup or down.

— Workers take unsafe positions on ladders (such asleaning out too far).

— Placement on poor footing or at improper anglescauses ladders to slide.

— Ladders are defective.— High winds cause ladders to topple.— Near electrical lines, ladders are carelessly handled

or improperly positioned.— Ladder stabilizers are not used where appropriate.

To assist supervisors and foremen in preventing suchaccidents, this chapter provides guidelines for selecting,setting up, maintaining, and using ladders. Becauseladders are the most common type of access equipmentin the construction industry, thousands are used everyworking day. As a result, there are many thousands ofhours of exposure to ladder hazards every week.

The extensive exposure, the high fatality rate, and the largenumber of lost-time injuries as well as the associated costsand suffering from ladder accidents justify increased trainingof the workforce and better supervision of ladder use.Worker training alone will not yield sufficient improvement.Any significant reduction in ladder accidents will requireregular supervisory reinforcement of training as well asimproved site control of operations involving ladders.

STANDARDS AND MATERIALSStandard manufacturing specifications exist for mosttypes of ladders. CSA Standard Z11 sets out standardrequirements for manufacturing portable ladders. TheOntario Ministry of Labour has established standards forjob-built wooden ladders, while the InternationalStandards Organization has issued Standard ISO-2860relating to “Access Ladders on Earth Moving Machinery”.

The most common materials for ladders are aluminum,wood, steel, and fiberglass-reinforced plastic.

Wooden ladders deteriorate more rapidly than thosemade of more durable materials. They must never bepainted because paint hides signs of deterioration andmay accelerate rotting by trapping moisture in the wood.However, they may be treated with a clear non-toxic wood

preservative or coated with a clear varnish. Inspectwooden ladders frequently for splits, shakes, or cracks inside rails and rungs; warping or loosening of rungs;loosening of attached metal hardware; and deformation ofmetal parts.

Although aluminum ladders are popular and more widelyused than wooden ladders in construction, they are alsomore susceptible to damage by rough usage. Becausethey conduct electricity well, aluminum ladders must notbe used where electrical contact is possible. Check siderails and rungs regularly for dents, bends, and looserungs. If dented, the ladder should be taken out of serviceuntil repaired by a competent person. If repair is notpossible, the ladder should be destroyed.

Fiberglass-reinforced plastic side rails are becoming morecommon and are generally used with aluminum rungs.They do not conduct electricity well and are resistant tocorrosion. They are lightweight and available in variouscolours. They are, however, costly and heat-sensitive.They must not be exposed to temperatures above 93.3°C(200°F).

Fiberglass ladders should be inspected regularly forcracks and “blooming.” This condition is evidenced bytufts of exposed glass fiber where the mat has worn off.The worn area should be coated with an epoxy materialcompatible with the fiberglass.

Because of their weight, steel ladders are generally notused as portable ladders in the construction industry.They are, however, often fixed to permanent structures ormobile machinery.

TYPESThe many types of ladders used on construction sitesrange from metal ladders permanently mounted onequipment to job-built wooden ladders.Portable Ladders (Figure 1)All portable ladders must have non-slip feet or be set upso that the feet will not slip.Portable ladders are available in various grades: light dutyor grade 3; medium duty or grade 2; heavy duty or grade1. The ladders may or may not be certified to CSAStandard Z11. For construction purposes, it is stronglyrecommended that only ladders bearing the CSAcertification label be purchased and used. They may beslightly more expensive but CSA certification assures thatthe ladder has been manufactured to a high standard setby experts in ladder construction and use.The type purchased should be compatible with the degreeof rough usage expected. For general constructionapplications, heavy duty portable ladders arerecommended. For certain types of finishing work, however,this degree of ruggedness may not be necessary andmedium duty ladders will provide acceptable service. Wheremedium duty ladders are used, they should be restricted tothe application for which they were manufactured and not“borrowed” for rougher service.

LADDERS

24 – 2

Step, Trestle and Platform Ladders (Figure 2)Apart from the standards of sound construction andreliable service that should apply to all ladders used onsite, the primary consideration with these ladders is thatthey have strong spreader arms which lock securely in theopen position.Fixed Ladders (Figure 3)Steel ladders permanently fixed to structures such asstacks and silos are designed for service after constructionis complete but are often used by work crews duringconstruction. If the ladders are vertical and there is a risk offalling more than 3 metres (10 feet), a body harness andlifeline, or body harness and channel lock device, should beused by workers climbing up and down or working from theladders. These ladders must have safety cages starting nomore than 2.2 metres (7 feet) from the bottom of the ladderand extending at least 0.9 metres (3 feet) above the toplanding. Rest platforms with ladder offsets are required atintervals no more than 9 metres (30 feet) apart where a fall-arrest system is not used. Vertical ladders permanentlyfixed to structures should comply with Ontario Ministry ofLabour Engineering Data Sheet 2-04.

Special Purpose Ladders(Figure 4)These ladders should beused in accordance withmanufacturers' directionsand only for the specialapplications intended.

Job-Built WoodenLadders (Figure 5)Job-built laddersshould be constructedaccording to goodstructural carpentrypractice.The wood should bestraight-grained and

free of loose knots, sharp edges, splinters, and shakes.Rungs should be clear, straight-grained, and free of knots.Job-built ladders must be placed on a firm footing and besecurely fastened in position.

LADDERS

Figure 1

Straight Ladder

Extension Ladder

SectionalLadder Hooked

Ladderor “Catwalk”

Figure 2

Extension TrestleLadder

Trestle Ladder

Locked

PlaformLadder

Step Ladder

SPREADER ARMS SHOULD LOCK IN THE OPEN POSITION

Figure 4

Special PurposeLadder

Single Width

Double Width

40 cm (15.75") minimum61 cm (24") maximum

Side Rail 38 x 89 mm (2" x 4") for laddersunder 5.8 m (19') and 38 x 140 mm (2" x 6")for ladders over 5.8 m (19'). Side rails must notbe longer than 9 m (30')

Filler Block 19 x 38 mm (1" x 2")Rung 19 x 64 mm (1" x 3") for side rails 40 cm(16") apart.Rung 19 x 89 mm (1" x 4") for side rails over 40 cm(16") apart and up to 61 cm (24") apart.

Filler Block38 x 38 mm (2" x 2")

Guardrail38 x 89 mm (2" x 4")

Rung38 x 89 mm (2" x 4")

Side Rail38 x 140 mm (2" x 6") andno longer than 9 m (30')

1.5 m (5')minimum2 m (6'6")maximum

30 cm(1')

30 cm(1')

Job-Built Ladders

Figure 5

Figure 3

Fixed Ladder

24 – 3

Remember — a wooden ladder should not be painted orcoated with an opaque material.A straight wooden ladder should not be longer than 9metres (30 feet).Job-built ladders are heavy and not recommended whereportability is important. Because they are made of woodand often used by a whole crew of workers, job-builtladders deteriorate rapidly. They should be inspectedevery day or so. If defective, they must be repairedimmediately or taken out of service and destroyed.

SUPERVISION AND USEThe Supervisor's TaskLadder injuries can be significantly reduced by control ofusage and improved site management. This requires thatsupervisory personnel— train workers to maintain and use ladders properly— evaluate the access requirements of a specific work

assignment— choose the best means of access for the job.

Because portable ladders are inherently hazardous, theyshould only be used where safer means of access such asstairs, scaffolds, manlifts, or ramps are not suitable orpractical. Supervisors must consider the number of workersrequiring access to elevated work locations as well as theextent and duration of the work before deciding on thesafest and most economical means of access.Ladders should not be used by large crews of workers.Basic considerations of efficiency usually indicate that othertypes of access such as stairs or even personnel hoists aremuch more suitable where significant numbers of workersare making repeated use of the access.Where a significant amount of elevated work is to beperformed by even one tradesman in an area, ladders arenot recommended. Other types of access such asstationary or rolling scaffolds or powered elevatingplatforms will usually be more efficient and significantlyreduce the potential for accidents.In deciding on the best type of access for various tasks andwork locations, management should also consider theamount of material involved; the time workers spend on theaccess equipment; weather conditions; equipment availableon site; condition of surface from which access must bemade; room available; potential for shared use with othertrades, and so on. It is critical that consideration be given toworker access for specific tasks and for entire work areas.Ladders must not be used where other means of accessare practical and safer.If there is no practical alternative to ladders, supervisorsshould ensure that ladders are suitable and in good conditionand personnel are trained to use them properly. Ladderstabilizers on straight and extension ladders are stronglyrecommended where ladders are the only means of access.In addition to proper training, planning, and organizing forworker access, supervisory personnel must exercise controlof all access situations. The supervisor must check thatplanning and directions are being carried out by workers.Although very important, the control function is often giveninsufficient attention by the busy supervisor. With ladders,

as with other supervisory responsibilities, details overlookedtoday can become problems tomorrow.Proper Use of LaddersMore than 80 percent of ladder accidents are related toimproper use or application of the equipment. Supervisorsmust control the application of equipment to particularsituations. But personnel using the equipment must alsobe trained to use it. Training should include the followingprecautions.— Check the ladder for defects at the start of a shift,

after it has been used in another location by otherworkers, or after it has been left in one location for alengthy period of time. (See the end of this chapter forinspection procedures.)

— Areas surrounding the base and top of the laddershould be clear of trash, materials and otherobstructions since getting on and off the ladder isrelatively more hazardous than other aspects of use.

— The base of the ladder should be secured againstaccidental movement. Use a ladder equipped withnon-slip feet appropriate for the situation, nail a cleatto the floor, or otherwise anchor the feet or bottom ofthe side rails (Figure 6).

— The ladder must be set up on a firm level surface. Ifits base is to rest on soft, uncompacted or rough soil,a mud sill should be used (Figure 7).

— The top of the ladder should be tied off or otherwisesecured to prevent any movement (Figure 8). If this isnot possible, given the type of ladder or circumstancesof its use, one worker should hold the base of theladder while it is being used.

— If a ladder is used for access from one work level toanother, the side rails should extend a minimum of900 millimetres (3 feet) above the landing. Grab railsshould be installed at the upper landing so that aworker getting on and off the ladder has securehandholds.

— All straight or extension ladders should be erected atan angle such that the horizontal distance betweenthe top support and the base is not less than one-quarter or greater than one-third the vertical distancebetween these points (Figure 9).

LADDERS

Figure 6Methods of securing ladder base against displacement

24 – 4

— Before setting up straight or extension ladders, checkthe area for overhead power lines. Ladders made ofaluminum or other conductive material should never beused near power lines. Only competent electricians andlinemen using ladders made of non-conductive materialare allowed to work in close proximity to energizedelectrical lines.

— Portable ladders should never be used horizontally assubstitutes for scaffold planks, runways, or any otherservice for which they have not been designed.

— When a task can only be done while standing on aportable ladder, the length of the ladder must be suchthat the worker stands on a rung no higher than thefourth from the top. The ladder should also be tied offor equipped with a suitable stabilizer.

— Short ladders must never be spliced together to makea longer ladder. Side rails will not be strong enough tosupport the extra loads.

— Straight ladders should not be used as bracing, skids,storage racks, or guys. They were not designed forthese purposes and the damage caused by suchabuse can later result in an accident during normaluse.

— Unless suitable barricades have been erected,ladders should not be set up in passageways,doorways, driveways, or other locations where theycan be struck or displaced by persons or vehiclesusing the access route.

— Only one person at a time should be allowed on asingle-width ladder. In the case of a double-widthladder, no more than two people should be allowed onit at one time and each should be on a separate side.

— Ladders should not be placed against flexible ormovable surfaces.

— Always face the ladder when climbing up or down andwhen working from it.

— Maintain 3-point contact when climbing up or down aladder. That means two hands and one foot or twofeet and one hand on the ladder at all times. This isespecially important when you get on or off a ladderat heights (Figure 10).

— When working from a ladder, keep your centre ofgravity between the side rails. A person's centre ofgravity is approximately in the centre of the body atbelt height. The location of your centre of gravity canshift when you reach out to either side of a ladder,especially with materials, tools, or equipment in yourhands. As the centre of gravity of your body andhand-held objects moves beyond the side rails, theladder is tending toward instability.

— Whenever possible, avoid climbing up or down aladder while carrying anything in your hands. Tools,equipment and materials should be placed in acontainer and raised or lowered by rope, if necessary.

— Workers should be instructed and frequently remindedto keep their boots free of mud, snow, grease, orother slippery materials if they are using ladders.

— Always hold onto the ladder with at least one hand. Ifthis is not possible because of the task to be doneand in particular if the work is 3 metres (10 feet) ormore above the floor, the worker must wear a safetyharness and tie the lanyard off to the structure or to alifeline before beginning work.

— Never straddle the space between a ladder andanother object (Figure 11).

LADDERS

Typical mud sill arrangements

Figure 7

Figure 9

Proper ladderangles

Tied-offextensionladder

3 ft. Min(900 mm)

Tie-Off

Point

Figure 10

Figure 8

24 – 5

— Persons frequently required to use or work fromladders should wear protective footwear with solesand heels made of slip-resistant materials such assoft urethane.

— Never erect ladders on boxes, carts, tables, or otherunstable surfaces.

— Fall-arresting equipment such as ladder climbingdevices or lifelines should be used when working fromlong fixed ladders or when climbing vertical fixedladders.

— Never rest a ladder on any of its rungs. Ladders mustrest on their side rails.

— When erecting long, awkward, or heavy ladders, twoor more persons should share the task to avoid injuryfrom over-exertion.

— Instruct all personnel to watch for overhead powerlines before attempting to erect any ladder. Whenoverhead power lines are in proximity of the work,aluminum ladders must not be used.

INSPECTION AND MAINTENANCERegular inspection and maintenance will increase theuseful life of ladders and reduce the number of accidents.A suggested checklist for inspection has been provided atthe end of this chapter. Repairs should only be carried outby someone competent and familiar with this kind of work.Ladders found to be defective should be taken out ofservice and either tagged for repair or scrapped. Oncetagged, the ladder must not be used until repaired. Ideally,the tag should only be removed by the person who took theladder out of service initially. The tag should be printed inbig bold letters with the words “DANGER – DO NOT USE”.

General ProceduresLadders should be inspected for structural rigidity. Alljoints between fixed parts should be tight and secure.Hardware and fittings should be securely attached andfree of damage, excessive wear, and corrosion. Movableparts should operate freely without binding or excessiveplay. This is especially important for gravity-action ladderlocks on extension ladders.Non-skid feet should be checked for wear, imbeddedmaterial, and proper pivot action on swivel feet.Deteriorated, frayed or worn ropes on extension laddersshould be replaced with a size and type equal to themanufacturer's original rope.Aluminum ladders should be checked for dents and bendsin side rails, steps, and rungs. Repairs should be madeonly by the manufacturer or someone skilled in goodaluminum or metal work practices. Replacing a rung witha piece of conduit or pipe is not good practice and shouldnot be permitted.Wooden ladders are susceptible to cracking, splitting, androt and should be either unpainted or covered with atransparent finish in order that checks, cracks, splits, rot,or compression failures can be readily detected. Repairsshould be consistent with good woodworking practice.Only wood equal to or better than the wood used by themanufacturer should be used in the repair.The bases, rungs, and steps of all ladders should beexamined for grease, oil, caulking, imbedded stone andmetal, or other materials that could make them slippery orotherwise unsafe.Methods of storage and transportation are important.Storage areas should permit easy access and be cool anddry, particularly if wooden ladders are kept there. Areaswhere the moving of other materials can damage laddersshould be avoided. Ladders should be supported duringstorage and transportation to prevent sagging or chafing.When being transported, ladders should be “top freight”— nothing should be piled on them. If damage doesoccur, the condition causing the damage should becorrected as well as having the ladder repaired.Special ConsiderationsAll trades have frequent ladder accidents. To improveaccident prevention, supervisors should devote more timeto training and reinforcement of training on the job.Approximately 50 percent of all ladder accidents occurwhile tasks are being performed from the ladder. Many ofthese accidents could be prevented by using other typesof access equipment such as scaffolds or poweredelevating platforms.Between 30 and 40 percent of all ladder accidents involveunexplained loss of footing. Because inattention may be acause, training should be strengthened to maintainawareness of the hazards involved in working fromladders.Many ladder accidents are related to unfavourableweather conditions such as wind, mud, ice, snow, and rainwhich create slippery and unstable situations. This is anespecially important consideration for the outside trades

LADDERS

Never straddle the spacebetween a ladder andanother object

Figure 11

24 – 6

such as labourers, bricklayers, sheet metal applicators,roofers, and carpenters.A surprising number of accidents occur when workerstake the first step onto the bottom rung of a ladder. Whilefalls from this distance are usually not as serious as thosefrom greater heights, they nevertheless create injuriessuch as sprains, strains, fractures, and contusions thatoften result in lost-time claims. Workers should be advisedto be careful when stepping onto any ladder. It is often atthis point that the unstable, insecure ladder will slide or tipand that muddy or snow-covered boots will slip on the firstor second rung. Make sure that boots are clean, thatladders are secure and stable, and that workers areaware of the hazards. Again, this involves supervisortraining and continuous reinforcement.Finally, a large number of accidents occur becauseworkers use straight ladders that are not secured. Sitesupervisors must rigidly ensure that ladders are eitherfirmly secured (Figures 6-8) or held in place by a secondworker.

LADDER USE CHECKLISTDO Familiarize personnel with your ladder safety policy.

Use a ladder properly suited to the task.

Construct job-built ladders properly.

Inspect ladders before use.

Erect ladders with the proper slope (between 4:1 and3:1).

Avoid placing ladders in areas with high traffic oractivity such as walkways, entrances, and exits.

Tie ladders off at the top.

Block or otherwise secure the ladder base or have theladder held by a second worker when in use.

When outdoors, place the ladder base on firmfootings such as compacted soil or mudsills.

Extend the ladder 900 mm (3 feet) above the toplanding.

Clear material, debris, and other obstructions from thetop and bottom of ladders.

WHEN CLIMBING Use a single-width ladder one person at a time only.

Maintain three-point contact.

Do not carry anything in your hands.

Face the ladder.

Use a fall-arrest system on long ladders.

DO NOT use ladders when a safer means of access is

available and practical.

use metal ladders near live electrical equipment orconductors.

use ladders horizontally or for some other purpose forwhich they haven't been designed.

damage ladders during transport and storage.

support ladders on their rungs.

erect long or heavy ladders by yourself.

LADDER INSPECTION CHECKLISTYES NO

1. Are any wooden parts splintered?

2. Are there any defects in side rails,

rungs, or other similar parts?3. Are there any missing or broken rungs?

4. Are there any broken, split, or cracked

rails repaired with wire, sheet metal,or other makeshift materials?

5. Are there any worn, damaged, or

missing feet?6. Are there any worn, damaged, or

unworkable extension ladder locks,pulleys, or other similar fittings?

7. Is the rope on extension ladders

worn, broken, or frayed?8. Has the rope on extension ladders

been replaced by material inferiorto the ladder manufacturer's originalrope?

9. Are the spreader arms on step

ladders bent, worn, broken, or otherwiserendered partly or totally ineffective?

If the answer is “YES” to any of the questions on theInspection Checklist, the ladder should be tagged so thatworkers will know it is defective and should not be used. Itshould be taken out of service immediately and placed ina location where it will not be used until repairs arecompleted. If the ladder is not to be repaired it should bedestroyed.

LADDERS

25 – 1

25 SCAFFOLDS

Contents1. Introduction2. Problem areas3. Selection4. Basic types of scaffolds5. Scaffold components6. Erecting and dismantling scaffolds7. Scaffold stability8. Platforms9. Proper use of scaffolds

1 INTRODUCTIONMore than half of scaffold accidents in Ontarioconstruction are falls. Several fatalities are also related toscaffolds each year. The number and severity of injuriesinvolved make scaffold accidents one of the more serioussafety problems in construction.

2 PROBLEM AREASThe main problem areas are• erecting and dismantling scaffolds• climbing up and down scaffolds• planks sliding off or breaking• improper loading or overloading• platforms not fully planked or “decked”• platforms without guardrails• failure to install all required components such as base

plates, connections, and braces• moving rolling scaffolds in the vicinity of overhead

electrical wires• moving rolling scaffolds with workers on the platform.2.1 Erecting and DismantlingFrom 15 to 20% of scaffold-related injuries involveerecting and dismantling. The most common problem isthe failure to provide an adequate working platform for aworker to use when installing the next lift of scaffold.Working from one or two planks is not recommended.The next important consideration involves components,such as tie-ins, which you should install as the assemblyprogresses. Failure to do so makes the scaffold lessstable and, while it may not topple, it may sway or moveenough to knock someone off the platform. This happensmore often when platforms are only one or two plankswide and guardrails are missing, as is frequently the caseduring erection and dismantling.2.2 Climbing Up and DownApproximately 15% of scaffold-related injuries occur whenworkers are climbing up and down. Climbing up and downframes is a common but unacceptable practice that hasresulted in numerous injuries and fatalities. Climbing upand down braces is also a frequent cause of accidents.You must provide adequate ladders to overcome thisproblem. In addition, workers must use proper climbingtechniques (three-point contact).

2.3 Planks Sliding Off or BreakingMany scaffold injuries involve problems with planks. Ifscaffold planks are uncleated or otherwise unsecured theyeasily slide off – this causes a surprising number ofinjuries. Scaffold planks can also break if they are in poorcondition or overloaded. It is therefore important to useproper grades of lumber and to inspect planks beforeerection to ensure that there are no weak areas,deterioration, or cracks. Another common problem isinsufficient or excessive overhang of planks at theirsupport. Excessive overhang can cause a plank to tip upwhen a worker stands on the overhanging portion.Insufficient overhang is a leading cause of planks slippingoff.2.4 Improper Loading or OverloadingOverloading causes excessive deflection in planks andcan lead to deterioration and breaking. Overloadingoccurs most often in the masonry trade where skids ofmaterial can exceed 1500 kg (3000 lb.). If material is leftoverhanging the scaffold platform it can cause animbalance leading to the scaffold overturning.2.5 Platforms Not Fully DeckedThis situation is related to injuries not only during erectionand dismantling but in general scaffold use. TheConstruction Regulation (Ontario Regulation 213/91)requires that all scaffold platforms must be at least 450mm (18 inches) wide. All platforms above 2.4 metres(8 feet) must be fully decked.2.6 Platforms without Guardrails

Platforms without guardrails are a serious safety problemin construction. Guardrails are an important fall preventionmeasure not only for high platforms but also for low ones.Over one-third of the falls from scaffolds are fromplatforms less than 3 metres (10 feet) in height.Therefore, guardrails are recommended during normaluse for all scaffold platforms over 1.5 metres (5 feet) high.Guardrails for all working platforms should consist of a toprail, a mid-rail, and a toeboard.2.7 Failure to Install All Required ComponentsFailure to use all of the proper scaffold componentsis a serious safety problem. Workers are more likely to cutcorners when scaffolds are only a few frames in height. Alltoo frequently they fail to install base plates, braces,proper securing devices such as “banana” clips or “pigtails” at the pins of frame scaffolds, and adequate tie-ins.Those erecting the scaffold must have all the necessarycomponents, and must use them to ensure that thescaffold is safe. Furthermore, workers should install theseparts as the scaffold erection progresses.2.8 Electrical Contact with Overhead WiresScaffolds seldom make contact with overhead electricallines, but when it does happen it almost always results ina fatality. Failure to maintain safe distances fromoverhead powerlines while moving scaffolds is a majorproblem. Before attempting to move rolling scaffolds inoutdoor open areas, check the route carefully to ensurethat no overhead wires are in the immediate vicinity.Partial dismantling may be necessary in some situationsto ensure that the scaffold will make the required safe

SCAFFOLDS

25 – 2

clearances from overhead powerlines. The requiredminimum safe distances are listed in Table 1. Hoistingscaffold material by forklift or other mechanical meansrequires careful planning and should be avoided in thevicinity of powerlines. Transporting already-erectedscaffolds by forklift, particularly in residential construction,has been the cause of many electrical contacts — this isa dangerous practice. Workers handling materials orequipment while working on the platform must also takecare to avoid electrical contact.

Table 1: Minimum distance from powerlines

2.9 MovingRolling ScaffoldswithWorkers on the PlatformMoving rolling scaffolds with workers on the platform canbe dangerous. Where it is impractical for workers to climbdown, and the scaffold is over 3 metres (10 feet) in height,each worker must be tied off with a full body harness andlanyard. Lifelines must be attached to a suitable anchorpoint other than the scaffold. Holes, depressions, curbs,etc. have all been responsible for scaffolds overturningwhile being moved. In some jurisdictions moving a scaffoldwith workers on the platform is prohibited if the platformexceeds a certain height.

3 SELECTIONThe safe and efficient use of scaffolding depends first onchoosing the right system for the job. If the scaffold’s basiccharacteristics are unsuited to the task, or if all the necessarycomponents are not available, personnel are forced to makedo and improvise. These conditions lead to accidents.Proper selection of scaffolding and related componentsrequires basic knowledge about site conditions and thework to be done. Considerations include• weight of workers, tools, materials, and equipment to

be carried by the scaffold• site conditions (e.g., interior, exterior, backfill, concrete

floors, type and condition of walls, access for theequipment, variations in elevation, anchorage points)

• height or heights to which the scaffold may be erected• type of work that will be done from the scaffold (e.g.,

masonry work, sandblasting, painting, metal siding,mechanical installation, suspended ceiling installation)

• duration of work• experience of the supervisor and crew with the types

of scaffolds available• requirements for pedestrian traffic through and under

the scaffold• anticipated weather conditions• ladders or other access to the platform• obstructions• configuration of the building or structure being worked on• special erection or dismantling problems including

providing practical fall protection for the erector

• the use of mechanical equipment to aid in erectingthe scaffold.

4 BASIC TYPES OF SCAFFOLDS4.1 Standard Tubular Frame ScaffoldsThis is the most frequently used scaffold in construction.Historically it has been made of steel tubing, butaluminum is gaining popularity. The scaffold ismanufactured in various configurations and spans. Onsome systems, ladder rungs are built into the end frames(Figure 4.1). These ladders are not suitable for tallscaffold towers unless rest platforms are installed atregular intervals and trapdoors are provided in theplatforms. Other models are equipped with ladders thatattach to the end frames (Figure 4.3). The ladder shownin Figure 4.3 is continuous and workers gain access viagates at theplatform level. Again this ladder is not suitable for highscaffolds. Scaffolds in excess of 9 metres (30 feet) shouldhave built-in stairs with rest platforms. Vertical ladders canreach up to 9 metres, but above 2.2 metres (7 feet) theyrequire a safety cage.The advantages of the frame scaffold are that it is simpleto assemble, many construction trades are familiar with itsuse, and the components can be lifted manually byworkers. However, as with other systems, all parts mustbe used. Failure to install any of the components, such as

bracing and base plates, may lead to accidents.4.2 Standard Walk-through Frame ScaffoldsThis is a variation of the standard tubular frame scaffold.An example is shown in Figure 4.2. Although primarilydesigned to accommodate pedestrian traffic at the groundor street level, the walk-through scaffold is frequently usedby the masonry trade to provide greater height per tierand easier distribution of materials on platforms atintermediate levels.

SCAFFOLDS

Voltage Rating of Power Line Minimum Distance750 to 150,000 volts 3 metres (10 feet)150,001 to 250,000 volts 4.5 metres (15 feet)over 250,000 volts 6 metres (20 feet)

Figure 4.1STANDARD FRAME SCAFFOLD

Ladder rungs builtinto frame not morethan 12” centre tocentre

Aluminum/plywoodcombination platform

25 – 3

4.2.1 Spans of Tower BaseSpan lengths are varied using different lengths of verticalbracing. Most manufacturers have braces providing spansbetween 5 and 10 feet in length, with 7-foot spans beingthe most common. The use of 7-foot spans is ideal whenusing 16-foot planks as this allows a 1-foot overhang ateach end. When using spans in excess of 7 feet, the load-bearing capacity of the platforms is reduced and must beaccounted for in the design.

4.3 Rolling ScaffoldsRolling scaffolds are best suited where short-durationwork must be carried out at multiple locations. They areused mainly by mechanical and electrical trades. Thereare two main types of rolling scaffold.• Castor Type. This type of scaffold is best suited for

work on smooth floors and is typically used insidebuildings. All castors should be equipped with brakingdevices (Figure 4.3). This kind of scaffold should beerected so that its height-to-width ratio is no greaterthan 3 to 1. This limits the height of platforms withstandard outrigger stabilizers and single span towersto approximately 9 metres (30 feet).

• Farm Wagon Type. Scaffolds erected on farm wagonsor other devices with pneumatic tires are frequentlyused for installing sheet metal siding and similarmaterials on industrial buildings. For safe, effectiveuse, the area around the building should be wellcompacted, relatively smooth and level. This type ofscaffold must also have outrigger beams with levellingdevices (Figure 4.4). It is subject to the 3-to-1 height-to-width ratio and is impractical for heights greaterthan 7.5 metres (25 feet). The scaffold should alwaysbe resting on the outriggers while workers are aboard.It should never be used as a work platform while it is“on rubber.”

Rolling scaffolds other than those that are lifted off theground on outriggers should have brakes on all wheels.All brakes should be applied when the scaffold reachesthe desired location.

It is best not to move rolling scaffolds while a worker is onthe platform. If people must remain on the platform whenthe scaffold is being moved they should be tied off to anindependent structure using a fall-arrest system. In somejurisdictions moving a scaffold with workers on theplatform is prohibited if the scaffold exceeds a certainheight. The area through which the scaffold is to bemoved should be free of bumps or depressions andcleared of all debris. Overhead hazards, especiallypowerlines, should be identified.Rolling scaffolds should always have guardrails. Theyshould also be securely pinned together and be fitted withhorizontal bracing as recommended by the manufacturer.

SCAFFOLDS

Figure 4.2WALK-THROUGH SCAFFOLD

Woodenguardrails

secured to frame

Tube-and-clampguardrails toprotect

outrigger/sideplatform

Note: Walk-through frame allowseasier distribution of materials

Horizontalbracing

Figure 4.3ROLLING SCAFFOLD

Gate

Bananaclip

Castor wheel with brakeand swivel lock

Brake

HorizontalBracing

Figure 4.4FARM WAGON ROLLING SCAFFOLD

NOTE:Screw jacks shouldbe adjusted to liftwheels off groundbefore workersmountthe scaffold.

NOTE:Access to this scaffoldshould be via ladder.The ladder is omittedhere for clarity.

25 – 4

Scaffolds that are not securely pinned together canseparate if they drop into a hole or depression, or run intoan obstacle at ground level. Horizontal bracing isnecessary on a rolling tower scaffold to keep it fromfolding up because the connections between frames andbraces are essentially pinned joints.Castors should be secured to the frame. A castordropping off in a hole or depression in floors has been thecause of serious accidents and injuries. Each castorshould have a brake and swivel lock which are in goodworking order and can be applied easily. The castors orwheels should be suitable for the surface on which thescaffold is being used. Small wheels are suitable forpavement or concrete floors. You need larger pneumaticwheels when soils are the working surface. Before usingrolling scaffolds, the surface must be smooth, free ofdepressions and reasonably level.4.3.1 Electrical ContactOne of the biggest concerns with rolling scaffolds is thepossibility of contact with overhead electrical wires.Scaffolds making accidental contact with powerlines havecaused many deaths. Before moving a rolling scaffold,check the intended path of travel and maintain therequired minimum clearances as set out in Table 1.4.4 Fold-up Scaffold FramesFold-up scaffold frames (Figure 4.5) are frequently usedby trades such as electricians, painters, and suspendedceiling erectors. Widths range from dimensions that willpass through a 750-mm (30-inch) opening to the standardwidth of about 1.5 metres (5 feet). Frequently made ofaluminum, this type of scaffold is easily and quicklytransported, erected, and moved about construction sitesand from job to job. It should be used only on a smooth,hard surface.

4.5 Adjustable ScaffoldsFigure 4.6 illustratesanother type of scaffoldwith uses similar to thefold-up model. Althoughit is not so easilyerected, the system islight and very easilyadjusted for height. Itbreaks down into aminimum of componentsreadily transported fromjob to job. These devicesshould also be used onlyon smooth, hardsurfaces. They are notintended to carry heavyloads.

4.6 Tube-and-Clamp ScaffoldsTube-and-clamp scaffolds (Figure 4.7) are frequently usedwhere obstructions or non-rectangular structures areencountered. The scaffolds are infinitely adjustable inheight and width. They can also be used for irregular andcircular vertical configurations.Personnel erecting tube-and-clamp scaffolds must beexperienced. It is strongly recommended that, for eachapplication, a sketch or drawing be prepared by someonewho understands general structural design and the needfor diagonal and cross bracing. In general, this type ofscaffold takes longer to erect than the standard tubularframe type. Tube-and-clamp scaffolds above 10 metres(33 feet) must be designed by a professional engineer.

4.7 Systems ScaffoldsEuropean scaffold systems have become very popular inapplications that were traditionally suited to tube-and-clamp. Although they are not as adjustable as tube-and-clamp scaffolds, they can be applied to a wide variety ofnon-rectangular, circular, or dome-shaped structures. Atypical example is shown in Figure 4.8. As with tube-and-clamp scaffolds, personnel carrying out the erectionshould be experienced with that type of system and asketch or drawing of the scaffold to be erected isrecommended for each application. Systems scaffoldsabove 10 metres (33 feet) in height must be designed bya professional engineer.There are a great many systems available, ranging fromlight-duty aluminum to heavy-duty steel supportstructures. They all employ different patented lockingdevices (wedges, locking pins, etc.) which are notintended to be interchanged with other systems.

SCAFFOLDS

Figure 4.5FOLD-UP SCAFFOLD

Figure 4.6SCAFFOLDwithADJUSTABLEPLATFORMHEIGHT

Node point

Clamp boltedto structure

Gate

Figure 4.7TUBE-AND-CLAMP SCAFFOLD

25 – 5

4.8 Mast-Climbing Work PlatformsThe use of mast-climbing work platforms (Figure 4.9) isbecoming increasingly common, particularly in the masonryindustry. They are best suited for medium to high-riseprojects, and are used also by siding installers, windowinstallers, drywallers, and other trades. For low to medium-height projects they can be freestanding, depending onground conditions and manufacturers’ instructions. For high-rise applications they can be tied to the structure at regularintervals as set out by the manufacturer.Mast-climbing work platforms can be used as a single toweror as multiple towers braced together. The platform climbsthe mast, normally powered by an electric or gas engine.The climbing mechanism will have a failsafe system toprevent accidental lowering or failing of the platform.

Although not shown here, the working platform can be aset distance below the material platform. This allowsmaterial to be stacked at a convenient height for theworker. The entire platform can be raised to whateverheight is required. As such it has significant ergonomicadvantages.

Engineered drawingsshould accompany thiswork platform outliningsuch components asload capacity, tie-inrequirements, andbracing.The potential for fall-related accidents isreduced when usingmast-climbing workplatforms since workersstay on a wide, securedplatform even duringerection anddismantling.Manufacturers’instructionsmust befollowed at alltimes. Acompetentworker shouldsupervise theerection.4.9 Crank-up or TowerScaffoldsAlthough crank-upscaffolds (Figure 4.10)are more popular in theUnited States, someCanadian masonrycontractors use them.They consist of towers,bases, and platforms thatcan be lifted by winches.The working platform islocated 600 to 900mm (2 to 3 feet)below thematerial platform,which is in anergonomically good position for the worker.The entire scaffold can be raised easily, allowing the workera comfortable working height. Crews must be trained toerect, use, dismantle, and maintain tower scaffolding safelyand efficiently. Manufacturers’ instructions must be followedat all times. Tower scaffolds must be tied to the structureaccording to manufacturer’s instructions.

5 SCAFFOLD COMPONENTSTubular Frame Scaffolds: There are many tubular framescaffold components available (Figures 5.1, 5.2). Somecomponents are necessary in almost all situations; othersare optional depending on use and manufacturers’instructions. In addition to scaffold end frames, theminimum components required are– base plates or castors– mudsills– adjustable screw jacks– vertical braces on both sides of frames unless

SCAFFOLDS

Figure 4.8SYSTEMS SCAFFOLD

Typical rosetteand wedge joint

Figure 4.9MAST-CLIMBING WORK PLATFORM

Figure 4.10TOWER SCAFFOLD

25 – 6

SCAFFOLDS

Toeboard bracket

Spring-loadedpin lock

Vertical braces

Horizontalbrace

Guardrail

Guardrailposts

Gravity locking pin

Figure 5.2FRAME SCAFFOLD COMPONENTS

Figure 5.1FRAME SCAFFOLD COMPONENTS

Frames

Fixed base plate

Swivel base plate

CastorsCoupling pins—used toconnect frames together

Pig tail—used to connectframes to coupling pins

Manufacturedguardrailsection

25 – 7

• frames are designed with “non-pinned” joints• additional bracing is provided by a designed systemusing tube-and-clamp accessories

– horizontal braces on every third tier of frames– platform materials to fully deck in the intended

working level– guardrails complete with toeboards– guardrail posts where working platforms will be at the

top level– ladders or stairs for access– intermediate platforms where required—not more than

9 metres (30 feet) apart and adjacent to vertical ladders.Tube-and-Clamp Scaffolds and Systems Scaffolds haveindividual components unique to each type. Thesecomponents are identified and discussed in detail in Section 6.5.1 PlatformsPlatforms for frame scaffolds are normally eitheraluminum/plywood platforms or wood planks. Planksnormally come in 8-foot or 16-foot lengths to cover one ortwo 7-foot bays with adequate overhang. Platforms aredealt with in depth in Section 8.5.2 Outrigger/Side BracketsThe use of outrigger brackets—also known as sidebrackets (Figure 5.3)—is very popular in the masonryindustry. They are attached to the inside of the frame andaccommodate a platform approximately 20" (two planks)wide. They provide a work platform for the mason at anergonomically convenient location, lower than the materialplatform. Intended as a work platform only, they are not tobe used for material storage.Instances have been reported of brackets installed on the“wrong” side of the scaffold—facing the forklift, forexample, to provide a landing area for skids of material.This is not acceptable because outrigger brackets are notdesigned for supporting material. Furthermore, thepractice may lead to unbalanced loading of the scaffold,causing tip-over.Figure 5.4 illustrates typical outrigger/side bracketsattached to the scaffold for masonry use. For efficient,comfortable work, the brackets should be adjustable inlifts of no more than 600 mm (24 inches). A space nogreater than 150 mm (6 inches) should be maintainedbetween the bracket platform and the wall. Although theoutrigger brackets illustrated are side brackets, endbrackets are also available from most manufacturers.

Use the following good work practices:• Do not drop or roughly handle outrigger/side brackets

during erection or dismantling. This can bend ordamage hooks.

• Use planks that are double-cleated at one end toensure that the cleats are engaged over a bracket toprevent the bracket from pivoting.

• Inspect brackets as they are being installed onthe scaffold to ensure that only sound brackets withno defects are used.

SCAFFOLDS

Figure 5.3 - Outrigger / Side BracketWhen purchasing outrigger/side brackets, look for the followingfeatures, numbered to correspond with Figure 5.3.1. Hook tops out at a V-point to sit securely on varying diameters

of horizontal frame members2. Hook and bottom shoe are prepared to receive pin3. Hook is heavy-gauge, fabricated from one piece of steel4. Ensure that the lower shoe won’t interfere with braces, locks,

or other features of different manufacturer’s frames5. Hook plate is wrapped around vertical member and welded

on three sides only

Tube-and-clamp end guardrailsfor outrigger platform

Cube of masonrylaid directly over frame

Outrigger/sidebracket

Tie-in

Figure 5.4MASONRY SCAFFOLD WITH OUTRIGGER/SIDE BRACKETS

Note:Ladder,

horizontal bracing,and means of

securing planksomitted for clarity

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• Tag for repair any brackets that have deformed orcracked hooks, cracked welds, or other defects.

• Make sure that brackets are mounted securely on theframe all the way down.

• Never stock material on the bracket working platform.The working platform is for the worker only.

• Make sure that planks laid on the brackets extend atleast 150 mm (6 inches) beyond the frames at either end.

• Place brackets so the level where the worker standsis no more than 1 metre (40 inches) below the levelwhere the material is stored.

Beware of common hazards with outrigger/side brackets:• hooks bent or deformed to the extent that they will roll

off the frame under load• hooks bent back into place, thereby causing cracks in

the metal or welds which then break under load• homemade brackets that are poorly designed and

fabricated, too flimsy to bear the load, or not sizedproperly to hold two planks

• failure to inspect brackets during erection to ensurethat they are not damaged

• failure to use planks that have double cleats on one end.

Other features to look for are• manufacturer’s plate showing name and model number• brackets that are hot-dipped galvanized• manufacturer’s literature stating that the bracket has

been designed and fabricated to meet loadingrequirements specified in the Ontario regulations andapplicable CSA standards.

5.3 LaddersWhether built into frames, attached as a separatecomponent, or portable, ladders are an important meansof access to scaffold platforms. We would substantiallyreduce the number of falls connected with climbing upand down scaffolds if workers always used adequate andproperly erected ladders. Unfortunately, suitable laddersare not often provided or used.A major problem with ladders built into the frame is thatplanks sometimes stick out so far that it’s difficult to getfrom the ladder to the platform. This situation results inmany injuries but can be overcome in one of three ways:• use manufactured platform components which do not

project beyond the support• use a portable ladder where platform elevations are

less than 9 metres (30 feet) in height (Figure 5.5)• use a stand-off vertical ladder with a cage if the

scaffold is above 3 metres (10 feet).

Ladder rails should extend at least 900 mm (3 feet) abovethe platform level to facilitate getting on and off. Injuriesare often connected with stepping on and stepping off theladder at the platform level.Rest stations should be decked in on scaffold towers atintervals no greater than every 9 metres (30 feet).Climbing is strenuous work and accidents happen morefrequently when climbers suffer from overexertion.5.4 GuardrailsFailing to use guardrails is one of the main reasons forfalls from scaffold platforms. Manufacturers of frame

scaffolds have guardrail components which can beattached to the scaffold frames. These have posts that sitdirectly onto the connector pins and to which the rails areattached using wing nuts.Where manufactured guardrails are not available,guardrails can be constructed from lumber (Figure 5.6) ortube-and-clamp components.Tube-and-clamp guardrails may be constructed fromstandard aluminum scaffold tubing using parallel clampsto attach the vertical posts to each frame leg (Figure 5.6).Top rails and mid-rails should be attached to the verticalposts using right-angle clamps. Connections in these railsshould be made with end-to-end clamps.Most manufacturers have toeboard clips to fastentoeboards quickly and easily to standard tubular posts oneither frames or guardrail posts.A guardrail should consist of:• a top rail about 1 metre (40 inches) above the

platform• a mid-rail about halfway between the platform and the

top rail• a toeboard at least 89 mm (31/2") high at the platform

level if made from wood, and• posts no more than 2.4 metres (8 feet) apart if made

from wood. Guardrail posts can be farther apart if thematerials used are adequate to support the loadsspecified.

Guardrails should be designed to resist the forcesspecified in the Construction Regulation.Frequently, guardrails must be removed to allow materialto be placed on the scaffold platform. Workers mustprotect themselves from falling by using a fall-arrestsystem properly worn, used, and tied off. The fall-arrestsystem should be worn while the worker is removing theguardrail, receiving the material, and replacing theguardrail. Too often, guardrails are removed to receivematerials and then not replaced. Many workers havefallen because other workers have left unguardedopenings on scaffold platforms.

SCAFFOLDS

Figure 5.5

NOTE:Ladder rails should extend at least1 m (3 ft) above platform

Note:Horizontalbracingomitted forclarity

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SCAFFOLDS

Figure 5.6GUARDRAILS

2" x 4" Top Rail(wide edge is horizontal)

2" x 4" Mid-Rail(positioned inside post)

1" x 6" Toeboard(positionedinside post)

2" x 4" posts securelynailed to flat bar u-clipsat 2 locations

Swivel clamps onside of guardrail

Right-angle clampson corners ofguardrail

Posts fastened to frame withparallel clamps

Wooden guardrail system

Tube-and-clampguardrail system

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6 ERECTING AND DISMANTLINGSCAFFOLDS

6.1 GeneralScaffolds should always be erected under the supervisionof a competent worker. Although scaffold systems varybetween manufacturers, certain fundamentalrequirements are common to all scaffold systems. Framescaffolds over 15 metres (50 feet) in height, and tube-and-clamp and systems scaffolds over 10 metres (33 feet),must be designed by a professional engineer. Supervisorsmust ensure that the scaffolds are constructed inaccordance with that design.6.1.1 Foundations and Support SurfacesScaffolds must be erected on surfaces that canadequately support all loads applied by the scaffold. Tosupport scaffolds, backfilled soils must be well compactedand levelled. Mud and soft soil should be replaced withcompacted gravel or crushed stone. Embankments thatappear unstable or susceptible to erosion by rain must becontained. Otherwise, the scaffold must be set far enoughback to avoid settlement or failure of the embankment.Where mudsills mustbe placed on slopingground, levelling thearea should be done,wherever possible, byexcavating rather thanbackfilling (Figure 6.1).In some cases it maybe necessary to usehalf-framesto accommodate gradechanges. For thesesituations theside bracing is usuallyprovided by using tube-and-clampcomponents.Floors are usuallyadequate to supportscaffold loads ofworkers, tools, andlight materials. Asloads become greater,floors, especially theolder wooden types, should be examined to ensure thatthey will support the anticipated loads. In some cases,shoring below the floor and directly under the scaffoldlegs may be necessary. In other situations, you may needsills that span the floor support structure.Scaffolds erected on any type of soil should have amudsill. At minimum the mudsill should be a 48 mm x 248mm (2" x 10") plank (full size) and should be continuousunder at least two consecutive supports. The scaffold feetshould rest centrally on the mudsill and the sill should,where possible, project at least 300 mm(1 foot) beyond the scaffold foot at the ends. Mudsills maybe placed either along the length or across the width ofthe frames.

Do not use blocking or packing such as bricks, shortpieces of lumber, or other scrap materials either underscaffold feet or under mudsills (Figure 6.2). If the scaffoldis subjected to heavy loading, bricks or blocks can break.Vibration can cause blocking to move or shift, leaving ascaffold leg unsupported. In such conditions the scaffoldcan topple when heavy loads are applied.

Take particular care when erecting scaffolds on frozenground. Thawing soil is often water-soaked, resulting inconsiderable loss of bearing capacity. You must takethawing into account when tarps or other covers will beplaced around a scaffold and the enclosure will beheated.If the scaffold is inside a building, preparing thefoundationmay mean• clearing away debris or construction materials and

equipment stored in the way• using sills or placing shoring under old wooden floors.

For a scaffold on the outside of a building, preparing thefoundation may include• replacing mud and soft ground with gravel or crushed

stone• levelling and compacting loose backfill• stabilizing or protecting embankments• providing protection against erosion from rain or

thawing• using mudsills.

Foundation preparation is important with any scaffold. It isespecially important when scaffolds will be heavily loaded,as in masonry work. Differential settlement may damagescaffold components even if no serious incident orcollapse occurs.

SCAFFOLDS

Figure 6.1MUDSILL ON SLOPING GROUND

Figure 6.2IMPROPER SUPPORT

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6.1.2 InspectionScaffold materials should be inspected before use for• damage to structural components• damage to hooks on manufactured platforms• splits, knots, and dry rot in planks• delamination in laminated veneer lumber planks• presence of all necessary components for the job• compatibility of components.

Structural components which are bent, damaged, orseverely rusted should not be used. Similarly, platformswith damaged hooks should not be used until properlyrepaired. Planks showing damage should be discardedand removed from the site so that they cannot be used forplatform material.6.1.3 LocationBefore erecting a scaffold, check the location for• ground conditions• overhead wires• obstructions• variation in surface elevation• tie-in locations and methods.

Checking the location thoroughly beforehand will eliminatemany of the problems that develop during erection andwill allow erection to proceed smoothly, efficiently, andsafely.6.1.4 Base PlatesBase plates and adjustable screw jacks should be usedwhether the scaffold is outside on rough ground orindoors on a smooth level surface. Base plates should becentred on the width of the sill and nailed securely afterthe first tier has been erected. Sills may run either acrossthe width or along the length of the scaffold depending ongrade conditions and other factors. Generally, bearingcapacity will be increased by running sills longitudinallybecause the sill has more contact with the ground.6.1.5 PlumbWhen the first tier of scaffold has been erected it shouldbe checked for plumb, alignment, and level. Wherenecessary, adjustments can be made using the screwjacks.Settlement or slight variations in the fit of the componentsmay require additional adjustments as tiers are added tothe scaffold tower. Braces should fit easily if the scaffoldtower is level. If braces do not fit easily it is an indicationthat the scaffold is out of plumb or out of alignment.6.1.6 Hoisting MaterialsWhere scaffolds will be more than three frames high, awell wheel or “gin” wheel and a hoist arm or davit willmake the hoisting of materials easier during erection(Figure 6.3).While materials can be pulled up by rope without thesedevices, the well wheel and hoist arm allow the hoisting tobe done by workers on the ground. This is much saferand eliminates the risk of workers falling from the scaffoldplatform as they pull materials up by rope. Loads lifted bya well wheel should normally be no more than 50 kg(100 lb.) unless special structural provisions are made.

The use of forklifts or other mechanical means of hoistingscaffold materials has become more common particularlyin masonry applications. The use of this type ofequipment greatly reduces the potential for overexertioninjuries due to lifting and pulling. However, extraprecaution must be taken to prevent powerline contactand other potential hazards such as overloading.6.1.7 Tie-insScaffolds must be tied in to a structure or otherwisestabilized —in accordance with manufacturer’sinstructions and the Construction Regulation—as erectionprogresses. Leaving such items as tie-ins or positiveconnections until the scaffold is completely erected willnot save time if it results in an accident or injury.Moreover, in most jurisdictions it is prohibited. For furtherinformation on tie-in requirements see Section 7.6.6.1.8 Fall Protection in Scaffold ErectionProviding practical fall protection for workers erecting anddismantling scaffold and shoring has been challenging forthe construction industry.In Ontario, revised fall protection requirements (Section26 of the Construction Regulation) were introduced inJune 2000 and require that workers erecting, using, ordismantling scaffolds must be protected from falling byusing guardrails, travel restraint, fall-restricting systems, orfall-arrest systems.For fall protection while workers are using a scaffold as awork platform, the safest solution is guardrails, providedthey can be erected safely. Workers involved in erectingor dismantling scaffolds face a different challenge.Erecting guardrails and using fall-arrest equipmentrequires specialized procedures since normally there isnothing above the erector on which to anchor the fallprotection system. For suggestions, see CSAO’sScaffolds and Frame Shoring Towers: Fall Protection,which you can download from www.csao.org.

SCAFFOLDS

Figure 6.3WELL WHEEL AND DAVIT

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In all cases ensure that procedures comply with theregulations. You must use engineered design andprocedures when required, and competent workers mustreview the installed scaffold before use. Pay special careand attention to anchorages.A competent person must give adequate oral and writteninstructions to all workers using fall protection systems.Like all scaffolds, this equipment must be used under thesupervision of a competent person.6.2 ERECTING FRAME SCAFFOLDSFrame scaffolds are the most common types of scaffoldsused in Ontario. Too often they are erected by people whoare inexperienced and do not know or recognize thepotential hazards. Erectors must be aware of the potentialdangers not only to themselves but also to the end user ofthe scaffold.6.2.1 Fittings and AccessoriesPeople are sometimes reluctant to install all the parts,fittings, and accessories required for a properly built framescaffold. This poor practice continues because parts arefrequently lost or otherwise not available at the site. Othertimes, it is due to haste, lack of training, or carelessness.Always use base plates with adjustable screw jacks. Theyallow for minor adjustments to keep the scaffold plumband level. Base plates usually have holes so you can nailthem to mudsills. This is good practice and should bedone as soon as the first tier is erected and plumbed withbase plates centred on the sills.You must brace in the vertical plane on both sides ofevery frame. Bracing in the horizontal plane should bedone at the joint of every third tier of frames starting withthe first tier. Horizontal bracing should coincide with thepoint at which the scaffold is tied to the building.Horizontal bracing is needed to maintain scaffold stabilityand full load-carrying capacity. The use of horizontalbracing on the first tier helps to square up the scaffoldbefore nailing base plates to mudsills.Every scaffold manufacturer provides coupling devices toconnect scaffold frames together vertically. Figure 6.4illustrates various types. Erectors often ignore thesedevices, believing that the bearing weight of the scaffoldand its load will keep the frame above firmly connected tothe frame below. This will probably hold true until thescaffold moves or sways. Then the joint may pull apart,causing a scaffold collapse. Coupling devices shouldalways be used and installed properly on every leg of thescaffold, at every joint, as assembly proceeds.If wheels or castors are used they should be securelyattached to the scaffold and be equipped with brakes.Failure to attach wheels or castors properly to the framehas been the cause of many serious accidents andfatalities involving rolling scaffolds. Wheels or castors musthave brakes which are well maintained and easily applied.Scaffolds should always have guardrails. Unfortunately,people frequently leave them out, especially on scaffoldsof low to moderate height. Workers have been seriouslyinjured as a result.

6.2.2 BracesOnce you have fitted the adjustable base plates on theframes you must then attach the braces for each towerspan. The braces should slide into place easily. If force isrequired, either the braces are bent or damaged or theframes are out of plumb or alignment.Secure braces at each end. The erection crew mustensure that self-locking devices move freely and havefallen into place. Rust or slight damage can prevent someof these devices from working properly and they thenrequire force to secure them in position. Maintain movingparts in good condition to prevent this situation fromdeveloping.6.2.3 Platform ErectionEnsure that parts and fittings are in place and securebefore placing platform components on a scaffold tier.When proceeding with the next tier, workers should useplatform sections or planks from the previous tier, leavingbehind either one platform section or two planks. Whilethis requires more material it speeds up erection becauseworkers have platforms to stand on when erecting ordismantling the platform above. At heights above 3 metres(10 feet), all workers involved in the erection ordismantling of scaffolds must be protected by a guardrailor by other means of fall protection.Frequently, low scaffolds one or two frames in height arenot fully decked in. This can lead to accidents and seriousinjury. Many lost-time injuries occur each year in Ontariobecause platforms are inadequately decked.6.2.4 LaddersWhere frames are not equipped with ladder rungs,ladders should be installed as the erection of each tierproceeds. Injuries involving scaffolds frequently occurwhen workers are climbing up or down the scaffold.Providing proper ladders will help prevent such injuries.See Section 5.3 for more information on ladders.

SCAFFOLDS

Figure 6.4COUPLING DEVICES

Pigtail

Thumbscrew

Bananaclip

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6.2.5 GuardrailsGuardrails must be installed at each working level as thescaffold is erected and also at the top level of the scaffold.This is recommended for all scaffolds regardless of height.Although you do not require guardrails until scaffolds are2.4 metres (8 feet) high, a considerable number of severeinjuries and even fatalities are due to falls from lowerscaffolds.Some manufacturers have recently introduced temporaryguardrails workers can use when erecting scaffolds. Aguardrail can be set in position from the previous leveland can provide a protected work platform for the workerto install the next level of components. Each type ofguardrail has a unique design and system of attachmentto the scaffold.Figure 6.5 shows one example of an “advanced guardrail”with the platform fully enclosed. The guardrail ispositioned on a bracket which is mounted from below onthe outside of the scaffold, and does not interfere with theplacement of subsequent frames and braces. As thescaffold goes up the guardrail may be raised as well, orleft in position to form the permanent guardrail. Theerector must use another fall protection method—permanent guardrails or a full body harness witha lanyard attached to the scaffold—while moving eitherthe platforms or the temporary guardrail.

6.3 ERECTING TUBE-and-CLAMP SCAFFOLDSMost of the general rules that apply to frame scaffoldingalso apply to tube-and-clamp scaffolding. Therequirements for mudsills, platforms, and guardrails areexactly the same for both types.The most important difference between the two is theadditional degree of skill and knowledge necessary toerect tube-and-clamp scaffolds safely and efficiently.Tube-and-clamp scaffolds should not be erected by anunskilled or inexperienced crew. Basic terms are identifiedin Figure 6.6.6.3.1 General RequirementsTube-and-clamp scaffolds are erected plumb and level likeframe scaffolds but the erection system is quite different.

The scaffold must start with a set of ledgers and transomsimmediately above the base plates. This is necessary tohold the base plates in their proper position. The typicalerection sequence for a simple tower is shown in Figure6.6. Each vertical and horizontal member should bechecked with a spirit level as erection proceeds.

6.3.2 Materials and ComponentsThe tubing normally used for tube-and-clamp scaffoldingin Ontario is schedule 40, 1.9” OD (11/2 ID) aluminum pipemanufactured of either 6061 or 6063 alloys.Clamps are usually made of steel and have a variety ofconfigurations. Depending on the manufacturer, clampscan be fastened using wedges, bolts, or other methods.The following types are used.• Right-Angle Clamp—a clamp used for connecting

tubes at right angles. They maintain the right-angledorientation providing rigidity to the structure.

• End-to-End Clamp—an externally applied clamp toconnect two tubes end-to-end.

• Swivel Clamp—a clamp used to connect two tubeswhen right-angle clamps cannot be used. Theyusually connect bracing.

• Parallel Clamp—a clamp used for lap jointing twotubes together. It can be used to connect shortguardrail posts to the standards or legs of framescaffolds.

• Concrete Tie Clamp—a clamp used to connect a tubeto concrete or other surfaces using a bolt or concreteanchor.

These and other devices are shown in Figure 6.8depicting a typical tube-and-clamp scaffold.

SCAFFOLDS

Figure 6.5ADVANCED TEMPORARY GUARDRAIL

Bracket mountedon frame to

accept guardrail

Figure 6.6ERECTION OF TUBE-AND-CLAMP SCAFFOLD

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Before using clamps, check them carefully for damage towedges or threads on bolts and distortion of the clamp body.6.3.3 Spacing of StandardsThe spacing of standards depends on the load-carryingrequirements of the scaffold. Wherever possible, tube-and-clamp scaffolding should have bay and elevationspacing of about 2 metres (6'-6") longitudinally andvertically. This allows for the front sway bracing to belocated at approximately 45° to the horizontal. It alsofacilitates the use of 5-metre (16-foot) planks withadequate overhang. The width of these platforms can varybut is usually approximately 1 metre (3 feet). This spacingallows the aluminum tubing specified earlier to carrynormal construction loads adequately. An advantage oftube-and-clamp scaffolding is that the platform height canbe easily adjusted to the most appropriate level for thework being done.6.3.4 Ledgers and TransomsLedgers should be connected to standards using right-angle clamps. These clamps maintain a rigid 90° anglebetween members.Transoms should be placed above the ledgers and bothshould be maintained in a horizontal position by levellingwith a spirit level. Transoms may be connected to eitherstandards or ledgers by using right-angle clamps.6.3.5 Joints in Standards and LedgersJoints in standards and ledgers should be made with end-to-end clamps. These joints should be as close to thenode points as the clamp arrangements will allow. Jointsin vertically-adjacent ledgers should not occur in the samebay but should be staggered to provide rigidity.A node point is the point at which the ledger-to-standard,transom-to-standard, and bracing-to-standard connectionscome together. An example of a node point is shown inFigure 4.7 and below.

6.3.6 Intermediate TransomsYou should install intermediate transoms when thescaffold will be supporting heavy loads. You can also usethem to avoid lapping planks and the tripping hazard thatcomes with it.6.3.7 Tie-insTie-ins are required with tube-and-clamp scaffolding. Theyshould be located at every second node vertically and

every third standard horizontally. The tie-in tube should beconnected to both standards or both ledgers, near thestandard to provide rigidity. Connections should be madewith right-angle clamps. Tie-ins should be capable ofwithstanding both tension (pull) and compression (push)forces (Figure 6.8).6.3.8 BracingInternal bracing (Figure 6.8) is connected standard-to-standard using swivel clamps. It should be clamped asclose to the node as possible. Internal bracing shouldnormally be placed at every third standard. The locationshould coincide with tie-in points. You should also installbracing for tube-and-clamp scaffolding as erectionprogresses.Face sway bracing should be installed to the full height ofthe scaffold. It may be located in a single bay or extendacross several bays (Figure 6.7). Where the bracing islocated in single bays it should be in the end bays and atleast in every fourth bay longitudinally. In practice, itbecomes difficult to get bracing close enough to the nodepoints if it extends more than four bays in width (see endsof bracing in Figure 6.7).

6.3.9 Drawings and InspectionsWe strongly recommend that a sketch or drawing beprepared before erecting tube-and-clamp scaffolding. It isimportant that you place the standard to accommodatethe anticipated loads adequately. Bracing must also bedesigned to provide stability and to transfer horizontalloads to tie-in points.

SCAFFOLDS

Figure 6.7TUBE-AND-CLAMP BRACING

Node point

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Where the platform will be more than 10 metres (33 feet)high or where unusual structures such as cantileveredplatforms are involved, a professional engineer mustdesign the scaffold. A professional engineer or acompetent worker must inspect the scaffold before it isused to ensure that it is erected in accordance with thedesign drawings.6.4 ERECTION of SYSTEMS SCAFFOLDSErection of systems scaffold is very similar to that of tube-and-clamp scaffold. The requirements for mudsills,platforms, and guardrails are the same as is therequirement for being built level and plumb. The maindifferences are the method of connecting individualmembers together and the fact that all the members areof a fixed length. As with tube-and-clamp scaffolds, allsystems scaffolds above 10 metres (33 feet) must bedesigned by a professional engineer.6.4.1 ComponentsStandards come in a variety of lengths and have a varietyof built-in connection points at equal distances along theirlength. These connectors are normally between 450 and500 mm (18 and 21 inches) apart depending on the

manufacturer. Typical connections are shown in Figure6.9, although others are available. An end-to-endconnection, normally a spigot, is formed at one end tofacilitate extension of the standard.Starter Collars are short standards with one set of systemrings or rosettes attached. They are convenient to usebecause they allow one person to put the first set oftransoms and ledgers in place easily (Figure 6.10).Ledgers or Runners for each system are available invarying lengths and have built-in connection devices forconnecting to the standards. The connection is securedby wedging, bolting, or by other methods.Transoms or Bearers are made wide enough for four orfive planks. They normally have end connections similarto those of ledgers and connect directly to the standard.Normally transoms have a lip or groove—particular to theindividual manufacturer—designed to accommodate theplatform.Braces are made in set lengths to fit the scaffold beingconstructed, with connections at both ends to fit directlyonto the connection point on the standard.

SCAFFOLDS

Figure 6.8COMPLETED TUBE-AND-CLAMP SCAFFOLD

Right-angleclamp

Swivelclamp

Concrete tieclamp

End-to-endclamp

Baseplate

Intermediate transoms fixedwith right-angle clamps allowplanks to meet without overlap

Internalbracing

Faceswaybracing

Revealtie Push-

pulltie

2" x 10"Timber sills

Note:End-to-endjoints in ledgersshould be closeto standards andin staggered bays.

Top rail, mid-rail and toeboardfixed to standards

Maximum 6'-6"

Maximum 6'-6"

End-to-endclamps

Ledgers fixed to standards with right-angleclamps – maximum vertical spacing 6'-6".

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Platform boards (also called staging) come in a variety oflengths and widths. They fit directly into the transoms andcan be secured to prevent wind uplift. To facilitateclimbing, some platforms have trap doors with built-indrop-down ladders.6.4.2 Erection ProcedureThe foundation for systems scaffolds should be preparedin the same way as other types of scaffolding, ensuring afirm level base, and using mudsills, base plates, andadjustable screw jacks.The base plates should be laid out in what you estimate isthe correct location. We recommend starter collars sincethey allow scaffolds to be laid out level and square.The first level of transoms and ledgers should be placed onthe starter collars and be levelled using the screw jacks.

When the scaffold is square and level you should tighten theconnections and nail the base plates to the mudsills.At this point set up an erection platform for installing thestandards for the next lift. You now install the second levelledgers and transoms as well as the deck.You must install ledger bracing at the ends of all systemscaffolds and at intervals according to the manufacturers’recommendations. Each brace will be the correct lengthfor the span being braced and should be connected to theattachment point on the standard.You must install face or sway bracing according to manu-facturers’ instructions. Again, attachment points are set onthe standards, and the braces come in specific lengths forthe span of the scaffold being constructed. Normally,every third bay is braced for sway.Figure 6.10 outlines the typical erection procedure forsystems scaffold.6.4.3 Tie-insSystems scaffolds must be tied in to structures using the3-to-1 rule as with other scaffolds. Some manufacturershave special adjustable ties which connect directly intothe standards, while others use a tube-and-clamp methodto tie in to the structure. Anchors attached to the structureare the same as in frame or tube-and-clamp scaffolds.6.4.4 GuardrailsGenerally, guardrails are installed at all working levels.These guardrail components come in modular lengths andare made from lighter materials than the ledgers. Theyattach directly to the connection points on the standards.

SCAFFOLDS

Figure 6.9TYPICAL SYSTEMS SCAFFOLD CONNECTORS

Figure 6.10ERECTION SEQUENCE OF TYPICAL SYSTEMS SCAFFOLD

1. Levelling runnersand bearers

4. Second set of bearersand runners (transomsand ledgers)

5. Ledger andface bracing

6. Installing the secondlift decking

2. Work platforms 3. Installing cornerposts (standards)

Level

Mud sill

Starter collar

PlatformStandards

LedgerBracing

Facebracing

TransomLedger

Base plate

Ledger

Transom

Certain manufacturers have developed advanced guardrailsystems that can be installed for a level above the erector,providing fall protection for the worker accessing the nextlevel.The example shown in Figure 6.11 consists of a “T”shaped temporary guardrail which is attached to thepermanent guardrails on the level underneath. Whenmounted, it extends the required distance past the deckabove to form a guardrail. The erector can then worksafely without being tied off and install the next level ofstandards, ledgers, and transoms.6.5 DISMANTLINGDismantling frame scaffolds is essentially erection inreverse. Each tier should be completely dismantled andthe material lowered to the ground before beginning todismantle the next tier.If platform sections or planks have been left at each levelduring erection, as suggested above, it should berelatively easy to lower platform materials from above anddeck in the current working platform completely. Extraplatform material can be lowered to the ground. Using thisprocedure, workers will be operating most of the time froma fully decked-in platform. This makes for easier removalof braces and frames.Dismantled materials should be lowered using a well wheeland hoist arm or by mechanical means. Dropping materialsnot only causes damage and waste, but also endangersworkers below—and is illegal in most jurisdictions.When scaffolds have been in the same location for a longtime, pins and other components frequently rust, bracesbecome bent, and materials such as mortar or paint oftenbuild up on the scaffold parts. All of these can preventcomponents from separating easily. Removing jammed orrusted scaffold components can be very hazardous.Tugging or pulling on stuck components can cause you tolose your balance and fall. Workers should wear a fullbody harness and lanyard tied off to a scaffold frame orlifeline before attempting to loosen stuck or jammed parts.Dismantling tube-and-clamp and systems scaffolding mustproceed in reverseorder to erection.Each tier should becompletelydismantled as far asconnections willallow before youbegin dismantling thelower tier. You mustdismantle them thisway because thebracing for tube-and-clamp scaffold is notlocated in each bayas it is for framescaffolding. The spanor spans with frontsway bracing shouldbe the last to bedismantled oneach tier.

7 SCAFFOLD STABILITY7.1 Three-to-One RuleThe ratio of height to least lateral dimension must notexceed 3 to 1 unless the scaffold is• tied to a structure, as discussed in Section 7.6• equipped with outrigger stabilizers (Figure 7.1) to

maintain the ratio of 3 to 1• equipped with suitable guy wires.

7.2 Outrigger StabilizersScaffold manufacturers usually make outrigger stabilizersthat can be attached to their equipment (Figure 7.1).

With devices of this type, ensure that the outrigger isadjusted so that vibration or dynamic loads on theplatform will not move the stabilizer. Where stabilizerswith castors are used the castors must rest firmly on asolid surface, with the brakes applied, and with thestabilizer secured in the extended position before workersuse the platform (Figure 7.2). Many of these stabilizersfold up to allow movement through smaller openings andaround obstructions (Figure 7.2).

SCAFFOLDS

Figure 6.11ONE STYLE OF

ADVANCED GUARDRAIL SYSTEM

Courtesy Layher Inc.

Horizontal bracefor stabilizer

Figure 7.2OUTRIGGERSTABILIZERS

Rolling scaffold withoutrigger stabilizers

Adjustableoutrigger stabilizers

Figure 7.1OUTRIGGER STABILIZERS

25 – 17

25 – 18

7.3 Limitations to the Three-to-One RuleThe 3-to-1 rule applies only to the extent that outriggersare extended symmetrically about the scaffold tower. If theoutriggers are extended only on one side, you preventtoppling only in that direction.7.4 DamageMost bracing systems for tubular frame scaffolds are manu-factured from light materials and are easily damaged.Do not use braces with kinks, bends, or deformations. Suchdamage can weaken them significantly. The ends of bracesare frequently damaged by dropping them on concrete orother hard surfaces during dismantling. Ends of braces arealso frequently bent by forcing them onto the locking pinduring erection. Constant bending can cause the ends tocrack. You should inspect them before use and discardbraces with cracked ends. You should maintain the lockingdevice onto which the brace fits in good condition. It shouldmove freely to accept and release the brace. Commonsecuring devices are shown in Figure 7.3.

7.5 Installation Problems and SymptomsEnsure that bracing is secured in place. Otherwise, scaffoldmovement can dislodge the braces and reduce the stabilityof the scaffold. These devices must secure the braces inplace but they must operate freely so that it is easy to erectand dismantle the scaffold. Many times a worker has lostbalance and fallen when trying to release a jammed orrusted drop hook while dismantling a scaffold.You should completely deck platforms used to installbracing. Trying to work from a platform one or two plankswide often results in a fall. In addition, it leads to greaterdamage to the ends of scaffold braces because they bendwhen they are not kept close to proper alignment duringinstallation and removal.If a brace does not easily drop onto pins something iswrong. The brace may simply be bent and should bediscarded. Often, however, it means the scaffold is twistedand out of plumb. Braces should not be forced orhammered onto the pin. The condition causing thisdifficulty should be corrected so that the brace slides ontothe pin easily. Adjusting screw jacks slightly will oftensolve this problem. However, you need to take care toensure the scaffold is not adjusted out of plumb.

7.6 Tie-in RequirementsScaffolds which exceed the 3-to-1 rule of height to leastlateral dimension must be tied in to a building or structure.Tie-ins should be applied at every third frame verticallysecond frame horizontally for tubular frame scaffolds. Tie-ins for tube-and-clamp scaffolds should be applied atevery second node vertically and every third standardhorizontally.These tie-ins must be capable of sustaining lateral loadsin both tension (pull) and compression (push). Examplesare shown in Figure 7.4.

Wind loads can affect tie-ins and bracing. These loadsvary not only with speed but also with the exposure of thelocation and the height and shape of structures where thescaffold is erected. In addition, scaffolds which are goingto be enclosed for winter construction or sandblasting willbe subjected to significantly greater wind loads. If severewinds are expected it is recommended that a professionalengineer be consulted for tie-in requirements

8 PLATFORMSBefore you select the platform material, you need toassess the weight of the workers, tools, and materials tobe supported. You must also take into consideration thespans being used in the scaffold.8.1 Typical Loads and RequirementsMinimum platform capacities vary from jurisdiction tojurisdiction. In Ontario, the minimum platform capacity is auniformly distributed load of 2.4 kn/m2 (50 lb./sq. ft.) forconstruction-related work. This is usually sufficient forworkers, their tools and equipment, as well as a moderateamount of light materials. It is not sufficient for heavyloads such as those used in masonry construction.For masonry construction where the scaffold will supportlarge pallets of concrete blocks, minimum capacity shouldbe at least a uniformly distributed load of 7.2 kn/m2 (150lb./sq. ft.). This means that scaffolds with spans of 2.1metres (7 feet) should be at least double-planked.Aluminum/plywood platforms should also have a layer ofscaffold planks on top.

SCAFFOLDS

Figure 7.4TYPICAL SCAFFOLD TIE-INS

Figure 7.3SECURING DEVICES FOR FRAME SCAFFOLD BRACES

For weights of construction materials and allowable load-carrying capacities of planks at various spans, consultTable 8.1 and Table 9.1.8.2 Aluminum/Plywood Platform PanelsMost manufacturers make their heavy-duty platformscapable of supporting a uniformly distributed load of 3.6kn/m2 (75 lb./sq. ft.) together with a concentrated load of227 kg (500 lb.) spread over an area near the centre ofthe span. The load-carrying capacity of these platformsvaries to some extent.It is recommended that the rated load-carrying capacitybe obtained from the supplier and marked on the platformpanel if the manufacturer has not provided suchinformation on the equipment already. The light-dutyplatforms available with much less capacity are notsuitable for construction.

SCAFFOLDS

Figure 8.1SECURING ALUMINUM/PLYWOOD PLATFORMS

Locking device

25 – 19

Table 8.1

No. 1

No. 1

No. 1

No. 1

5'-0" 7'-0"

SELSTR

No. 1

No. 1

No. 1

No. 1

150lbs.

100lbs.

75lbs.

50lbs.

Layersof Planks

UNIFORM

LOAD

PER

SQUA

REFO

OT

SELSTR

No. 1

No. 1

No. 1

No. 1

SELSTR

No. 1

No. 1

SELSTR

No. 1

No. 1

No. 14000

2900

2430

1760

1520

4'X4

'PAL

LETLO

ADS

(POUN

DS)

No. 1

Maximum loads on planks for scaffoldplatforms 5 feet in width

Notes 1. Planks are spruce-pine-fir species group (SPF).2. Planks are at least 17/8" thick and at least 93/4" wide.3. Grade is either number one (No. 1) or select structural (SEL STR).4. Allowable stresses conform with CSA Standard CAN3-086-1984 “Engineering Design in Wood.”5. No stress increases are included for load sharing or load duration.6. Scaffold platforms are 5' wide and fully decked in.7. Loads indicated aremaximum for grade and loading conditions. Shaded areas indicate that no

SPF grades are capable of carrying the loads.

25 – 20

The advantage of aluminum/plywood platform panels isthat they are light and durable. Worn-out plywood caneasily be replaced. However, they are expensive and thehooks on most models can be damaged if dropped fromthe scaffold repeatedly during dismantling. Check theplatform hooks and fastening hardware regularly forlooseness, cracking, and distortion. When used outdoors,these platforms should be secured to the scaffold framesusing wind locks. Otherwise, when left unloaded, they canbe blown off the scaffold by strong winds.8.3 Laminated Veneer LumberThis material is really a special type of exterior plywoodwith laminations oriented longitudinally rather than in twodirections. The wood is usually spruce or Douglas fir,although other structural species can be used. Thematerial is manufactured in large sheets of variousthicknesses that can be sawn to the sizes required.The use of laminated veneer lumber as a scaffoldplatform material is increasing. The strength varies frommanufacturer to manufacturer depending on method offabrication and species of wood used. Users of thematerial should ask suppliers to furnish rated workingloads for the scaffold spans on which the lumber will beused. In general, the material will be stronger than sawnlumber scaffold planks of similar size and species. Thestrength is also more uniform than sawn lumber.Like all lumber and plywood, laminated veneer lumber issubject to deterioration from weathering and rot. It musttherefore be inspected periodically. Sections showingdelamination, cracks, serious damage to several layers oflamination, fungi, or blisters should be discarded.8.4 Sawn Lumber PlanksRough sawn planks 48 mm x 248 mm (2 inches by 10inches) or larger have been the standard scaffold platformmaterial for many years. They are also the leastexpensive of the common platform materials. Dressedlumber should never be used for scaffold platforms.The proper use of planks on a scaffold or other workplatform is governed by the Construction Regulationunder Ontario’s Occupational Health and Safety Act. Theregulation specifies that wooden planks used on ascaffold must• be number 1 grade spruce• bear a legible stamp or be permanently identified as

being number 1 grade spruce• be at least 48 mm by 248 mm (17/8" x 93/4")• be arranged so their span does not exceed 2.1

metres (7 feet)• overhang their supports by no less than 150 mm (6")

and no more than 300 mm (12")• be laid tightly side by side across the full width of the

scaffold at the working level• be cleated or otherwise secured against slipping• be capable of carrying any load likely to be applied

and as a minimum be capable of carrying 2.4kilonewtons per square metre (50lb./sq. ft).

It is recommended that planks should meet or exceed therequirements for select structural grades of the speciesgroup used, which should be either spruce-pine-fir (SPF)or Douglas fir. Although the SPF group has less strength,

it is usually lighter and therefore easier to handle thanDouglas fir. Table 8.1 provides maximum loads based onunit stresses from Canadian Standards AssociationStandard 086.1-1994 “Engineering Design in Wood” forNumber 1 and select structural SPF plank platforms.Sawn lumber planks must be stamped by themanufacturer identifying them as scaffold planks.Since wood planks deteriorate they must be regradedand culled periodically. For most situations, visual gradingis recommended. Scaffold planks must be inspectedregularly because they deteriorate with use and age, andare subject to damage. Figure 8.2 illustrates defects tolook for when inspecting planks. Cull out planks with largeknots in the edge, spike knots, checks, wanes, wormholes, and steeply sloping grain patterns. Planks withthese defects should not be used as scaffold material andshould be destroyed. Scaffold planks can also beweakened by dry rot. It is not easy to notice this conditionin its early stages, especially if the exterior of the planks isweathered. Planks substantially infected with dry rot areusually lighter than sound planks of similar size andspecies. For this reason do not use planks which feellighter than normal.

8.5 Reinforcing Wood PlanksWood planks may be reinforced with metal nailer strips orplates. Research conducted by the Construction SafetyAssociation of Ontario has indicated that the strength ofweaker planks may be increased considerably by thistechnique but it should only be used to increase the strengthof planks that are of the proper grade. Do not use this as amethod of upgrading inferior grades for scaffold use.The advantages of strengthening planks by this methodare twofold:• planks are not as likely to be cut up or used for

purposes other than scaffold planks• you have additional assurance that poorer quality

planks undetected in the grading process will notbreak prematurely causing an accident.

WARNING: Nailer plates should not be placed overthe portion of the plank resting on the scaffoldsupport—unless cleats are used to prevent the plankfrom sliding—since there is little friction between thebearing surfaces.Take care when handling planks reinforced in this waysince sharp edges can cut your hands.

SCAFFOLDS

Check

Split

Sap Line

Spike Knot

Wane

Figure 8.2DEFECTS IN LUMBER PLANKS

Worm Hole

25 – 21

8.6 Securing Platforms to the FrameBe sure to secure platforms against sliding or movement.Workers frequently fall from platforms because they didnot first secure the platform materials. Aluminum/plywoodcombination platforms have hooks that preventlongitudinal movement but will slide sideways on thescaffold unless the platform is fully decked in.Sawn lumber planks should be cleated on at least oneend to prevent longitudinal movement (Figure 8.4). Youcan also prevent movement by wiring a plank (Figure 8.6).Unless you carefully apply it, the wire can present atripping hazard on the platform. Again, the platform shouldbe fully decked in to prevent sideways movement.

If you have overlapping planks, the cleated end should beresting on the scaffold support. Be aware that theoverlapped section presents a tripping hazard (Figure 8.5).

8.7 Wind UpliftWind can lift light platform materials from the scaffold ifthey are not secured. When you anticipate severe windconditions or when you are using high scaffolds, youshould secure platform materials such asaluminum/plywood panels to the scaffold. With some typesof platform panels you can do this with wire or nails.

Others have a sliding locking device (Figure 8.1). Theselocking devices, however, can be easily damaged and areoften difficult to apply and release.

9 PROPER USE OF SCAFFOLDSMuch of this chapter deals with the erection anddismantling of various types of scaffolds. Frequently, theend user of the scaffold is not the person who erects it. Inorder for scaffolds to provide efficient access to workareas they must be used properly by all workers.9.1 Ladders and ClimbingWe discussed ladder access in Section 5.3. The laddermust be properly erected with rails projecting 1 metre (3feet) above the platform of the scaffold. You should cleardebris, extension cords, and tools away from areasaround the top and bottom of ladders. Store materialsaway from these locations.Falls often happen when workers are getting on or off theladder at the platform level. Both hands must be free tohold guardrails or ladder rails. Do not carry tools ormaterials by hand when climbing ladders. Wear a tool beltand pouch and move material up or down by rope.You should always place portable straight ladders with anadequate slope and secure them to the scaffold structure(Figure 5.5).Always use three-point contact (Figure 9.1) when climbingladders. This means using two hands and one foot, or twofeet and one hand, to maintain contact with the ladder at alltimes. Always face the ladder when climbing and alwayskeep your centre of gravity between the two ladder rails.For more information, refer to the Ladders chapter of thismanual.9.2 Guardrails Missing or Removed

There may be situations where scaffolds must be usedwithout guardrails. If the scaffold is more than one frameor tier in height and there are no guardrails, personnel onthe platform must tie off with a full body harness and

SCAFFOLDS

Figure 8.3PLANK REINFORCED WITH NAILER PLATES

Figure 8.4PLANK CLEATED TO PREVENT SLIDING

Note:Cleat onlyone end ofeach plank.

Figure 8.6PLANKS WIRED TO PREVENT UPLIFT

Figure 8.5OVERLAPPING PLANKS FOR MULTI-SPAN TOWERS

lanyard (Figure 9.2). Many falls and serious injuries occurwhen workers use platforms without guardrails. Anyworker who removes a guardrail for any reason mustreplace it when the task is completed.

9.3 Standing on Objects Above the Platform

People working from the platform should have both feeton the platform. Standing on a barrel, box, stepladder,guardrail, or other object to gain extra height is extremelydangerous and is illegal in most jurisdictions, includingOntario. You should know the required height of thescaffold before erecting it, so you can obtain all therequired material, including half frames when necessary.

9.4 Overloading

Overloading scaffold platforms in the masonry trades isone of the most frequent violations of good scaffoldpractice. Placing full pallets of bricks or concrete blockson a single layer of 48 mm x 254 mm (2" x 10") scaffoldplanks is, in most cases, overloading the platform. Youmay have to double plank decks to support pallets ofmasonry materials. Place the pallets over the supportswherever possible. In addition, inspect planks used tosupport masonry materials for damage or fordeterioration regularly and often. Table 8.1 indicates theload-carrying capacities of various grades of plank. Table9.1 lists the approximate weights of common buildingmaterials. Bear in mind overloading may affect stability aswell as load-carrying capacity.

Differential settlement is often a problem when you applyheavy loads to scaffolds resting on uncompacted soils. Ascaffold tower 9 metres (30 feet) high that settles 25millimetres (1 inch) on one side can move 150 millimetres(6 inches) at the top. Settlement puts stress on braces,tie-ins, and frame joints. Place heavy loads symmetricallyon the platform to ensure that soil settlement is uniform.

Finally, the scaffold structure must be capable of carryingthe load that you will apply. Both light-duty and heavy-dutyframes are available on the market. Do not use light-dutyframes where you have heavy loads. If you do not knowthe load-carrying capacity of the frames, consult themanufacturer or supplier. The load-carrying capacity offrames usually varies with the height of the towers.

9.5 Debris on Scaffold Decks

Scaffold decks are small, narrow, and confined. Storetools and materials in an orderly fashion. Do not allowdebris and waste materials to collect on the platform. Putthem in a container or remove them from the platformimmediately. Set up a plan for dealing with wastematerials. Simply throwing garbage off the scaffold isextremely dangerous—don’t do it. If work on the scaffoldis likely to result in debris falling, such as in masonrywork, then cordon off the scaffold to prevent workers fromentering the area.

Waste pieces of lumber, pipe, wire, miscellaneous metal,and small tools are tripping hazards which have caused

SCAFFOLDS

Note: Vertical ladders above 3 metres inheight must have a safety cage beginning 2.2metres above the ground or platform.The cage is omitted here for clarity.

Figure 9.1THREE-POINT CONTACT

Figure 9.2FALL PROTECTION WITHOUT GUARDRAILS

25 – 22

25 – 23

SCAFFOLDS

Workers wet asbestos ascovering is removed

Decontamination Trailer

ASBESTOS REMOVAL

APPROXIMATE WEIGHTS OF BUILDING MATERIALS

Material Metric Unit Weight Imperial Unit WeightAluminum 2643 kg/cu m 165 lb/cu ftIron (Wrought) 7769 kg/cu m 485 lb/cu ftSteel 7849 kg/cu m 490 lb/cu ftNickel 8730 kg/cu m 545 lb/cu ft

Glass (plate) 2563 kg/cu m 160 lb/cu ft

Lumber (dry)Cedar (white) 352 kg/cu m 22 lb/cu ftDouglas Fir 513 kg/cu m 32 lb/cu ftMaple 689 kg/cu m 43 lb/cu ftRed Oak 657 kg/cu m 41 lb/cu ftSpruce 433 kg/cu m 27 lb/cu ft

Concrete 2403 kg/cu m 150 lb/cu ft

Granite 2803 kg/cu m 175 lb/cu ftBrick 1922 – 2243 kg/cu m 120 – 140 lb/cu ftLimestone, Marble 2643 kg/cu m 165 lb/cu ftSandstone 2082 kg/cu m 130 lb/cu ft

Steel Pipe (standard)1" I.D. 2.49 kg/m 1.68 lb/ft2" I.D. 5.43 kg/m 3.65 lb/ft3" I.D. 11.27 kg/m 7.58 lb/ft4" I.D. 16.05 kg/m 10.79 lb/ft

Copper Pipe1" I.D. 2.71 kg/m 1.82 lb/ft2" I.D. 6.28 kg/m 4.22 lb/ft3" I.D. 13.02 kg/m 8.75 lb/ft4" I.D. 19.20 kg/m 12.90 lb/ft

Aluminum Pipe (standard)1" I.D. 0.86 kg/m 0.58 lb/ft1-1/2" I.D. 2.40 kg/m 1.61 lb/ft2" I.D. 3.08 kg/m 2.07 lb/ft3" I.D. 4.57 kg/m 3.07 lb/ft

Drywall (1/2" thick) 10.25 kg/m2 2.10 lb/ft2

Table 9.1

25 – 24

many serious falls from scaffolds. You need an orderlywork area to work safely on scaffolds.

9.6 Exposure to Hazardous Material

Frequently scaffolds are erected for work involvinghazardous substances: e.g., refurbishing structurespainted with lead-based paint. If you are sandblastingpainted surfaces, lead can accumulate on planks andother components. Workers carrying out these activitiesmust use appropriate personal protective equipment. Thescaffold worker who has to dismantle the scaffold can alsobe at risk from the lead residue. Under these conditionsyou should do the following.

1. Clean components that are likely to be contaminatedby lead dust, preferably by washing with a hosebefore dismantling begins.

2. Cap scaffolding frames and standards as the scaffoldis being erected to prevent lead dust fromaccumulating inside and being subsequently releasedduring the dismantling process.

3. If it is not possible to wash down the scaffoldingbefore dismantling, then scaffold workers should wearproperly fitting N100 filtering facepiece respiratorswhile dismantling. The scaffold should then bewashed before it is removed from the site.

4. Proper attention to personal hygiene is critical whendealing with lead. Workers must be instructed not toeat, drink, or smoke without washing their hands. Asign or notice indicating this should be conspicuous.

5. Workers should be provided with separate “clean”and “dirty” areas. Use the dirty area for changing outof contaminated clothing and the clean area forchanging into uncontaminated clothing and eating.Washing facilities with clean water, soap, andindividual towels should separate the two areas.

6. Scaffold workers should inform their physician if theyare exposed to lead. The physician may want tomonitor the level of lead in the person’s blood to see ifit is within normal parameters.

SCAFFOLDS

26 – 1

26 ELEVATING WORKPLATFORMS

Basic TypesThere are two basic types of elevating work platforms—boom and scissor. Both types come in• on-slab models for use on smooth hard surfaces such

as concrete or pavement• rough-terrain models for use on firm level surfaces

such as graded and compacted soil or gravel.Both types share three major components: base, liftingmechanism, and platform assembly.Scissor-Type MachinesThese are raised and lowered by hydraulic pistons and anexpanding scissor mechanism. Platforms are available invarious configurations with different capabilities forextension and movement. Some have extendableplatforms or platforms that can rotate. Extendableplatforms should be retracted before raising or loweringthe device. Typical machines are illustrated in Figure 1.1.On-slab units- not designed for uneven or sloping ground- normally have solid rubber tires- generally powered by rechargeable DC battery- some powered by internal combustion engine, either

gasoline or propane- most have “pothole protection”—a metal plate lowered

close to the ground to afford some protection againstinadvertent movement into depressions or debris.

Rough-terrain units- similar in design to on-slab machines- built to handle rigorous off-slab challenges- normally have wider wheel bases, larger wheels, and

pneumatic tires- some fitted with outriggers for extra stability- usually powered by internal combustion engines,

gasoline, diesel, or propane- DC units also available but not common- lifting mechanism is hydraulic.

Scissor-type machines range in capacity from 500 toseveral thousand pounds. They are available with platformheights often reaching 15 metres (50 feet) and beyond.Scissor-type machines must be set up on stable levelground, even with outriggers deployed. A slightimbalance or instability is amplified when the machineis raised.

Figure 1.2 shows one example of controls. Although fixedto the platform, the controls are moveable from one sideof the platform to the other. This enables the operator tosee the path of travel.The controls must be oriented correctly so that theoperator does not inadvertently move the machine in thewrong direction. Many machines have colour-codeddirectional arrows on the chassis to aid the operator inmoving the machine.

Self-Propelled Boom-Supported Platforms- normally fitted with rough-terrain undercarriages- some smaller on-slab units- platforms have lifting capacity of about 227 kg (500

pounds) or two workers- lack capacity of scissor-type machines; not intended

for lifting materials- usually powered by an internal combustion engine,

gasoline, diesel, or propane.

Figure 1.4 shows one example of controls for a boommachine. Although controls are fixed in position, theoperator may become disoriented by machine rotationand must remain aware of the direction of movement.Many machines have colour-coded directional arrows tohelp the operator move the machine in the right direction.

ELEVATING WORK PLATFORMS

Figure 1.1: Scissor-type powered platforms

Controls1. Emergency stop button2. Choke3. Stop/start switch4. Run/idle switch5. Lift up/down switch6. Drive high range/low rangeswitch

7. Forward/reverse joystick8. Left/right steer switch9. Traversing deck out/inswitch

10. Outriggers up/down switch

Figure 1.2: Example of controls on scissor-type platforms

Booms- telescopic, articulating, orcombination of both

- raised and extended by hydrauliccylinders

- can reach up to 45 metres (150feet)

- can extend well beyond thewheelbase.

Figure 1.3: Boom-type powered platforms

26 – 2

As with mobile cranes, stability decreases with length ofboom and boom angle as the centre of gravity moves inrelation to the platform position. The machine will overturnif the centre of gravity moves outside the machine’s base.Machines come with load charts that show safe operatingconfigurations. Machines with booms long enough tocause overturning at low boom angles are required tohave radius-limiting interlocks to prevent operation inunstable configurations.The reach chart shown in Figure 1.5 indicates the safeoperating configurations for a machine with 36 metres(120 feet) of reach operating on a level surface.The reach diagram in Figure 1.6 shows the safe operatingenvelope for a 10-metre boom machine.Notice that the machine does not achieve its maximumheight directly overhead. Nor does it achieve its maximumreach at ground level.

Users must be familiar with the operating range of theindividual make and model they are using. Thisknowledge is essential in order to position the machinecorrectly and reach the work location safely.Non-Self-Propelled or Push-AroundsAs the name indicates, these units are not self-propelledand must be transported from one location to another withan independent power source or manually in the case ofthe smaller devices.The machines are intended primarily for use on smooth,level, hard surfaces or on-slab conditions. Some trailer-mounted units are available.Many of these devices can fold up to pass through astandard door and can be transported by pick-up truck. As aresult they are suitable for maintenance or renovation work.

Push-Arounds- Raising mechanism normally powered by gasoline or

propane engine or by electric motors, either AC or DC- normally raised and lowered by hydraulic cylinders- platform capacities vary from 300 to 1000 pounds or

more but are generally less than 500 pounds- devices with capacity less than 500 pounds are not

recommended for construction—better suited tomaintenance activities


Figure 1.4: Example of boom-machine controls

REACH IN FEET (METRES) FROM AXIS OF ROTATIONFigure 1.5: Reach chart for a 120-foot (36-metre) machine

Figure 1.6: Reach diagram for a 10-metre articulating boom platform

Figure 1.7: Push-around powered platforms

PLATFORM

HEIGHTINMETRES

26 – 3

- platforms don’t usually exceed 11 metres (36 feet) inheight

- as platform is raised, risk of overturning increases- extra care required when operating at maximum

height.

SelectionElevating work platforms are designed for different uses. Itis essential to select the right machine for the job.Typical Mistakes• using an on-slab machine on rough terrain• using a unit undersized with respect to height, reach,

and lifting capacity• lifting large materials that overhang the platform• using a scissor lift where the reach of a boom-type

machine is needed• extending the platform with planks, ladders, or other

devices because the machine can’t reach the requiredheight.

Factors to Consider

Capacity – Does the machine have the lifting capacity,the reach, and the height to complete the task?Surface conditions – Are the surface conditions hard orsoft, sloped or level? Will the ground have an effect onthe type of machine selected?Platform size and configuration – Do you need aregular or extendable platform? Is rotation required? Arethere space restrictions to consider?Mobility – Is a boom type better suited than a scissor liftto the task at hand?Material to be lifted – Will the machine be able to lift thesize and weight of material required for the job?Access – Will the machine be able to travel around theworkplace safely? Are there obstructions or depressionsthat will restrict the use of certain machines?Operator skill or training – Are the people on sitecompetent to operate the machine? If a propane-poweredengine is used, has the operator received propanetraining?Work environment – If the work is to be done indoors orin a poorly ventilated area, will an electrically poweredmachine be required?

Basic HazardsThe following are some basic hazards.Machine tipping or overturningMany factors cause instability—sudden stops,depressions, drop-offs, overreaching, overloading, etc.Overturning and tipping result in many fatalities andinjuries.Overriding safety featuresDisarming features such as the tilt or level warning andthe deadman switch can prevent operators from knowingwhen they are in a dangerous situation. Overriding thedeadman switch has resulted in a fatality; so hasmalfunction of the tilt warning.

Overhead powerline contactContacting overhead wires can cause electrocution. Thiscan happen with any type of machine—and with the loadscarried by or overhanging the machine.Makeshift extensionsWhen the machine can’t reach the working height desired,don’t compensate by using scaffold planks, ladders,blocks of wood, or other makeshift arrangements. Suchpractices lead to falls and machine instability.Overloading the platformEWPs overloaded or loaded unevenly can becomeunstable and fail. Boom-type machines are especiallysensitive to overloading. Always stay within the operatingrange specified by the manufacturer.Failure to cordon off- EWPs have been struck by other construction

equipment or oncoming traffic when the work area isnot properly marked or cordoned off.

- Workers have been injured when they inadvertentlyentered an unmarked area and were struck by fallingmaterial, tools, or debris.

- In unmarked areas, workers have also been injured byswinging booms and pinched by scissor mechanisms.

Accidental contactMany EWPs have blind spots. Moving the machine orplatform may cause contact with workers or with obstacles.Use a designated signaller on the ground to guide theoperator when the path of travel isn’t clear or access is tight.Improper maintenance or modificationsEWPs should be maintained by competent workers inaccordance with manufacturer’s instructions. Nomodifications should be made to the machine without themanufacturer’s approval.Improper blocking during maintenanceFailing to block, or improperly blocking the machine,boom, or platform can cause serious crushing injuries andproperty damage.Improper accessDon’t enter or leave the platform by climbing the scissors orthe boom. Don’t use extension ladders to gain access.Ladders exert lateral loads on the platform that can causeoverturning. For the safest access, lower the machinecompletely.Moving with platform raisedLower the platform before moving the machine unless1) the machine is designed to move with platform raised and2) the supporting surface is smooth and level. Slight dipsand drops are amplified when the platform is raised andcan cause the machine to overturn.Improper refuellingTake care when refuelling. Gasoline, for instance, shouldbe kept in approved containers and dispensed to preventspills and sparking.Pinch pointsClothing, fingers, and hands can get caught in scissormechanisms. As platforms are raised, machines maysway. Workers can be pinched between guardrails andthe structure. Position the platform so that work takesplace above guardrail height.


26 – 4

Regulations and ResponsibilitiesThe construction regulation (Ontario Regulation 213/91)includes the following requirements:• Elevating work platforms must be engineered and

tested to meet the relevant standard for thatequipment [section 144(1)(a)]. Standards include CSA B354.1: non-self-propelled elevating workplatforms

CSA B354.2: self-propelled elevating work platforms CSA B354.4: boom-type elevating work platforms.

• The devices must be checked each day before use bya trained worker [section 144(3)(b)].

• The owner or supplier must keep a log of allinspections, tests, repairs, modifications, andmaintenance [section 145(2)].

• The log must be kept up to date and include namesand signatures of persons who performed inspectionsand other work [section 145(3)].

• A maintenance and inspection tag must be attachednear the operator’s station and include the date of thelast maintenance and inspection and the name andsignature of the person who performed the work[section 146].

• Workers must be given oral and written instructionbefore using the platform for the first time. Instructionmust include items to be checked daily before use[section 147].

• All workers on the platform must wear a full bodyharness or a safety belt attached to the platform whilethe platform is being moved [section 148(e)].

The health and safety responsibilities of all parties on aconstruction site are outlined in the “green book”—theOccupational Health and Safety Act and Regulations forConstruction Projects.Because elevating work platforms are often rented froman equipment supplier, there is confusion as to theresponsibilities of the parties involved. Generally, theresponsibilities can be summarized in the following way.The owner or supplier must ensure that the machine• is in good condition• complies with regulations• is maintained in good condition• conforms to the appropriate CSA Standard• includes the correct load rating charts if required.

The employer and supervisor on the project must• ensure that the operator is competent• ensure that the machine has the correct load rating

capacity for the job• maintain the equipment and all its protective devices• maintain a log book for each platform• ensure that workers use appropriate personal

protective equipment• keep the manufacturer’s operating manual on site• train workers on each class of equipment being used.

The worker or operator of the equipment must• receive adequate training to be fully competent• only operate the machine when competent• operate the machine in a safe manner and as

prescribed by the manufacturer and the company’s

health and safety policy• inspect the equipment daily before use• perform function tests before use• report any defects to the supervisor• read, understand, and obey the manufacturer’s safety

rules, including the operating manual and warning decals.

When a defect is reported to the supervisor, theequipment must be taken out of service until therepairs are completed and the equipment is inspectedand approved for use.

Stability and TippingIn general, EWPs are well manufactured and are safe touse within their specific limitations. As with any equipmentor tool, there are do’s and don’ts to follow.One of the most dangerous hazards in operating EWPs istipping over. This can be caused by one or several of thefollowing factors:• sudden movement of the unit or parts of the unit when

elevated• sudden stopping when elevated• overloading or uneven loading of the platform• travelling or operating on a slope or uneven terrain• changing the weight distribution of the machine by

replacing parts with others of a different weight oradding attachments not approved by the manufacturer

• holes or drop-offs in the floor surface causing onewheel to drop suddenly

• operating the equipment in windy conditions (refer tothe operator’s manual for safe operating conditions).

It is important that users understand what makes aplatform stable and what causes it to overturn. Tounderstand stability, one must understand the concept ofcentre of gravity, tipping axis (or tipping point), and forcesthat shift the centre of gravity.Stability is resistance against tipping over. Stabilitydepends on the location of the centre of gravity in relationto the tipping axis.Centre of Gravity

Every object has a centre of gravity. It isthe point where the object’s weight wouldbe evenly distributed or balanced. If asupport is placed under that point, theobject would be perfectly balanced.The centre of gravityis usually locatedwhere the mass ismostly concentrated.However, the locationdoesn’t always remainthe same. Any actionthat changes themachine’sconfiguration—such as raising the platform, extending theboom, or travelling on a slope—can change the locationof the centre of gravity.Figure 4.1 shows how raising a scissor-type platformaffects the centre of gravity.


Figure 4.1 Centre of gravity on scissor lifts

26 – 5

Tipping Axis and Area of Stability

When an EWP turns over, it tips around an axis or point.This is called the tipping axis or tipping point. EWPstypically have four tipping axes – front, back, left, andright.Each EWP has its own area of stability. This varies fromplatform to platform and from model to model. In mostcases, the area of stability is bound by the four tippingaxes (or the four tires or outriggers). The platform isstable as long as the centre of gravity remains inside thearea of stability. This is the key to safe operation.Figure 4.2 shows how lowering the boom angle affectsthe centre of gravity. In this example the centre of gravitymoves towards the platform but remains inside the area ofstability.When the centre of gravity shifts beyond the area ofstability, the machine will tip over. Some factors that cancause a shift beyond the stability area are overloading,moving on excessively sloped ground, a sudden drop ofone wheel, and shock loading.

Raising the platform also raises the EWP’s centre ofgravity. When a scissor lift is situated on a slope, and theplatform is raised, the platform’s centre of gravity willmove toward the tipping axis. If the centre of gravitymoves beyond the tipping axis, the platform will overturn.Boom-supported EWPs work in the same way. When theboom is extended outward, the centre of gravity movesoutwards towards the tipping axis. The EWP will overturnif the boom is extended such that the centre of gravitymoves beyond the axis. Boom-type machines have aninterlocking system that prevents the machine frommoving into an unstable configuration.Factors Affecting StabilityDynamic Forces

Dynamic forces are forces generated by movement orchange of movement. For example, applying the brakessuddenly or travelling too fast around corners can causeinstability – as in a car or van. Sudden stops while raisingor lowering the platform can also cause instability.

Travelling

Travelling theplatform over roughor uneven ground canalso cause instability.Figure 4.3 showshow a tire dropping100 mm can causethe boom to sway600 mm. It isimportant to lower theplatform fully or toretract telescopingsections whiletravelling, particularlyon uneven surfaces.

Equipment InspectionAll components which bear directly on the safe operationof the EWP and can change from day to day must beinspected daily. Inspection is mostly visual – done in aquick but thorough manner.Users must check the operator’s manual for a completelist of pre-operational checks.Minimum Requirements

Before climbing into the platform, check

Tires for proper pressure and wheels for loose ormissing lug nuts

Steer cylinder, linkage, and tie rods for loose ormissing parts, damage, and leaks

Hydraulic hoses, lift cylinder(s), and connectionsfor leaks or loose connections (for example, asmall pool of hydraulic fluid)

Fuel supply – adequate fuel, filler cap in place,no damage, leaks, or spills

Hydraulic oil for leaks and fluid level, battery forfluid level and state of charge

Proper connection of all quick-disconnect hoses

Structural components for damage, broken parts,cracks in welds, including scissor arms, outriggerarms, and pads

Ladder or steps for damage and debris (laddermust be firmly secured to the platform andrelatively free of grease, mud and dirt)

Beacon and warning lights for missing anddefective lenses or caps

Ground controls (manual and powered)—including emergency stop switch and platformlower/lift switch—for proper function anddamaged and missing control sticks/switches

Decals and warning signs to make sure they’reclean, legible, and conspicuous.


Figure 4.2: Centre of gravity for a boom-supported machine

14-metre boom(40 feet)

Tire drop Boom Sway100 mm 600 mm150 mm 850 mm

Figure 4.3: Effect of uneven groundon boom sway

26 – 6

On the platform, check

Platform assembly for loose and missing parts,missing or loose lock pins and bolts

Platform floor for structural damage, holes, orcracked welds and any dirt, grease, or oil thatcan create a hazard

Operator’s manual to make sure it’s in place

Extendable platform deck for ease ofextension/retraction and proper function oflocking position of platform

Guardrails to make sure they’re in place

Access gate for ease of movement, missingparts, latch, and locking capabilities

All fall protection anchorage points

All control mechanisms for broken or missingparts

All emergency controls for proper function—stopping, descending, master OFF switch

All safety devices such as tilt and motion alarmsfor malfunction

Swivels for freedom of rotation

Scissors for smooth movement up and down

Brakes for stopping capabilities

Horn for proper function.

Manuals, Signs, and DecalsSection 144(8) of the construction regulation (OntarioRegulation 213/91) specifies the signs that are requiredon an EWP.Signs clearly visible to the operator at the controls mustindicate• the rated working load• all limiting operating conditions, including the use of

outriggers, stabilizers, and extendable axles• the specific firm level surface conditions required for

use in the elevated position• such warnings as may be specified by the

manufacturer• other than for a boom-type elevating work platform,

the direction of machine movement for each operatingcontrol

• the name and number of the National Standards ofCanada standard to which the platform was designedand

• the name and address of the owner.

In addition to the above, the CSA standards for EWPsrequire the following signs:• the make, model, serial number, and manufacturer’s

name and address• the maximum platform height• the maximum travel height, if not equal to the

maximum platform height

• the nominal voltage rating of the batteries, if battery-powered

• a warning to study the operating manual before usingthe equipment

• a notice outlining the required inspections• diagrams or description of the various configurations

in which the platform can be used• the capacity in each configuration• a statement as to whether or not the platform is

insulated• warnings against replacing, without the manufacturer’s

consent, components critical to the machine’sstability—for example, batteries or ballasted tires withlighter weight components (the minimum weights ofsuch components must be specified).

Many of these signs are vitalto the operation of themachine and the protectionof workers. All signs anddecals must be kept clear ofdust and grease so they canbe easily read. Torn ordamaged signs must bereplaced. A typical warningsign is shown in Figure 5.1.CSA standards also requirethat the manufacturer providea manual containing thefollowing information:• description, specifications, and capacities of the

platform• the operating pressure of the hydraulic or pneumatic

system that is part of the work platform• instructions regarding operation and maintenance,

including recommended daily, weekly, and monthlyinspection checklists

• information on replacement parts.

The manual must be stored on the platform in a weather-proof storage container.

Safe PracticesSpecific RequirementsFor the specific EWP they will use, operators must befamiliar with• the manufacturer’s operating manual• the manufacturer’s warning and caution signs on the

machine• the location of all emergency controls and emergency

procedures• the daily maintenance checks to perform.

General Guidelines• Always check for overhead powerlines before moving

the machine or operating the platform. You mustobserve the minimum permitted distances fromoverhead powerlines (see table, next column). Whenequipment operates within reach of (and couldtherefore encroach on) the minimum distance from apowerline, make arrangements with the owner of theutility to have the powerline de-energized. Otherwise,


Figure 5.1

26 – 7

the constructor is required to have written proceduresin place to prevent equipment from encroaching onthe minimum distance. Copies of the procedures mustbe available for every employer on the project.See section 188 of the Construction Regulation forfurther requirements.

• Allow for movement or sway of the lines as well as theplatform. Be aware of overhanging tools or equipment.

Voltage Rating of Powerline Minimum Distance

750 to 150,000 volts 3 metres (10 feet)150,001 to 250,000 volts 4.5 metres (15 feet)over 250,000 volts 6 metres (20 feet)

• Wear a full body harness and tie off to a designatedtie-off point while the machine is moving.

• Do not leave the machine unattended without lockingit or otherwise preventing unauthorized use.

• Don’t load the platform above its rated working load(RWL). Wherever possible, keep the load below 2/3 ofthe RWL.

• Make sure that all controls are clearly labeled withaction and direction.

• Keep guardrails in good condition and ensure that thegate is securely closed before moving the platform.

• Shut off power and insert the required blocking beforemaintenance or servicing.

• Deploy stabilizers or outriggers according to themanufacturer’s instructions.

• Don’t remove guardrails while the platform is raised.• Position the boom in the direction of travel where

possible.• Keep ground personnel away from the machine and

out from under the platform.• Don’t access the platform by walking on the boom.• Don’t try to push or move the machine by telescoping

the boom.• Do not use the machine as a ground for welding.• Don’t use a boom-supported platform as a crane.• Don’t operate the equipment in windy conditions. For

safe wind speeds refer to the operator’s manual forthe specific make and model you are using.

• Do not place theboom or platformagainst anystructure to steadyeither the platformor the structure.

• Secure loads andtools on theplatform so thatmachine movementwon’t dislodgethem.

• Make sure thatextension cords arelong enough for thefull platform heightand won’t get pinched or severed by the scissormechanism.

• Use three-point contact and proper climbingtechniques when mounting or dismounting from themachine (Figure 6.1).

Never operate equipment on which you have not beentrained or which you are not comfortable operating.The safety of you and others on site depends on thecompetent, knowledgeable operation of equipment.

Work Area Inspection

Before operating the EWP, check the workarea for

drop-offs or holes in the ground

slopes

bumps or floor obstructions

debris

overhead obstructions

overhead wires, powerlines, or other electricalconductors

hazardous atmospheres

adequate operating surface—ground or floor

sufficient ground or floor support to withstand allforces imposed by the platform in every operatingconfiguration

wind and weather conditions.


Figure 6.1: Three-point contact

27 SUSPENDED ACCESSEQUIPMENT

CONTENTS1. Introduction2. Equipment types, limitations, and applications3. Components and rigging4. Set-up and operation5. Fall protection6. Checklists

1 INTRODUCTIONSuspended access equipment of various kinds has beenused in construction and restoration for many years. Withthe increase in high-rise construction there has been acorresponding increase in the number and diversity ofapplications for this equipment. Unfortunately, there has alsobeen an increase in the number of injuries and fatalities.In an average year, two fatalities and over 100 lost-timeinjuries are connected with suspended access equipmentin Ontario construction and window cleaning.This chapter covers the main types of suspended accessequipment used in construction, restoration, andmaintenance work. It explains the fundamentalrequirements for set-up, rigging, and use; the necessaryprovisions for fall arrest; and the importance of assessingeach job carefully in order to select the equipment mostsuitable for safe, efficient operation.

2 EQUIPMENT TYPES, LIMITATIONS,AND APPLICATIONSEquipment discussed in this section is restricted tofactory-built stages, work cages,and bosun’s chairs such as thetypes shown in Figure 1.Unusual or non-conventionalarrangements of equipment shouldbe reviewed by a professionalengineer to ensure compliance withapplicable standards,regulations, and goodpractice. In somecases, the services ofa professionalengineer are requiredunder the ConstructionRegulation (OntarioReg. 213/91).2.1 SpecialRequirementsTiered stages andsetups where thesuspended platformand associatedsuspended equipmentweigh more than 525kilograms (1,157 Ib.)must be designed by aprofessional engineer.

A copy of the design drawings must be kept on theproject. In addition, a professional engineer must inspectthe suspended scaffold before use and confirm in writingthat it has been erected in accordance with the drawings.2.2 Manual Traction Climber Equipped Stage (Figure 2)

For many years this was the predominant type ofsuspended access equipment in the industry. Morerecently it has been replaced by various types of poweredclimbers, especially where considerable movement isrequired or heights are greater than 100 feet.

Figure 1Types of Equipment

Described in this Section

Figure 2Manual Traction Climber Equipped Stage

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SUSPENDED ACCESS

This type of equipment is, however, quite suitable formoderate heights where the stage will remain inapproximately the same position for a reasonable periodof time and where only limited climbing is required.2.3 Drill-PoweredTraction ClimberEquipped Stage (Figure 3)

The climbers on thesedevices are powered byspecially designedelectric drills. Oneadvantage is that theyoperate on a 120-voltpower supply. Thiseliminates therequirement for special220-volt wiring commonlyrequired on largerpowered climbers. Adisadvantage is that therate of climb is somewhatslower than for othertypes of poweredclimbers.Drills powering theclimbers can be easilyremoved and storedwhen not in use,eliminating some of theweather damage andvandalism that occurwhen other climbingdevices are leftoutdoors.2.4 Powered TractionClimber EquippedStage (Figure 4)

This is the mostcommon type ofpowered climber in usetoday. Its fast rate ofclimb makes it idealwhere verticaldistances are large orfrequent movement isrequired. Usuallypowered by a 220-voltpower source, the unitmay require installationof a temporaryelectrical supply depending onlocation.Because of the relatively fast rate ofascent and descent (up to 35 ft/min),operators must take care that thestage does not catch on obstructionssuch as architectural features andoverload the suspension system. Thiscaution, of course, applies to alldevices but is most important whereclimbers operate at greater speeds.

2.5 Powered Drum Hoist Climber Equipped Stage(Figure 5)

This equipment is common in the industry today. Oneadvantage is that the suspension lines are wound up onthe drum of a hoist rather than extending to the ground.This keeps the free ends of suspension lines fromcrossing, catching on the building, entangling, orotherwise hindering safe operation. This feature improvesthe safety of the equipment. Although not common, othertypes of climbers can be equipped with a reel to providethe same feature.2.6 Bosun’s Chair (Figure 6)

Bosun’s (or boatswain’s)chairs were used forcenturies on ships.Originally equipped with arope fall, the chairs requiredconsiderable physical effortto be raised and lowered.Today with descent controldevices or poweredclimbers, bosun’s chairs canbe used for various purposesin construction, repair,maintenance, andinspection.In some cases, it may besafer and more efficient touse work cages equippedwith powered climbers.Whether equipped with a descent control device or powerclimber, all bosun’s chairs must use wire rope supportcables if• the distance from the fixed support to the work

platform will exceed 90 metres (295 feet)• corrosive substances are used in the vicinity of the

support cables, or• grinding or flame-cutting devices are used in the

vicinity of the support cables.

As with all suspended access equipment, a fall-arrestsystem (Figure 7) is essential with a bosun’s chair. Thesystem must be used at all times when a person is gettingon, working from, or getting off the chair.For more information on fall arrest, see the chapter onPersonal Fall Protection in this manual.

Figure 3Drill-Powered Traction Climber

Equipped Stage

Figure 5Powered Drum Hoist Climber

Equipped Stage

Figure 6

Figure 4Powered Traction Climber

Equipped Stage

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SUSPENDED ACCESS

2.7 Bosun’s Chair withDescent Control Device(Figure 8)

This arrangement iscommonly used in thewindow cleaning trade. It isvery useful in situationswhere workers mustprogressively descend fromone level to another. Itcannot be used to climb.The main advantage ofdescent control devices isthat they are light to carryor move and simple to rig.

It is standard practice for such devices to be reeved withtwo suspension lines. The reason is that the ropes areeasily damaged and the second suspension line providesadded safety. A second suspension line is mandatory forwindow cleaning applications.2.8 Bosun’s Chair withPowered Climber (Figure9)

These devices are fittedwith a seat attached toa powered climber unit.They are often used forwork which requires aconsiderable amount oftravel in restrictedareas wherepowered work cageswould becumbersome. Theyare compact in sizeand generally lighterthan work cages.Inspection work is atypical applicationfor these devices.

2.9 Work Cage with Powered Climber (Figure 10)

In construction, work cages are often used in place ofbosun’s chairs for both safety and efficiency. Thesedevices are usually equipped with powered climberssimilar to those used for stages. Some of the devices foldup for easy transport. Others may be equipped withplatform extensions providing a wider working area.

3 COMPONENTS AND RIGGING3.1 Planning and Selection of EquipmentWhen starting a new job on an unfamiliar site, alwaysinspect the roof and work area before deciding on theequipment required.The following are some of the points to check duringinspection. Building height—you need this to determine the

length of suspension lines and lifelines. Location, type, and capacity of permanent roof

anchors. If there are no permanent anchors, what provisions

are required to adequately anchor support cables aswell as travel-restraint and fall-arrest system?

Area available for set-up. Location of any electrical hazards. Roof capacity—is it capable of supporting all of the

required equipment? Is there a parapet wall? Has it been designed to

accommodate a parapet clamp outrigger system orwill outrigger beams have to be set up on standsabove the wall elevation to protect it from damage?

How much overhang will be required for outriggerbeams?

Once you have determined these and other site-specificconditions, select the suspended access equipment andfall-arrest system that will best accommodate the job.Always ensure that the proposed set-up and equipmentwill meet the requirements of the Construction Regulation(O. Reg. 213/91) under the Occupational Health andSafety Act.

Figure 7

Figure 9Bosun’s Chair withPowered Climber

Figure 10Work Cages

Figure 8Bosun’s Chair with Descent Control Device

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SUSPENDED ACCESS

3.2 PlatformsPlatforms of various types are illustrated in Figures 3, 4,and 5. Load ratings of platforms and platformcombinations are available from manufacturers. Typicalplatforms have 500-Ib or 750-Ib ratings. The platformmust be capable of supporting all loads to which it is likelyto be subjected without exceeding the manufacturer’srated working load. The load includes air or water hosesand similar equipment suspended from the stage. Westrongly recommend that only stages rated for 750 lb orgreater be used on construction projects.Each platform should be equipped with• an adequate guardrail system that includes

– a securely attached top rail between 0.9 metres(36 inches) and 1.1 metres (43 inches) above

the work platform– a securely attached mid-rail– toeboards

• wire mesh• a skid-resistant platform• adequately sized, securely

attached stirrups.

On many platforms, the frontguardrail (closest to the buildingface) can be lowered toaccommodate the work being done.It’s good practice to use frontguardrails in the fully raised positionat all times. You must use themwhen the stage is more than 75 mm(3 inches) from the building facade.If the stage is less than 75 mm fromthe facade and properly secured tothe face of the structure, you canlower the front guardrails.

Stock platforms are available from most suppliersfrom 4 feet to 32 feet long in increments of 2 feet.

Various combinations of shorter modularplatforms are designed to be connected

together (Figure 11). Use onlymanufacturer-designed connection

methods.To ensure that the stage remains

close to the facade during work,it must be secured to the

building wherever possible,unless the stage is being

raised or lowered.The wire mesh [38 mmx 38 mm (11/2" x 11/2")]should be in goodcondition andfastened in position tocover the area from

top rail to toeboard. This will prevent debris and tools fromfalling off the platform and injuring personnel below.Various platform accessories are available from suppliersto improve safety and operation. For example, guides orwire rope stabilizers attached to the stirrups (Figure 12)will reduce platform sway. Ground castors on the bottom

of the platform(Figure 13) facilitatehorizontal movement.Bumper or guiderollers attached to thefront of the platformprovide clearancearound smallobstacles and protectthe building face fromthe platform. Specialadjustable roller orcastor systems areavailable for platformsused on slopingsurfaces (Figure 14).This type of set-upshould only be used

with the advice of the supplier and in accordance withmanufacturers’ recommendations.

Stirrups must be securely attached to the platform. This isusually done with a threaded rod or bolts. These shouldbe equipped in turn with lock nuts or drilled and fitted withlocking pins.A suspended stage must be anchored to the buildingwherever possible, unless the stage is being raised orlowered. Newer buildings are equipped with mullionguides. Devices attached to the stage slide up and downthe guides to reduce lateral movement. Mullion guides areusually not found on older buildings or buildings underconstruction.

Figure 11Typical Platform Modules

Figure 13Ground Castors and Wall Rollers on Platform

Wall Roller Ground Castor

Figure 12Wire Rope Stabilizers

on Stirrups

Figure 14Stage Equippedwith Castors

for Sloped Roof

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SUSPENDED ACCESS

Most platform structures are manufactured from aluminumcomponents for strength, light weight, and easy handling.However, aluminum platforms are not recommendedwhere caustic or acidic materials and fumes may beencountered. In these instances special provisions mustbe made to protect the platform from the particularhazardous substance. Where aluminum platforms areexposed to caustic or acidic conditions, they should berinsed off with clean water regularly and inspectedregularly for signs of degradation or damage. Aluminumstages may be given a protective coating.Components of the platform such as the main structure,handrails, and stirrups should be inspected regularly andany damage promptly repaired. Only competent personsshould repair the platform structure. Welding repairs shouldbe done only by a certified welder with the manufacturer’sapproval using proper equipment and procedures.Connector bolts, brackets, and shackles should be checkedfor wear and torque regularly and often.3.3 Outrigger BeamsVarious types of outrigger beams are in common use.Most beams are steel while others are aluminum. Theyhave two or sometimes three sectional components tokeep them light and portable.The outrigger beam should be rated to withstand four timesthe maximum load applied without exceeding its ultimateunit stress. These beams are not indestructible, however,and should be used only in accordance with themanufacturer’s or supplier’s table of counterweights andallowable projections beyond the fulcrum for varioussuspension line loads. Adequate legible instructions for theuse of counterweights must be affixed to the outriggerbeam.It must be understood that outrigger beams have maximumallowable projections beyond the fulcrum due to strengthlimitations. Consult the manufacturer or supplier if thisinformation is not provided on the equipment.Sectional outrigger beams must have a means ofpreventing pins from loosening and falling out (Figure 15).Otherwise, pins can work loose with movement of thestage and action of the climbers.Beams should be free of any damage, dings or kinkssince these can reduce structural capacity considerably.

3.4 CounterweightsCounterweights range from 50 to 60 Ib. each. Only manu-factured counterweights compatible with the outriggerbeam should be used. The counterweights should have ameans of being secured in place on the beam. Anadequate number of counterweights should be availableto provide the counterweight capacity required for the

beam projection beyond the fulcrum, as discussed inSection 4.3.3.5 Wire RopeFor suspension lines on any type of climbing equipmentuse only wire rope of the type, size, construction, andgrade recommended by the manufacturer of the climbingunit. The minimum size of steel wire rope used forclimbing devices on suspended access equipment is 7.8mm (5/16 inch) diameter.

Take care to ensure thatthe solid core wire ropeintended for some tractionclimbers is not replacedby fibre core wire rope.The compressibility of thefibre core can cause therope to slip through thetraction climber. Manualtraction climbers use awire rope of relatively stiffconstruction (usually 6 x17). Powered climbersuse a more pliable wirerope construction (usually6 x 19 or 6 x 31).Wire ropes should be freeof kinks, birdcaging,excessive wear, brokenwires, flat spots, or otherdefects (Figure 16).When brazing the end ofwire ropes, cut the coreback 3 or 4 inches shortto allow for movement in the rope and easier threadingthrough the climber.Wire ropes may be used as static lines or tieback lines foroutrigger beams. In either case, the wire rope must beproperly secured to adequate anchorage.The use of secondary safety devices commonly known as“block stops” simplifies the installation of wire rope tiebacks.These devices must be installed, used, inspected, andmaintained according to manufacturer’s instructions.Cable clips used with wire rope tiebacks or static linesshould be the right size and number, torqued up tightly, andcorrectly installed (Figure 17).Cable clips must never be used on fibre or synthetic ropeunless the procedure is authorized by the ropemanufacturer.

Figure 15Secured Pin in Outrigger Beam

Figure 16Wire Rope Defects

Flattened areas indicate wear spots

Bird-Caging

Wrong Right

Figure 17Cable Clips

27 – 5

SUSPENDED ACCESS

Table 1 specifies the number of cable clips required forvarious types and sizes of wire rope commonly used fortiebacks and static lines. Although U-bolt clips are the mostcommon, double saddle clips (sometimes called J-clips orfist grips) do not flatten the wire rope and are moreappropriate to this application.Note: Cable clips are not recommended for use onsuspension lines. Loops in suspension lines shouldhave thimbles and be either spliced or secured with amechanically swaged fitting.

Table 1

Wire ropes used with suspended access equipment musthave a safety factor of 10 against failure (themanufacturer’s catalogue breaking strength). This appliesto all wire ropes used in rigging the equipment, includingsuspension lines and tiebacks.Wire rope suspension lines supporting a stage used forelectric welding must be protected from the danger ofwelding current passing through them. This can be doneby using an insulated thimble on the suspensionline/outrigger beam connections and covering the climberand suspension lines in the vicinity of the stage with aninsulating material such as a rubber blanket. The groundconnection for the material being welded should be asclose as possible to thewelding zone. The deckand rails of the stageshould be covered withinsulating rubber and thestage should haverubber bumpers.3.6 Rigging HardwareRigging hardware for usewith suspended accessequipment should becapable of supporting atleast 10 times themaximum load to whichit may be subjected. Thisapplies to all hooks,shackles, rings, bolts,slings, chains, wire rope,and splices.Shackles and hooksshould be forged alloy

steel (Figure 18). The capacity of these devices fornormal hoisting purposes is usually based on a safetyfactor of 5 and should be stamped on the device. For usewith suspended access equipment, this capacity must bedivided by two to ensure a safety factor of 10.3.7 Manual Traction ClimbersThe mechanical action of these devices is similar to hand-over-hand pulling on a rope. While one mechanism pulls,the other changes position to pull in turn. The jaws of thedevice grip the wire without damaging it. They are self-locking. As the load increases, their grip increases—thegreater the load the tighter the grip.

27 – 6

SUSPENDED ACCESS

RopeDiameter(inches)

INSTALLATION OF WIRE ROPE CLIPS

MinimumNumberof Clips

Amount ofRope TurnBack From

Thimble(inches)

Torque inFoot-PoundsUnlubricated

Bolts

5/16 3 11-1/2 303/8 3 11-1/2 457/16 3 11-1/2 651/2 3 11-1/2 659/16 3 12 955/8 3 12 953/4 4 18 1307/8 4 19 225

Figure 18Forged Alloy Hook withStamped Capacity

STEP 1

APPLY FIRST CLIP – one base width from dead endof wire rope – U-Bolt over dead end – live end restsin clip saddle. Tighten nuts evenly to recommended torque.

STEP 2

APPLY SECOND CLIP – as close to loop as possible– U-Bolt over dead end – turn nuts firmly but DONOT TIGHTEN.

STEP 3

APPLY ALL OTHER CLIPS – Space equally betweenfirst two and 6 -7 rope diameters apart.

STEP 4

APPLY tension and tighten all nuts torecommended torque.

ApplyTension

ApplyTension

STEP 5

CHECK nut torque after rope has been in operation.

Lifting capacity varies with the size of the device. Checkthe manufacturer’s literature to ensure that the capacity isadequate for the load. A maximum load rating for pullingand maximum load rating for hoisting will usually bespecified in the literature. Use the load rating for hoisting.Only the size, type, construction, and grade of wire ropespecified by the manufacturer should be used with theseclimbers. Maintenance is usually limited to daily inspectionand periodic cleaning. Field personnel should not try torepair these devices. Repairs should be left to anauthorized dealer with factory trained personnel.3.8 Secondary Safety DevicesA secondary safety device is a wire rope grabbing devicethat provides protection in case the wire rope connectionor primary hoisting system fails. Figure 19 illustrates howthe device is mounted on each wire rope above the hoistwith a whip or sling connected to the stirrup of the stage.These devices may also be a fixed component onpowered climbers.As these devices advance on the wire rope their jawsopen slightly to let the rope pass through. When a sharpdownward pull is exerted, the jaws automatically close onthe rope and grip it with a degree of tightness determinedby the load.

3.9 Powered ClimbersPowered climbers come in a variety of sizes with differentclimbing speeds, power requirements, and safety devices.The majority are powered by electricity. Some operate at115 volts, 60 Hertz, while others operate at 220 volts, 60Hertz. Air- and hydraulic-powered systems are alsoavailable.Most powered climbers have automatic overspeed brakesfor situations where descent takes place too quickly. Mostalso have a manual system for lowering the stage in case

of power failure or other emergency. Workers using thestage should be fully instructed in the operation andpurpose of these devices.Manufacturers usually list a safe working load either onthe device or in their literature. Along with this informationthe climbing speed will usually be noted. Climber liftingcapacities range from 304 to 1,134 kg (750 to 2,500 Ib.)and climbing speeds vary from 0.178 to 0.76 metres persecond (15 to 35 ft/min). You must not exceed the ratedworking load of either of the two climbers on your stage.To ensure that you are not overloading the climbers, takethe combined total ofa) half of the weight of the stage, motors, climbers, and

power cablesplus

b) the full weight of all the people, workingmaterials, tools, equipment, and anything else that thestage may carry.

This combined total must not exceed the manufacturer’srated working load of each of your climbers taken alone.Before selecting an electrically powered climbing devicefor a particular application, determine what circuits areavailable at the site. If circuits do not meet the voltageand amperage required, temporary wiring will benecessary to accommodate the climbers. Where thewiring runs are long, voltage drops may be so large that aportable step-up transformer is needed to maintain currentlevels so that the motor will not overheat.Also consider the amount of climbing necessary for thejob. Climbing speeds vary with the size of the climber.Small climbers carrying loads up near their safe workingload limits over large distances may overheat andautomatically cut off power. Workers should be advisedwhy such situations can occur. It is usually because ofimproper climber selection, an inadequate circuit for thesupply of power, or a cable too small for the length of run.Power supply cables or cords must have wire heavyenough to minimize voltage drop in the line. Most supplycable is either 10 or 12 gauge 3 wire cab tire (neoprenerubber protected) depending on size of climber motorsand length of run. Twist-lock outdoor male and femaleconnectors should be used. “Sock” supporting devicesshould be used to relieve the strain on connections forlong vertical cable runs (Figure 20).

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SUSPENDED ACCESS

SecondarySafetyDevice

Figure 19Stage Equipped with Secondary

Safety Device

Figure 20Sock Supporting Device

3.10 LifelinesVertical lifelines must meet or exceed the requirements forperformance, durability, impact strength, and elasticityspecified in the current version of CAN/CSA Z259.2.There must be an individual lifeline for each worker on astage, platform, or chair. Each lifeline must have aseparate anchor. Do not attach lifelines to the sameanchor point as outrigger beam tiebacks.Each lifeline must be long enough to reach the ground ora working level where a worker can exit from theequipment onto a solid, flat, level surface. Each lifelinemust also have a means of preventing a rope grab fromrunning off the end of the rope.Before each use, lifelines should be inspected for damagefrom abrasion and chafing. When in use they should beprotected from such damage.Protection is necessary where lifelines are tied oranchored and where they extend over a wall, roof, orstructural framing, as illustrated in Figure 21. Provide forprotection when preparing for the job.Lifelines must never be used to raise or lower material andequipment. When work is done, lifelines must be loweredto the ground, not dropped or thrown from the roof.3.11 Fall-Arrest EquipmentFull body harnesses (not safety belts) must be used for allapplications involving suspended access equipment.These devices transfer fall-arrest loads to the lower parts ofthe body such as thighs and buttocks instead of the mid-torso area containing a number of vital organs. The thighsand buttocks are not only more capable of sustaining thefall-arrest loads, but can also more comfortably and safelysupport the person awaiting rescue.Lanyards must meet or exceed the requirements of the

current version of CAN/CSA-Z259. It is recommended thatlanyards be fitted with locking snap hooks (Figure 22) orbe spliced to rope grabs. Following this recommendationwill reduce the risk of rollout (see section 5.5 in thischapter).Shock absorbers must be used in any fall-arrest system.Shock absorbers should be manufactured to CSAStandard Z259.11-M92 and carry the CSA label. Shockabsorbers may be attached to harnesses and lanyardswith locking snap hooks in D-rings. It should be noted thatshock absorbers can add asmuch as 1.2 metres (4 feet) tothe fall distance before the fallis arrested.Fibre rope lifelines are notrecommended where causticor acidic solutions or sprayswill be used, as in buildingcleaning, or where sparks fromwelding or cutting can causedamage. In such situations usewire rope lifelines. When usinga wire rope lifeline, a shockabsorber, connected betweenthe “D” ring of the full bodyharness and the lanyard, or anintegrated shock absorbinglanyard, must always be usedto keep the forces on the bodyresulting from a fall arrestwithin acceptable and safelimits.In addition, wire rope lifelinesshould be insulated wheneverelectric welding is taking place.

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SUSPENDED ACCESS

Rubber Air HoseSecured with

Clamps

Carpet orRubber Pad

Figure 21Protection for Lifelines

Figure 22Locking

Snap Hook

4 SET-UP AND OPERATION4.1 Two Independent Means of SupportA fundamental concept in the use of suspended accessequipment is that there must be two independent meansof support for workers on the equipment.One independent means of support is the suspensionsystem of the stage or bosun’s chair (Figure 23). Thisusually consists of climbers, suspension lines, outriggerbeams and counterweights or parapet clamps, andtiebacks secured to adequate anchorage.The second independent means of support for the workeron a typical two-point suspension single stage is a fall-arrest system (Figure 24). This consists of a full bodyharness, lanyard, rope grab, and lifeline secured toadequate anchorage.An alternative method for providing a second independent

means of support is a second complete and independentsuspension system (Figure 25). In this case, the workershould tie off directly to one of the stirrups or to a properlydesigned horizontal lifeline securely fastened to bothstirrups.This type of secondary suspension system must bedesigned by a professional engineer.In practice two complete suspension systems are notused unless the application involves a tiered stage (Figure26). In this case workers on the lower stage could notadequately be protected by a lifeline if the upper stagewere to fall. Therefore the arrangement must besupported by two independent support systems. Workerson the lower stage must tie off to the stage they are on orthe one above. Workers on the upper stage may tie off tothe stage they are on or a lifeline.Tiered stages must not be used unless the system isdesigned for the specific application by a professionalengineer familiar with this type of equipment. The systemmust be rigged according to the design. Drawings of thedesign should be kept on-site for easy reference andinspection. In addition, the rigging should be checked by aprofessional engineer before the first drop is made.

4.2 Outrigger Beams, Counterweights, and TiebacksOutrigger beams may be used for either stages orbosun’s chairs. Procedures for both are essentially thesame and in both cases the instructions on counterweightrequirements and overhang limitations must be affixed tothe outrigger beam being used.Beams must be• counterweighted to maintain

a 4-to-1 safety factor againstoverturning or failure

• tied back to adequateanchorage as shownin Figure 27

• firmly attached to thecounterweights

• free of damage, dings, orkinks

• light enough to be manuallyhandled and transported.

SUSPENDED ACCESS

Figure 24Two Independent Meansof Support—SuspensionSystem and Fall-Arrest System

Figure 25Two Independent Means of Support —Two Complete Suspension Systems

Figure 23One Independent Means of Support

Suspension System

Figure 26TieredStage

Figure 27OutriggerBeam

Tied Back

27 – 9

4.3 Loads and 4-to-1 Safety FactorThe dynamic loads involved and the unforgiving nature ofsuspended equipment require that the outrigger beam/counterweight arrangement must have a safety factor of 4against overturning.This means that the tipping tendency holding the beam fromoverturning must be at least 4 times the tipping tendencycreated by the suspension line load acting on the beam.4.3.1 Suspension Line Load with Powered ClimbersFor both suspended stages and bosun’s chairs operatedby powered climbers, the line load used to calculate thenumber of counterweights is the same as themanufacturer’s rated capacity of the climber. Theinformation plate on the climber should provide thisinformation. The rated capacity must match the load limitinformation on the outrigger beams.Powered climbers operating at speeds up to 35 feet per minutecan load up very quickly if the stage or chair gets caught onan obstruction. In this situation the line load will reach thecapacity of the climber before it automatically cuts out.4.3.2 Suspension Line Load with Manual ClimbersStages and bosun’s chairs with manual climbers do notmove nearly as quickly as powered climbers so there isno need to consider the capacity of the climber as themaximum possible suspension line load. We recommendthe following criteria for establishing these loads onmanually powered systems.Two-point Suspended Stages: Calculate the weight ofpeople, tools, and material expected to be on orsuspended from the stage plus the weight of the stage,suspension lines, and climbers. Consider this load to beat least 1,000 lb. Then take 1,000 lb or the total weight ofthe suspended system— whichever is greater—as thesuspension line load for calculation purposes. Considerthis the load on each suspension line.For example, if a stage weighs 200 lb, 2 workers weigh400 lb, and climbers and other gear weigh 200 lb, thetotal load is 800 lb. In this case we recommend that eachsuspension line be rigged for 1,000 lb of line load. If theload had been 1,200 lb we would recommend rigging fora suspension line load of 1,200 lb after checking with thesupplier to ensure that the equipment is capable of takingsuch a load.Bosun’s Chairs: Calculate the weight of the person, tools,materials, chair, suspension line and climber, but not lessthan 350 lb The greater value then becomes thesuspension line load for calculation purposes.4.3.3 Calculation of Counterweight Load

Each outrigger beam should have an informationlabel attached to it. This label will state the number ofcounterweights you need for a given loading andoverhang situation. This information applies only tothat beam, and to the counterweights provided by themanufacturer for use with that particular system. If thelabel is missing, you must not attempt to calculatethe number of counterweights needed unless youknow all the characteristics of that beam and of thecounterweights being used.

The first operation in calculating the proper counterweightload is determining the appropriate suspension line loadas discussed in 4.3.1 and 4.3.2.For calculating the proper counterweight load, Figure 28adescribes a formula for people with a good understandingof mathematics and the “law of the lever.”

We can also look at the problem in terms of what we have“working against us” versus what we need “working for us.”What we have working against us are the suspension lineload and its distance from what we call the “fulcrum” orthe tipping point. What we have working for us are thecounterweights and the distance from the tipping point tothe centre of the weights (Figure 28b).

Because of dynamic loads and the unforgiving nature ofthe equipment, we need to build in a safety factor. Thesafety factor is 4. We need 4 times as much for us as wehave against us (Figure 28c).

A dynamic load is greater than a static or stationary load.We have all caught something dropped to us. The articleis heavier when we catch it than when we simply hold it.The increase is due to the article moving. Its load whenmoving is called the dynamic load. This is one morereason why we need a safety factor.The law of the lever says that the “tipping effect” or“moment” is equal to the load multiplied by the length ofthe lever. We have all used a pry bar to move heavyobjects. The longer the bar the easier it is to move theheavy object, or the heavier the person on the bar theeasier it is to move the object. This concept and thesafety factor of 4 form the basis for our calculation.

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SUSPENDED ACCESS

Figure 28(a)

Figure 28(b)

Figure 28(c)

If we assume our line load is 1,000 lb and the suspensionpoint is located 1 foot beyond the outrigger beam’s tippingpoint (Figure 28d), then the tipping force (moment) is:

1,000 lb x 1 foot = 1,000 lb ftTo resist this tipping force of 1,000 lb ft and at the sametime ensure a built-in safety factor of 4, we need to have4 times this value, that is, 4,000 lb ft, working for us.If overall beam length is 12 feet, then the section workingfor us to resist tipping force extends from the tipping pointto the far end, that is,

12 feet – 1 foot = 11 feet.However, in our calculation we can only consider thedistance from the fulcrum or tipping point to the centre ofthe counterweights.Let’s assume that there are 400 lb of 50-lb counterweightseach 1/2 foot in width. In Figure 28d you can see that thelever arm from the fulcrum to the centre of thecounterweights can only be 11 ft – 2 ft = 9 ft. What wehave working for us is: 400 lb x 9 ft = 3,600 lb ft.

This is less than the 4,000 lb ft we require. We will haveto change something. We cannot change the suspensionline load but we can change some of the other conditions.If we reduce the distance that the suspension pointextends out from the tipping point to 9 inches (.75 ft) thevalue of what we have working against us is:

1,000 lb x .75 ft = 750 lb ftWhat we now need working for us is:

4 x 750 = 3,000 lb ftIf we keep the same number of counterweights, the leverarm working for us becomes 9.25 feet long. It gained 3inches (0.25 feet) when the other side was reduced 3inches (Figure 28e). We now have:

400 lb x 9.25 ft = 3,700 lb ft

This would be satisfactory since 3,700 lb ft exceeds whatwe actually need (3,000 lb ft). See what a difference a fewinches can make in this calculation!

Remember—the load line must remain vertical. Thisaffects whether or not the beam projection can bereduced and by how much.Another approach is to add more counterweights. If weadd two more, our counterweights total 500 lb. However,our lever arm is reduced by 6 inches since the centre ofthe counterweights has shifted.What we have working against us is still the same:

1,000 lb x 1 ft = 1,000 lb ftWhat we need working for us is still:

4 x 1,000 lb ft = 4,000 lb ftWhat we have working for us is:

500 lb x 8.5 ft = 4,250 lb ftAgain, this would be satisfactory. We have more workingfor us than we actually need (Figure 28f).

Before deciding whether or not to add morecounterweights, keep in mind that every manufacturedsteel outrigger beam has a defined limit to the number ofcounterweights that can be placed and secured on it. Thislimit should be indicated on thebeam label.4.4 CounterweightsCounterweights vary in size anddesign from manufacturer tomanufacturer. This is the mainreason why one manufacturer’stables for counterweights cannotbe used with anothermanufacturer’s equipment.Counterweights should besecurely attached to theoutrigger beam so that thevibration or movement of thebeam will not dislodge or movethem. Typical counterweightsecuring systems are shown inFigures 29 and 30.4.5 Roof LoadsCounterweights can overloadroofs of light material such asmetal roof deck. Most roofs are designed for the weight ofthe roof plus the design snow load which may rangebetween 45 and 80 lb per sq/ft for areas in Ontario. Loadsexerted by counterweights can be considerably greaterthan this and should be spread over a larger area byusing plywood or planks (Figure 30). This also helps toreduce damage to built-up bituminous roofing.

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Figure 28(d) Inadequate Arrangement

Figure 28(e) Adequate Arrangement

Figure 28(f) Adequate Arrangement

Figure 29

27 – 12

4.6 Parapet WallsParapet walls often present an obstruction to outriggerbeams that must be overcome by the use of scaffolding ora special support structure (Figures 31 and 32).Note: The fulcrum is the point supported by the scaffoldor support structure—not the edge of the roof.

It is especiallyimportant to spreadthe loads on scaffoldlegs or the specialsupport structure overa large area of theroof. Otherwisedamage to the roofingmaterial and possiblythe deck itself mayoccur. Note planks andplywood under scaffoldlegs in Figure 31.A scaffold system, orother specializedmanufactured supportsystem used to raiseoutrigger beams

above the level of the parapet wall, must be designed bya professional engineer. A copy of the design drawingsmust be used to erect and inspect the system accordingto the engineer’s design and must be kept on site as longas the system is in place.4.7 Outrigger BeamsOutrigger beams should be placed at right angles to theedge of the roof wherever possible (Figure 33).If it’s not possible to set up outrigger beams at rightangles to the edge, the beams must be adequatelysecured or braced to resist any lateral movement whilethe system is in use.Suspension points on the beams must be the samedistance apart as stirrups on the stage. Position beams toensure that spacing is the same. Failure to do so hasresulted in many serious accidents.Figure 34 illustrates what happens when the properdistance between outrigger beams is not maintained. Thedifficulty becomes serious as the stage nears the roof. Atthis point, sideways forces can move the outrigger beam,often causing a serious accident.

The pins on sectional outrigger beams must be properlyinstalled and secured (Figure 15).Wiring the pin in position or securing the nut on the pinwith a cotter pin is also important. If the pin is not

SUSPENDED ACCESS

Counterweight

Counterweight

Beam

Figure 30Planks and Plywood to

Spread Counterweight Load

Figure 31Scaffolding Used to Clear Parapet Wall

Figure 32Special Support Structure Used to Clear Parapet Wall

Figure 33Outrigger Beamsat Right Anglesto Roof Edge

Figure 34Improper Spacing of Outrigger Beams

As the stage goes up, the angle of suspension lines increases,causing dangerous side loads.

27 – 13

secured, vibration can easily dislodge it and make thebeam come apart. This is especially important wheremanual climbers are used because the uneven jackingaction of the climbers can apply intermittent loads to thebeam and easily shake out a loose pin. This requirementalso applies to shackle pins and eyebolts used onoutrigger beam systems.4.8 TiebacksTiebacks should extend from the thimble of the suspensionline back along the outrigger beam, with at least one half-hitch tied around the beam through the handles on eachsection. Tiebacks should then loop around thecounterweight handles if they are so equipped, and thenextend on back to an adequate anchorage (Figure 35).Wire ropes are recommended for tiebacks with allsuspended access systems. Fibre rope tiebacks areconsidered suitable for stages equipped with manualtraction climbers. If fibre rope tiebacks are used, theyshould be 3/4-inch diameter polypropylene. Tiebacks forbosun’s chairs should be 5/8 inch diameter polypropylenerope. Other manufactured rope that equals or exceeds theimpact resistance, elasticity, and UV protection of 16-millimetre (5/8 inch) diameter polypropylene rope can alsobe used. Nylon is not recommended because it stretchestoo much and manila rope is not recommended because itis much more subject to deterioration.Wire rope used for tiebacks should be at least equal insize to the wire rope used for the climber. After wire ropehas been used for tiebacks it should not be used forsuspension line because of damage and deformation fromcable clips, bends, and hitches.Wire ropes should be fastenedwith cable clips in the correctmanner (Figure 17) andrecommended number (Table1). Polypropylene rope shouldhave either a spliced loop andthimble with a safety hook orshackle or be tied using a roundturn and half-hitches (Figure 36)or a triple bowline knot (Figure37). Knots may reduce the safeworking load of the ropesdepending on the means ofsecuring and are therefore aless desirable alternative.Protect fibre rope from sharpbends. Figure 38 shows onemethod.

Where scaffolds are used for support structures, thetieback line should also be looped around the top of thescaffold (Figure 31).

SUSPENDED ACCESS

Figure 35 Tieback Rigging on Outrigger Beam

Figure 36Round Turn

andHalf-Hitches

Figure 37Triple Bowline

Figure 38Wire RopeSling toProtectFibreRope

PVC/ABSTubesto protectwire rope

27 – 14

4.9 Adequate Anchorage for TiebacksAdequate anchorage for tiebacks includes• the base of large HVAC units• columns on intermediate building floors or stub

columns on roofs• designed tieback systems such as eye bolts and rings• large pipe anchorage systems (12-inch diameter

or greater)• large masonry chimneys• roof structures such as mechanical rooms• parapet clamps attached to reinforced concrete

parapet walls on the other side of the building.

Never tie back to• roof vents or “stink pipes”• roof hatches• small pipes and ducts• metal chimneys• TV antennas• stair or balcony railings.

4.10 Parapet Clamps (Figure 39)Where parapet walls are constructed of reinforcedconcrete or reinforcedmasonry, parapet clamps may beused. Before using any type of parapet clamp, obtainconfirmation from the owner of the project that the parapethas been constructed with sufficient strength andperformance characteristics to support the intended clamp.Clamps must always be installed according to the manu-facturer’s drawings and written instructions. Ensure thatclamps are securely fastened to the parapet wall and tiedback to an adequate anchorage in a manner similar totiebacks for standard outrigger beams.

5 FALL PROTECTIONA fundamental concept in the use of the suspendedaccess equipment is that there must be two independentmeans of support for each worker using the equipment.The first means of support is the access equipment itself.The second is provided by an appropriate fall protectionsystem consisting of a full body harness, lanyard, shockabsorber, rope grabbing device, and lifeline, as illustratedin Figure 40.

A fundamental concept inthe use of any type of fallprotection system is that itmust be fully rigged, inplace, properly adjusted, andworn by all workers• while they are setting up

and taking down thesuspension equipmentand working within 2metres (6 feet) of theperimeter edge;

• while they are getting onand off the suspendedaccess equipment; and

• at all times while they areon the equipment.

5.1 Fall Protection PlanningThe pre-job inspection must determine not only thesuspended access equipment to be used but also theproposed fall protection system.When assessing fall protection requirements, check thefollowing points. Is there a parapet wall higher than 1 metre (3 feet)

around the roof perimeter? Are engineered anchors installed on the roof? How

many are there? Where are they located? How far arethey from the set-up area?

SUSPENDED ACCESS

Figure 39Parapet Clamp

RopeGrab

LockingSnap Hooks

Lanyard

Lifeline

Figure 40Full Body Harness and Fall-Arrest System

Full BodyHarness

ShockAbsorber

27 – 15

If there are no engineered anchors, are any existingstructures big and strong enough to serve as anchors?An adequate anchor should be capable of supportingthe weight of a small car (about 3,600 pounds).

Are there any sharp edges requiring lifelines to beprotected?

Fall protection planning must include• type of fall protection equipment to be used• type, length, and number of lifelines required• travel restraint or warning barriers to be used when

setting up or dismantling the suspended accesssystem on the roof

• fall protection procedures to follow while setting up,getting on, getting off, working from, and dismantlingthe suspended access equipment.

Finally, all horizontal and vertical work surfaces where thesuspended access equipment will be assembled,operated, and dismantled must be evaluated to determineescape, rescue, and other emergency procedures in theevent of mechanical failure or breakdown.5.1.1 Fall-Arrest Rescue PlanningBefore any fall-arrest equipment is used on a constructionproject, the employer is legally required to have in place awritten procedure outlining how to rescue a workerinvolved in a fall arrest. This procedure is in addition tothose required by law to cover general emergencyresponse on a project.A worker hanging in harness after a fall arrest must berescued and brought to a stable work surface, platform, orground within 30 minutes. Left suspended for more than30 minutes, the worker may experience increasingdiscomfort, nausea, dizziness, and fainting. If leftsuspended for a prolonged period of time, the worker mayhave heart and breathing difficulties and may even die.To ensure timely, effective rescue, an employer maycreate generic procedures to cover all potential fall rescuerequirements for the company’s typical work.The employer must then• provide staff training in the procedures• ensure that the procedures are reviewed and modified

as necessary to meet specific job conditions• provide staff training in these modified, site-specific

procedures.

Use the following checklist to prepare rescue proceduresfor workers involved in fall arrest. Is there a safe practical means of self-

rescue? Can a worker involved in fallarrest reach a work platform, ground, orother safe place? Is any specialequipment or training necessary forself-rescue?

How will the worker communicate his orher predicament to other workers?

What is the procedure when workers seea co-worker hung up in fall arrest? Whoshould be notified and how? Whatinformation needs to be conveyed? Whatshould be done before help arrives?

In an arrested fall from the highest point on theproject, can the worker be reached by ground? Isthere an adequate ladder or other device for rescue?Where is the equipment stored and who has accessto it?

Can a suspended worker be rescued from a levelabove or below? Is access unobstructed? Is a keynecessary? Is there a way of quickly removing awindow or other feature to reach the worker?

If a suspended worker can’t be reached from ground,another level, or a work platform, what specializedrescue equipment is needed? Are workers trained touse this equipment?

What procedures are in place to rescue a suspendedworker who is unconscious, injured, or otherwiseunable to assist rescuers?

What service, private or public, is available to aid inhigh-reach rescue? Has the service been notified andsupplied with project information such as location,access, size, height, and available anchorage? Is thephone number of the service posted where everyonecan see it? Have employees been advised to contactthe service when high-reach rescue is needed?

5.2 Fall Protection SystemsThere are two main types of fall protection systems:1) fall prevention2) fall arrest.

5.2.1 Fall Prevention SystemsFall prevention is a system that prevents a worker fromgaining access to a known fall hazard. A guardrail is oneexample.Fall prevention is primarily used around areas on the roofwhere workers set up or take down the suspensionsystem. It can also be used to protect personnel workingon balconies or similar structures.A parapet wall 0.9 metres (3 feet) high or highersurrounding a roof provides fall prevention. This isequivalent to having a guardrail around the perimeter.Workers can work near the edge of the roof withoutadditional protection as long as they don’t reach over orbeyond the parapet wall. Otherwise they must wearappropriate fall protection equipment and be properly tiedoff (Figure 41).

SUSPENDED ACCESS

Figure 41Fall Protection

Parapetwall acts as

fallprevention

Fallpreventionequipmentrequired

A bump line or warning barrier can be set up 2 metres(6 feet) from any perimeter edge. Inside this cordoned-offarea, workers do not require fall protection equipment.The barrier acts as a physical boundary by keepingunprotected workers away from the perimeter.Where no bump or warning line is used, or where thework requires workers to be less than 2 metres (6 feet)from the edge, a travel-restraint system is required. Thishas all the same components as a fall-arrest system—fullbody harness, shock absorber, lanyard, rope grab, andadequately anchored lifeline (see 5.2.2). The differencebetween the two systems is how they are used.The lifeline in a travel-restraint system must have a positivestopping device or knot tied in it to prevent the rope grabfrom travelling beyond that point. The device or knot mustbe positioned so that the distance back to the anchor point,plus the combined length of the rope grab, lanyard, and D-ring on the harness, is less than the distance from theanchor point to the edge of the work surface. With thesystem arranged in this way, a worker falling toward theedge will be stopped before going over the edge.5.2.2 Fall-Arrest SystemsWorkers getting on, getting off, or working fromsuspended access equipment must wear a fall-arrestsystem and be properly tied off to an adequatelyanchored lifeline. This also applies to workers working onbalconies or similar structures without other means of fallprotection.A fall-arrest system must include• a full body harness that meets or exceeds the current

CSA standard• a shock absorber that meets or exceeds the current

CSA standard and is attached to the D-ring on theharness

• a lanyard that meets or exceeds the current CSAstandard and is connected to the free end of theshock absorber and properly connected to theconnecting ring of a rope grab

• a rope grab properly attached to an adequatevertical lifeline

• a vertical lifeline that meets or exceeds the currentCSA standard and is properly secured to an adequateanchor

• an independent anchor which has been designed bya professional engineer for that purpose or which acompetent worker can reasonably consider strongenough to support the weight of a small car (about3,600 pounds).

In cases where the second means of support consists ofa second, properly designed, fully rigged, and completesuspension system, workers can tie off directly to thesuspended access equipment, as per designspecifications for that particular system.5.2.3 Fall Protection TrainingEmployers must ensure that any worker who may use afall protection system is properly trained in its use andgiven adequate oral and written instructions by acompetent person.

Training should include, but not be limited to,• basic inspection, care, and maintenance of personal

fall protection equipment• proper methods of assembling, putting on,

and adjusting equipment• how to protect, handle, and secure lifelines• safe versus unsafe anchor points• procedures for tying off• explanation of all work procedures that require

fall protection• explanation of company policy regarding

mandatory use of fall protection on the job.

Employers must keep written records of all employeestrained in fall protection.5.3 LifelinesEach lifeline must be tied back to an adequate anchorage.In practice, adequate anchorage is usually a matter ofjudgment rather than calculated capacity. As a rule ofthumb, the anchorage should be capable of sustaining theweight of a small car.On new construction, lifelines usually can be secured toexposed structural components such as beams orcolumns. On existing buildings adequate anchorageincludes the points itemized in section 4.9.Each lifeline must be tied off to an adequate anchor pointseparate and independent from the anchor points used forother lifelines and for tiebacks (Figure 42). Where therearen’t enough independent anchor points to meet thisrequirement, an anchoring system must be designed by aprofessional engineer.

5.4 Protection for LifelinesLifelines must be protected from abrasion or chafing andfrom sharp corners which can break the lines under heavyshock loads.A spliced eye and thimble, complete with a safety hook, isthe recommended connection device. However, where therope must be tied to the anchorage it is recommendedthat the rope be doubled back and tied with either a roundturn and half-hitches (Figure 36) or a triple bowline knot(Figure 37).

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Figure 42Parapet Clamps andBuilt-in Roof Anchors

Although tying to the anchorage with knots is necessary insome situations, it is not recommended where the splicedeye and safety hook can be used. Knots may reduce theload-carrying capacity of the rope significantly.Lifelines must also be protected from abrasion where theypass over a parapet wall or the edge of a roof. A rubberhose clamped to the lifeline to hold it in position is aneffective means of providing protection. Rubber mats orcarpeting also provide protection but should be fixed tothe lifeline or be wide enough to allow for considerableshifting of the lifeline because of wind or workermovement below (Figure 21).The lifelines should be reasonably taut. Loose coils on theroof should be lined out. Lifeline anchors should beperpendicular to the roof edge at the point where thelifelines drop over. The anchor point should be areasonable distance from the roof edge—preferably 3metres (10 feet) or more. This will allow the rope to absorbmore energy in the event of a fall arrest at the roof edge.Lifelines must also be protected from entanglement intraffic on the ground below or in construction equipmentsuch as tower cranes. This can be done by tying thelifeline to the structure at ground level or weighting itdown with counterweights (Figure 43). Always allowenough slack for the movement of workers on the stage.

5.5 Lanyards and Rope GrabsLanyards should be attached to the lifeline by a ropegrab. The rope grab should meet the requirements ofCSA Standard Z259.2M-1998.Rope grabs and lanyards should be attached by a lockingsnap hook, a karabiner looped through a spliced loop andthimble, or a loop and thimble spliced into the rope grabring. These methods will prevent “roll-out.”Roll-out can occur when a regular snap hook attached toa small ring in the connection system releases itself underload (Figure 44). Small rings are sometimes found onolder rope grabs.5.6 Full Body HarnessWith suspended access equipment, it is a legalrequirement in Ontario to wear a full body harness—not asafety belt. The harness absorbs fall-arrest loads at thethighs and buttocks rather than the upper abdomen andchest where many of the body’s vital organs are located.Lanyards should be attached to shock absorbers whichshould, in turn, be attached to the full body harness. Theattachment should be a locking snap hook or a splicedhook loop and thimble. Looping a splice around a D-ringis not recommended.The fall-arrest system must be in place and properlyrigged, with attachments suitably adjusted, before theworker gets on the suspended access equipment. Theworker must wear the fall-arrest system and be properlytied off at all times when getting on, using, or getting offthe suspended access equipment.

Figure 43Lifeline Securedto Counterweightat Ground Level

Figure 44 Roll-out

27 – 17

SUSPENDED ACCESS

6 ChecklistsThe following list identifies points which should bechecked before anyone uses suspended accessequipment. Operator knowledgeable and competent to operate

the equipment involved? All required components available, properly rigged,

and in good condition? Failsafe devices such as rope grabs, secondary

safety devices, and overspeed controls installed andoperating?

Power supplies for climbers adequate, grounded, andsecured?

All tiebacks for outrigger beams, parapet clamps, andlifelines properly secured to adequate anchoragecapable of supporting 10 times the applied load?

Adequate number of counterweights securelyattached to outrigger beams?

Fibre ropes protected from chafing and abrasion? Emergency rescue arrangements planned, prepared,

and communicated to everyone involved? Access to and from the work area planned and

arranged?The answer to each of these questions should be yes.

27 – 18

SUSPENDED ACCESS

27 – 19

SUSPENDED ACCESS

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28 – 1

TRENCHING

28 TRENCHINGContents•Background

•Soil types

•Causes of cave-ins

•Protection against cave-ins

•Other hazards and safeguards

•Emergency procedures

BackgroundFatalities

A significant number of deaths and injuries insewer and watermain work are directly relatedto trenching.

Trenching fatalities are mainly caused bycave-ins. Death occurs by suffocation orcrushing when a worker is buried by falling soil.

Over half of all powerline contacts involve buriedcable. Before excavating, the gas, electrical, andother services in the area must be accuratelylocated and marked. If the service poses ahazard, it must be shut off and disconnected.

Injuries

The following are the main causes of lost-timeinjuries in the sewer and watermain industry:

• material falling into the trench

• slips and falls as workers climb on and offequipment

• unloading pipe

• handling and placing frames and coversfor manholes and catch basins

• handling and placing pipe and othermaterials

• being struck by moving equipment

• falls as workers climb in or out of anexcavation

• falling over equipment or excavatedmaterial

• falling into the trench

• exposure to toxic, irritating, or flammablegases.

Many of these injuries are directly related totrenching.

Regulations

Supervisors and workers in the sewer andwatermain industry must be familiar with the“Excavations” section of the ConstructionRegulation.

It is important to understand, for instance, theterms “trench” and “excavation.” An excavationis a hole left in the ground as the result ofremoving material. A trench is an excavation inwhich the depth exceeds the width (Figure 1).

The “Excavations” section of the ConstructionRegulation identifies the various types of soilsand specifies the type of shoring and timberingto be used for each. It also spells out therequirements for trench support systems thatmust be designed by a professional engineer.

Difference between excavation and trench

Figure 1

Excavation Trench10'

5'

10'

5'

28 – 2

TRENCHING

Soil typesThe type of soil determines the strength andstability of trench walls.

Identifying soil types requires knowledge, skill,and experience. Even hard soil may containfaults in seams or layers that make it unstablewhen excavated.

The foreman or supervisor must beknowledgeable about soil types found on aproject and plan protection accordingly. Thisknowledge must include an awareness that soiltypes and conditions can change over very shortdistances. It is not unusual for soil to changecompletely within 50 metres or for soil tobecome saturated with moisture over evensmaller distances.

The Construction Regulation sets out four soiltypes.

Type 1 — It is hard to drive a pick into Type 1soil. Hence, it is often described as “hardground to dig”. In fact, the material is so hard, itis close to rock.

When excavated, the sides of the excavationappear smooth and shiny. The sides will remainvertical with no water released from the trenchwall.

If exposed to sunlight for several days, the wallsof Type 1 soil will lose their shiny appearancebut remain intact without cracking andcrumbling.

If exposed to rain or wet weather, Type 1 soilmay break down along the edges of theexcavation.

Typical Type 1 soils include “hardpan,”consolidated clay, and some glacial tills.

Type 2 — A pick can be driven into Type 2soil relatively easily. It can easily be excavatedby a backhoe or hand-excavated with somedifficulty.

In Type 2 soil, the sides of a trench will remainvertical for a short period of time (perhapsseveral hours) with no apparent tension cracks.However, if the walls are left exposed to air andsunlight, tension cracks will appear as the soilstarts to dry. The soil will begin cracking andsplaying into the trench.

Typical Type 2 soils are silty clay and less densetills.

Type 3 — Much of the Type 3 soil encounteredin construction is previously excavated material.Type 3 soil can be excavated without difficultyusing a hydraulic backhoe.

When dry, Type 3 soil will flow through fingersand form a conical pile on the ground. DryType 3 soil will not stand vertically and thesides of the excavation will cave in to a naturalslope of about 1 to 1 depending on moisture.

Wet Type 3 soil will yield water when vibratedby hand. When wet, this soil will stand verticallyfor a short period. It dries quickly, however,with the vibration during excavation causingchunks or solid slabs to slide into the trench.

All backfilled or previously disturbed materialshould be treated as Type 3. Other typical Type3 soil includes sand, granular materials, and siltyor wet clays.

Type 4 — Type 4 soil can be excavated withno difficulty using a hydraulic backhoe. Thematerial will flow very easily and must besupported and contained to be excavated to anysignificant depth.

With its high moisture content, Type 4 soil isvery sensitive to vibration and otherdisturbances which cause the material to flow.

Typical Type 4 material includes muskeg orother organic deposits with high moisturecontent, quicksand, silty clays with highmoisture content, and leta clays. Leta clays arevery sensitive to disturbance of any kind.

28 – 3

TRENCHING

Causes of Cave-InsSoil properties often vary widely from the top tothe bottom and along the length of a trench.

Many factors such as cracks, water, vibration,weather, and previous excavation can affecttrench stability (Figure 2). Time is also a criticalfactor. Some trenches will remain open for along period, then suddenly collapse for noapparent reason.

Figure 3 shows the typical causes of cave-ins.

The main factors affecting trench stability aresoil type, moisture, vibration, surcharge,previous excavation, existing foundations, andweather.

Moisture content

The amount of moisture in the soil has a greateffect on soil strength.

Once a trench is dug, the sides of the openexcavation are exposed to the air. Moisturecontent of the soil begins to change almostimmediately and the strength of the walls maybe affected.

The longer an excavation is open to the air, thegreater the risk of a cave-in.

Trench open for extended duration may collapse without apparent reason.

Equipment vibrationaffects stability.

Backfill isless stable thanundisturbed soil.

Surcharge such as spoil pile puts more pressure on trench walls.

Figure 3

Large Load

Rain

Insufficient ShoringVibration

Cracks

Broken Line High Water TableWater Seepage

Settling

Figure 2 - Many factors affect trench stability.

28 – 4

TRENCHING

Vibration

Vibration from various sources can affect trenchstability.

Often trench walls are subject to vibration fromvehicular traffic or from construction operationssuch as earth moving, compaction, pile driving,and blasting. These can all contribute to thecollapse of trench walls.

Surcharge

A surcharge is an excessive load or weight thatcan affect trench stability.

For instance, excavated soil piled next to thetrench can exert pressure on the walls.Placement of spoil piles is therefore important.Spoil should be kept as far as is practical fromthe edge of the trench. Mobile equipment andother material stored close to the trench alsoadd a surcharge that will affect trench stability.

One metre from the edge to the toe of the spoilpile is the minimum distance requirement(Figure 4). The distance should be greater fordeeper trenches.

Previous excavation

Old utility trenches either crossing or runningparallel to the new trench can affect the strengthand stability (Figure 5).

Soil around and between these old excavationscan be very unstable. At best it is consideredType 3 soil — loose, soft, and low in internal

strength. In some unusual circumstances it maybe Type 4 — wet, muddy, and unable tosupport itself.

This kind of soil will not stand up unless it issloped or shored.

Existing foundations

Around most trenches and excavations there is afailure zone where surcharges, changes in soilcondition, or other disruptions can causecollapse.

When the foundation of a building adjacent tothe trench or excavation extends into this failurezone, the result can be a cave-in (Figure 6). Soilin this situation is usually considered Type 3.

Weather

Rain, melting snow, thawing earth, and overflowfrom adjacent streams, storm drains, and sewersall produce changes in soil conditions. In fact,water from any source can reduce soil cohesion(Figure 7).

Existing foundations are surrounded bybackfill and may add a surcharge load to the pressure on the trench wall.

Figure 6

Move spoil pile farther back for deep trenches

Figure 4

Old utilities are surrounded by backfilled soil which is usuallyless stable than undisturbed soil.

Figure 5

1m 1m 1m

28 – 5

TRENCHING

Frozen soil does not mean that you can havereduced shoring or that a heavier load can besupported. Frost extends to a limited depth only.

Protection AgainstCave-InsThere are three basic methods of protectingworkers against trench cave-ins:

• sloping

• trench boxes

• shoring

Most fatal cave-ins occur on small jobs of shortduration such as service connections andexcavations for drains and wells. Too oftenpeople think that these jobs are not hazardousenough to require safeguards against collapse.

Unless the walls are solid rock, never enter atrench deeper than 1.2 metres (4 feet) if it is notproperly sloped, shored, or protected by atrench box.

Sloping

One way to ensure that a trench will notcollapse is to slope the walls.

Where space and other requirements permitsloping, the angle of slope depends on soilconditions (Figures 8, 9 and 10).

For Type 1 and 2 soils, cut trench walls back atan angle of 1 to 1 (45 degrees). That's onemetre back for each metre up. Walls should besloped to within 1.2 metres (4 feet) of thetrench bottom (Figure 8).

For Type 3 soil, cut walls back at a gradient of 1to 1 from the trench bottom (Figure 9).

For Type 4 soil, slope the walls at 1 to 3. That’s3 metres back for every 1 metre up from thetrench bottom (Figure 10).

Although sloping can reduce the risk of a cave-in,the angle must be sufficient to prevent spoil notonly from sliding back but also from exerting toomuch pressure on the trench wall (Figure 11).

Sloping is commonly used with shoring ortrench boxes to cut back any soil above theprotected zone. It is also good practice to cut abench at the top of the shoring or trench(Figure 12).

Moisture affects stability, especially where heavy rainfall has occurred

Figure 7

GOOD SOIL Type 1 & 2 Soil

MinimumBank SlopeMaximum

1.2 m (4 ft.)

Figure 8

Figure 10

Figure 9

FAIRLY GOOD SOIL Type 3 Soil

MinimumBank Slope

BAD SOIL Type 4 Soil

MinimumBank Slope

Spoil piles can exert too much pressure on sloped trench wall.

Figure 11

28 – 6

TRENCHING

If sloping is to be used above a trench box, thetop portion of the cut should first be sloped 1 to1 (or 1 to 3 for Type 4 soil — see previouspage). Then the box should be lowered into thetrench (Figure 13).

Trench boxes

Trench boxes are not usually intended to shoreup or otherwise support trench walls. They aremeant to protect workers in case of a cave-in.

Design drawings and specifications for trenchboxes must be signed and sealed by theprofessional engineer who designed the systemand must be kept on site by the constructor.

Boxes are normally placed in an excavated butunshored trench and used to protect personnel.A properly designed trench box is capable ofwithstanding the maximum lateral load expectedat a given depth in a particular soil condition.

Trenches near utilities, streets, and buildingsmay require a shoring system.

As long as workers are in the trench theyshould remain inside the box. Workers must notbe inside the trench or the box when the box isbeing moved. A ladder must be set up in thetrench box at all times.

Excavation should be done so that the spacebetween the trench box and the excavation isminimized (Figure 14).

The two reasons for this are

1) allowing closer access to the top of thebox

2) limiting soil movement in case of acave-in.

Check the drawings and specifications for thetrench box to see if the space between the boxand the trench wall needs to be backfilled andthe soil compacted.

Shoring

Shoring is a system which “shores” up orsupports trench walls to prevent movement ofsoil, underground utilities, roadways, andfoundations.

Shoring should not be confused with trenchboxes. A trench box provides worker safety butgives little or no support to trench walls orexisting structures such as foundations andmanholes.

The two types of shoring most commonly usedare timber and hydraulic. Both consist of posts,wales, struts, and sheathing.

Figures 15 and 16 identify components,dimensions, and other requirements for timbershoring in some typical trenches.

Keep space between trench box and excavation as small as possible.

Backfillif necessaryto prevent acave-in.

Figure 14

Cut back unshored top position with a 1 to 1 slope(or a 1 to 3 slope for Type 4 soil)

Figure 13

Figure 12

It is good practice to cut abench at top of shoring

28 – 7

TRENCHING

“Hydraulic shoring” refers to prefabricated strutand/or wale systems in aluminum or steel. Strictlyspeaking, these may not operate hydraulically.Some are air-operated or manually jacked. Designdrawings and specifications for prefabricatedshoring systems must be kept on site.

One major advantage of hydraulic shoring oversome applications of timber shoring is safetyduring installation. Workers do not have to enterthe trench to install the system. Installation canbe done from the top of the trench.

Most hydraulic systems are

• light enough to be installed by one worker

• gauge-regulated to ensure even distributionof pressure along the trench line

• able to “pre-load” trench walls, therebyusing the soil's natural cohesion to preventmovement.

• easily adapted to suit various trench depthsand widths.

Wherever possible, shoring should be installedas excavation proceeds. If there is a delaybetween digging and shoring, no one must beallowed to enter the unprotected trench.

All shoring should be installed from the topdown and removed from the bottom up.

Access/egress

Whether protected by sloping, boxes, or shoring,trenches must be provided with ladders so thatworkers can enter and exit safely (Figure 17).

Ladders must

• be placed within the area protected by theshoring or trench box

• be securely tied off at the top

• extend above the shoring or box by atleast 1 metre (3 feet)

Figure 15

Figure 16

Ladders shouldbe placed withinshored area andtied off to preventslipping.

Figure 17

28 – 8

TRENCHING

• be inspected regularly for damage.

Ladders should be placed as close as possible tothe area where personnel are working andnever more than 7.5 metres (25 feet) away.

Anyone climbing up or down must always facethe ladder and maintain 3-point contact. Thismeans that two hands and one foot or two feetand one hand must be on the ladder at alltimes.

Maintaining 3-point contact also means handsmust be free for climbing. Tools and materialsshould not be carried up or down ladders. Pumps,small compactors, and other equipment should belifted and lowered by methods that prevent injuryfrom overexertion and falling objects.

Inspection

Inspection is everyone's responsibility. Whateverthe protective system, it should be inspectedregularly.

Check hydraulic shoring for leaks in hoses andcylinders, bent bases, broken or crackednipples, and other damaged or defective parts(Figure 18).

Check timber shoring before installation. Discarddamaged or defective lumber. After installation,inspect wales for signs of crushing. Crushingindicates structural inadequacy and calls formore struts (Figure 19).

Inspect trench boxes for structural damage,cracks in welds, and other defects (Figure 20).During use, check the box regularly and oftento make sure that it is not shifting or settlingmuch more on one side than the other. If it is,leave the trench and ask the supervisor to checkfor stability.

Check ground surface for tension cracks whichmay develop parallel to the trench at a distanceone-half to three-quarters of the trench depth(Figure 21). If cracks are detected, alert the crewand check all protective systems carefully.

Check areas adjacent to shoring where watermay have entered the trench. A combination ofwater flow and granular soils can lead toundermining of the trench wall. Such conditionshave caused fatalities.

Finally, make sure that tools, equipment,material, and spoil are kept at least 1 metre(3 feet) back from the edge of the trench toprevent falling objects from striking workers.

Check hydraulicshoring

for leaks.

Figure 18

Cracked sheathing

Inspect walesfor crushing at struts. Strut off level

Bowed sheathingand wales

Loose ormissingcleats

Figure 19

28 – 9

TRENCHING

Summary

Sloping, trench boxes, and shoring are meant toprotect workers from the hazards of cave-ins.

The method chosen must meet the specificrequirements of the job at hand. Depending onapplication, one method may be better suited tocertain conditions than another.

Whatever the system, inspect it regularly tomake sure that it remains sound and reliable.

Remember: Never enter a trench more than1.2 metres (4 feet) deep unless it is sloped,shored, or protected by a trench box.

Other Hazards andSafeguardsThe risk of a cave-in is not the only hazard intrenching. Injuries and deaths are also related tosix other major areas:

• personal protective equipment

• utilities underground and overhead

• materials handling and housekeeping

• heavy equipment

• traffic control

• confined spaces.

Personal protective equipment

Personal protective equipment is an importantdefence against certain types of injury.

Injuries from falling and flying objects, forinstance, can be reduced by wearing hard hatsand eye protection.

Everyone on a construction project must wearGrade 1 safety boots certified by the CanadianStandards Association (CSA) as indicated by theCSA logo on a green triangular patch (Figure 22).

Under the wet, muddy conditions oftenencountered in trenching, you may also requirerubber safety boots displaying the same CSAlogo on a green triangular patch.

Deformed PlateCheck welds on

sleeves and strutsfor bendsand distortion

Damage

BentStrut

MissingStrut

Figure 20

Sidewall

Check fortension cracks Strut

Knife edge

Figure 21

28 – 10

TRENCHING

It is mandatory for everyone on a constructionproject to wear head protection in the form of ahard hat that complies with the currentConstruction Regulation.

Eye protection is strongly recommended toprevent injuries from construction operationssuch as chipping and drilling and site conditionssuch as dust.

Personnel exposed for long periods to noisyequipment should wear hearing protection.

Work in confined spaces such as manholes andvalve chambers may require respiratoryprotection against hazardous atmospheres.

See the chapters on personal protectiveequipment in this manual for more information.

Underground utilities

Locates — Services such as gas, electrical,

telephone, and water lines must be located by

the utility before excavation begins.

The contractor responsible for the work mustcontact the owners of any underground utilitiesthat may be in that location or phone OntarioOne Call. Request locates for all theunderground utilities in the area whereexcavation will be taking place.

The service locate provided by the utility ownershould indicate, using labelled stakes, flags,and/or paint marks, the centre line of theunderground utility in the vicinity of theproposed excavation.

The excavator should not work outside of thearea covered by the locate stakeout informationwithout obtaining an additional stakeout.

Locate stakeout accuracy should be consideredto be 1 metre on either side of the surfacecentre line locate unless the locate instructionsspecifically indicate other boundary limits.

Where the underground utility cannot belocated within the locate stakeout limits, theutility owner should be contacted to assist withthe locate.

Mechanical excavation equipment should not beused within the boundary limits of the locate

Figure 22

Properly laced safety bootswith CSA labels

CSA label, stamped into the shell, indicating Class E hard hat.Existing utility lines may require support.

Figure 23

Figure 24

Have existingutilities locatedbeforeexcavating.

28 – 11

TRENCHING

without first digging a hole or holes using theprocedure below to determine the undergroundutility's exact centre line and elevation.

Test holes should, in general, be excavated byone of the following methods:

(a) machine excavation immediately outsidethe boundary limits and then hand digginglaterally until the underground utility isfound; or

(b) (i) hand excavation perpendicular tothe centre line of the locate in cuts of atleast 1 foot in depth;

(ii) mechanical equipment can then beused carefully to widen the hand-dugtrench to within one foot of the depthof the hand-dug excavation;

(iii) repeat steps (i) and (ii) until theutility is located; or

(c) a hydro-excavation system — acceptableto the owner of the utility — which useshigh-pressure water to break up the covermaterial and a vacuum system to remove itcan be used to locate the undergroundutility.

Centre line locates should be provided and testholes dug where a representative of the utilityidentifies

(a) alignment changes

(b) changes in elevation.

Where an underground utility may need supportor where it may shift because of disturbance ofsurrounding soil due to excavation, guidelinesfor excavation and support should be obtainedfrom the owner of the utility (Figure 23).

Breaks — Breaks in electrical, gas, and waterservices can cause serious injuries, even deaths.Hitting an underground electrical line can resultin electrocution, while hitting a gas line cancause an explosion. A broken water line canrelease a sudden rush of water, washing outsupport systems and causing a cave-in.

Cutting telephone lines can create a seriousproblem if emergency calls for police, fire, orambulance are required.

In the event of gas line contact, call the gascompany immediately. The company will checkthe line and close down the supply if necessary.

If a leak is suspected, people in the immediatearea should be told to evacuate. Where service toa building or home has been struck, peopleinside should be advised to leave doors andwindows open; shut off appliances, furnaces, andother sources of ignition; and vacate the premisesuntil the gas company declares it safe to return.

Construction personnel should take twoprecautions.

1)Put out smoking materials and shut offother sources of ignition such as enginesand equipment.

2) Leave the trench immediately. Gas cancollect there.

Overhead powerlines

When equipment operates within reach of (andcould therefore encroach on) the minimumpermitted distance from a live overhead powerline,

Services shouldbe exposed firstby hand digging,then by machine.

Figure 25

28 – 12

TRENCHING

the constructor must have written procedures inplace to prevent the equipment from encroachingon the minimum distance.

If equipment touches a high-voltage line,the operator should take the followingprecautions.

1) Stay on the machine. Don’t touchequipment and ground at same time.Touching anything in contact with theground could be fatal.

2)Anyone operating accessory equipmentshould also remain on that equipment.They should also avoid making contactwith the ground and the equipment at thesame time.

3)Keep others away. Warn them not to touchthe load, load lines, boom, bucket, or anyother part of the equipment (Figure 26).

4)Get someone to call the local utility to shutoff power.

5) If possible, the operator (while remainingon the machine) can try to break contactby moving the machine clear of the wires.

Warning: Beware of time relays. Evenafter breakers are tripped by linedamage, relays may be triggered torestore power.

6) If the operator can’t break contact bymoving the machine (while remaining onit), do not move the machine until theutility shuts down the line and confirmsthat power is off.

7) If an emergency such as fire forces you toleave the machine, jump clear (Figure 27).Never step down. If part of your bodycontacts the ground while another parttouches the machine, current will travelthrough you.

8) Jump with feet together and shuffle awayin small steps. Don’t take big steps. Withvoltage differential across the ground, onefoot may be in a higher voltage area thanthe other. The difference can kill you(Figure 28).


750 or more volts, but not 3 metres (10')more than 150,000 volts

more than 150,000 but 4.5 metres (15')not more than 250,000 volts

more than 250,000 volts 6 metres (20')

Keep people away from machineif there is a powerline contact.

Stay on the machine unless thereis an emergency such as fire.

Figure 26

If an emergency forces you to leave the machine, jump clearwith feet together and shuffle away — never step down.

Figure 27

28 – 13

TRENCHING

Special precautions are required for casualties incontact with live powerlines or equipment.

1)Never touch the casualty or anything incontact with the casualty.

2) If possible, break contact. Use a dry board,rubber hose, or dry polypropylene rope tomove either the casualty or the line. Anobject can sometimes be thrown toseparate the casualty from the wire.

Warning : Touching the casualty, evenwith dry wood or rubber, can bedangerous. With high voltage lines,objects that are normally insulatorscan become conductors.

3)Call emergency services — in most casesambulance, fire department, and utility.

4)Provide first aid once the casualty is free ofcontact. If the casualty is not breathing,begin artificial respiration immediately(mouth-to-mouth is most efficient) or CPR.Apply cold water to burns and cover withclean dressing.

Materials handling

Many lost-time injuries in trenching involvematerials handling. Moving rock and soil, liftingpipe and manhole sections, laying downbedding material, or lowering pumps andcompactors into the trench can all be hazardous.

Pipe — Trucks should always be on level

ground when pipe is unloaded. Pipe should be

chocked or staked before tie-downs are

released. These measures will reduce the risk of

sections rolling off the truck.

Plastic and small diameter pipe is often bandedwith metal straps. Be careful cutting the straps.They are under tension and can fly back and hityou.

Personnel often injure fingers and hands whenlaying and joining sections of pipe. While sectionsare suspended from hoisting equipment, keephands away from slings or chokers in tension.When guiding and pushing sections together byhand, never curl fingers around ends or flanges.

As pipe is placed along the trench, each sectionshould be blocked or set so that it cannot rolland cause injury.

Voltage differentialacross the ground caninjure or kill you.

Figure 28

To maintainbalance, keepone foot aheadof the other.

Figure 29

28 – 14

TRENCHING

Back injuries can occur when small-diameterpipe is being homed into position (Figure 29).The worker pushing the bar should place hisfeet directly in front of the pipe with one footahead of the other.

Large-diameter pipe should be placed with pipepullers (Figure 30).

Bedding material — Personnel shovellingbedding material in the trench are usuallyworking in a confined area where footing ismuddy and uneven.

The result can be overexertion or slips and fallsleading to back and other injuries. Mechanicalequipment can significantly reduce this hazard.For instance, bedding material can be put in theexcavator bucket with a front-end loader, thenspread evenly along the trench bottom.

Rigging — Rigging is essential to safe, efficientmaterials handling since pipe, manhole sections,and equipment are lowered into the trench bycranes or other hoisting devices.

Rigging these loads properly can prevent injury.

Inspect slings and rigging hardware regularlyand replace any damaged or worn devices.

With nylon web slings, damage is usuallyeasy to spot: cuts, holes, tears, worn or distortedfittings, frayed material, broken stitching, heatburns. Damaged web slings should be replaced.

When using wire rope slings, inspect forbroken wires, worn or cracked fittings, looseseizings and splices, flatening, and corrosion.Knots or kinks indicate that wire rope slings arepermanently damaged and should not be used.

Damage most often occurs around thimbles andfittings. Don't leave wire rope lying on the

ground for any lengthof time in damp orwet conditions.

Eyes in wire ropeslings should be fittedwith thimbles. Tomake an eye withclips, put the U-boltsection on the dead orshort end of the ropeand the saddle on thelive or long end(Figure 31).Remember — neversaddle a dead horse.

At least three clips arerequired for wire ropeup to 5/8" diameter,and four are requiredfor wire rope greaterthan 5/8" up to andincluding 7/8"diameter.

Avoid binding the eye section of wire ropeslings around corners. The bend will weakenthe splice or swaging.

When using choker hitches, do not force theeye down towards the load once tension isapplied.

When using chain slings, inspect for elongatedlinks. A badly stretched link tends to close up(Figure 32).

Look for bent, twisted, or damaged links thatcan result when chain has been used to lift aload with unprotected sharp edges.

Inspect for cracks. Although sometimes hard todetect, cracks always indicate that the chainshould be removed from service. Also look forgouges, chips, cuts, dents, peen marks, andcorrosive wear at points where links bear oneach other.

Dead end

Live endSTEP 1 - Apply first clip one base width fromdead end of rope. U-bolt is placed over deadend and live end rests in clip saddle. Tightennuts evenly to recommended torque.

STEP 2 - Apply second clip as close to loopas possible. U-bolt is over the dead end.Turn nuts firmly but do not tighten.

STEP 3 - Apply all other clips, spacedequally between the first two. They shouldbe 6-7 rope diameters apart.

STEP 4 - Apply tension and tighten all nutsto recommended torque.

STEP 5 - Check nut torque after rope hasbeen in operation.

ApplyTension

ApplyTension

Figure 31

Figure 30

28 – 15

TRENCHING

Rigging Tips

• Wherever possible, lower loads onadequate blockage to prevent damage toslings.

• Keep hands away from pinch pointswhen slack is being taken up.

• Stand clear while the load is being liftedand lowered or when slings are beingpulled out from under it.

• Use tag lines to control swinging,swaying, or other unwanted movement ofthe load.

Housekeeping

Accident prevention depends on properhousekeeping at ground level and in the trench.

At the top of the trench, sections of pipe,unused tools and timber, piles of spoil, and

other material must be kept at least 1 metre(3 feet) away from the edge.

The slips and falls common on excavationprojects can be reduced by cleaning up scrapand debris. Trenches should also be kept as dryas possible. Pumps may be required.

Proper housekeeping is especially importantaround ladders. The base and foot of the laddershould be free of garbage and puddles. Laddersshould be tied off at the top, placed inprotected areas, and inspected regularly fordamage (Figure 33).

Heavy equipment

Excavators, backhoes, and other heavyequipment can cause injuries and fatalities tooperators and personnel on foot.

Excavator handsignals — Communicate

clearly with your co-workers. Use the following

handsignals.

New link

Stretchedlink

Figure 32

Ladders should be placed within shoredarea and tied off to prevent slipping.

Figure 33

28 – 16

TRENCHING

Operators — Improperly climbing on and off

equipment has caused injuries to operators for

many years. The best prevention is to maintain

3-point contact (Figure 34).

Equipment should be fitted with steps, grabs,and rails that are repaired or replaced whendamaged.

Operators have also suffered serious injurieswhen equipment upsets because of soil failurenear excavations (Figure 35), improper loadingon floats, or inadvertently backing intoexcavations.

Moving equipment — Signallers are required

by law

• if the operator's view of the intended pathof travel is obstructed, or

• if a person could be endangered by themoving equipment or its load.

Back-up alarms are required on dump trucks

and recommended for all moving equipment.Where vehicles have to operate in reverse,warning signs must be conspicuously posted.

Ground rules for truck drivers

• Understand and obey the signaller at alltimes.

• Remain in the cab where possible.

• Ensure that mirrors are clean, functional,and properly adjusted.

• Do a circle check after being away from thetruck for any length of time (walk aroundthe truck to ensure the area is clear beforemoving).

• Stop immediately when a signaller, worker,or anyone else disappears from view.

Workers on foot — Personnel on foot are

frequently stuck by machine attachments such

as excavator buckets and bulldozer blades when

they stand or work too close to operating

equipment, especially during unloading and

excavation.

Workers on foot are also injured and killed byequipment backing up.

Ground rules for workers on foot

• Beware of common operator blind spots.See chapter on Backing Up in this manual.

• Stay alert to the location of equipmentaround you.

• Avoid entering or standing in blind spots.

• Always remain visible to the operator.Make eye contact to ensure that youare seen.

• Never stand behind a backing vehicle.

• Remember — the operator may be able tosee you while you are standing but notwhen you kneel down or bend over.

Use 3-point contacton steps and rails.

Figure 34

Try to push backfill intoexcavation rather thandumping it.

Figure 35

28 – 17

TRENCHING

Signallers — In heavily travelled or congested

work areas, a signaller may be necessary to

direct equipment and prevent injuries and

deaths caused by vehicles backing up.

Ground rules for signallers

• Wear a fluorescent or bright orangesafety vest.

• Use standard hand signals (Figure 37).

• Stand where you can see and be seen.

• Stay in full view of the operator and theintended path of travel.

• Know where the operator's blind spotsare.

• Warn other workers to stay clear ofequipment.

Traffic control

On trenching projects along public roadways,the construction crew must be protected fromtraffic. Regulations specify the followingmethods for protecting personnel:

• traffic control persons (TCPs) using signs(Figure 38)

• warning signs

• barriers

• lane control devices

• flashing lights or flares.

Supervisors must train TCPs on site and explainthe nature of the project, where constructionequipment will be operating, and how publictraffic will flow. TCPs must wear a fluorescentor bright orange safety vest.

Training must also include the proper use of theSTOP/SLOW sign, where to stand, how tosignal, and communication with other TCPs.(See chapter on Traffic Control in this manual.)

After presenting this information, the supervisorsmust give TCPs written instructions in alanguage they can understand.

Confined spaces

A confined space is defined as a place

a) that is partially or fully enclosed

b) that is not both designed and constructedfor continuous human occupancy, and

c) where atmospheric hazards may occurbecause of its construction, location, orcontents, or because of work that is donein it.

All three critera have to be met before a spaceis defined as a confined space.

In the sewer and watermain industry, confinedspaces can be locations such as excavations,manholes, valve chambers, pump stations, andcatch basins. The atmosphere in these spacesmay be

• toxic

• oxygen-deficient

Figure 38

Back up

Clearance

ChangeDirection

Stop

Figure 37

28 – 18

TRENCHING

• oxygen-enriched

• explosive.

Sewage not only smells bad but can createdangerous atmospheres. Decaying wastereleases hazardous gases such as hydrogensulfide and methane. The bacteria in sewage arenot only a source of infection but can alsoconsume oxygen and leave the atmosphereoxygen-deficient.

Other sources of contamination can include

• fumes from welding or patchingcompounds

• chemicals from waste disposal sites

• engine exhaust

• propane or other explosive gases that areheavier than air and collect in the bottomof the trench

• leaks from underground storage tanks

• decomposing material in landfill sites.

Protecting the health and safety of personnelstarts with some basic steps.

• A competent worker must test a confinedspace to determine whether it is hazard-free before a worker enters, and continuetesting to ensure that it remains hazard-free.

•Where testsindicate safe airquality,workers maybe allowed toenter theconfined space.

• Where testsindicate ahazardous levelof fumes,vapours, gases,or oxygen,

entry must not be allowed until the spacehas been adequately ventilated andsubsequent tests indicate that the air is safeto breathe.

• Where possible, mechanical venting shouldbe continued in any confined spacecontaining hazardous levels of fumes,vapours, gases, or oxygen, even afterventing has corrected the hazard. Thespace must also be continuously monitoredwhile personnel are working there.

• In situations where ventilation hasremoved a hazard, workers entering thespace should still wear rescue harnessesattached to individual lifelines. A workershould also be posted at the entranceprepared, equipped, and trained toprovide rescue in an emergency. Forrescue situations, workers entering thespace should wear supplied-air respirators(Figure 40).

For more information on confined spaces andcontrols, see the chapter on Confined Spaces inthis manual.

Hydrostatic testing

Hydrostatic testing involves entry into a confinedspace such as a manhole or valve chamber. Theprocedures listed above should be followed.

Testing new lines can be very hazardous ifcomponents break or plugs let go. For thatreason, additional precautions are required.

When testing watermains, ensure that all lines,elbows, and valves are supported and equippedwith thrust blocks. Otherwise the line couldcome apart under test pressure.

Arrange watermain testing so that lines arepressurized when no one is in the manhole orvalve chamber.

For sewer line testing, all requirements forentering confined spaces apply.

Self-containedbreathingapparatus(SCBA)

Figure 40

28 – 19

TRENCHING

Ensure that plugs are secure. No one should bein a manhole when the upstream line is beingfilled. Plugs that are not properly installed canlet go, causing injury and letting a manhole fillquickly, depending on the size of the line.

Flooding is another reason why no one shouldbe in a manhole without a rescue harness and aworker outside ready and prepared for anemergency.

Emergency ProceduresGeneral

Emergency telephone numbers — ambulance,fire, police, local utilities, senior management,Ministry of Labour — should be posted in thefield office for quick reference.

If someone is seriously injured, take thefollowing steps.

1)Protect the area from hazards.

2)Prevent further injury to the casualty.

3)Administer first aid.

4)Call an ambulance or rescue unit.

5)Have someone direct the ambulance orrescue unit to the accident scene.

All projects must have a person qualified andcertified to provide first aid.

Cave-ins

It is natural to try to rescue casualties caught orburied by a cave-in. But care must be taken toprevent injury and death to rescuers, whetherfrom a further cave-in or other hazards.

The following procedures may be suitable,depending on conditions.

1)To get down to the casualty, use atarpaulin, fencing, plywood, or similarmaterial that can cover the ground and willride up over any further cave-in.

2) Sometimes a further cave-in can be

prevented by placing a backhoe bucketagainst the suspected area or excavating it.

3)Rescue workers should enter the trenchwith ropes and wear rescue harnesses ifpossible.

4)To prevent further injury, remove thecasualty by stretcher whenever possible.Tarps or ladders can be used as amakeshift stretcher.

5) Stabilize the casualty.

Breathing — Ensure that the casualty isbreathing. If not, open the airway and startartificial respiration immediately. Mouth-to-mouth is the most efficient method.

Bleeding — Control external bleeding byapplying direct pressure, placing the casualty ina comfortable position, and elevating the injuredpart if possible.

Unconsciousness — This is a priority becauseit may lead to breathing problems. Anunconscious person may suffocate when leftlying face up. If injuries permit, unconsciouspersons who must be left unattended should beplaced in the recovery position (Figure 41).

Recovery position

Figure 41

29 – 1

29 BACKING UP

Reversing vehicles and equipment on constructionprojects pose a serious problem for personnel onfoot.Fatal accidents resulting from workers beingbacked over by dump trucks and other equipmentoccur all too frequently.Anyone on foot in the vicinity of reversing vehiclesand equipment is at risk. More then 20 deathshave occurred on construction sites over a ten-year period as a result of reversing vehicles.

Blind SpotsThe main problem with reversing vehicles andequipment is the driver or operator's restricted view.Around dump trucks and heavy equipment suchas bulldozers and graders there are blind spotswhere the operator has no view or only a verylimited view.The operator may not see someone standing inthese blind spots. Anyone kneeling or bending overin these areas would be even harder to see.Consequently the driver or operator must rely onmirrors or signallers to back up without running oversomeone or into something. Figure 1 shows theblind spots for common types of constructionequipment.Dump trucks and cranes are the kinds of equipmentthat hit overhead powerlines most often. Beware ofpowerline contact whenever a crane, dump truck, orother vehicle is going to be operated near anoverhead electrical conductor. If equipment operateswithin reach of (and could therefore encroach on)the minimum permitted distance from an overheadpowerline (see the chapter on Electrical Hazards inthis manual), the constructor is required to havewritten procedures in place to prevent theequipment from encroaching on the minimum distance.

Accident PreventionTo prevent injuries and deaths caused by vehicles andequipment backing up, there are four basic approaches:1) site planning2) signallers3) training4) electronic devices.

Site planningWherever possible, site planners should arrange for drive-through operations to reduce the need for vehicles toback up (Figure 2).Foot traffic should be minimized where trucks andequipment operate in congested areas such asexcavations. Where feasible, a barricade can help to

BACKING UP

Figure 1 – Dark areas indicate operator blind spots.

Figure 2

29 – 2

protect workers: for example, by keeping excavation workseparate from forming operations (Figure 3).The hazards of reversing vehicles can also be reducedthrough separate access for workers on foot. Wherepossible, for instance, a scaffold stair system should beprovided for worker access to deep excavations.Near loading and unloading areas, pedestrian walkwayscan be roped off or barricaded.

SignallersOn some projects, you cannot avoid having reversingvehicles or equipment on site. Often, they must share anarea with other vehicles and operating equipment – aswell as workers on foot.

You must have a signaller or spotter whena) a vehicle or equipment operator’s view of the

intended path of travel is obstructedb) a person could be endangered by the operation of the

vehicle or equipment, or by its loadc) any part of the equipment could encroach on the

minimum distance to an overhead powerline (see thechapter on Electrical Hazards in this manual forminimum distances).

A signaller must be a competent worker and must nothave any other duties to fulfill while acting as a signaller.Before a worker can act as a signaller, the employer mustensure that the worker has been given adequate oral andwritten instructions in a language that he or sheunderstands. The employer must keep, on site, a copy ofthe written instructions and a record of the training.A signaller must wear a garment – usually a nylon vest –that is fluorescent or bright orange, with 2 vertical 5-centimetre-wide yellow stripes on the front and 2 similarstripes forming a diagonal "X" pattern on the back. Thesestripes must be retro-reflective and fluorescent. The vestmust have an adjustable fit and have a front and sidetear-away feature.If a signaller has to work during the night, he or she mustwear retro-reflective silver stripes around each arm and leg.The signaller must maintain clear view of the path that thevehicle, machine, or load will be travelling and must beable to watch those parts of the vehicle, equipment, orload that the operator cannot see. The signaller mustmaintain clear and continuous visual contact with theoperator at all times while the vehicle or equipment ismoving (Figure 5), and must be able to communicate withthe operator using clearly understood, standard handsignals (Figure 6). The signaller must warn other workerson foot of the approaching vehicle or equipment, andmust alert the operator to any hazards along the route.

TrainingInstruction for drivers,operators, signallers, andworkers on foot is essential toreduce the hazards created byreversing vehicles andequipment.For example, all constructionpersonnel must be madefamiliar with blind spots – theareas around every vehiclethat are partly or completelyinvisible to the operator ordriver, even with the help ofmirrors (Figure 1).Specific training can then focuson the following points.

BACKING UP

Figure 3

Figure 5

Back up

Clearance

Stop

Change directionFigure 6

29 – 3

Workers on Foot• Know how to work safely around

trucks and operating equipment.• Understand the effect of blind

spots (Figure 7).• Avoid entering or standing in

blind spots.• Make eye contact with the driver

or operator before approachingequipment.

• Signal intentions to the driver oroperator.

• When possible, use separateaccess rather than vehicleramps to enter and exit the site.

• Avoid standing and talking near vehicle paths, gradingoperations, and other activities where heavyequipment is moving back and forth.

Drivers and Operators• Always obey the signaller or spotter. If more than one

person is signalling, stop your vehicle and determinewhich one to obey.

• If possible, remain in the cab in areas where otherequipment is likely to be backing up.

• Make sure that all mirrors are intact, functional, andproperly adjusted for the best view.

• Blow the horn twice before backing up.• When no spotter is present, get out and quickly walk

around your vehicle. If the way is clear, back up atonce (Figure 8).

• Stop the vehicle when a spotter, worker, or anyoneelse disappears from view.

Signallers• Stay alert to recognize and deal with dangerous

situations.• Know and use the standard signals for on-site traffic

(Figure 6).• Wear a reflective fluorescent or bright orange vest

and a bright hard hat for high visibility.• Use a signalling device such as a bullhorn in

congested excavation areas.• Understand the maneuvering limitations of vehicles

and equipment.• Know driver and operator blind spots.

• Stand where you can see and be seen by the driveror operator.

• Make eye contact with driver or operator beforesignalling or changing location.

Electronic EquipmentSince 2000, automatic audible alarms that signal when avehicle is being operated in reverse have been requiredon dump trucks.Alarms offer the greatest benefit when traffic is limited toonly one or two vehicles. The warning effect of the alarmis greatly reduced, however, when it simply becomes partof the background noise on-site.This is a common shortcoming with devices that soundcontinuously when the transmission is put in reverse,especially in areas where several vehicles are operatingat once.Newer devices using a type of radar to sense objects orpeople within a pre-set radius appear to be more effectivebut are not readily available or widely used.Other technologies such as infrared or heat sensors andclosed-circuit television are limited by the effects ofvibration, dust, and dirt — conditions all too common onconstruction sites.

BACKING UP

Figure 7 - This illustration shows how some personnel on foot are visible to the driver while others are not.The driver cannot see the dark figures because they are passing through blind spots at the front and rearof the truck.

Figure 8

30 – 1

30 TRAFFIC CONTROL

Attention: SupervisorsTraffic control persons (TCPs) must be given written andoral instructions regarding their duties. This section isdesigned to help you meet the requirement for writteninstructions set out in Section 69(4) of the ConstructionRegulation.A worker who is required to direct vehicular traffic,

(a) shall be a competent worker;(b) shall not perform any other work while directing

vehicular traffic;(c) shall be positioned in such a way that he or she is

endangered as little as possible by vehicular traffic; and(d) shall be given adequate written and oral instructions,

in a language that he or she understands, withrespect to directing vehicular traffic, and thoseinstructions shall include a description of the signalsthat are to be used.

In addition, the written instructions must be kept on theproject.

What are the objectives of traffic control?• To protect construction workers and the motoring

public by regulating traffic flow.• To stop traffic whenever required by the progress of

work. Otherwise to keep traffic moving at reducedspeeds to avoid tie-ups and delays.

• To allow construction to proceed safely and efficiently.• To ensure that public traffic has priority over

construction equipment.

What equipment do I need?Personal• Hard hat that meets regulated requirements.• Safety boots, CSA-certified, Grade 1 (green triangular

CSA patch outside, green rectangular label inside).• Garment, usually a vest, covering upper body and

meeting these requirements:- fluorescent or bright orange in colour- two vertical yellow stripes 5 cm wide on front,covering at least 500 cm2

- two diagonal yellow stripes 5 cm wide on back, inan X pattern, covering at least 570 cm2

- stripes retro-reflective and fluorescent- vests to have adjustable fit, and a side and fronttear-away feature on vests made of nylon.

We recommend that garments comply with CSA standardZ96-02—and in particular a Class 2 garment, Level 1 orLevel 2.SignA sign used to direct traffic must be• octagonal in shape, 450 mm wide, and mounted on a

pole 1.2 m long• made of material with at least the rigidity of plywood

6 mm thick• high-intensity retro-reflective red on one side, with

STOP printed in high-intensity retro-reflective white150 mm high

• on the other side, high-intensity retro-reflective micro-prismatic fluorescent chartreuse, with a blackdiamond-shaped border at least 317 mm x 317 mm,with SLOW printed in black 120 mm high.

After DarkSection 69.1(4) of the Construction Regulation requiresthat you wear retro-reflective silver stripes encircling eacharm and leg, or equivalent side visibility-enhancing stripeswith a minimum area of 50cm2 per side.The following measures are recommended:• Wear a hard hat with reflective tape.• Use a flashlight with a red cone attachment as well as

the sign and carry spare batteries.• Place flashing amber lights ahead of your post.• Stand in a lighted area under temporary or street

lighting, or illuminated by light from a parked vehicle(stand fully in the light without creating a silhouette).

What are the requirements of a good trafficcontrol person?• Sound health, good vision and hearing, mental and

physical alertness.• Mature judgment and a pleasant manner.• A good eye for speed and distance to gauge

oncoming traffic.• Preferably a driver's licence.• The ability to give motorists simple directions, explain

hazards, and answer questions.• Liking, understanding, and respect for the

responsibilities of the job.

How do I prepare for each job?Before starting work, make sure that you know• the type of construction you will be involved with —

paving, installing pipe, grading, cut and fill, etc.• the type of equipment to be used, such as scrapers,

trucks, compactors, and graders• how the equipment will be operating — for instance,

crossing the road, along the shoulder, in culverts, oron a bridge

• whether you will have to protect workers settling upcomponents of the traffic control system such assigns, delineators, cones, and barriers

• any special conditions of the contract governing roaduse (for instance, many contracts forbid work duringurban rush hours)

• how public traffic will flow — for example, along atwo-lane highway, around curves or hills, by detour oron a road narrowed to a single lane. This last is avery common situation and requires two traffic controlpersons to ensure that vehicles do not move inopposing directions at the same time (see next page).In some cases, where the two cannot see oneanother, a third is necessary to keep both in view andrelay instructions (see “Positioning of Traffic ControlPersons,” next page).

TRAFFIC CONTROL

30 – 2

What should I check each day?• Make sure that the STOP-

SLOW sign is clean,undamaged, and meets heightand size requirements.

• Place the TRAFFICCONTROL PERSON AHEADsign at an appropriatedistance to afford motoristsadequate warning.

• Remove or cover all trafficcontrol signs at quitting timeor when traffic control is temporarily suspended.

• Arrange with the supervisor for meal, coffee,and toilet breaks.

Where should I stand?• Stand the correct distance from the work area. Refer

to TCP Table on the following page.• Do not stand on the travelled portion of roadway and

always face oncoming traffic.• Be alert at all times. Be aware of construction traffic

around you and oncoming traffic on the roadway.• Stand alone. Don't allow a group to gather around you.• Stand at your post. Sitting is hazardous because your

visibility is reduced and the ability of a motorist to seeyou is reduced.

• Adjust distances to suit road, weather and speedconditions. Remember these points:- Traffic must have room to react to your directions tostop (a vehicle can take at least twice the stoppingdistance on wet or icy roads).- Stand where you can see and be seen byapproaching traffic for at least 150 metres (500 feet).- Avoid the danger of being backed over or hit by yourown equipment.

• Hills and curves call for three TCPs or some othermeans of communication. The job of the TCP in themiddle is to relay signals between the other two.

• Once you have been assigned a traffic controlposition by your supervisor, look over the area formethods of escape — a place to get to in order toavoid being injured by a vehicle heading your way, iffor some reason the driver has disregarded yoursignals.If this should happen, protect yourself by moving outof the path of the vehicle and then warn the crew.

Where am I not allowed to direct traffic?Section 69 of Ontario Regulation 213/91 specifies that:A worker shall not direct vehicular traffic for more thanone lane in the same direction. s. 69(2)

A worker shall not direct vehicular traffic if the normalposted speed limit of the public way is more than 90kilometres per hour. s. 69(3)

How should I signal?• Use the STOP-SLOW sign and your arms as shown

below.

TRAFFIC CONTROL

Typical Arrangement on Two-lane Roadway

TCP TABLE

POSTED SPEED60 km/h OR LESS, ONE LANEOR REDUCED TO ONE LANEIN EACH DIRECTION

70 km/h TO 90 km/h, ONE LANEOR REDUCED TO ONE LANEIN EACH DIRECTION

TRAFFIC VOLUME

DISTANCE OF TCPFROM WORK ZONE

LOW

10 – 15 m

LOW

30 – 40 m

HIGH

20 – 30 m

HIGH

40 – 50 m

Note:On curves and hills, three TCPs or some other means ofcommunication are required.The duty of TCP #2 is to relay signals between TCP #1 and #3.

Positioning of Traffic Control PersonsCurve

Hill

30 – 3

• Hold your sign firmly in full view of oncoming traffic.• Give the motorist plenty of warning. Don't show the

STOP sign when the motorist is too close. The averagestopping distance for a vehicle travelling at 50 kilometresper hour (30 miles per hour) is 45 metres (150 feet).Higher speeds require more stopping distance.

• When showing the SLOW sign, avoid bringing trafficto a complete halt. When motorists have sloweddown, signal them to keep moving slowly.

• When showing the STOP sign, use firm hand signalsand indicate where you want traffic to stop. When thefirst vehicle stops, step into the centre of the road sothe second vehicle can see you.

• Before moving traffic from a stopped position, makesure the opposing traffic has stopped and that the lastopposing vehicle has passed your post. Then turnyour sign and step back on the shoulder of the road.

• Stay alert, keep your eyes on approaching traffic,make your hand signals crisp and positive.

• Coordinate your effort with nearby traffic signals toavoid unnecessary delays, tie-ups, and confusion.

• Do not use flags to control traffic.• In some situations, two-way traffic may be allowed

through the work zone at reduced speed, with a trafficcontrol person assigned to each direction. Sincemotorists can be confused or misled by seeing theSTOP side of the sign used in the opposite lane, thesigns must be modified. The STOP side must becovered to conceal its distinctive shape and command.This should prevent drivers from stopping unexpectedly.

How can I improve safety for myselfand others?• Don't be distracted by talking to fellow workers or

passing pedestrians. If you must talk to motorists,stay at your post and keep the conversation brief.

• When using two-way radios to communicate with anothertraffic control person, take the following precautions:- Establish clear voice signals for each situation andstick to them.

- Be crisp and positive in your speech.- Test the units before starting your shift and carryspare batteries.

- Avoid unnecessary chit-chat.- Don't use two-way radios in blasting zones.

• When two traffic control persons are working together,you should always be able to see each other in orderto coordinate your STOP-SLOW signs. Signalsbetween you should be understood. If you changeyour sign from STOP to SLOW or vice-versa, youmust signal the other person by moving the sign upand down or sideways. This will ensure that trafficcontrol is coordinated. Two-way radios are the bestway of communicating.When you can't see the other traffic control person, athird should be assigned to keep you both in view.

What are my rights under the law?Additional requirements for traffic control are spelled out inthe Ontario Traffic Manual, Book 7: TemporaryConditions, available through Service Ontario Publications(1-800-668-9938). Ask for item number 170076. It can also

be downloaded for free from www.mto.gov.on.ca through alibrary search for the Ontario Traffic Manual.The information applies to traffic control by any persons oragencies performing construction, maintenance, or utilitywork on roadways in Ontario.The Construction Regulation under the OccupationalHealth and Safety Act makes it mandatory that trafficcontrol persons be protected from hazards. This includesnot only personal protective clothing and equipment butmeasures and devices to guard against the dangers ofvehicular traffic. Safety should receive prime considerationin planning for traffic control. Regulations under theOccupational Health and Safety Act are enforced by theMinistry of Labour.Traffic control persons have no authority under theHighway Traffic Act and are not law enforcement officers.If problems arise, follow these steps.• Report dangerous motorists to your supervisor.• Keep a pad and pencil to jot down violators' licence

numbers.• Ask your supervisor for assistance from police in

difficult or unusual traffic situations.• Never restrain a motorist forcibly or take out your anger

on any vehicle.• Always be alert to emergency services. Ambulance,

police, and fire vehicles have priority over all other traffic.

Remember• Always face traffic.• Plan an escape route.• Wear personal protective clothing.• Maintain proper communication with other traffic

control persons.• Stay alert at all times.• Be courteous.Traffic control is a demanding job, often a thankless job,but always an important job. How well you succeed willdepend largely on your attitude.

TRAFFIC CONTROL

RIGGING

31 – 1

31 RIGGING

Tradespeople who are not professional riggers mustnonetheless rig loads at times on the job. Carpenters, forinstance, are often involved not only in handling but inhoisting and landing material. When in doubt about rigging,consult an experienced rigger or a professional engineer.Information in this chapter covers only the basics of rigging.InspectionUse this checklist to inspect rigging components regularlyand before each lift.

Manila RopeManila rope is not recommended for constructionuse and is illegal for lifelines and lanyards.

Dusty residue when Wear from inside out.twisted open Overloading. If extensive,

replace rope.Broken strands, fraying,spongy texture Replace rope.

Wet Strength could be reduced.Frozen Thaw and dry at room

temperature.Mildew, dry rot Replace rope.Dry and brittle Do not oil. Wash with cold water

and hang in coils to dry.

Polypropylene and Nylon RopeChalky exterior Overexposed to sunlight (UV)appearance rays. Possibly left unprotected

outside. Do not use. Discard.Dusty residue when Worn from inside out. Iftwisted open extensive, replace.Frayed exterior Abraded by sharp edges.

Strength could be reduced.Broken strands Destroy and discard.Cold or frozen Thaw, dry at room temperature

before use.Size reduction Usually indicates overloading

and excessive wear. Use caution.Reduce capacity accordingly.

Wire Rope (Figure 87)Rusty, lack of Apply light, clean oil. Do notlubrication use engine oil.Excessive outside wear Used over rough surfaces, with

misaligned or wrong sheavesizes. Reduce load capacityaccording to wear. If outsidediameter wire is more than 1/3worn away, the rope must bereplaced.

Broken wires Up to six allowed in one ropelay, OR three in one strand in onerope lay, with no more than one

at an attached fitting. Otherwise,destroy and replace rope.

Crushed, jammed, Replace rope.or flattened strandsBulges in rope Replace, especially non-rotating

types.Gaps between strands Replace rope.Core protrusion Replace rope.Heat damage, torch Replace rope.burns, or electricarc strikesFrozen rope Do not use. Avoid sudden

loading of cold rope.Kinks, bird-caging Replace rope. Destroy defective

rope.

Polypropylene and NylonWeb SlingsChalky exterior Overexposed to sunlight (UV)appearance rays. Should be checked by

manufacturer.Frayed exterior Could have been shock-loaded

or abraded. Inspect very carefullyfor signs of damage.

Breaks, tears, Destroy. Do not use.or patchesFrozen Thaw and dry at room

temperature before use.Oil-contaminated Destroy.

Wire Rope SlingsBroken wires Up to six allowed in one rope

lay or three in one strand in onerope lay with no more than oneat an attached fitting. Otherwise,destroy and replace rope.

Kinks, bird-caging Replace and destroy.Crushed and jammed Replace and destroy.strands

Core protrusion Replace and destroy.Bulges in rope Replace and destroy.Gaps between strands Replace and destroy.Wire rope clips Check proper installation

and tightness before each lift.Remember, wire rope stretcheswhen loaded, which may causeclips to loosen.

Attached fittings Check for broken wires. Replaceand destroy if one or more arebroken.

Frozen Do not use. Avoid suddenloading of cold ropes to preventfailure.

31 – 2

Sharp bends Avoid sharp corners. Use padssuch as old carpet, rubber hose,or soft wood to prevent damage.

Chain SlingsUse only alloy steel for overhead lifting.Elongated or Return to manufacturer forstretched links repair.Failure to hang straight Return to manufacturer for

repair.Bent, twisted, or Return to manufacturer forcracked links repair.Gouges, chips, Ground out and reduceor scores capacity according to amount

of material removed.Chain repairs are best left to the manufacturer. Chainbeyond repair should be cut with torch into short pieces.

HardwareKnow what hardware to use, how touse it, and how its working loadlimits (WLLs) compare with the ropeor chain used with it.All fittings must be of adequatestrength for the application. Only

forged alloy steel load-rated hardware should be used foroverhead lifting. Load-rated hardware is stamped with itsWLL (Figure 88).Inspect hardware regularly and before each lift. Telltalesigns include– wear– cracks– severe corrosion– deformation/bends– mismatched parts– obvious damage.Any of these signsindicates a weakenedcomponent thatshould be replacedfor safety. Figure 89shows what to checkfor on a hook.

Sling ConfigurationsThe term “sling” includes a wide variety of configurationsfor all fibre ropes, wire ropes, chains,and webs. The most commonly usedtypes in construction are explained here.Single Vertical HitchThe total weight of the load is carried bya single leg. This configuration must notbe used for lifting loose material, longmaterial, or anything difficult to balance.This hitch provides absolutely no controlover the load because it permits rotation.Bridle HitchTwo, three, or four single hitchescan be used together to form abridle hitch. They provide excellentstability when the load is distributedequally among the legs, whenthe hook is directly over thecentre of gravity of the load, andthe load is raised level. The leglength may need adjustmentwith turnbuckles to distribute theload.Single Basket HitchThis hitch is ideal for loads withinherent stabilizing characteristics.The load is automaticallyequalized, with each legsupporting half the load. Do notuse on loads that are difficultto balance because the loadcan tilt and slip out of the sling.Double Basket HitchConsists of two single basket hitchespassed under the load. The legs ofthe hitches must be kept far enoughapart to provide balance withoutopening excessive sling angles.

RIGGING

Replace wire rope if there are– 6 or more broken wires in one lay– 3 or more broken wires in one strandin one lay

– 3 or more broken wires in one lay instanding ropes.

Estimate rope's condition at sectionshowing maximum deterioration.

Core protrusion as a result oftorsional unbalance created byshock loading.

Protrusion of core resultingfrom shock loading.

Figure 87 — Wire Rope Inspection

WornSection

EnlargedView ofSingleStrand

Where the surface wires areworn by 1/3 or more of theirdiameter, the rope must bereplaced.

Multi-strand rope “bird cages” due totorsional unbalance.Typical of build-upseen at anchorage end of multi-fall craneapplication.

A “bird cage” caused by sudden release oftension and resultant rebound of rope fromoverloaded condition.These strands andwires will not return to their original positions.

Check for wearand deformation.

Check for signsof opening up.

Check for wearand cracks.

Check forcracks andtwisting.

Figure 89Hook Inspection Areas

Figure 88

SingleVerticalHitch

BridleHitch

60° or more

DoubleBasketHitch

SingleBasketHitch

Caution: Load maybe carried by only2 legs while 3rdand 4th merely

balance it.

Detail

31 – 3

Double Wrap Basket HitchA basket hitch that is wrapped completelyaround the load. This method is excellent forhandling loose materials, pipes, rods, orsmooth cylindrical loads because the rope orchain exerts a full 360-degree contact withload and tends to draw it together.Single Choker HitchThis forms a noose in the rope andtightens as the load is lifted. It doesnot provide full contact and must notbe used to lift loose bundles or loadsdifficult to balance.Double Choker HitchConsists of two single chokersattached to the load and spread toprovide load stability. Does not grip theload completely but can balance theload. Can be used for handling loosebundles.Double Wrap Choker HitchThe rope or chain iswrapped completelyaround the load beforebeing hooked into thevertical part of the sling.Makes full contact with load andtends to draw it together. If thedouble wrap choker is incorrectlymade and the two eyes are placedon the crane hook, the supportinglegs of the sling may not be equal inlength and the load may be carriedby one leg only. Do not run the slingthrough the hook, permitting anunbalanced load to tip.Braided SlingsFabricated from six or eight smalldiameter ropes braided together toform a single rope that provides alarge bearing surface, tremendousstrength, and flexibility in alldirections. They are veryeasy to handle and almostimpossible to kink. Especiallyuseful for basket hitcheswhere low bearing pressureis desirable or where thebend is extremely sharp.Metal (Wire or Chain)Mesh SlingsWell adapted for use whereloads are abrasive, hot, ortend to cut fabric or wire rope slings.Chain SlingsMade for abrasion and high temperatureresistance. The only chain suitable for liftingis grade 80 or 100 alloy steel chain. Grade

80 chain is marked with an 8, 80, or 800. Grade 100 ismarked with a 10, 100, or 1000. The chain must beembossed with this grade marking every 3 feet or 20 links,whichever is shorter – although some manufacturers markevery link. Chain must be padded on sharp corners toprevent bending stresses.Wire Rope SlingsThe use of wire rope slings for lifting materials providesseveral advantages over other types of slings. While notas strong as chain, it has good flexibility with minimumweight. Outer wires breaking warn of failure and allowtime to react. Properly fabricated wire rope slings are verysafe for general construction use.On smooth surfaces, the baskethitch should be snubbedagainst a step or change ofcontour to prevent the ropefrom slipping as the load isapplied. The angle between theload and the sling should beapproximately 60 degrees orgreater to avoid slippage.On wooden boxes or crates, therope will dig into the woodsufficiently to prevent slippage. Onother rectangular loads, the ropeshould be protected by guards orload protectors at the edges toprevent kinking.Loads should not be allowed toturn or slide along the rope during a lift. The sling or theload may become scuffed or damaged. Use a doublechoker if the load must turn.

Hooking Up• Avoid sharp bends, pinching, and kinks in rigging

equipment. Thimbles should be used at all times insling eyes.

• Never wrap a wire rope sling completely around ahook. The tight radius will damage the sling.

• Make sure the load is balanced in the hook. Eccentricloading can reduce capacity dangerously.

• Never point-load a hook unless it is designed andrated for such use (Figure 91).

• Never wrap the crane hoist rope around the load.Attach the load to the hook by slings or other riggingdevices adequate for the load.

• Avoid bending the eye section of wire rope slingsaround corners. The bend will weaken the splice orswaging.

• Avoid bending wire rope slings near any attachedfitting.

• Understand the effect of sling angle on sling load(Figure 92) and pull angle on beam load (Figure 93).

Rig the load with its centre of gravity directly below thehook to ensure stability. The crane hook should bebrought over the load's centre of gravity before the lift isstarted. Crane hook and load line should be verticalbefore lifting. Weights of common materials are listed inTables 7 to 11.

RIGGING

RIGHT

WRONGLegs will

slide together.

DoubleWrapChokerHitch

BraidedSlings

MetalMeshSlings

60° or more

To prevent slippage,keep angle 60° or more.

SingleChokerHitch

DoubleWrapBasketHitch

DoubleChokerHitch

ChainSlings

31 – 4

Basic Knots and HitchesEvery worker should be able to tie thebasic knots and hitches that are usefulin everyday work.Round Turn and Two Half HitchesUsed to secure loads to behoisted horizontally. Two areusually required because theload can slide out if liftedvertically.Timber Hitch and Two HalfHitchesA good way to secure ascaffold plank for hoistingvertically. The timber hitchgrips the load.Reef or Square KnotCan be used for tying tworopes of the same diametertogether. It is unsuitable for wetor slippery ropes and shouldbe used with caution since itunties easily when either free end is jerked. Both live anddead ends of the rope must come out of the loops at thesame side.Two Half HitchesTwo half hitches, which can be quickly tied, are reliableand can be put to almost any general use.

RIGGING

Caution: This table contains sample values for the purposes ofillustration only. Refer to the manufacturer of the equipment you’re usingfor precise values.

WIRE ROPE SLINGS6 x 19 Classification Group, Improved Plow Steel, Fibre Core

MAXIMUM WORKING LOAD LIMITS - POUNDS(Design Factor = 5)

RopeDiameter(Inches)

SingleVerticalHitch

SingleChokerHitch

Single BasketHitch

(Vertical Legs)

2-Leg Bridle Hitch &Single Basket HitchWith Legs Inclined

60° 45° 30°

3/161/45/163/87/161/29/165/83/47/81

1-1/81-1/41-3/81-1/21-5/81-3/41-7/82

2-1/42-1/22-3/4

6001,1001,6502.4003,2004,4005,3006,6009,500

12,80016,70021,20026,20032,40038,40045,20052,00060,80067,60084,000

104,000122,000

450825

1,2501,8002,4003,3004,0004,9507,1009,600

12,50015,90019,70024,30028,80033,90039,00045,60050,70063,00078,00091,500

1,2002,2003,3004,8006,4008,800

10,60013,20019,00025,60033,40042,40052,40064,80076,80090,400

104,000121,600135,200168,000208,000244,000

1,0501,9002,8504,1505,5507,6009,200

11,40016,50022,20028,90036,70045,40056,10066,50078,30090,000

105,300117,100145,500180,100211,300

8501,5502,3503,4004,5006,2007,5009,350

13,40018,10023,60030,00037,00045,80054,30063,90073,50086,00095,600

118,800147,000172,500

6001,1001,6502,4003,2004,4005,3006,6009,500

12,80016,70021,20026,20032,40038,40045,20052,00060,80067,60084,000

104,000122,000

If used with ChokerHitch multiply abovevalues by 3/4.

Notes: Table values are for slings with eyes and thimbles in bothends, Flemish Spliced Eyes and mechanical sleeves.Eyes formed by cable clips – reduce loads by 20%.

Figure 91Point Loading

Capacity Severely Reduced

Angle of pull affects loadon beam.

Angle Load onof Pull Beam90° 200 lbs60° 187 lbs45° 171 lbs

Figure 93Effect of Pull Angle on Beam Load

90° 60° 45°

100 lbs

Best Good

MinimumRecommended

AVOID

Figure 92Effect of Sling Angle on Sling Load

Round Turnand TwoHalf Hitches

TimberHitchand TwoHalfHitches

Reef orSquare Knot

TwoHalfHitches

31 – 5

Running BowlineThe running bowline is mainly used for hanging objectswith ropes of different diameters. The weight of the objectdetermines the tension necessary for the knot to grip.Make an overhand loop with the end of the rope heldtoward you (1). Hold the loop with your thumb and fingersand bring the standing part of the rope back so that it liesbehind the loop (2). Take the end of the rope in behind thestanding part, bring it up, and feed it through the loop (3).Pass it behind the standing part at the top of the loop andbring it back down through the loop (4).

BowlineNever jams or slipswhen properly tied.It is a universal knotif properly tied anduntied. Twointerlocking bowlinescan be used to jointwo ropes together.Single bowlines canbe used for hoistingor hitching directlyaround a ring orpost.Sheet BendCan be used fortying ropes of lightor medium size.

RIGGING

Bowline

Single Sheet Bend Double Sheet Bend

STEEL STUDS AND TRIMS – WEIGHTSPcs./Bdl. Lbs. (per

STUD SIZE–.018 THICKNESS 1,000 Lin. Ft.)1 5/8 All Lengths 10 2902 1/2 All Lengths 10 3403 5/8 All Lengths 10 4156 (.020) All Lengths 10 625TRACK SIZES–.018 THICKNESS1 5/8 Regular Leg 10 2402 1/2 Regular Leg 10 2953 5/8 Regular Leg 10 3656 (.020) Regular Leg 10 5701 5/8 2 Leg 12 3652 1/2 2 Leg 6 4153 5/8 2 Leg 6 470DRYWALL FURRING CHANNELElectro-Galvanized 10 300DRYWALL CORNER BEAD1 1/4 x 1 1/4 Various 120RESILIENT CHANNELElectro-Galvanized 20 210DRYWALL TRIMS1/2 Door & Windows L. 20 1005/8 Door & Window L. 20 1003/8 Casing Bead J. 20 1101/2 Casing Bead J. 20 1205/8 Casing Bead J. 20 130DRYWALL ANGLE1 x 2 Drywall Angle 10 200

Table 9

WEIGHTS OF MATERIALS (Based On Volume)Approximate ApproximateWeight Weight

Material Lbs. Per Material Lbs. PerCubic Foot Cubic Foot

METALS TIMBER, AIR-DRYAluminum 165 Cedar 22Brass 535 Fir, Douglas, seasoned 34Bronze 500 Fir, Douglas, seasoned 40Copper 560 Fir, Douglas, wet 50Iron 480 Fir, Douglas, glue laminated 34Lead 710 Hemlock 30Steel 480 Pine 30Tin 460 Poplar 30MASONRY Spruce 28Ashlar masonry 140-160 LIQUIDSBrick masonry, soft 110 Alcohol, pure 49Brick masonry, common (about Gasoline 423 tons per thousand) 125 Oils 58Brick masonry, pressed 140 Water 62Clay tile masonry, average 60 EARTHRubble masonry 130-155 Earth, wet 100Concrete, cinder, taydite 100-110 Earth, dry (about 2050 lbs.)Concrete, slag 130 per cu. yd.) 75Concrete, stone 144 Sand and gravel, wet 120Concrete, stone, reinforced Sand and gravel, dry 105(4050 lbs. per cu. yd.) 150 River sand (about 3240 lbs.

ICE AND SNOW per cu. yd.) 120Ice 56 VARIOUS BUILDINGSnow, dry, fresh fallen 8 MATERIALSSnow, dry, packed 12-25 Cement, portland, loose 94Snow, wet 27-40 Cement, portland, set 183MISCELLANEOUS Lime, gypsum, loose 53-64Asphalt 80 Mortar, cement-time, set 103Tar 75 Crushed rock (about 2565 lbs.Glass 160 per cu. yd.) 90-110

Table 7

DRYWALLWEIGHTSNon-Fire Rated 8' 10' 12'1/2" 58 lbs. 72 lbs. 86 lbs.5/8" 74 lbs. 92 lbs. 110 lbs.Fire-Rated1/2" 64 lbs. 80 lbs. 96 lbs.5/8" 77 lbs. 96 lbs. 115 lbs.

Table 8Running Bowline

1 2

4

3

Caution: This table contains sample values for the purposes of illustrationonly. Refer to the manufacturer of the material you’re using for precisevalues.

Caution: This table contains sample values for the purposes of illustrationonly. Refer to the manufacturer of the material you’re using for precisevalues.

Caution: This table contains sample values for the purposes of illustrationonly. Refer to the manufacturer of the material or equipment you’re usingfor precise values.

31 – 6

RIGGING

SUSPENDED CEILING GRID SYSTEMS–WEIGHTSSystems Qty./Ctn. Lbs./Ctn.

(Lin. Ft.) (Lbs.)NON-FIRE RATED GRID SYSTEM1 1/2 x 144" Main Runner 240 581 x 48" Cross Tee 300 551 x 24" Cross Tee 150 281 x 30" Cross Tee 187.5 351 x 20" Cross Tee 125 231 x 12" Cross Tee 75 14FIRE-RATED GRID SYSTEM1 1/2 x 144" Main Runner 240 701 1/2 x 48" Cross Tee 240 701 1/2" x 24" Cross Tee 120 35WALL MOULDINGSWall Mould 3/4 x 15/16 x 120" 400 49Reveal Mould 3/4 x 3/4 x 1/2 x 3/4 x 120" 200 36ACCESSORIESHold-Down Clips (for 5/8" tile) 500 pcs. 3BASKETWEAVE & CONVENTIONAL5' x 5' MODULE – NON RATED1 1/2 x 120" Main Member 200 491 1/2 x 60" Cross Tee 250 61Wall Mould 3/4 x 15/16 x 120" 400 57THIN LINE GRID SYSTEM – NON-RATEDMain Runner 1 1/2 x 144" 300 65Cross Tee 1 1/2 x 48" 300 65Cross Tee 1 1/2 x 24" 150 33Wall Mould 15/16 x 9/16 x 120" 500 62Reveal Mould 1 x 3/8 x 3/8 x 9/16 x 120" 300 48Main Runner 1 1/12 x 144" 300 65Cross Tee 1 1/2 x 48" 300 65Cross Tee 1 1/2 x 24" 150 33Wall Mount 15/16 x 9/16 x 120" 500 62

Table 11

HAND SIGNALS FOR HOISTING OPERATIONSLoad Up Load Down Load Up

SlowlyLoad DownSlowly

Boom Up

Boom Down Boom UpSlowly

Boom DownSlowly

Boom UpLoad Down

Boom DownLoad Up

EverythingSlowly

Use WhipLine

Use MainLine

Travel Forward Turn Right

Turn Left ShortenHydraulic Boom

ExtendHydraulic Boom

Swing Load Stop

Close Clam Open Clam Dog Everything No responseshould bemadeto unclearsignals.

1

6

11

16

21

2

7

12

17

22

3

8

13

18

23

4

9

14

19

5

10

15

20

WEIGHTS OF MATERIALS (Based On Surface Area)Approximate ApproximateWeight Weight

Material Lbs. Per Material Lbs. PerSquare Foot Square Foot

CEILINGS(Per Inch of Thickness)Plaster boardAcoustic and fire resistive tilePlaster, gypsum-sandPlaster, light aggregatePlaster, cement sandROOFINGThree-ply felt and gravelFive-ply felt and gravelThree-ply felt, no gravelFive-ply felt, no gravelShingles, woodShingles, asbestosShingles, asphaltShingles, 1/4 inch slateShingles, tilePARTITIONSSteel partitionsSolid 2" gypsum-sand plasterSolid 2" gypsum-light agg. plasterMetal studs, metal lath, 3/4"plaster both sidesMetal or wood studs, plasterboard and 1/2" plaster both sidesPlaster 1/2"Hollow clay tile 2 inch

3 inch4 inch5 inch6 inch

Hollow slag concrete block 4 in6 in

Hollow gypsum block 3 inch4 inch5 inch6 inch

Solid gypsum block 2 inch3 inch

MASONRY WALLS(Per 4 Inch of Thickness)BrickGlass brickHollow concrete blockHollow slag concrete blockHollow cinder concrete blockHollow haydite blockStone, averageBearing hollow clay tile

528412

5.56.534232.51014

42012

18

18413161820252435101315.516.59.513

4020302420225523

FLOORING(Per Inch of Thickness)HardwoodSheathingPlywood, firWood block, treatedConcrete, finish or fillMastic baseMortar baseTerrazzoTile, vinyl 1/8 inchTile, linoleum 3/16 inchTile, cork, per 1/16 inchTile, rubber or asphalt 3/16 inchTile, ceramic or quarry 3/4 inchCarpetingDECKS AND SLABSSteel roof deck 1 1/2" - 14 ga.

- 16 ga.- 18 ga.- 20 ga.- 22 ga.

Steel cellular deck 1 1/2" - 12/12 ga.- 14/14 ga.- 16/16 ga.- 18/18 ga.- 20/20 ga.

Steel cellular deck 3" - 12/12 ga.- 14/14 ga.- 16/16 ga.- 18/18 ga.- 20/20 ga.

Concrete, reinforced, per inchConcrete, gypsum, per inchConcrete, lightweight, per inchMISCELLANEOUSWindows, glass, frameSkylight, glass, frameCorrugated asbestos 1/4 inchGlass, plate 1/4 inchGlass, commonPlastic sheet 1/4 inchCorrugated steel sheet, galv.

- 12 ga.- 14 ga.- 16 ga.- 18 ga.- 20 ga.- 22 ga.

Wood Joists - 16" ctrs. 2 x 122 x 102 x 8

Steel plate (per inch of thickness)

52.53412121012.51.510.52112

5432.521186.553.512.59.57.564.512.55

5-10

8123.53.51.51.5

5.5432.521.53.532.540Table 10 Rigging Safety Tips

With two or more slingson a hook, use a shackle.

Use tag lines for control.

Block loose loads before unhooking. Make sure loads are secure.

Stay back whenslings are pulled outfrom under loads.

Caution: This table contains sample values for the purposes ofillustration only. Refer to the manufacturer of the material you’re using forprecise values.

Caution: This table contains sample values for the purposes of illustrationonly. Refer to the manufacturer of the material or equipment you’re usingfor precise values.

31 – 7

RIGGING

For Cranes Operating “On Outriggers”

For Crawler-Mounted Cranes or When Lifting “On Rubber”

32 – 1

32 SPECIALIZED RIGGING

CONTENTS• Rigging with hydraulic gantry systems• Overhead cranes• Jacks and rollers• Tuggers

RIGGING WITH HYDRAULICGANTRY SYSTEMS

1. INTRODUCTION ANDOBJECTIVES

Hydraulic gantries are a useful type of heavy equipmentfor lifting and manoeuvring heavy loads. Gantry systemsrange from those using small, five-ton capacity jacks up tosystems capable of lifting 1,000 tons. The fully extendedheight of some systems can reach 40 feet.Proprietary systems may also be engineered and built bycontractors capable in specialized lifting and moving.In virtually all heavy lifting applications with thisequipment, you will need knowledgeable engineering,planning, and coordination. Professional engineeringassistance should be considered a necessity for someaspects of this type of work.Tradespersons, supervision, and management can allbenefit from having more information on the subject ofgantry lifting. This chapter is intended to provide usefulinformation on a number of related topics, including• description of a basic hydraulic gantry system• hazards• responsibilities of workplace parties• lift types• planning, coordination, and preparation• personnel training and safety• information to be expected on the equipment, and

questions to ask.This chapter is intended to provide constructiontradespersons, supervision, and management with anawareness of hydraulic gantry lifting. It focuses particularlyon hazards, as well as on good procedures and practicesto follow when using this equipment. It is intended to be auseful planning, preparation, and training tool.

2. BASIC SYSTEM TYPES ANDCOMPONENTS

TYPESA basic two-leg gantry system consists of a number ofparts as illustrated.

At the heart of the system are the gantry jacking unitswhich support a header beam.If wheel-mounted, thejacking units can run on track beams.The lifted load is usually picked up using a slingarrangement which is attached to the header beam bymeans of lifting links on the beam.In more elaborate systems, using more sophisticatedlifting links, the load can be shifted laterally along theheader beam.Four-leg gantries

• Capacity is from about 20 tons. Large systemcapacity is from 200 to 1,000 tons.

• Typical height capabilities are from 20 to 30 feet.• The height capability of some is up to about 40 feet.

COMPONENTS

GANTRY JACKING UNITScan be divided into two types:1. Vertical lift cylinder

Bare cylinder machines usuallyconsist of a fabricated steelstructural base, which is wheel-mounted, and have one to fourvertically mounted hydrauliccylinders on top. They can beeither single-stage or multiple-stage. The cylinders can beeither one-way (pressureextend, gravity retract) ordouble-acting (pressure extendand retract). The units aregenerally less complex andlighter than telescopic boomunits.2. Vertical telescopic liftboom

Telescopic boom machineshave a similar, but usuallylarger and often wheel-mounted, structural base. Thebase carries square or

SPECIALIZED RIGGING

32 – 2

rectangular multiple-section steel boxes or booms, similarto a hydraulic crane boom, which can resist horizontalforces during lifts. The telescoping of the boom is drivenby one or more internal or external hydraulic cylinders.This type of gantry system usually allows the sections tobe locked together to support the load structurally, ratherthan hydraulically, if the load has to be held elevated forany length of time. A desirable safety feature is thesystem’s ability to lock the leg mechanically as it extendsor retracts to prevent unbalanced loading and collapse, inthe event of hydraulic failure.

CONTROL/POWER UNITThis is a remote control station that provides power toactuate the cylinders in the jacking units.On all-hydraulic machines, this unit contains a motor andhydraulic pump that pressurizes the system. It also hascontrol valves which the operator uses to control oil flowthrough hoses to the lift cylinders.In some machines, the controls at the station used toactuate the operation of the jacking legs are electric. Inthese systems there are only electrical connections to thejacking units, which have a self-contained hydraulicsystem composed of the oil reservoir, motor, andhydraulic pump.

HEADER PLATEThe header plate is an adapter plate with a swivel fitting,located at the top of the lift cylinder or boom. It is used toattach the header beam to the jacking unit.

HEADER BEAMSHeader beams arestructural sections—usually rolled wide flangeshapes or fabricated boxsections. They aresupported on the headerplates.Different header beamarrangements are usedwith four-leg gantrysystems. A four-beam header arrangement allows moreflexibility in positioning lifting links to match the pickuppoints on the load, or in putting slings on the load.Typically the lower two beams span the jack legs whilethe upper header beams span the lower beams.

CROSS BEAMSCross beams are typically used to make up a four-beamheader arrangement and are a second set of headerbeams (or one beam), to which the load is attached,placed across the first set.

TRACK SYSTEMSTrack systems consist of two parallel beams, usually wideflange shapes or fabricated box sections, that are fittedwith a wheel guide to direct the jacking unit’s wheels. Thefunction is to provide a smooth and guided surface for thewheels.

The track beams are normally tied together at regularintervals. The spacing matches the transverse wheelspacing of the jacking unit. The track units are usuallyfabricated in sections short enough to be shipped easilyand then bolted together end to end.Track units can be designed to carry the jacking unitwheel loads over clear spans, such as pits or weak floorsections, or they can be designed for full support from anunderlying surface.Hydraulic gantry systems must be solidly supported Ifwheeled, they must run on strong, solidly supported tracksystems with minimal deflection to keep them both stableand upright.PROPULSION DEVICES

The jacking system must be propelled along the track orfloor. There are three basic concepts for the propulsiondevices:1) Built-in: The jacking unit has a motor that drives someor all of its wheels using chain or gears.2) External cylinder(s): For use on free-wheeling units, acylinder is pinned close to the bottom of the jacking unit’sbase at one end, and to the track at the other. Thecylinder is extended and retracted repeatedly to move thejacking system along the track.3) External drive wheels: One or more drive wheels aremounted to the base of the jacking unit. In order todevelop enough friction and tractive force to drive thejacking unit, the wheels must be loaded somehow.

LOAD SENSORS/GAUGESThese are devices used to measure the weight beingcarried by each jacking unit. They can be installed on thecontrol panel or on each jacking unit. It is better to installthem on each cylinder directly—not on the hydraulicpressure line—so that they provide more accurate andindividual readings.

LIFTING LINKSLifting links are a meansof attachment betweenthe header beams and theload rigging. They areoften made from a pieceof flat plate cut to fitaround the header beamwith a hole at the bottomfor attaching rigging

SPECIALIZED RIGGING

32 – 3

hardware such as a shackle. Simple static-plate stylelifting links are adequate for simple lift-and-lower or lift-and-roll jobs. More complex lifting link configurations areneeded for side-shifting or rotating a load using swivels.

RIGGINGA variety of hardware is used to attach the lifted load tothe lifting links. Typical rigging items include shackles,wire rope slings, synthetic slings, chains, or slings madefrom wire rope and clips.

LONGITUDINAL DIRECTIONThis is the horizontal direction parallel to the axis of thejacking system track.

LATERAL DIRECTIONThis is the horizontal direction perpendicular to the axis ofthe jacking system track.

SIDE-SHIFTINGThis is the lateral movementof a suspended load, usuallyusing wheel-mounted orsliding lifting links with ameans of lateral propulsion.

DRIFTThis is the horizontalmovement of the top of atelescopic lifting boom due toclearance between the boomsections.PUNCHING

This is the failure of astructural support, such as aconcrete floor, due toexcessive shear stress from aheavy locally concentrated load.

3. HAZARDS

Headings suggest the area of deficiency.

PLANNING• Inadequate knowledge or training• Loading that exceeds floor load capacity or causes

unexpected deflection• Poor load distribution for weak or irregular structural

support conditions• Poor sub-grade conditions.

PREPARATION• Excess track deflections• Track beam deflection causing “uphill” or “downhill”

condition, or differential movement of track sections atconnections

• Unequal track deflection from side to side, e.g., due topits, obstacles

• Lack of system manual or load chart information• Unanticipated loads: rigging misaligned due to

clearance problems.

SETUP• Track misalignment• Damage to high-pressure hydraulics and hoses• Unbalanced or non-centred loads• Unequal load distribution between legs, e.g., corner

loading on 4-leg bridles, etc.• Water such as ground water or leaks.

OPERATIONAL• A gantry or an individual leg going out of plumb• Jack misalignment, “racking” during load travel along

the track beams• Debris or obstacles on the track or path of travel• Rigging not vertical, causing horizontal forces on the

header beams• Horizontal forces: transferred through the rigging

during up-ending or standing up a load, or frompendulum action of the load

• Lateral forces• Excess lift boom drift• Chock stops/locks not deployed• Electrical contacts (powerlines or power rails)• Vibrations (operating plant or moving equipment)• Environmental (wind forces, etc.)

PERSONNEL• Fall hazards while rigging• Fall hazards while preparing mating surfaces• Fall hazards during assembly and breakdown• Overexertion injuries during setup and dismantling

operations• Pinch points and crush injuries.

4. GENERAL PRACTICES

This type of equipment was originally developed for liftingand moving heavy machinery components inside buildingswhere clearances were small and where conventionalcranes were not practical. It remains an effective andeconomical alternative to cranes for lifting heavy loads.The majority of gantry lifts are of the basic rig-lift-and-rolltype or straight-up-and-down type for transloading fromone carrier to another. Types of lifts will be discussed inmore detail later in this chapter.The basic procedures for using hydraulic gantry systemsfor lifting are not unlike those for using conventionalcranes.• The supplier provides a set of manufacturer’s

operating instructions and a load chart or charts withthe equipment.

• The user is responsible for the selection of rigging,the preparation of the base on which the equipmentwill be set up, and the safe operation of theequipment.

• As a general rule it is advisable to use rigging whichhas excess capacity—some suppliers recommendrigging that will support twice the anticipated load.This recommendation should definitely be followed ifthere is any chance of “cross-cornering”—i.e., whentwo slings can end up carrying all the load of a four-

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point lift (or any multi-point lift). As in all liftingactivities, be sure to include the weight of the riggingin the calculations.

• A competent operator is required, one who is familiarwith the gantry system being used. Sometimes thesupplier will provide a skilled operator.

• Prevent unauthorized personnel from entering theworking area by using warning signs and bycordoning off the area with barrier tape.

• Before starting operations, make sure that the plantsupervision is informed.

• Check that no other operations are going on in thework area and/or are locked out, such as overheadcranes or heavy equipment.

• Check the area for hazards such as electrical contact(powerlines), vibration (operating equipment), water(ground water, leaks, etc.), or environmental hazards(wind forces, etc.).

5. RESPONSIBILITIES OFWORKPLACE PARTIES

OWNER/CONSTRUCTOR• clearly define the required tasks and schedule• provide necessary drawings and information about the

plant or facility• cooperate in planning and emphasize that safety must

be a priority in all operations• cooperate with other requirements such as limiting

access of nonessential personnel during moves.

CONTRACTOR• plan and organize all activities• work with the supplier and owner/constructor to plan

and schedule the moves• make sure that accurate load information has been

provided and approved, including load weights, sizes,shapes, and rigging plans

• perform detailed “risk assessment” activities beforethe moves

• have competent supervision on the job• ensure there is a trained competent operator—

checked out or provided by the supplier• ensure there are trained competent operators for

other equipment (e.g., forklifts)• designate crew members for all tasks• make sure that your crew is trained on the equipment

and given job-specific training• provide necessary personal protective equipment

(PPE) and equipment for the crew.MANUFACTURER/SUPPLIER

• provide the lifting equipment in proper workingcondition

• provide all necessary documentation such as manualsand load charts for the equipment

• ensure that the equipment has enough capacity forthe job

• provide a competent, experienced operator if required• ensure that adequate training is provided on the use

of the equipment.

CONTRACTOR/TRADESPERSONS

• understand fully the use and operation of the liftingequipment

• be sure there is job-specific training• know and follow the load-handling procedures• make sure you are informed about emergency

preparedness and procedures• work in a safe manner.

6. LIFT TYPES

Straight up and down. This type of lift consists ofrigging, lifting, and holding the load, then lowering it whenits new support is in place.A common use is for transferring a heavy piece ofequipment from one vehicle to another—for instance, froma railcar to a trailer. In this case the gantry might be setup over the rails while the loaded rail car is drivenbetween the gantry tracks. The load is then rigged to theheader beams and the gantry extended to lift the loadclear of the car. The railcar can be moved out and thetrailer moved in under the load. The load can then belowered to the trailer bed for transport.Straight up and down with travel. This type of liftconsists of rigging the load, lifting it with the gantry, drivingthe loaded gantry along a track system, raising andlowering the load as required, and then finally lowering itto its final location.

An example of this kind of lift is placing a largecomponent—such as the crown—on top of a mill or pressinside a plant. Some form of motive power is required tomove and control the longitudinal travel of the loadedgantry along the tracks.Stand up/lay over. In this lift, the longitudinal axis isrotated to stand up a tall component which has beenshipped horizontally, or to lay one over.This type of lift can be used to place tall vessels or largecastings. More complex than straight lifting, it requires thecoordination of simultaneous horizontal and verticalmovement of at least one pair of gantry legs.

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In operations with afour-legged system,the gantriessupporting theupper end aretypically stationaryand lift only. Thegantries controllingthe lower end arerolled along thetracks to bring thebottom end underthe top of the load,similar to the use of atailing crane.Advance planning is veryimportant, along withcareful coordinationduring the lift, in order tominimize horizontalforces being generatedby out-of-plumb riggingduring such lifts.Lifts on top of headerbeams. In this lift, the load is carried on the header beamsystem rather than being suspended below.This technique allows the load to be elevated when theplacement location has insufficient headroom for theheaders and rigging to place the load in its final position.In order to do this the gantry must be able to pass underthe load either by positioning the load in an elevatedpickup location or by using a pit arrangement whichpermits the gantry to pass under the load for pickup.The bearing points or surfaces on which the load issupported prior to pickup must leave clear access for thepickup locations on the header beams when the gantrymoves under the supported load. Similarly, at theplacement location, there must be no interference as theload is moved and placed on its final bearing surfaces.Combination lifts with a crane, forklift, etc. This type oflift is similar in some ways to a tilt-up or lay-down situationwith two gantries. In this case, one of the gantries hasbeen replaced by a crane, forklift, or other equipment.Such lifts are both complex and potentially hazardous.They require specialized knowledge and careful planning,as in any type of tandem lift.Care must be taken to keep the rigging vertical in order toavoid horizontal loading which can quickly make thewhole system unstable, resulting in rapid tipover. Cranesand forklifts are not designed to take on and resisthorizontal loads or components of loads. Tiebacks orholdbacks tied to the structure or other stable anchorpoints may be required to stabilize the load to preventkickout or swing as the load balance shifts duringmovement. Take care that tiebacks don’t introduceunbalanced tipping forces.

Ideally, the support structures or vehicles (gantry, crane,or forklift) should be tied together to minimize theopportunities for horizontal components of load and

tipping—if only due to the simple rigidity of the load. Themotive power for travel can come from one of the piecesof equipment, such as a forklift.Straight up and down with side-shift. The load is lifted,movedlaterallyalong headerbeams, thenlowered. Amorecomplexlifting link isneeded toenable lateraltravel alongthe headerbeams aswell as a means of powering the travel. Even morecomplex lifting links are necessary for other movementssuch as rotating the load. As the load moves within thegantry framework, the load on each leg changes as doesthe potential deflection of track beams, which can causethe legs to lean and drift.

Other configurations: Boom lifters

Equipment such as “boom lifters” can offer more flexibilityfor somewhat lighter loads.The safety standard to which these units are made isASME Standard B 56.7 for Industrial Mobile Cranes.These units operate on a counterbalance principle. Theycan have adjustable extendable booms and extendablecounterweighting systems which can be adjusteddepending on the counterbalance moment required.Several types and capacities of unit are available. Liftingfeatures or options may allow the unit to• pick and carry suspended loads, as shown above, for

tilt-up or other work in tight areas• be equipped with a fork-type attachment and perform

as a high-capacity forklift• operate as a gantry, lifting on top of the boom, for

tasks such as installing or removing overhead cranebridges

• travel with a suspended load, carefully secured or tiedback to control load swing. Follow the manufacturer’sdirections.

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7. SYSTEM SUPPORT ANDLOAD DISTRIBUTION

Qualified professionals should carry out an engineeringassessment and detailed calculation of these factors inadvance. It’s valuable, however, for all personnel involvedin the lifting process to understand factors that must beconsidered.Uniformity of settlement or deflection of the track iscritical to keep the entire gantry system stable.

Any vertical movement under the load must be keptuniform to prevent one side or corner of the gantry systemsettling more than others, and to prevent the system fromleaning and becoming unstable. The whole system mustbe kept essentially plumb throughout the move in order toavoid the risk of total collapse.

SUPPORT COMPONENTS ANDMETHODS

TRACK SYSTEMThe ideal support for the track would allow no deflectionand therefore no tilt or drift. If such conditions can beachieved, then levelling the track at the beginning isadequate. In reality there will always be some deflection.It’s important to remember that track deflection must bepredicted and controlled to cause little or no tilt of thegantry—especially sideways.

Any deflection of the track beams on both sides must bekept within tight limits. The deflection must also beessentially equal for both tracks to prevent tilting of thegantry structure. A number of things can be done to helpmake this happen, including:• allowing little or no track deflection by laying track on

a solid, strong base• using very stiff track beams to keep deflections to a

minimum

• if a track beam on one side must span a pit orobstacle, shimming the track beam on the other sideat locations matching the span supports

• shimming the track beams to provide firm supports atmatching positions on both sides so that expecteddeflections will be the same on both sides (but stillwithin acceptable limits)

• matching the height of adjacent sections of trackbeam, and adequately bracing and supporting them,to prevent height differences when the loaded gantrytravels across the joint.

The sketch below illustrates some steps to take to helpensure that track beam deflection is constant on bothsides.

PLATESSteel plates can provide a hard surface for the jackingunits to bear on and thus distribute loads over a largeenough area to prevent punching through a slab on gradeor a floor slab. Plates can sometimes reduce the bearingpressure on a weak subgrade to an acceptable level.Plates are also used as shims to support the track beamsat predetermined locations.

STANDSStructural frames can be made to support a jacking unit ora track system and distribute the loads.

MATS/TIMBERCrane mats, built-up cribbing, or other timbers can beused to support jacking system legs or track beams inorder to provide a system of load distribution—spreadingthe load over a wider area.

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DEALING WITH SITECONDITIONS

SOIL/STONE/ASPHALTPoor or weak subgrade conditions might exist at the site.Compaction may be needed and/or the placement oftimbers, mats, or cribbing to spread the load over a largearea.Whatever method of support or load distribution isselected, the deflection must be predictable to preventdifferential settlement of the track beams when loaded.Inconsistencies in the subsoil or undergroundconstruction, such as buried pipelines or other services,may require bridging over to provide consistent support.

SLAB ON GRADESlabs on grade need to be checked for strength. The loadmust be sufficiently distributed to prevent punchingthrough the slab or overloading any section. One solutionmay be to use steel plates.If heavy loading is applied well away from the centre of aslab—or especially near the edge—there can be a greaterchance of the slab cracking, deflecting, or tipping.

FLOOR OR DECK SYSTEMSThe capacity of existing floor systems must be checked.Floors must be checked for both local and generalweakness and inspected for deterioration. If loadingexceeds floor capacity, reinforcing or shoring the floormay be required to strengthen it. Steel plates are onemeans to distribute the load enough to prevent failure.

PITS OR BULKHEADSA typical two-leg gantry has one leg on each of two trackbeams. Track beams can be designed or selected to bestrong enough to span, with limited deflection, supportpoints over pits or obstructions.Deflection of track beams must be limited. When it doesoccur, deflection of both beams must be more or lessequal to prevent the gantry from going out of plumb. Bothtrack beams can be designed to have equivalent stiffnessand deflection to keep the gantry level from side to side.To ensure equal deflection of both track beams they canbe shimmed at matching support points on both sides—even if only one side has to span a pit.

OFFSHORE/WATER SUPPORTEDIf the use of floating platform or barge-mounted gantrysystems is being considered, other factors must be takeninto account. The transfer of a load onto or off a floatingplatform will cause the platform to lower in the water as itreceives the weight and to rise in the water as the weightis off-loaded. The floating platform will be raised orlowered relative to any adjacent dock or structure.Load transfers on water require careful assessmentbecause of many factors, including the following:

• risk of off-centre loads tilting a floating platform andcausing tipping forces on the gantry

• grounding or partial grounding of the barge whenloaded

• tidal and weather conditions• need to anchor or tie the floating platform to prevent

movement.

OTHER CONDITIONS OR VARIATIONSAll support conditions must be considered and planned forin order to provide a stable and solid foundation andprevent any chance of instability during the lift.

8. GANTRY COLLAPSE VS.STAYING PLUMB

Lifting using hydraulic gantries can be done safely. It isimportant, however, to understand that gantries canquickly become unstable and topple. Gantry legs havelimited safety factors against tipping because their basesare small compared to their height.Engineering checks must be done before any lifts aremade in the field. Personnel familiar with this type of workmust do the design, planning, and coordination.

Workers must appreciate the critical importance of thelegs staying vertical or plumb as well as the need toeliminate any horizontal forces. A sure sign that somehorizontal forces are beginning to be applied to thetop of the jacking leg, at the header plate level, is thatthe rigging is not vertical, but is out-of-plumb. If notcorrected, these forces can lead to overturning orcollapse.

Overturning in the direction of the tracks, due tolongitudinal forces, is avoided by keeping the line of thevertical loads within the wheel spread, or wheel base, andfar enough inside the tipping axis to more than balanceany overturning forces.Causes of longitudinal horizontal forces, in the direction ofthe tracks, include• off-level setup of track beams causing an

uphill/downhill track configuration• sway of suspended load due to overcoming inertia or

a change in travel speed along the track• forces from out-of-plumb rigging during standing up or

laying down of a load• adjacent sections of track beam that are out of level.Another cause is that during standing up or laying downof a load using dual two-leg gantries, opposing horizontalforces can be imposed on each due to tension in out-of-plumb rigging.Side-to-side (lateral) overturning comes from sidewaysforces and is avoided by keeping the line of vertical loadswithin the wheel span at the top surface of the track andby the vertical forces staying within the track width atground level.

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SPECIALIZED RIGGING

Loads on gantry legs

Each factor or a combination can lead to collapse

32 – 9

Possible causes of sideways (lateral) horizontal loadsinclude• hangup of a suspended load during side-shift along

the header beams• uneven deflection of the track beams on each side

due to different size beams or different supportconditions

• rotation of single track rails because they are off-levelor poorly supported

• twin track rails on each side which are not at thesame level or poorly supported.

Other possible sources of horizontal forces include

• the jacking legs operating at different rates during thejacking (raising or lowering) of a load (Install a tapemeasure on each leg to allow for frequent checking.)

• wind on large loads being rigged outdoors• equipment vibration or earthquake forces.

Centre loads on the header plateVertical loads should be applied at the centre of eachjacking leg on the header plate. If the jacking leg is plumb,then the vertical force will pass through the vertical axis tothe ground or supporting structure. Loads applied off-centre will make the system less stable. Vertical loadsapplied to an already out-of-plumb jacking leg will force itmore out-of-plumb.A number of conditions can contribute to a jacking legbeing non-vertical, including the following:• There can be lateral drift of the jacking leg in

telescopic boom gantries. Clearances between boomsections can allow the top of the jack to drift off-centre. Even when on a level track the top can leanone way or another due to these clearances.

• Off-level track beam or beams, or rotation of a trackbeam, will cause a tilting of the entire jacking leg,reducing the line of action of vertical loads which keepthe leg upright.

• The track beam or beams can deflect unequally.If several conditions are present, then the effect will becumulative.The figure below illustrates these effects and theirpossible combined result. If the jacking leg is not plumb,any vertical load that is applied will reduce its resistanceto overturning and could lead to a collapse of the entiregantry system.

9. PLANNING THE MOVE

Planning is the key step in this kind of work, as in mostcomplex rigging. Always keep some basic considerationsin mind.Know the scope: Have a clear definition of what must bedone.Preliminary layout: Prepare or use a preliminaryequipment layout to define the lift parameters, includingthe clearances and any potential obstacles.

Preliminary equipment: Assess lift type and makepreliminary selection of lifting equipment as well asalternative methods of lifting.Accurate loads: Knowing the load weight and size iscritical.Load shape and orientation: The load’s shape, weightdistribution (location of centre of gravity), and pickuppoints must be accurately determined in order to select ordesign header beams, rigging, etc. Calculations must becompleted and must be made available.Site Assessment: Do a detailed assessment of the sitefor track support, obstacles, and inconsistencies that needto be considered. Do subgrade and/or floor assessments.Determine whether cribbing or other support is needed.Lifting equipment: Select gantry system, size, andcapabilities as well as all the components of the system.Lay out the system to minimize side-loading. Confirm thatthe gantries can lift the load high enough for clearances.Also confirm the clearances above the header beams atthe roof, etc.Shifting loads: If the lift includes such moves as standingup, laying over, or side-shifting a load, be sure that in thecapacity checks of the equipment you account for thechanging distribution of the load among the jacking units.Rigging plans: Have rigging devices and assembliesdesigned and approved for each load and type. Havecalculations done and available. Confirm that the load canbe raised high enough to clear any obstacles and that theload or rigging clears the roof or other overheadobstacles. This is similar to preventing two-blocking incrane operations.Select the pickup location carefully to ensure that the loadaligns accurately when reaching its placement location.Locate any supports or stands accordingly. In a pick-and-travel lift, such as placing a crown on a press, attemptingto pull over an elevated but misaligned crown isdangerous and could cause gantry collapse. If the riggingis pulled out-of-plumb, the lateral horizontal loadsintroduced at the header beams can quickly tip over theentire system.When up-ending a load, check that there is clearancebetween the load and gantries in all positions and confirmthat the rigging can be kept plumb during the operation.When planning a four-point lift, consider the possibleeffects of “cross-cornering”— when two slings and liftpoints might be carrying all or most of the load.Assignments: Provide and communicate clearassignments to personnel for each task.Training: Ensure that personnel are properly trained fortheir assignments.Site safety: Ensure fall prevention and fall protection.Protect pits and access openings. Do a complete sitecleanup. Remove any loose objects. Identify barrierlocations to cordon off the area.System and rigging inspection: Ensure that there arecertificates of test for rigging devices and assemblies andthat there has been adequate inspection of riggingcomponents. Ensure compliance with rigging plans, themanual, and the load charts for the gantry system.

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10. SAFE OPERATINGPRACTICES

When using a hydraulic gantry system, good operatingpractices include the following.• Follow the manufacturer’s directions and load charts

Is there a load-equalizing feature in the system?• Confirm that the load, in its pickup location, is

oriented to be properly aligned for final accurateplacement at its destination.

• Mount a tape measure on each jacking leg to monitorthe rate of extension or contraction of each leg whileraising or lowering the load in order to ensure that thesystem stays level.

• Keep unnecessary personnel out of the work area.Cordon off the area.

• Conduct a site hazard assessment before any gantrymove to make sure that the track is clear of debris orobjects and that the travel path is obstacle free. Whenseveral lifts are made using the same track setup,make sure the track has not shifted or suffereddamage before each move.

• As in all other heavy rigging, move slowly. This helpsprevent unsafe movements such as side-loading,pendulum action, jerking, or sudden stops. Operatingslowly provides more time to notice potentialproblems and take corrective action.

• Keep the load as low as possible—just high enoughto clear obstacles, especially while moving it along thetrack or moving it laterally.

• Constantly monitor the pressures in the hydraulicsystem and in each jacking leg if they haveindependent hydraulic systems. Increasing pressuresor a variation in pressure between the jacking legscan indicate problems such as corner-loading withtwo of four legs carrying most of the load instead of itbeing shared equally.

• Make sure the track beams along the line of travel arekept clear of objects, debris, or dirt that can obstructtravel.

• During longitudinal movement of gantries (moving aload along the track beams) make sure that the twolegs of each gantry move in unison so that one sidedoes not lag behind.

• When using two two-legged gantries, the leading andtrailing gantries must move in unison.

• Monitor the rigging to make sure it stays plumb. Anout-of-plumb condition indicates the presence ofhorizontal forces on the system.

• At any sign of a problem, STOP and find outwhat’s wrong.

• Periodically—and whenever changing any conditionor direction of lift or travel—stop and check thefollowing items: Are the jacking units plumb and level at their base?

Are jacking unit supports, stands, or track rails stilllevel? Have they settled under the load?

Are there signs of horizontal drift of any jackingleg?

Is there excessive header beam deflection,especially if side-shifting a load?

Is the header beam staying level and not rotating? Is the loading on each jacking leg equal or as

predicted? Are the jacking units travelling uniformly and in-

sync (side-to-side, no racking, etc.)? Is there still adequate clearance past obstructions,

including those overhead? Is the rigging staying plumb? Out-of-plumb rigging

indicates dangerous horizontal loads being appliedat the top of the jacking legs.

Has the travel path been inspected for debris,obstructions, and signs of track shifting?

11. POST-LIFTCONSIDERATIONS

Dismantling and removing the equipment must beplanned and carried out in a safe way.Heavy lifts using hydraulic gantries are usually a centralfocus of construction activities during their set-up andwhile they are under way. When the lifts are complete, thepressure is off and participants naturally relax after a jobwell done. It’s easy for a less-than-cautious, complacentattitude to develop.Safe practices can slip when your attention begins tofocus on the next job. Disassembly and removal of thegantries can be seen as a routine job. At times such asthis, it is easy for accidents and injuries to occur. Safetyand safe practices must remain in the forefront at alltimes. The gantries themselves are large and heavypieces of equipment. Their breakdown and removal mustbe planned and carried out carefully, as in any otherrigging job.

12. TRAINING GUIDELINES

Identify the training requirements for both tradespersonsand supervisors.1) Manufacturers must make training available in the

operation and servicing of every piece of equipmentthey sell. They must also provide the necessarydocumentation, including manuals and load charts,with each piece of equipment.

2) The division of responsibility between thesupplier/manufacturer and contractor(s) must beclearly defined to permit clear accountability foradequate training before the job proceeds.

3) The contractor providing the lifting services usinghydraulic gantries must ensure that, at all times, onlyoperators trained and competent in the operation ofthe specific equipment are used on the site.

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4) Job-specific training must be provided to all personnelon the tasks which they are assigned.

Adequate engineering and planning must be performedfar enough in advance to allow for enough training toaccomplish all designated tasks safely.

13. SAFETY OF PERSONNEL

GENERAL• Everybody on the site must comply with the

legislated, site, and contractor requirements forpersonal protective equipment (PPE) includingfootwear, hard hats, eye protection, and hearingprotection where required.

• Keeping a clean, well-ordered work site is a constantrequirement for gantry operations since once themove starts, worker attention should not be divertedfrom lift responsibilities.

• Use a safety person with a warning air horn who isfamiliar with the lift operation to look out for anypotential hazards and to make sure that no unwantedpersonnel or traffic enters the work area.

FALL HAZARDS• Working at heights is a frequent requirement in this

kind of work, especially during the preparation andcleaning of mating surfaces and during theengagement and disengagement of rigging. Fallprotection systems must be provided and installed forany workers exposed to fall hazards during thesetasks. The systems should only be installed inlocations where they won’t interfere with any of theload-handling and rigging activities or subject aworker to injury in the event of a fall.

• Individual vertical lifelines or retractable block lifelinescan be provided in appropriate locations.

• In some situations horizontal lifelines for multipleattachment can be installed. Their design andinstallation must be performed or at least reviewed bya professional engineer. Suitable anchor locationsmust be identified and used. They must be strongenough to support any potential fall-arrest forces.

EQUIPMENT HAZARDS• Hoses and electrical cables must be protected from

damage, especially when a gantry is moving a loadalong the track. Hoses and electrical cables are alsoa constant tripping hazard.

• High-pressure hydraulic systems are the core ofgantry lifting systems. There are ongoing hazards ofinjury from hydraulic leaks due to their high pressures.

14. PRE-LIFT CHECKLIST

1. SECURE AREA Close off the work area with caution tape and other

visible warning signs or barriers necessary toprevent unauthorized entry.

Check for overhead crane operations. Notify area foremen of impending operations. Have non-essential personnel cleared from the

area. Check for hazards: electrical, wind, vibrations,

water, etc. Move other heavy equipment clear of lift area.

2. NOTIFY OWNER Notify plant security of impending lift. Notify plant engineer of impending lift and invite to

pre-lift safety meeting.

3. PRE-LIFT SAFETY MEETING Check area for debris. Assign personnel to specific lift tasks. Explain in detail how lift will be safely

accomplished. Verify that personnel understand tasks. Identify escape routes and other emergency

procedures. Confirm alignment of pickup and placement

locations to avoid adjustments after the load iselevated.

Perform a dry run.

4. JACKING SYSTEM CHECK Fuel supply Fluid levels Loose couplings Rigging Jack alignment.

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15. REVIEW EXERCISES

This chapter can be used as a supplement to supportyour safety training for rigging with hydraulic gantry lifts. Auseful awareness exercise is to brainstorm the hazards toavoid when using gantries and list the hazards onflipcharts. This can be an introductory exercise beforehanding out the data sheet or after the session as areview exercise. Refer to Section 3 (Hazards) to confirmand supplement the hazard lists developed during theexercise.

QUESTIONS (BY SECTION)Section 4—General Practices

1. What two documents need to be supplied and usedwith a hydraulic gantry system in order to operate itsafely?

2. Some suppliers recommend that rigging should havedouble the calculated capacity requirement. Therigging must have at least this “double” capacity ifthere is any chance of “cross-cornering” during four-point or multi-point lifting.a) In cross-cornering, how many lines must be able to

carry the entire load?b) In addition to the weight of the object being rigged,

what must be included in the load weight?3. Before starting operations, list at least four activities

which must be carried out.

Section 8—Gantry Collapse vs Staying Plumb

4. List at least two things which prevent gantry collapseduring lifting operations.

5. List at least four conditions that can reduce thestability of a gantry during a move.

Section 10—Safe Operating Practices

6. Fill in the missing words in these incompletestatements:a) A useful means of monitoring the rate of extension

or contraction of each leg is to mount a________________ on each.

b) When moving a load with a gantry system, as withall heavy rigging, always ______________.

c) Always keep the load as __________________ aspossible.

d) Constantly monitor the ___________ in the___________ system and in each jacking leg ifthey have independent hydraulic systems.

e) If there is any sign of a problem during a heavyequipment move with a gantry system, you should________________.

ANSWERS1. • Manufacturer’s operating instructions

• Load chart(s)2. a) Two of the lines must be able to carry the entire

load.b) The rigging.

3. • Inform plant/owner management before workcommences.

• Check site area for hazards such as electricalcontact (powerlines), vibrating equipment, and waterleaks.

• Inspect the site for unexpected changes which mighthave taken place and for environmental effects(such as wind forces).

• Review with the crew the procedure andresponsibilities.

• Check that no other operations are going on nearthe work area that can interfere. Examples includeoverhead cranes and mobile equipment.

• Make sure steps are in place to preventunauthorized personnel from entering the workarea—such as using warning signs and cordoningoff the work area with barrier tape.

4. • gantry legs must stay vertical or plumb• no horizontal force on gantry• make sure rigging remains vertical

5. • off-level track beams• misaligned track beams• horizontal forces on header plate during stand-up or

lay-over of load• unequal deflection of track beams• uneven raising or lowering of jacking legs• external forces such as wind or heavy equipment

vibration• load swing while moving• off-centre load bearing on header plate

6. Fill in the missing word or words in the followingincomplete statements.a) A useful means of monitoring the rate of extension

or contraction of each leg is to mount a tapemeasure on each.

b) When moving a load with a gantry system, as withall heavy rigging, always move slowly.

c) Always keep the load as low as possible.d) Constantly monitor the pressures in the hydraulic

system and in each jacking leg if they haveindependent hydraulic systems.

e) If there is any sign of a problem during a heavyequipment move with a gantry system, you shouldstop.

SPECIALIZED RIGGING

OVERHEAD CRANES

Overhead cranes are generally used for indoor hoistingactivities. They are often installed for specific repetitivetasks. The capacity of these cranes is wide-ranging.Contractors may use them for specialized hoistingoperations such as removing or installing major plantequipment.Safe operation of overhead cranes requires operators tohave the knowledge and competence to employ saferigging practices. The rigger must rig the load to ensureits stability when lifted.The following points highlight safety tips for overheadcrane operation.• Before use, ensure the crane is suitable for the

planned hoisting tasks. Confirm it has appropriatetravel, lift, and capacity.

• Visually and physically inspect the crane before use.Check for damage, wear, and proper operation of allfunctions.

• Confirm the load weight. Check the capacity of allequipment including the hardware, rope, and slings.Do not exceed these capacities.

• Select the right sling for each lift. Inspect slings andother rigging hardware before use for wear, stretch, orother damage. Do not use damaged or defectiveslings. Use softeners around sharp corners. Do notsplice broken slings.

• When communicating with a crane operator, use clear,agreed-upon signals. Except for the stop signal, thecrane operator should follow instructions from only oneperson – a designated signaller. Where a wired orremote controller is used, the operator should becomefamiliar with all of its functions before lifting the load.

• Warn all people in the load lift area before starting thelift. Ensure that the path of the load is clear of personsand obstructions. Do not lift loads over anyone.

• Centre the crane hoist over the load before hoisting toprevent swinging of the load.

• Slide the sling fully onto the hoisting hook and ensurethe safety catch is closed. Do not load the hook tip orhammer a sling into place.

• Secure unused sling legs. Do not drag slings or leaveloose materials on a load being hoisted.

• Keep hands and fingers from being trapped whenslack is taken out of a sling. Step away before the liftis made.

CautionEnsure that the load is free to move. If a load is stuckand the crane begins or continues to lift, it may reachits full capacity quickly. There may be little or nowarning of this condition and rigging componentsmay fail.

• Move the load and controls smoothly. Minimize loadswing.

• Walk ahead of the load during travel and warn peopleto keep clear. Use a tag line to prevent rotation orother uncontrolled motion. Raise the load only as highas necessary to clear objects. Do not ride on hook orload.

• Set loads down on blocking, never directly on a sling.Do not pull or push loads out from under the hoist.

• Do not leave the load (or the crane) unattended whilethe load is suspended.

• Where crane operation by other personnel must berestricted, employ lockout and tagging procedures.

• Store slings off the floor in a clean, dry location onhooks or racks. Do not leave slings, accessories, orblocking lying on the floor.

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JACKS AND ROLLERS

1. INTRODUCTION

Sometimes large and heavy loads must be moved andplaced with pinpoint accuracy. Cranes may not have thecapacity or be available to reach the point of location.Jacks and rollers are two types of moving systemscommonly used in such circumstances.Safety has to be first and foremost in planning workinvolving large or heavy loads. A mishap can result incatastrophic failure of the whole rigging system andpossibly the injury or death of workers. Use and maintainall equipment in accordance with manufacturers’recommendations.

2. JACKS

While there are a great many types of jacks, themechanical jack and heavyduty hydraulic jack are twotypes commonly used in construction.

MECHANICAL JACKSMechanical jacks work on the same principle as jacksfound in some automobiles. Mechanical jacks are usuallylimited to capacities under 20 tons because of thephysical effort required to raise such a load. They do,however, have a much longer travel than hydraulic jacksand can therefore lift loads higher without having toreblock. Most mechanical jacks have a foot lift or “toe”near the base for lifting loads that are close to the ground.Lifts can be made from either the “head” or the “toe” ofthe jack.Two types of mechanical jacks are prevalent inconstruction, the rack and pinion type and the ratchettype. These jacks are sometimes called toe jacks or trackjacks.

Ratchet jacks require aremovable handle. Avoidleaning over the handle. Asudden release of the load,or release of the hand forceon the bar could result in asudden violent upwardmovement or release of thebar. Stand to one side. Donot release the speed triplever when under load. Thespeed trip lever is to beused only for dropping therack bar under no load.Ensure the mechanisms arefree of grit and rust.Lubricate only those partsrecommended forlubrication with amanufacturer-approvedlubricant. Do not lubricate the tooth side of the rack bar.Rack and pinion mechanical jacks incorporate a crankoperated, gear lift design. Lifting and lowering isperformed by turning a safety crank which operates thespur gears, raising orlowering the toothedrack depending on thedirection you turn thecrank. Reduction gearsare always engaged,allowing for smaller liftincrements than istypical of ratchet-typejacks.Ensure that the gearboxeson your jacks arelubricated periodically inaccordance with theoperating instructions. Donot lubricate the brake.

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Before placing any jack under load, become familiarwith its operation by reading the manufacturer’sinstructions.

Operate the jack without a load to ensure that allmechanisms work properly. Inspect jacks before use forsigns of damage. Check the jack before use for• wear• improper engagement of pawl and rack• excessive lubricant• cracked or broken rack teeth• damage to housing• bent frame.Lifting jacks must be equipped with a positive stop toprevent over-travel or, if a positive stop is not present, anover-travel indicator. A lifting jack must have its ratedcapacity legibly cast or stamped on it in a place where itcan be readily seen. Confirm the load to be raised iswithin the capacity stamped on the jack and the liftdistance is within the jack’s stated travel range.When you’re ready to lift, ensure that the jack is firmlysupported on a flat stable surface, that the jack is secure,and that it’s located directly under the load. Do not useextensions or “cheaters” on the handles supplied withjacks. If you need cheaters, the jack is overloaded. Verifythat there is enough room for the lever bar to travelthrough its operating range.During lifting, follow the load with cribbing or blockingwhenever possible. Lift vertically, keeping the centre ofgravity from shifting. When you’re using multiple jacks,ensure that all the operators understand the proceduresand signals to use. Ensure that the load is distributedevenly by working the jacks in unison with slow,coordinated strokes.When not raising or lowering the load, remove jackhandles (if applicable) and secure the load with cribbingor blocking.

Uneven load distribution can result in• a sudden shift of the load’s centre of gravity• overloading the jack• the inability to hold or control the load or lever bar.

HYDRAULIC JACKSHydraulic jacks are very popular inconstruction because they are quitecompact and can lift very heavyloads. They are readily available incapacities ranging from a few tons to100 tons. Some specialty units havecapacities up to 1,000 tons. Liftheights are usually limited toapproximately 8 inches or less butsome can go as high as 36 inches.Hydraulic jacks are also available in low-profile modelsthat can be positioned under a load that is close to theground. Also known as “button jacks,” these are useful forlifting a load high enough to get a regular jack in place.

Like mechanical jacks, hydraulic jacks are available withtoe lifts.Selecting a jack is the first step for any lift. Choose ajack that is rated for a capacity of at least 10% morethan the load weight. Where multiple jacks are used,each jack may not share the load equally due to theconfiguration of the load, or fluctuating jack heights mayshift the load’s centre of gravity as the load is raised.Inspect the system before using it. Familiarize yourselfwith the operation of the equipment. Run each jackthrough a lift-and-release cycle prior to loading, andinspect each jack for• cracked or broken cylinders• hydraulic fluid leaks• scored or damaged plungers• damaged or improperly assembled accessories• damaged threads or leaking fittings• reservoir oil level• frayed or damaged electric cords (on electric pumps)• dirt or foreign matter in ports• hose damage such as punctures, nicks, cracks, and

kinks.Pay careful attention to the hoses connecting pumps tojacks. Check the couplings, especially at the crimp. Thisarea is prone to cracking and is often the weak link in thehose assembly. Check hoses for cracks, kinks, or otherdamage. Threads should also be checked for damage,wear, cross threading, and tightness. Some hoses have towithstand pressures up to 10,000 PSI. Do not usedamaged or worn components. Do not use hydraulic jacksthat are leaking oil. Turn them in for repair orreplacement. Use only approved fluids in hydraulicjacks—never use water in a hydraulic jack as a temporarymeasure.Don’t use hoses that areunnecessarily long.Shorter hoses will leavethe area less congestedand reduce the chance ofaccidental damage. Whenmaking connections withquick disconnectcouplings, ensure thecouplings are fullyengaged. Tightenthreaded connections to prevent leaks without usingexcessive force that may distort the fittings.Check for the capacity rating on the jack, and verify thatthe load will not exceed it. All components in the systemshould be rated for a pressure equal to or greater than thepressures generated by the pump.

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The pump powering a hydraulic jack may be containedwithin the jack itself, or as a separate external power unitthat can be operated at a safe distance from the load.Separate units may be hand-operated or electricallypowered. Most external power units are equipped withpressure relief valves. One valve is typically factory-set atthe absolute maximum pressure, while another will beadjustable to lower settings by the user. Make sure youare familiar with the operation of this safety feature. Usecaution around pressure relief valves. The valve candischarge oil with considerable force—you can beseriously injured.Most hydraulic jacks can be fitted with a gauge on thehousing or at the pump to monitor hydraulic pressure. Thegauges can be calibrated to measure the approximateload on the unit.Wear personal protective equipment. At a minimum, wearsafety glasses, a hardhat, a long sleeve shirt, and longpants. Failure of any component under pressure can sendmetal fragments and oil through the air. Avoid contact witha hydraulic leak—escaping oil can penetrate the skin andcause serious injury.Support each ram in the jacking system on a solid, firm,non-sliding foundation that supports the full base of thejack. Because jack bases are relatively small, ensure thatthe floor or ground can withstand the high pressures oftenassociated with jacking operations. Blocking or mattingunder the jacks will distribute the load over a greater areaand reduce the bearing pressure. Centre the load on thelifting point. Ensure that the point on the load whichcontacts the ram can withstand the pressures it will take.Jacks should only be used in a true vertical position forlifting. Otherwise, side-loading can cause the piston to rubagainst the housing. If this happens, the piston will bescored and allow fluid to leak at the seal which may causethe jack to slip.Where multiple jacks are used, space the jacks todistribute the load evenly between them as much aspossible. Check valves should be incorporated into eachbranch to protect against pressure loss, and moreimportantly to prevent interflow between jacks.Hydraulic jacks are generally not equipped with checkvalves. But it’s good practice to install check valves in thehoses of an external pump. Alternatively, some hydraulicjacks have retaining nuts that can be screwed against thehousing to hold the load for a short time.

The handles on jacks or hand-operated pump units aredesigned so that you can get to the rated capacity andpressure with little physical effort. Do not use extensionsor “cheaters” on the handles If the load cannot be raisedwith the handle supplied, the jack is probably overloaded.With all types of hydraulic jacks it is critical that no furtherforce be applied after the ram has run its full travel. Theresultant high pressure in the hydraulic fluid can damagethe seals and, in the case of external power units, burstthe hoses.Place blocking or cribbing under the load as it’s beingraised. When placing blocking under the load, positionyour body to keep clear of the load and keep hands fromgetting between the load and the blocking. Do not rely ona jack as a permanent support—blocking or cribbingshould be used whenever you need to hold the load for alength of time.Never disconnect hydraulic hoses while the jack is underload. Release the pressure with the appropriate valves.Depressurized hoses will become less stiff and moreflexible. If your pump has gauges, check them for theamount of pressure.Be extremely careful when using hydraulic jacks aroundwelding or corrosive chemicals. Sparks or acids can pitthe ram or damage the hoses.

GENERALBoth types of jacks are marked with load capacities ontheir nameplates and should not be loaded beyond these.Lift loads a little at a time on one end only and followclosely with blocking. The load should be progressivelyblocked as jacking proceeds. Always jack loads at the end(as opposed to jacking the side)—this will make the liftmore stable. The farther apart you place the jacks, themore stable your load.Using blocks between the jack and the load can avoiddamage to the surface. However, ensure the blocking isclean, dry, and will not slip. Ensure the floor or groundunder the jack can withstand the high pressures createdat the base of the jack. Blocking or matting under the jackcan be used to distribute the load over a greater area.The base should be fully supported by a solid, firmfoundation that will not slide.Jacks should never be used at an angle.Don’t use jacks for long-term support—blocking andcribbing are much more stable. If you need to work undera load, or even reach under it while it is on the jacks,place safety blocking under the load as a precaution.All jacks should be thoroughly inspected periodically,depending on how they are used. They should beinspected more frequently if the lifts approach capacity.Jacks sent out for special jobs should be inspected whenreceived on site and when returned to the shop. Jackssubjected to high loads or shock should be inspectedimmediately.Further information on jacking systems is contained in thechapter on Rigging with Hydraulic Gantry Systems.

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3. BLOCKING

Blocking timbers are used to support heavy loads or as afoundation for jacks. They may be used individually or intiers to form cribbing. Timbers should be large enough forthe load and be asuitable type ofwood. Often usedare Douglas firand white oak, andin some cases anexotic Africanhardwood (called“Ipe”) because ofits durability andcompactness.

Avoid pinch-points while blocking.

4. CRIBBING

Cribbing gives you heightand stability and reducesbearing pressure bydistributing the load over agreater area.The two mainconsiderations in blockingoperations are stability andbearing pressure. Makesure the timbers used forblocking or cribbing arelong enough to distributethe load over a large enough area to provide sufficientstability. The height of the cribbing should not exceed thelength of the timbers used. For example, cribs built with 4-foot timbers should be no more than 4 feet high. Cribbingand blocking must be• sufficient to support the load• set on firm, level ground or floor• close together• dry and free of grease or oil• distributed over a large enough area to provide

stability.Blocking and cribbing should have enough area in contactwith the ground or floor so that you don’t exceed thebearing capacity and there is no chance of settlement.Rigged steel or hardwood mats can be used between thecribbing and the ground surface to distribute the load andreduce the bearing pressure. For extremely heavy loads,use solid layers of timbers for the cribbing. This willdistribute the load over more timbers and prevent damageby crushing.Centre loads on blocking and cribbing to ensure that theload is transmitted evenly to the ground.Cribbing is frequently used with jacks for lifting loads instages. Cribbing is built up so the jacks contact the pick

up points intheir loweredposition. Oneend is thenjacked justenough (2inches forexample) toallow a smallpiece ofblocking to beinsertedbetween the load and cribbing. The process is repeated atthe other end. The jacks at the first end are then loweredand another piece of 2-inch blocking is placed under thejack. After jacking the load another 2 inches, the 2-inchblocking can be replaced with a 4-inch timber, whichforms part of the cribbing. This process is repeated untilyou reach the desired height.Always jack the load one end at a time and follow closelywith blocking.Never jack a load one side at a time, since this will be farless stable than jacking the ends.If you need to work under a load, or even reach under itwhile it is on the jacks, place safety blocking under theload as a precaution.

5. ROLLERS

Rollers can be used for moving loads horizontally or onslight inclines, provided the surface is firm and even.Rollers may be aluminum or steel round stock, heavysteel pipe, or a manufactured caster unit.

CYLINDER ROLLERSCylinder rollers are useful for short distances or where theload will have to negotiate corners. Cylinder-type rollersare generally 2 to 3 inches in diameter. Cylinder rollersshould be round, true, and smooth to minimize the forcerequired to move the load. The rollers can be placed onangles to swing the ends of the load, allowing turns intight areas.

CASTER ROLLERSCaster rollers are available in a number of configurationsfor flat surfaces, tracks, I-beams or channels. They createminimal friction and allow heavy loads to be moved withrelatively little force.

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Caster-type rollers havethe advantage of nothaving to be continuallyrepositioned in front of aload. They operate withcaterpillar-like action androll freely under load.These rollers are availablewith capacities rangingfrom 1 to 500 tons and can be equipped with swivel topsfor turning and positioning loads.Whatever type is used, each roller must be inspectedbefore use. Check the following:• Inspect for cracks and/or corrosion.• Check for pin wear on ends.• Check chain linkage for excess freedom of

movement.• Ensure chain and chain rolls are moving freely and all

other parts are functional.In addition, check the roller housing for cracks, corrosion,excessive wear, and tightness of bolts. You can apply alight oil or grease to keep the parts moving freely. Cleanoff excessive grease and dirt prior to use.Before installing rollers, ensure that you won’t exceed theload rating. Read and follow the manufacturer’s operatinginstructions. The rolling or floor surface should be free ofall debris andprotrusions.Although rollershave a lowprofile, usecaution whenraising loads.Top-heavyloads may tipwhen you’reinstalling therollers andduring travel.Rollers should be aligned to reduce surface friction.Severe misalignment may cause the load to shift.The load should rest upon the roller’s entire load plate.The roller should be fixed to the load if there is a chancefor contact to be broken or for the load to shift, and also ifyou’ll be moving the load on inclined or uneven surfaces.As well, manufacturers offer various kinds of rollersurfaces in order to accommodate varying load surfaces.For uneven load surfaces, you can use compressionpadding to maintain contact between the load and theroller. When elevations differ under the load, you can usewood spacers to fill the gap.

High pressures candamage floors—don’tfail to consider andanticipate thesepressures. Thebearing capacity of afloor is a function ofits intended use, itssize, and its general condition, among other factors.Confirm its capacity with the building owner or generalcontractor. Confirm that recently poured floors have hadtime to cure. The area should be carefully inspected at theplanning stage of the move. Using more rollers and largesteel or aluminum mats to distribute the stress can reducebearing pressure on the surface. Make sure the joints inthe mats or skids are staggered. You often need toassess the structure that supports the floors. You mayneed temporary shoring.When deciding on roller capacity, remember that unevensurfaces can lead to uneven loading. Loads could bebalanced on three or possibly two points. Alwayscalculate at least 25% extra capacity when sizingrollers.

Use the steering handles provided with caster rollers forsteering only—they should not be used for towing.

Moving on inclined planes demands extra caution.

When there is not enough headroom for a crane, andwinches and tackle systems are insufficient to lift a loadvertically, you may need to erect an inclined plane to rollor skid the load up.When moving loads on an incline, the most importantaspect in rolling is controlling the load. Make sure that allequipment including slings and hardware is sufficient tohandle the loads that will occur at each stage of theoperation. Always attach a second means of restraint tothe load—such as a tirfor or winch—to allow for theunexpected. Consider the possibility of shock loads whensizing winches or tirfors.Generally, caster rollers are designed for flat surfaces, notfor moving loads on an incline. While on an incline, theloading characteristics change. Horizontal forces cancause the load to shift on the caster much more easily.Floor surface changes are a particular concern. Pointloading can occur where the caster is in contact with twodifferent surface planes. For clarity, the explanations ofpoint loading below will use the term “caster” to mean thewhole body of the device, and “roller” to mean a singlewheel upon which the device rolls.

POINT LOADINGThere are additional concerns you need to address ifyou’re moving down or up an incline. Point loading occurswhen all or part of the load is on one or more rollers (thatis, when the load is on anything less than all the rollers).Point loading of the caster can happen where an inclinemeets a horizontal surface. Depending on circumstances,it is possible for only one roller to bear the total forces onthat caster. To reduce stress on individual rollers, slow themovement of the load at the intersection of the two

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surfaces. A near stopof the load will permita slow controlledtransfer of the loadforces to the differentinclined surfaces androllers.In addition to pointloading the rollers,the load may losecontact with thecaster. As the castertries to follow theplane of the floorsurface, it may fallaway from or pivot onthe load surface. Youmay need to attachthe caster to the loadto ensure that itmaintains contactwith the load. Or, thecaster may bedesigned to pivotover the floor surfaceso that it maintainsfull contact with boththe load and the floorsurface.Poor planning aroundpoint loading ofcasters may result incaster failure ordamage. The castercan slip under oraway from the load.Many scenarios couldplay out. Be cautious,plan for point loading,and go slow.

Another potential hazard occurs at the point where thecaster travels from the upper elevation (such as aconcrete floor edge or raised slab surface) to the builtincline surface. At this point, the load will be at the veryedge of the concrete and the weight of the load couldcause the corner to break away. Also, the leading roller ofthe caster may fall into any gap between the inclinesurface and the concrete slab, or the incline may bepushed away from the slab by the force of the roller,creating a gap the roller could fall into. Examine the slaband incline, and take preventive measures to ensure asmooth transfer from slab to incline. Ensure that thesupporting surfaces are capable of supporting the loadand that any added support (such as steel plating) is inplace.It is also dangerous when the load’s centre of gravityshifts. When the load has one end on the incline and oneon the horizontal surface, the load’s centre of gravity willtypically shift toward the lower rollers. Top-heavy loadsmay tip over.

CALCULATING PULL REQUIREDHorizontal moves require relatively little force to move.Generally, the force to move the load on a smooth, cleanand flat surface, using rollers in excellent condition will beabout 5% of the load weight. This is roughly the forcerequired to overcome friction and start the load moving.To calculate the amount of pull you need to move up anincline, use the following method.

Caution:

Though widely used because of its simplicity, thismethod provides an approximate value that is higherthan the actual force required. The formula is moreaccurate for slight inclines (1:5) than steep inclines(1:1). Table 1 shows the difference between the actualpull required and the pull calculated. This simplifiedmethod is adequate for most applications. You mayneed more accurate calculations for large loads.

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EXERCISECalculate the force of the load in the following situation. A15-ton compressor is to be lowered 10 feet. A ramp hasbeen built with a horizontal run of 50 feet.

Note: For illustration purposes, a second means ofrestraint has been omitted.

FormulaF (total force) = WxH÷L (lift force) + .05W (horizontal forceor resistance)F = Force that the winch must overcome, H = Height,L = Length, W = Weight of Load

The slope of the ramp is 10 divided by 50 or 1/5th; so theforce required is then 15 tons times 1/5th, plus 5% of 15tons to allow for friction.This is equal to 3 tons plus .75 tons. Therefore therequired pull is 3.75 tons.With a winch, use its rated capacity for vertical liftingrather than its horizontal capacity so that you maintain anadequate margin of safety.Table 2 lists some examples of coefficients of friction.Note that some of the combinations of materials have aconsiderable range of values.

6. SAFETY ZONES

You must establish safety zones before jacks or rollersare put into operation. Here are two types of safety zones:Interior zone – This includes areas where immediatehazards exist, such as underneath a raised load ordownhill on a slope where the load is being raised orlowered. No one should enter this zone.Exterior zone – This includes the area where workersinvolved in moving the load are working. Personnel notdirectly involved in moving the load should be restrictedfrom this zone.To keep personnel not directly involved in the work fromentering the work area (exterior zone), the area

immediately around the moving operation must becordoned off. There must be signage with wording suchas “Danger – Authorized Personnel Only.” The barricade(rope, fence, etc.) must be placed at a distance farenough from any hazard to eliminate the potential forinjury to personnel outside the barricaded area. Theremust be enough signs on the barricade so that at leastone sign is visible from any point of the barricade. Theother zone (interior zone) exists to keep all personnel out,and will ideally have similar signage with words such as“Danger – No Entry.” The requirement for signs is statedin the Construction Regulation (Ontario Regulation213/91).In addition, it is good practice to post information at thesite describing the nature of the hazard. The informationshould also include the name of a person to contact formore information about the hazard and the procedures forentry, particularly if workers will be away from the site forsome period of time.The risk of injury is greatest during the moving operation.No one should be in an area where failure of acomponent would create a danger. For example, if a loadis being raised up an incline, no one should be working orwalking downhill from the load (in the path of a potentialrunaway load), or uphill alongside the rigging attached tothe load (a snapped cable could whip back towards itsanchorage). Workers involved in the operation should bepositioned to minimize exposure to danger while handlingthe load.When a load is being raised up an incline with a tugger,there is “potential” energy stored in the tugger and riggingcomponents. A failure could result in a violent and quickenergy release, causing a sudden whipping of the line, ormovement of other components or the load. Every personinvolved must be made aware of such hazards, andworkers must avoid these areas when the tugger isoperating. Prevent access to these areas when practical.

7. REVIEW EXERCISES

1. Which is the number-one issue in planning anoperation involving moving large and/or heavy loads?a) Load calculationsb) Route planningc) Speedd) Safety

2. List four things to look for when you’re inspecting amechanical jack before use.

3. List five things to look for when you’re inspecting ahydraulic jack before use.

4. What should all jacks be clearly marked with?5. Stability and floor bearing pressure are two major

considerations in blocking operations. Specify fouradditional requirements applicable to cribbing.

6. Each caster must be inspected before use. List threethings to check for.

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7. How many means of attachment should be used on aload being raised up an incline?a) Oneb) Twoc) Three

8. The capacity of the floor or slab should be confirmedwith the building owner or general contractor in theplanning stage of a tugger operation.a) Trueb) False

9. What is the force exerted on the hook inthe diagram?a) 2000 lb.b) 1500 lb.c) 1000 lb.d) 500 lb.

10. You must establish safety zones beforejacks or rollers are put into operation.What are two types of safety zones?

ANSWERS1. d) Safety2. 1) Wear

2) Improper engagement of pawl and rack3) Excessive lubricant4) Cracked or broken rack teeth5) Damage to housing6) Bent frame

3. 1) Cracked or broken cylinder2) Hydraulic fluid leaks3) Scored or damaged plungers4) Damaged or improperly assembled accessories5) Damaged threads or leaking fittings6) Reservoir oil level7) Frayed or damaged electric cords (on electric

pumps)8) Dirt or foreign matter in ports9) Hose damage such as punctures, nicks, cracks,

and kinks4. Load capacity5. 1) Sufficient to support the load

2) Set on firm, level ground or floor3) Close together4) Dry and free of grease or oil5) Distributed over a large enough area to provide

stability6. 1) Inspect rolls for cracks and/or corrosion.

2) Check for pin wear on ends.3) Check chain linkage for excess freedom of

movement.4) Ensure chain and chain rolls are moving freely and

all other parts are functional.7. b) Two8. a) True9. a) 2000 lb.10. 1) Interior

2) Exterior

TUGGERS

1. INTRODUCTION

Many trades in construction use tuggers (or poweredwinches). These are basically rope-pulling machines,often described as boomless cranes. The rope may befibre or wire, depending on application. Compared tocranes, tuggers• have lower operating costs• weigh less and are more portable• are smaller and better suited to tight spots – ideal for

use inside buildings.Tuggers can be usedfor hoisting (vertical lift)and hauling (horizontalor incline pulls). Theymay be powered

hydraulically,electrically, bycompressed air, or byinternal combustionengine. The mostcommon tuggers inconstruction areelectric tuggers for lightlifting and pulling and air-powered tuggers forheavier loads. Heavyapplications use wirerope while lighter onesuse fibre rope.Tuggers are used inconstruction to• pull electrical cables• move heavy machinery• lift vessels• install structural steel.Tuggers are often used with other rigging attachments.The most common attachments include snatch blocks,sheaves, and rollers. Snatch blocks and sheaves areused to change the direction of pull while rollers are usedto support the load. Because tugger operations involverigging, users must beware of rigging hazards.This section of the chapter is intended to foster hazardawareness and provide a general understanding of safetugger operation. Personnel should know rigging andhave completed training in rigging safety. Further job-specific planning and equipment training are required.The Ontario Construction Regulation (O. Reg. 213/91)does not specifically address tugger operation. However,as a minimum, tugger operation should comply with thesections under “General Equipment” (sections 93-116).These sections deal with maintenance, inspection, worker

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competence, and overhead lifting. Training, capacity, andrecords are covered under sections 150-156. The riggingaspect of tugger operation must comply with sections168-179. Please refer to the Construction Regulation fordetails.

2. HAZARDS

Hazards in tugging operations are similar to those inrigging operations:• Poor communication• Lack of training• Overloading• Failure of assembly• Failure to incorporate a fall protection system• Failure of anchorage points• Undesired movement under load• Brake failure under load• Worker or equipment struck or crushed while handling

the load• Hand pinched or crushed at drum or sheaves• Loose clothing or jewellery caught in drum or sheaves• Electrocution (with electrically powered tuggers)• Carbon monoxide poisoning from combustion by-

products• Fire or explosion during operation in a combustible

area or atmosphere• Rope jumping off the drum• Operational area not isolated from other workers or

public during hoisting or hauling.When a tugger is under load, it will have stored energy. Inmost cases, this stored energy is more than enough tomove the load. For example, a tugger with a 5-ton pullcapacity can create as much as 15 tons of energy in thesystem (larger loads develop larger energy forces). Afailure anywhere in the rigging system can result in aviolent whipping action of the line.In addition, the hazards of tugger operation are notconfined to the tugger. It is absolutely essential to ensurethat all rigging and all anchorage points can bear not onlythe load but any potential load they may be subjected to.

All rigging components and anchorage points can besubjected to forces greater than the force beinggenerated by the tugger itself.

3. TUGGER SELECTION

LOAD CALCULATION

To plan a rigging application, all load information must beknown. This involves calculating the total load. Total loaddetermines the selection of the tugger, associated riggingaccessories, and restrictions in travel route. When tuggerselection is limited, total load is also used to determinethe type of reeving needed on the line. Total loadcalculation must determine the maximum load the tugger

will be subjected to and includes the following:• friction—ground surface (horizontal pulls) and sheave• weight of all rigging attachments (mainly on vertical

lifts)• load weight• additional dynamic forces such as shock, wind, and

snow or ice loads (in some cases, static loads mayneed to be estimated to free stuck equipment).

Calculation of load weight and potential dynamic forcesinvolves adding up each factor and arriving at a total.Once the total load is calculated, the anchorage methodfor the tugger and the capacity of associated rigging canbe determined. The direction in which the load will bemoved (pulling or hoisting) must also be determined.

Remember—the strength of your rigging assembly isonly as strong as its weakest link.

HORIZONTAL PULL VERSUSVERTICAL LIFTSome manufacturers distinguish between hauling(horizontal pull) and hoisting (vertical lift) tuggers. This isbecause the factor of safety is different for each. Haulingcapacity is based on a factor of safety of 3:1 whilehoisting capacity is based on a factor of safety of 5:1.When ordering a tugger, tell the supplier whether or notthe operation involves hoisting.

HOISTING WITH CAPSTANSDue to pull of the load, capstans generally do notreverse. However, that does not prevent the load fromreversing direction. The load is only held in place bythe force applied to the fall line and the bindingfriction around the drum. Should the operator fail tomaintain a pulling force on the fall line for any reason(such as a fall, distraction, heart attack, etc.) the ropecan slip around the drum permitting the load to fall.For this reason, using a capstan for hoisting requiresextreme caution.

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DIAMETER AND LENGTH OF ROPEThe total load weight calculation determines the minimumrope diameter required. The distance between the tuggerand the load determines the length of rope required;however, if the lift involves blocks and multiple reeving,additional rope will be needed. These requirements mustbe compared with the tugger manufacturer’srecommendations for rope size and rope construction forthe particular tugger being considered. When determiningthe length of rope, take into account that there should bea minimum of three full wraps of rope on the drum at alltimes—i.e., the rope encircles the drum three times.

DRUM SIZE

Once the length of rope is determined, the drum diameterand overall size can be specified. Ideally, there would onlybe one layer of rope on the drum. As the number of layersincreases, there is a greater chance of crushing thebottom layer and pinching the ends. Ensure smooth,uniform wrapping to reduce this effect. The drum designand the type of rope influence the maximum number oflayers you should put on the drum. Check themanufacturer’s recommendations regarding the maximumnumber of layers. Try not to exceed three layers. Somerope types, because of their construction, are verysusceptible to crushing. ASME Standard B30.7 requires aminimum of 2 inches between the top wrap and the edgeof the flange to prevent the rope from winding off thedrum. It is recommended to have at least 2 times the ropediameter or 2 inches (whichever is greater) for grooveddrums, and 2 times the rope diameter or 2 1/2 inches(whichever is greater) for smooth drums.

ROPE TYPETuggers can be designed for either fibre rope or wirerope. The rope must be compatible with the drum in loadcapacity, size, and groove diameter. Tuggers equippedwith wire rope hardware should not be used with fibrerope and vice-versa.

DRUM SPEEDAs the load increases, the hauling or hoisting speed tendsto decrease. If the hauling or hoisting speed is too slow, itmay be necessary to select a tugger with greater capacity.Some manufacturers feature variable speed winches. Thisfeature not only changes the line speed, but can alsochange the capacity of the tugger.

Where drum speed may be too fast, adding lines in thereeving of the rigging system will reduce travel speed ofthe load.

BRAKING DEVICEBrakes should be self-setting and capable of supportingall rated loads. The tugger should have sufficient brakingpower, complete with adjustments to compensate forwear and to maintain adequate force in springs whereused. For hoisting, tuggers should always be equippedwith a brake (usually electromagnetic) that will activateautomatically in the event of a power failure. A clutch orpower-engaging device should facilitate immediatestarting and stopping motions.Gear reducers used to change drum speed can performlike a secondary braking system, though the reducer willnot hold the load at a stop.Lowering a load should not be done using only thebraking system. Tuggers are typically designed to allowthe load to be “powered down.” When “powered down,”the load is lowered under the power and control of thetugger in the same way it is hoisted. This featureeliminates the potential for the load to free-fall and isessential in hoisting operations.

GROOVED ORSMOOTH DRUMSA grooved drum reducesrope friction. A morepractical benefit of using agrooved drum is the abilityto reduce the minimumdistance to the firstsheave and the ability tocorrect the fleet angle – avaluable asset in tightspaces. But thisadvantage only applieswhen the first layer of the

rope is exposed.

TUGGER SAFETY FEATURESSome manufacturers provide tuggers with safety featuressuch as• anti-reversing mechanism• guards on drive system• guarded on and off switch• guard on rope drum• drive chain limiting internal force

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Grooved DrumsIn installations where space isrestricted, grooved drums are

necessary to correct the fleet angleand ensure level winding. For

critical push-pull type applications,grooved drums ensure that equaldiameters are maintained during

winding and unwinding operations.Grooved drums also eliminate

excessive rope friction.

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• rope overlap prevention system• tapered drum for capstan rope tension release• pressure regulator• emergency stop button.Other safety features that can be installed include• slack rope detector• limit switches, such as a rotary limit switch on the

drum that regulates the number of turns of the drum• drum rotating indicator that provides a method of

sensing the rotation of the drum when the operatorcannot see drum or rope.

The chart below summarizes the main steps in selectingthe right tugger for the job.

TUGGER SELECTION PROCESS

4. RIGGING ATTACHMENTS

LOAD REQUIREMENTSAll rigging attachments must be able to hold the load theyare subjected to. A safety factor of 5 to 1 should be usedfor all hardware in construction applications.

WIRE AND FIBRE ROPEMatch the block and tackle with the type of rope used.Block and tackle designed for fibre rope has wider groovesthan that designed for wire rope. In addition, blocksdesigned for fibre rope employ softer sheave material and,if used with wire rope, the sheave will deteriorateprematurely. When fibre rope is used with blocks designedfor wire rope, the rope will fatigue quicker.Two types of wire rope construction are widely used inrigging. For diameters less than 3/8 inches, galvanizedaircraft cable is used (typically 7x19 construction). Forheavier applications, a rope (such as 6x37 construction)with independent wire (or fibre) rope core (IWRC) is oftenused. A swivel connection to this type of rope is notrecommended.

SNATCH BLOCKS AND SHEAVESThe most common rigging accessories used with tuggersare snatch blocks and sheaves. Snatch blocks andsheaves typically come with a hook, swivel shackle, oreye. Some snatch blocks are designed for multiplereeving.Snatch blocks and sheaves are used to change thedirection of pull. When selecting blocks or sheaves,consider the type of rope used, the speed of the line, andthe D/d ratio.

D/d RATIOOther than changing direction of pull, the function of asheave is to support the shape of the rope. The bendingaction of a wire rope as it runs through a sheave reducesthe rope’s strength. This reduction in capacity isproportional to the ratio of the diameter of the sheave (D)to the diameter of the rope (d)— the D/d ratio. As thesheave diameter is reduced, so too is the capacity of therope. The sheave diameter must be compatible with therope diameter. The minimum ratio of sheave diameter to

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rope diameter (D/d) is 15. In most cases, the groove sizeof a sheave is directly proportional to the diameter of thesheave. Wider (or larger) grooves are found on largerdiameter sheaves.

Sheaves

The use of sheaves changes the rope’s capacity and thetotal friction force. The number of sheaves used is directlyproportional to the decrease in rope capacity and increasein friction force. This is true whether the riggingarrangement uses a multi-part-line configuration or usesseveral sheaves throughout its layout.When the groove of a sheave is too large for the diameterof the rope, thesheave groove willnot fully support therope under load. Asa result, the rope willtend to flatten.Continual flatteningof the rope willeventually lead topremature failure.When the groove ofthe sheave is toosmall, the ropebecomes pinched between the sheave flanges, causingthe rope to rub and wear the flange prematurely.Check for proper sizing of the rope when selecting blocksand sheaves. The following diagrams illustrate therelationship between sheave and rope diameter.

SHEAVE BEARINGSThe speed of the line determines the type of sheavebearing suitable for the application:• plain or common bore bearings—designed for very

low line speeds and very infrequent use• self-lubricating bronze bushings—used for slow

line speeds with infrequent use• bronze bushings with pressure lubrication—used

for slow line speed and more frequent use at greaterloads

• anti-friction bearings—used for faster speed andmore frequent use at greater loads.

Some sheave manufacturers provide options for bearingselection with certain models.

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In properly matchedropes and sheaves,the rope should besupported by thesheave over an arc

of 120-150°.

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5. SAFETY CONSIDERATIONS

PLANNINGSafe completion of hoisting and rigging operations usingtuggers requires careful hazard assessment. Before atugger operation begins, all potential hazards must beidentified. The operation must be planned and reviewed toensure that tasks can be completed safely and potentialhazards controlled.

LOAD SHAPE, ORIENTATION, ANDROUTE OF TRAVELLoad shape and orientation can affect handling of theload. If the load must be turned or rotated at any pointduring travel the following questions should be answered:• Does the rigging set-up permit turning and rotating?• Do other factors prevent turning or rotating the load

(for example, vessels with fluid or gas inside)?• Is there enough room to manoeuvre the load?Once the load shape and orientation are determined, atravel path can be mapped out. Route of travel must bechecked to ensure that it can accommodate the size andorientation of the load and will permit the load to berotated or turned if needed. Before committing to anyroute, however, the structural strength of the buildingmust be verified.

STRUCTURAL STRENGTH OF BUILDINGThe building must be able to carry all loads and all forcesgenerated by the tugger operation. In most cases, thisinvolves checking structural strength of floors, beams,trusses, and columns.

FLOOR OR SLABFloors are supported directly by the ground or by columnsand beams. In both cases, the floor must have enoughcompressive and bending strength to carry the load.

When the tugger operation requires working onrecently poured concrete floors, care must be taken toensure that the concrete slab has had time to cureand reach full strength.

The floor surface must be protected from damage byrollers or movement of the tugger. In some cases, it maybe necessary to cover the floor with steel sheets. In suchinstances, the weight of the steel sheets must also betaken into account as part of the load on the floor slab.

COLUMNS, TRUSSES, AND BEAMSColumns, trusses, and beams are often used as points ofanchorage. Their structural integrity and capacity must beverified before designating them as anchorage points. Ifthere is doubt about the ability of the structure to takeexpected additional forces, get a written opinion from astructural engineer.

SURROUNDING CONSTRUCTIONACTIVITYWhen combined with tugger operations, otherconstruction activity above or below the work area maycreate excessive loads on the building structure. Consultwith the client, general contractor, and othersubcontractors before starting a tugger operation. This willhelp to ensure that loads on the building structure arewithin safe parameters.

6. ANCHORING

Aside from knowing load weight and tugger capacity,method of anchorage is probably the most critical aspectof safe tugger operation. Always confirm the structuralintegrity of any anchor point before relying on it. When indoubt, get a written opinion from a structural engineer.Safety concerns over anchorage apply equally to thetugger and to rigging accessories such as sheaves andblocks.

FLOORSTuggers are often anchored to the floor when the locationof the first sheave (relative to the tugger) does not varymuch during the tugging operation. Most tuggermanufacturers supply a template for anchor layout. Themanufacturer will also specify the size and grade ofanchor bolts to use.

The anchorage must be able to withstand the direct pulland torsion (twisting) forces when the tugger is underload. Similarly the bolts must be strong enough to preventthem from shearing off under load.When securing to floors, it isimportant to verify the integrity ofthe floor to prevent the anchorfrom pulling out.If job conditions necessitatereeving the tugger with a straightupward pull, the tugger needs tobe secured to the floor carefully.To ensure hold, use onlyfasteners with a known pullout value of sufficient strength.Although all anchors resist some force, the anchors onthe pull side will bear most and should be selectedaccordingly. Blocks and sheaves are sometimes anchoredto the floor, but more practical anchoring methods areusually available nearby.

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COLUMNSColumns are generallynot designed towithstand lateral forces.Anchorage pointsshould be placed asclose to the base aspossible, near aconnection to a beamor other lateral support.Since columns arealready under load,additional forces on thecolumn could overload it, causing it to buckle.The common way of anchoring to a column includes using

1) welded lugs or plate2) choking a sling3) framing.

1) WELDED LUGS (PLATE)Welded lugs can be installed either on the web or on theflange of the column. Lugs welded on the web and in linewith the flange are preferable since the column isdesigned to take forces in this direction. Welding the lugon the flange is less preferable because it will notwithstand the same pulling force.

Welding to structural steel requires a weldingprocedure and approval by a structural engineer.

Welded lugs are designed to take a force in line with thesame plane as the welded plate. Loading from any otherdirection should be avoided.

2) CHOKINGChoking a sling to a column is one of the simplest,quickest, and most common methods of anchoring. Mostblocks are anchored this way for relatively lightapplications. Anchoring to columns permits easymovement of the block (or tugger) when there is a need tochange the direction of pull.

Where the first sheave from the tugger changes location,the line should be pulled slowly to allow the tugger to re-align itself to the new direction of pull. The choke on thecolumn may need to be loosened to facilitate equaltension on both sides of the sling legs.The integrity of the column to withstand forces fromvarying directions must be verified before the operation.Softeners must be used around the column to protect thechoker. The floor must be relatively smooth to allow thetugger to slide to varying orientations.

3) FRAMING AROUND COLUMNSFraming steelmembers around acolumn is anothermethod of securingtuggers.Channel iron is thepreferred choice(rather than angleiron or beams) sincethe shape provides a

good combination of rigidityand lightness.The illustration above showsa typical framing method,using four channels to boxthe column. The tugger isbolted to the “legs” of theframe. Another method usestwo channels, framed tightlyagainst the column by

anchor bolts. The tugger is secured to the channel bymeans of two plates.

BEAMSAs with columns, anchorage points to beams should beinstalled closest to a connecting column or other verticalsupport to increase support strength and prevent bendingof the beam. To withstand the additional forces, beamsmay need to be stiffened by welding a plate to the web.Securing methods for anchoring to beams commonlyinclude 1) beam clamps, 2) beam trolleys, and 3) chokinga sling.

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1) BEAM CLAMPSThe most common hardware for anchoring to a beam is abeam clamp.

When using beam clamps, ensure that the pullingforces do not deform the beam or the clamp.

Special care must be taken when clamping to beams withwide and thin flanges. These types of beams are notdesigned to take this kind of loading and will tend todeform. Using an undersized clamp can cause clampdeformation.

The angle of pull at the clamp should be kept as small aspossible to prevent the web from deforming and the clampfrom slipping.

Drifting a load is not advisable when beam clampsare used.

Beam clamps should be centred on the flange andproperly seated. Remember—the load rating on the beamclamp applies only to the clamp, not to the beam. Thecapacity of the beam must be determined separately.

2) BEAM TROLLEYSBeam trolleys are beam attachments that can movehorizontally along the beam’s length. The arrangementabove works similar to a gantry crane. It permits up-and-down as well as horizontal movement. In addition, thesystem uses, at minimum, a two-part-line system thatslows the hoisting speed (compared to drum reelingspeed) for safe application. An electric hoist could beattached to the beam trolley for similar results.This arrangement can exert loading forces anywherealong the length of the beam. Ensure that loadcalculations are verified before using such a system.

3) CHOKINGChoking around beams requires the same safetyprinciples as choking around columns. The sling used forchoking must be protected from sharp edges by softenersand should be choked (or otherwise secured) to prevent itfrom sliding along the beam because of horizontal pullfrom the load line.

7. WIRE ROPE HANDLING

Handling any kind of rope can be hazardous. Handlingwire rope presents particular hazards. Personnel shouldwear appropriate personal protective equipment such asgloves and use caution to keep clothing or gloves fromgetting caught in sheaves or drums during tuggeroperation.

WINDING ONTO DRUM OR REELWhen winding wire rope onto a drum or reel, make surethat its bending direction is maintained on the new reel(see diagrams above). When transferring rope from drumto drum, feed it from the top of one reel to the top of theother, or from the bottom of one reel to the bottom of theother. Applying tension to the rope is also necessary toachieve good spooling. A simple brake such as a plank,rigged to bear against the reel flanges, can provide amplerope tension for winding.On flat-faced drums (as opposed to groove-faced drums),it is important that the rope winds in a straight helix at itsproper angle.This can beaccomplishedby installing ataper to fill thespace betweenthe first turnand the flange(see diagram atleft). It isimportant thatthe first layer onthe drum betight and true. Open or wavy winding will result in seriousdamage under multiple windings due to abrasion andwedging action between layers.

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LOCATING DRUM ANCHORAGE POINT

Most tuggers have an overwound configuration on thedrum. The anchorage point on the drum depends on thelay of the rope. Check the diagram above for properanchorage point for right and left lay rope.

CUTTING WIRE ROPE

Each side of the rope should be properly seized beforecutting (see above). Seizing is ideally done using soft ironwire.

DEAD-ENDINGAlways use forged or stainless steel clips made forhoisting and rigging applications. Do not use softmalleable clips. Follow manufacturer’s instructions for thecorrect number of clips, spacing between clips, andtorquing requirements. Please note that wire rope clipsneed to be re-torqued after loading, especially when usingnew rope. Check tightness of wire rope clips after eachshift.Although most tugger operations use wire rope clips fordead-end termination, other methods such as wedgesockets can be used. When using wedge socketconnections, ensure that the live end of the wire rope isleft unclipped.

8. OPERATIONAL SET-UP

DIRECTION OF PULLWhenever possible, direction of pull coming to the tugger

should either beparallel to the groundor slope downwards.When the pull isupwards, the force willhave a tendency to liftthe tugger up, possiblydislodging it from itsanchorage. Regardlessof the direction of pull,

the anchors located on the side opposite to the directionof pull may bear most of the pull-out force. The tugger willwant to pivot on the leading anchors (those closest to thefirst pulley). Anchors must therefore be sized to accountfor this potential effect.

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DISTANCE TO THE FIRST SHEAVEGenerally, the minimum distance to the first sheave is 15times the drum width. Other factors may permit somevariation. For example, grooved drums can reduce theminimum distance to the first sheave, and correct the fleetangle. See “Grooved or smooth drums” under section 3,Tugger Selection. Check with the tugger manufacturer forthe actual minimum distance. The first sheave should belocated in line and square with the centreline of the winch.

PULLING ANGLEChanging the angles of a pull can dramatically change theforce exerted on the anchor point. As the following figuresillustrate, reducing the angle between the load line andthe pull line increases the load on the anchor. A 0° pullingangle doubles the load force on the anchor.

When the operation involves load drifting, choose a higherpoint to attach a block or sheave. Higher pick pointsreduce the lateral forces needed to drift a load, thereforeincreasing control, travel distance, and ease in driftingloads.

9. COMMUNICATION

An appropriate method of communication must be pre-arranged between all personnel involved in the tuggingoperation. When the material being pulled or hoistedcannot be seen by the tugger operator, a radio or othercontinuous and reliable form of communication must beprovided.

SAFETY ZONES

Safety zones must be established before the tugger is putinto operation. The following are two examples of safetyzones:Interior zone—This would include areas such as wherethe load is being landed. No personnel should enter thiszone.Exterior zone—This would include the area whereworkers involved in the tugging operation are working.Personnel not directly involved in the tugging operationshould be restricted from entering this zone.To keep personnel not directly involved in the work fromentering the work area (exterior zone), the areaimmediately around the tugger operation must becordoned off and must be signed with wording such as“Danger – Authorized Personnel Only.” The barricade(rope, fence, etc.) must be placed at a distance farenough from any hazard to eliminate the risk of injury topersonnel outside the barricaded area. Signs must alsobe placed on this barricade in sufficient number so that atleast one sign is visible from any point of the barricade.The other zone (interior zone) is in place to keep allpersonnel out, and should have similar signage withwords such as “Danger— No Entry.” Signs are requiredunder section 44 of the Construction Regulation.Additionally, it is good practice to post information at thesite describing the nature of the hazard and the name of aperson to contact for more information about the hazardand for entry, particularly if workers will be away from thesite for any period of time.

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The risk of injury is greatest during the tugger operation.No one should be in an area where failure of acomponent involved in the operation would create adanger. For example, if a beam is used as a point ofanchorage, no one should be working or walking underthe beam or the rigging attached to it. Workers involved inthe tugger operation should be positioned to minimizetheir exposure to danger while handling the load.When a tugger is under load, “potential” energy is stored inthe tugger and the rigging. Failure of any component canresult in a quick, violent release of energy causing a suddenwhipping of the line, movement of other components, ormovement of the load. Therefore every person involvedmust be made aware of such hazards and warned to avoidareas where the tugger is operating. Access to such areasshould be prevented wherever practical.

INSPECTIONInspect the tugger and rigging before use. Ensure theintegrity of all components before the operation getsunder way.

TUGGER POWER SOURCE• Electrically powered units—check the power cord.• Gas-powered units—check the gas tank for fuel and

for leaks; make sure ventilation will be adequate toremove products of combustion and vapours from thefuel tank.

• Air-powered units—check hoses and fittings; makesure connections are secure and cannot work loose.Ensure hoses are out of the way of traffic andprotected from damage. Ensure there is anuninterrupted air supply at a pressure high enough topower the tugger.

TUGGER BRAKESBrakes should be checked on the first lift:• Lift the load slightly off the ground and apply the

brakes for a few minutes.• The load should remain in position.• Any load movement may signal that the brakes are

failing or that the tugger is too small for the load.

ROPE• Wire rope must be checked for wear and defects.

Look for kinks, birdcaging, knots, and broken wires instrands.

• Fibre rope must be inspected for tear in the weaveand any other signs of damage or degeneration. Withfibre rope, it is recommended that a new rope beused at the start of a new project.

ANCHORAGEAll anchorage points must be inspected before use.During use they must be inspected for signs of

deformation or movement. If such signs are detected, thetugging operation must cease immediately. Theanchorage point should not be reused until it has been re-evaluated and shown to be safe.Inspect anchor bolts and nuts for signs of loosening orshearing. Check for signs of loose concrete around theanchorage.When anchorage involves a plate welded to a column,check for cracking around the weld and signs of the platebending. Make sure the column has not moved ordeformed. Check the hole in the lug for signs of fatigue.When beam clamps are used, inspect clamps and beamfor deformation. Check that the clamp has not movedfrom its original position.When using a choker on a beam• check for horizontal movement• make sure that softeners around the column remain in

place• make sure that the sling is in good condition• check for kinks• look for broken wires in strands• pay particular attention to areas that have been

subjected to sharp bends (these areas are under thegreatest stress).

SHACKLES AND BLOCKSBlocks must beinspected for sheavewear and seizedbearings. Beforeusing blocks that canbe opened, ensurethat the pins are inplace. Blocksequipped with a hookand/or shackles mustbe inspected for hookand shackle wearand deformation.Hooks must have a working safety latch with positive lock.Shackle bolts or pins must also be inspected for tightness.

WORKAREABefore and during the tugger operation, safety zonesmust be respected. Ensure that barricades and warningsigns are in place and that signallers are in position.

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REVIEW EXERCISES1. What forces could be exerted on rigging components

where a 5-ton pull capacity tugger is being used?a) 2.5 tonsb) 5 tonsc) 10 tonsd) 15 tons

2. When hoisting with capstan winches, what isrequired?a) Wire ropeb) Gas powerc) Extreme cautiond) Cannot be used

3. In construction applications, all rigging attachmentsrequire a factor of safety of:a) 2 to 1b) 3 to 1c) 5 to 1d) 10 to 1

4. The D/d ratio describes:a) The diameter of the rope to the diameter of the

sheaveb) The diameter of the sheave to the diameter of the

rope5. The minimum D/d ratio is:

a) 5b) 10c) 15

6. Complete the following sentence. Rope diametershould be:a) just larger than the groove in the sheave.b) equal to the groove in the sheave.c) just smaller than the groove in the sheave.

7. Aside from the rigging hardware and the tugger, nameat least two other things that may be subject to stressor weight from the tugger operation.

8. When using beam clamps, drifting a load is notadvisable.a) Trueb) False

9. Ideally, the direction of pull off the tugger should be:a) Slightly upward from the tuggerb) Parallel to the tuggerc) Slightly down from the tugger

10. Generally, the distance to the first sheave from thetugger should be no less than:a) 10 times the drum widthb) 10 feetc) 15 times the drum widthd) 15 feet

11. What is the force exerted on the hookin the diagram?a) 2000 lb.b) 1500 lb.c) 1000 lb.d) 500 lb.

12. List five things that must be inspected prior tobeginning a tugger operation.

ANSWERS1. Any of a), b), c), or d).2. c) Extreme caution3. c) 5 to 14. b) The diameter of the sheave to the diameter of the

rope.5. c) 156. b) Equal to the groove in the sheave.7. 1) Floor or slab

2) Columns3) Trusses4) Beams

8. a) True9. c) Slightly down from the tugger.10 c) 15 times the drum width.11. a) 2000 lb.12. 1) Tugger

2) Shackles3) Blocks4) Rope5) Work area

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33 HELICOPTER LIFTING

1. Introduction2. General Information3. Helicopter Lifting Accidents4. Planning and Preparing for the Lift5. Construction Regulation—Helicopters6. Responsibilities of Workplace Parties7. Contractor Ground Crew Procedures

1) PPE and Clothing

2) Signalling

3) Hooking up

4) Receiving the load

8. Staging Area Requirements9. Placement Area Requirements10. Pre-flight Briefing and Inspection11. Hazardous Loads12. General Precautions around Helicopters13. Exercises

1. Introduction

Helicopter lifting can be a fast and efficient way to movematerials and equipment to locations beyond thepractical reach of perimeter cranes. For buildings orplants with large plan areas, helicopter lifting is often anefficient alternative to crane access through the roof,which can require major structural work and disrupt plantoperations. Locations suited to helicopter lifting includeauto plants with their typically large, sprawling plans.

The operation and control of helicopters requires highlytrained and experienced personnel. Helicopter liftingdemands careful planning. The work must be organizedaround the aircraft and the factors that govern itsoperation such as load limitations, surrounding terrainand structures, and weather conditions. The primemovers and key personnel during lifting operations arethe pilots and the mechanics or marshallers who normallywork for the helicopter rigging subcontractor.

This chapter provides information on hazard awarenessand control. The information can be used to facilitategeneral introductory training for construction tradesinvolved in helicopter lifts. To work safely on a particularlift, further job-specific planning and training will alwaysbe required.

Contractors who hire specialized companies forhelicopter lifting have responsibilties before and duringoperations. This chapter outlines those responsibilities sothat contractors can better understand the planning,procedures, and coordination required. This informationwill also help tradespeople work safely and effectively onhelicopter lifting jobs.

2. General Information

Load CapacitiesCapacity Range Aircraft

up to 1,000 lb. Bell 206 B

1,000 to 1,200 lb. Bell 206 Long Ranger

2,000 lb. AS 350 A-Star

4,000 lb. Bell 204/205

8,000 to 9,500 lb. Super Puma e.g. Gross weight 20,500 lb.

(AS 332) Max. load 10,500 lb.

Max. fuel load 2,500 lb.

Sikorsky S 61

Up to 20,000 lb. Sikorsky S 64 - Sky Crane

Basic Operating ConditionsAbout the aircraft and flight crew

• A typical crew consists of 1 or 2 pilots (depending onaircraft) and 2 mechanics acting as loadmasters/signallers: 1 at staging area (ground) and 1 at droparea (roof).

• Aircraft load capacity varies depending on fuel load.The larger the fuel load on board, the less load theaircraft can carry. For example, a Super Puma withmaximum fuel load has its load capacity reduced toabout 8,000 lb.

• In addition, aircraft load capacity depends ontemperature, relative humidity, altitude, wind strength,size of staging area, and available flight space(Transport Canada regulations prohibit lifting overpeople or buildings).

During load handling

• The ground activity must be under the control of thesignaller and the pilot.

• The pilot needs direction from the ground signaller.The signaller has a clear view of the load and itsposition as well as a clear view of the personnel andsituation on the ground.

• The pilot generally cannot see the hook location fromthe cockpit. It’s difficult even with plexiglass sidebubbles on the cockpit or with removable doors. Thepilot must rely on the signaller for communication.

• Hover time with a load should be kept as short aspossible. It’s a difficult and potentially dangerousactivity, requires high concentration by pilots, and isfatiguing.

• The air crew controls a remote electric hook releaseat the bottom end of the load line.

• In case of an emergency, the air crew also has aremote electric hook release and access to a manualrelease at the aircraft end of the load line for cuttingeverything loose.

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Under the aircraft

• Downwash from aircraft rotors produces high windsand turns dust, dirt, and loose objects into airborneprojectiles.

• Noise and high wind under a hovering helicoptercontribute to tense working conditions that can betiring for the ground crew.

• Constant concentration, safe practice, and vigilanceare required.

• High wind conditions require extra protectiveclothing, especially in winter.

3. Helicopter Lifting Accidents

Statistics

• 90% of accidents occur during pickup or laydown• 5% are caused by defective sling gear• 5% have other miscellaneous causes.

Source: Department of National Defence(DND does a lot of bulk lifting using nets as rigging.)

Accident locations41% occur at pickup point51% occur in flight8% occur in drop zone

Accident causes20% due to sling failure (material failure)21% due to air crew error49% due to improper load preparation10% due to inadvertent load release

Note: DND summarizes that up to 70% of the accidents aredue to human error

Hazardous Conditions

• Fatigue—air crew or ground crew

• rushing or taking chances

• overloading the helicopter

• short load line which can lead to 1) increasing theeffective weight of some loads, 2) aircraft instabilitydue to downwash, and 3) higher wind effects on theground

• static build-up and discharge on contact with theload (This can occur when there is no non-conductiveelement in the load line or no static dischargeprocedure. The discharge can give a ground worker ahigh-voltage jolt. The result can be injury to those atrisk—workers with heart problems, for instance—orloss of balance, slips, and falls.)

• untrained or inexperienced ground crew (Unpreparedfor high winds and noise, they can be injured byflying objects or distracted from their jobs andinjured.)

• poorly equipped ground crew (for instance, withunsecured hard hats or inadequate eye protection)

• poor communications (confusion over signals,inaudible radio messages, etc.)

• ground crew too small or poorly organized

• no pre-flight briefing

• unsecured loads overhead

• fall hazards: unprotected roof openings, hatches offor open, roof edges

• long tether or tag lines that can blow into rotors

• weighted tag lines (such as shackles) that becomedangerous when they blow around

• loose garments or PPE worn by ground crew

• injury from blown objects, unsecured structures, orobstacles on the ground

• impact or pinch-point injuries from loads swinging asthey first clear the ground

• crush injuries during lowering and placement of load

• pinch points during load alignment (using “rat tails”,drift pins, etc.) or during initial clamping and bolting up.

4. Planning and Preparing forthe Lift

The key element in a helicopter lift is planning. Thisrequires the participation and cooperation of allworkplace parties. Planning includes, but is notlimited to, the following points.

Communications

Several planning meetings are required to arrangecontracts and organize the work. Some training and apre-job briefing are also essential.

Load weights and sizes

It’s critical to know accurate as-built load weightsand sizes since each helicopter, no matter how largeor powerful, has a limited lifting capacity. Certifyingload weights is recommended. This can be doneduring offloading by using a crane or boomtruckfitted with a load cell. Load weights can be stampedor otherwise marked on loads.

HELICOPTER LIFTING

33 – 3

Load shape, orientation, and packaging

Load shapes can affect in-flight handling. Loads canbe marked with their required orientation by usingnorth or other marks to match mark to laydownlocations. Remove loose sheeting, tarps, or otherwrappings. Loose material can blow around, injureworkers, and damage the aircraft if drawn into engineintakes.

Rigging plans

Rigging devices and assemblies must be selected ordesigned, and plans drawn up and approved, foreach load or type of load. Nylon slings are lighter andless damaging to weaker loads than wire rope but aremore susceptible to abrasion and cuts.

Lifting equipment

The lifting contractor must be selected and thehelicopter type and capacity determined.Considerations include load line, hook-up device andconfiguration, cable and sling lengths and type, and adevice or procedure to protect against staticdischarge. One possible procedure is to clamp oneend of a jumper cable to the roof structure anddischarge each load by touching the other end of thecable to it before it contacts the laydown location.Static buildup is greater with larger aircraft.

Flight plan

• Locate and plan the staging area.

• Designate a refuelling area.

• Provide for fire watch and spills.

• Prepare flight plans.

• Divide the job into lifting zones.

• Plan the load lifting sequence.

• Do alternate day planning.

Lifting plan

Prepare a lifting plan to cover load identification,lifting sequence, and load orientation marks or tags.Loads that don’t require upending should be orientedin the same direction in the staging area that they willrequire in the laydown area. Plan the layout of thestaging area to avoid flying over any light or unstablematerial that may blow around. Plan the lifting andflight path to avoid flying over workers and anymaterial still being installed or not yet secure in thelaydown area.

Risk assessment

Identify, assess, and eliminate or provide protectionagainst risks posed by

• powerlines

• cranes in the area

• structures, roof and structure profiles

• loose, unsecured material in staging or roof landingarea

• temporary, unsecured structures in staging orlanding area

• roof openings and roof access—cover both toprevent building pressurization and to eliminate fallhazards

• unprotected roof edges

• pinch, crush, and similar danger points in theload/lift/land sequence

• weather conditions

• public safety.

Rigging inspection

Inspect, record, and have certificates of testing forrigging components and assemblies.

Site safety

• Follow up on all points identified during the riskassessment.

• Provide fall prevention and protection.

• Do a complete site cleanup.

• Remove any loose, unsecured material.

• Secure temporary structures.

• Make sure that roof structures are secure as wellas cladding, decking, etc.

• Where necessary, wet down the staging area tominimize dust.

Security and notification

• Notify workplace parties of where and whenhelicopter lifts will be conducted.

• Prohibit access to non-essential personnel.

HELICOPTER LIFTING

Simplified pickup/laydown sequence & orientation plan

33 – 4

• Notify public safety and local authorities, Ministryof Labour, and local air traffic control.

• Confirm insurance coverage (certificate ofinsurance on aircraft).

• Obtain Transport Canada approvals (underCanadian Aircraft Regulations the licence holdermust apply for a waiver—special operationspermit—to operate below 1,000 feet; site inspectionand approval of flight plans are required).

Ground crew

• Determine crew size.

• Plan crew cycling or rotation.

• Assign individual assignments and responsibilities.

• Provide training in personal protective equipment,fall hazards and safeguards, pinch points, etc.

Hoisting communications

Arrange for radio, hand signals, emergency signals,and warning signals. Air horns can be useful whensignallers/marshallers need to alert ground crew.

Emergency preparedness

• Arrange and communicate designated emergencytelephone contacts.

• Prepare and communicate an emergency plan incase of accidents, including signals in case ofemergency, exits, and escape routes for groundcrews.

• Determine whether helicopter is equipped withwarning siren and advise ground crew accordingly.

5. Construction Regulation:Helicopters

1) The pilot of a helicopter that is hoisting materialsshall be competent to fly an externally-loadedhelicopter.

2) The pilot shall be in charge of the hoisting operationand shall determine the size and weight of loads tobe hoisted and the method by which they areattached to the helicopter.

3) Ground personnel including signallers for a helicopterbeing used to hoist materials shall be competentworkers.

4) The constructor shall take precautions againsthazards caused by helicopter rotor downwash.

6. Responsibilities ofWorkplace Parties

Owner/constructor

• Clearly identify and define needs, tasks, andschedule.

• Work with the lifting subcontractor to locate and sizean appropriate staging area, develop lift and flightplans, and make lift and laydown arrangements.

• Cooperate with other workplace parties to makesafety a priority in planning and carrying outhelicopter lifts.

• Comply with other requirements such as securityalong flight path and limiting access of non-essentialpersonnel.

Trade contractor

• Work with the lifting subcontractor and owner/generalto plan and schedule moves.

• Make sure that accurate information about loadweight, size, and shape has been provided andapproved.

• Make sure that rigging equipment is selected andapproved and plans are prepared and approved.

• Coordinate risk assessment activities, including sitevisits at staging area, along flight path, and atlaydown area.

• Make sure that necessary local, provincial, andfederal authorities have been notified.

• Designate crew members for all tasks.• Make sure that ground crew is trained and receives

pre-job briefing.• Take direction from the lifting subcontractor. Don’t

pressure pilots to push limits or take chances.• Provide required personal protective and other

equipment for ground crew.

HELICOPTER LIFTING

33 – 5

Lifting Subcontractor (helicopter company)

General

• Provide proper equipment, competent pilot(s), andcrew for the job.

• Conduct site visits and risk assessment in advance ofthe job.

• Select/approve staging area, flight plan, refuellingarea, and emergency landing location.

• Identify load and lift information required.

• Specify ground crew identification needed fromcontractor such as coloured hard hats, vests, orcoveralls.

• Provide ground crew training and pre-lift briefing.

• Support actions and judgments of air crew.

• Explain weather limitations and plan for alternatedays.

Pilot

• Confirm any changes in load specifications.

• Conduct and review risk assessment.

• Make sure all parties are well briefed.

• Be well-rested before job.

• Don’t put yourself or others at unnecessary risk.

• Inspect all equipment before job—rigging, hooks(electric and manual release).

• Confirm communication methods, signals, andequipment.

• Confirm load sequence and orientation markings.

• Prepare and communicate emergency plans.

Ground crew—loadmasters, signallers

• Know and check out communication equipment andsignalling methods.

• Know the procedures for emergency preparedness.

• Know the loads and all lift requirements.• Brief the ground crew at your location and make surethey know their tasks.

Ground crew—contractor employees

• Be sure there is a briefing on load rigging, loadsequence, and flight plan (direction of approach).

• Know and follow load-handling procedures.

• Know the load orientation requirements andmarkings.

• Know the procedures for emergency preparedness.

• Wear appropriate protective clothing and safetyequipment.

7. Contractor Ground CrewProcedures

1) Personal Protective Equipment (PPE) and Clothing

PPE must be appropriate to very high wind and noiseconditions:

• hard hats with secure chin straps

• goggles—not glasses—that fully cover the eyesand can be strapped on

• protective work gloves

• hearing protection.

Fall protection includes

• permanent or temporary guardrails

• when required, fall-arrest system consisting of fullbody harness, lanyard, shock absorber, rope grab,lifeline, and lifeline anchor

• appropriate anchor or tie-off locations.

Clothing is important for protection andidentification.

• Clothing should be appropriate to weather—in coldconditions, for instance, balaclava and snowsuit.

• The signaller should wear apparel distinctive incolour—vest, coveralls, hard hat—which can beidentified from the aircraft.

• Other ground crew involved in the lifts should bedistinctively dressed but be readily distinguishablefrom the signallers.

2) Signalling

• Signalling is the job of lifting contractor personnelbecause of their experience in working with theaircraft and its crew.

• Helicopter signals are different from theinternational hand signals used in hoistingoperations with cranes.

• Emergency signals must be confirmed in thepre-flight briefing.

3) Hooking up

The procedures to be used for hooking up must beconfirmed during the pre-flight briefing.

• There must be no loose wrapping, packing, orobjects on the load.

• The hook-up person stands with back to the windwhile the aircraft approaches into the wind.

• The hook-up person stays with the load.

• The aircraft will approach and hover over thehook-up person.

• If the downwash is too strong, or the load is largeand flat, or catches the wind, it can be blownaround dangerously and the aircraft will be harderto control. The load line may have to belengthened. Load lines will have to be longer forlarger aircraft.

HELICOPTER LIFTING

33 – 6

• Keep the angle of load rigging greater than 45° tothe horizontal.

• Place the pear ring onto the hook and have thesignaller contact the pilot to start lifting.

When attaching tag lines to loads,keep the following points in mind.

• Keep tag lines shorter thanthe load line so they can’tblow into the rotors.

• Use synthetic fibre rope.

• Make sure tag lines don’t gettangled with load lines.

• Weighting tag lines at oneend, with shackles forinstance, can be a hazard tothe ground crew if the linesare blown about.

Before the load clears the ground:

• Stay with the load and guide the cables to ensurethey don’t get snagged as the helicopter climbs totake up slack.

• Don’t turn your back on the load.

• Double-check to make sure that the load’s centreof gravity is below the rigging attachment points.

• Look again at the load shape for trappingdownwash or chances of “flying” when travelling.

• A large, light load may have to be weighted so asnot to “fly”.

Lift-off

• When satisfied that load, rigging, or tag lines won’tget snagged, the hook-up person will have themarshaller contact the pilot to HOLD position whilethe hook-up person walks out from beneath thehelicopter to the marshaller.

• Once the hook-up person joins the marshaller, thesignaller can give the signal for the helicopter to

continue lifting until the load is clear.

• The helicopter is now free to deliver the load.

4) Receiving the load

• Stay with the signaller until given the go-ahead toapproach the load.

• Approach the load when it’s at eye level and facethe load at all times.

• Control the load by using tag lines.

Don’t pull down on tag lines when you grab them.This effectively adds weight to the load. For anaircraft near maximum load, especially a lighteraircraft, the extra load can make control difficult.

• Keep your arms outstretched while guiding theload into position. Don’t get under the load. At alltimes, for safety, behave as if the load is going tofall.

• Large and heavy loads are harder to control fromthe ground.

• Remember that precise control of loads is notpossible from a hovering aircraft.

• Before the load is lifted, check for, andmake sure you understand, any markings,lugs, tabs, or rat tail holes to be used fororientation.

Various methods can be used to orient and place loads intheir final position. The methods depend on load type,shape, size, and can include:

Rat tails

Rat tails are typically made from 1/4" or 3/8" wire rope 3to 6 feet long with a button or nut attached at the topend to keep them from sliding through the flange holes.Rat tails can be used for the final alignment of matingflanges. Once the flanged load is over and close to itsfinal location, rat tails can be slotted through the markedholes in the mating flange and pulled tight as the load islowered into position.

Drift pins

Drift pins can be used to locate and match load flangeholes to base flange holes. Drift pins, or spud wrenches,can also be used to lever parts into place.

Tabs and lugs

Locating tabs or lugs can be fastened to the bottom of theload to fit over and align it with the mating base orsupport. Tabs or lugs installed in pairs to frame a cornerof the load can be mated with the matching corner of thebase. This corner can then be used as a locating andpivot point to assist the pilot or ground crew in aligning therest of the load.Collars

Collars on loads can sometimes be used to align andmate slung loads with their bases.

• Locate load orientation marks, rat tail locations, orlugs or tabs used for load orientation before finalplacement.

HELICOPTER LIFTING

33 – 7

• If rat tails are being used, insert them through thecorrect holes and pull them through.

• Make the final alignment according to the agreedprocedure—spud wrenches, clamps, etc.

• Keep hands and feet away from areas where theymay be pinched, wedged, or crushed by the load orthe rigging.

• Wear a fall-arrest system where required. Always lookfor possible trip hazards with lifelines.

• Plan escape routes in case of an emergency.• When the load is in place and secured, only the

signaller can give the pilot the go-ahead to releasethe load.

• Disengage the load hooks and make sure they don’tsnag.

• Only the signaller can signal the pilot to leave andpick up the next load.

8. Staging Area Requirements

The staging area must be

• level and firm• large enough to spread out loads for organized

sequential pickup and to avoid blowing adjacentmaterial around—a problem with short load lines andan increasing problem as helicopter type gets bigger

• large enough for aircraft to climb out safely (ahelicopter near its capacity can only climb at agradual rate and needs clear space to do this safely)

• located to avoid lifting loads over occupied areas orbuildings

• free of debris, demolition waste, stored materials, lightequipment

• free of obstacles—powerlines, vehicles, stacks,towers, cranes, etc.

• clear of excessive dust (if necessary, water down thearea to suppress dust)

• free of spectators and unnecessary personnel• posted with warning signs and cordoned off with

barricades (signs and barricades should be securedagainst downwash).

9. Placement AreaRequirements

The placement area must have

• no loose debris or unsecured materials, equipment,signs, or barricades

• unsecured roof covers securely tied down• a crew the appropriate size for the job• crew members aware of assigned responsibilities,

protected by guardrails or fall-arrest systems wherenecessary, and familiar with placement areahazards—usually fall hazards on a roof.

HELICOPTER LIFTING

33 – 8

10. Pre-flight Briefing andInspection

A pre-flight briefing should be held immediately prior tothe lift commencing. By this time the ground crew and thelifting contractor should have had training and receivedfinal information for the lift as well as confirmation that allinspections have been carried out.

11. Hazardous Loads

Some loads or load conditions are dangerous and need tobe treated with extreme care. All workplace parties—owner, constructor, contractor, ground crew, liftingcontractor—must be warned accordingly.Loads with a moving centre of gravity

One example is a tank filled, or partially filled, with liquid.Liquid moving around or surging in the tank as it’s liftedand carried in flight will change the load’s centre ofgravity. The pilot must always be informed of such a load.If it can be carried at all, a single-point suspension shouldbe used. Even a relatively small amount of liquid canhave an effect on load stability.Loose materials in containers

Downwash and turbulence can cause spillage and dangeron the ground. Make sure sheet coverings such asshrinkwraps or tarpaulins are securely lashed down or—better—removed altogether.Large loads

Very large loads carried flat or loads that trap downwashcan increase their effective weight and create problems.They are also prone to oscillation and aerodynamiceffects.Environmental effects

• Under cold conditions, loads can freeze to the groundand require unpredictable force to break them free.

HELICOPTER LIFTING

PROCEDURES CHECKLIST

weather and wind check, corresponding actionsrequired

flight pattern to follow—approach and departuredirections, etc.

briefing by air crew on operational andemergency procedures and signals for groundcrew

review of rigging, loading, and unloadingprocedures for ground crew

review and test of communication system(s)—radio, warning air horns, etc.

confirmation of loading sequence and loadorientations

markings and methods to convey correct loadorientation from staging to placement areas

review of emergency disconnect procedure forhook(s)

confirmation that fall prevention and protection

measures are in place

INSPECTION CHECKLIST

personal fall protection equipment

loads as specified

loads within aircraft’s safe lifting capacity

loads inspected by lifting contractor and pilot

pilot/marshaller’s confirmation that slings,lanyards, swivels, cables, tethers, and otherrigging arrangements are correct

pilot/marshaller’s confirmation of methods andmarkings used to indicate load orientation

loose debris, plastic bags, wrapping, and otherpackaging removed or secured in staging andplacement areas

loose material and temporary structures securedin staging and placement areas

pilot’s confirmation that cargo hook(s) areappropriate and in good working order

confirmation that large light loads, loads withrotating components, or loads with wind-trapping features will be kept from rotating indownwash (light loads may need to be weigheddown for stability in flight)

33 – 9

• Snow can enter or ice can form in a container orhollow fabricated piece, adding unexpected weight orchanging the centre of gravity.

• When lifting loads from water, remember that thesubmerged weight is less than the free weight.

• Objects in water or a flooded area for any time canacquire unexpected weight from silt or mud.

Containers of flammable or harmful liquids

Take care with containers holding fuel, solvent, or otherflammable liquids. Static discharge can cause fire orexplosion. Discharge static buildup by using a weightedchain or other conductor reaching to ground. Fuelcontainers must be vented. For harmful or toxic liquidscheck the Transportation of Dangerous Goods Act. Allworkplace parties must be advised when such loads areto be handled.

12. General Precautions aroundHelicopters

Approaching• Rotors can kill.• Pilot’s blind area is anywhere around the rear of the

aircraft.• Stay in view of pilot and keep your back to the wind.

Boarding• Note if engine will be running.• Note location of door(s).• Approach aircraft from the side—never from the rear.• Crouch low under main rotor.• Don’t carry objects extending above body height.• Remove loose headgear.

• Never approach downslope—the main rotor can killyou.

Leaving• Exit straight out the door. Don’t change direction until

well clear of the helicopter.• Stay away from rear of aircraft.• Crouch low under main rotors.• Don’t carry objects extending above body height.• Never walk away upslope—the main rotor can kill

you.

HELICOPTER LIFTING

33 – 10

13. Exercises

1. Which two workers must control load-handlingactivities during helicopter lifting?

______________________________________________

______________________________________________

2. When a loaded helicopter is hovering over a pickupor laydown location, the pilot needs direction fromthe ground signaller because

- the signaller has a clear view of the load and itsposition

- the signaller has a clear view of personnel and theground situation, and

- the pilot generally cannot see the ______________and the ________________________location.

3. What special features are required for headprotection and eye protection during helicopterlifting?

hard hat with ____________________________________

eye protection consisting of ______________________

4. Why are these features required?

______________________________________________

______________________________________________

5. What is the one safe practice activity which must becarried out at both the staging and laydown areasbefore any helicopter lift and to which all sitepersonnel can contribute?

______________________________________________

______________________________________________

6. In helicopter lifting, why do long tag lines present ahazard?

______________________________________________

______________________________________________

7. During a helicopter lift, static electricity can build upand discharge through the load line to a rigger on theground. What two precautions can be taken againstthis hazard?

______________________________________________

______________________________________________

8. Identify two purposes served by rat tails in helicopterlifting.

______________________________________________

______________________________________________

9. Identify at least four points to know about a load tobe lifted by helicopter.

______________________________________________

______________________________________________

______________________________________________

______________________________________________

10. What documentation must be available for all riggingequipment?

______________________________________________

______________________________________________

11. Which workplace party generally has primaryresponsibility for providing accurate load weights andrigging plans?

______________________________________________

______________________________________________

12. As the helicopter approaches to pick up the load,how should ground crew stand in relation to thewind?

______________________________________________

______________________________________________

13. When working with a load suspended from ahelicopter, never turn your _________ to the load.

14. When a load is being picked up from the stagingarea, where should the hookup person stand afterhooking up the load and before the signal is given forthe load to clear the ground?

______________________________________________

______________________________________________

15. Cross out the item of PPE which is NOT adequate foruse by ground personnel during a helicopter lift?

protective work gloves

safety glasses

green-patch workboots

hard hat with chin strap

For answers, see next page.

HELICOPTER LIFTING

33 – 11

Answers1. pilot; signaller/marshaller

2. load hook; pickup or laydown location

3. chin straps; goggles

4. high winds generated by rotor downwash

5. site hazard assessment

6. tag lines may drift or blow into rotors

7. install a non-conductive element in load line; follow astatic discharge procedure to prevent shocks toground crew touching load or load line

8. orienting load in relation to base; aligning load onbase

9. accurate weight; size; location of centre of gravity;pickup points; shape

10. certificate of test

11. trade contractor

12 with backs to the wind

13. back

14. out from under the helicopter

15. safety glasses

HELICOPTER LIFTING

34 – 1

34 HAND AND POWER TOOLS

Employers are responsible for maintaining in good repairany tools and equipment supplied to workers. Workersmust use tools and equipment properly and report anydefects to supervisors.The Construction Regulation (O.Reg. 213/91) requiresthat tools and equipment be used according tomanufacturers’ operating manuals, that operating manualsfor tools and equipment rated at more than 10horsepower be kept readily available on the project, andthat tools and equipment be inspected regularly.Our finest tools are our hands. Too often they aredamaged by tool accidents. Hands can be caught inmachines, crushed by objects, or cut by sharp-edgedtools such as chisels, knives, and saws. Hands can alsobe damaged by being burned, fractured, or sprainedunless you stay alert.Eyes are highly susceptible to injury from tool use but eyeinjuries are almost always preventable. Use the guardsand personal protective equipment which we all know areneeded but sometimes tend to overlook.Noise is a hazard inherent in construction. Tools and theworking environment can both be noisy, particularly forconstruction trades operating in plants and mills.Exposure to excessive noise can impair hearing.Prolonged excessive exposure can result in permanentdamage to the hearing and eventually deafness. Hearingprotection should be worn whenever there is a risk ofexcessive exposure.

Common Causes of AccidentsTypical causes of hand and power tool accidents includethe following:• using the wrong tool for the job• tools falling from overhead• sharp tools carried in pockets• using cheaters on tool handles• excessive vibration• using tools with mushroomed heads• failure to support or clamp work in position• carrying tools by hand up or down ladders• using damaged electrical cords or end connectors• failure to use ground fault circuit interrupters (GFCIs),

especially outdoors.

Safe PracticesBasic hazard awareness and common sense can preventserious injuries with hand and power tools. As a generalrule follow the safe practices listed below.1) Always wear eye protection. There is always the risk

of flying particles and dust with hand and power tools.Appropriate eye protection is essential and must beworn by the user and others nearby. For eyeprotection see the Personal Protective Equipmentchapter in this manual.

2) Use the right tool for the job. Using a screwdriver asa chisel, using a cheater on a wrench handle, orusing pliers instead of a proper wrench are typical

examples of the mistakes which commonly lead toaccidents and injuries.

3) Use tools as recommended by the manufacturer. Forexample, don’t use cheaters on handles. This willexert greater forces on the tool than it was designedfor and is likely to cause breakage and possible injury.

4) Damaged or broken tools should be removed fromservice. Chisels with mushroomed heads, hammerswith cracked or loose handles, wrenches with wornjaws, damaged extension cords, and ungroundedtools are all unsafe and should be removed fromservice and be either repaired or destroyed.

5) Maintain tools in safe operating condition.Prevent mushrooming. Tools which are struck byhammers, such as chisels or punches, should havethe head ground periodically to prevent mushrooming.See Figure 21.1

Keep handles secure and safe. Don’t rely on frictiontape to secure split handles or to prevent handlesfrom splitting. Check wedges and handles frequently.Be sure heads are wedged tightly on handles. Keephandles smooth and free of rough or jagged surfaces.Replace handles that are split, chipped, or that cannotbe refitted securely.Keep hand tool cutting edges sharp. Sharp toolsmake work easier, improve the accuracy of your work,save time, require less effort, and are safer than dulltools.

6) Never climb ladders with tools in your hand. Toolholders and pouches (Figure 21.2) free the handswhile workers are climbing or working on ladders,scaffolding, and other areas where access may bedifficult. When carrying tools up or down fromelevated places, put them in substantial bags orboxes and raise and lower them with strong ropes.

7) Spark-resistant tools (non-ferrous tools) arerecommended where flammable materials orexplosive dusts or vapours might be present. Thesetools, such as brass or copper hammers or mallets,should still be used with caution; remember, they maynot guarantee safety in all explosive situations such

HAND AND POWER TOOLS

Figure 21.1

Figure 21.2

34 – 2

as in the presence of gasoline vapours. It is alwayssafer to eliminate the hazard by ensuring a safeatmosphere through isolation, ventilation, or purging.

8) Protect the cutting edges of tools when carrying them.Carry them in such a way that they won’t be a hazardto yourself and others. Carry pointed or sharp-edgedtools in pouches or holsters.

9) Keep your hand tools clean. Protect them againstdamage caused by corrosion. Wipe off accumulateddirt and grease. Dip the tools occasionally in cleaningfluids or solvents and wipe them clean.

10) Lubricate adjustable and other moving parts toprevent wear and misalignment.

11) When swinging a tool, be absolutely sure that no oneelse is within range or can come within range of theswing or be struck by flying material.

12) Falling tools are a dangerous hazard for workersbelow. Keep track of tools, especially when working atheights on scaffolds or other access equipment. Anunnoticed file or chipping hammer, if accidentallykicked off the work platform, is a deadly missile aswell as a tripping hazard for you. If practical, tie toolsoff when working at heights.

13) Hearing protection should be worn whenever there isa chance of excessive noise exposure. Noise fromtools and equipment is an inherent hazard inconstruction. Exposure to excessive noise can impairhearing. Prolonged excessive exposure can result inpermanent damage to hearing and eventuallydeafness. Although the tools being used are only oneof several possible sources of noise, efforts should bemade to provide the least noisy power tools that willstill do the job.

Inspection and RepairTools should be inspected by a person qualified throughtraining and experience to determine the safe condition ofthe tool.Worn or damaged tools should be tagged “DEFECTIVE –DO NOT USE” and returned to the shop for repair orreplacement.Regular inspection of all tools is necessary and shouldcover tool maintenance and service as outlined in theoperator’s manual. Observing proper handling andstorage of tools should also be a part of the inspectionprocess. Responsibility for inspection is usually left to thesupervisor. However, tools should be checked by thosewho use them daily.Hand tools that get the heaviest use and abuse, such aschisels, hammers, and wrenches, should be inspectedfrequently and regularly.To maintain and repair tools properly requires the rightfacilities and equipment. A good workbench, repair tools,vises, and good lighting are necessities. Only personsskilled in the repair of tools should be allowed to do therepairs. Otherwise tools should be sent out to a qualifiedrepair depot.

Redressing ToolsFollow the tool manufacturer’s recommendations to repair,shape, or maintain tools.

When redressing the cutting edge on a tool, ensure thatthe tool is supported firmly. Use only a hand file orwhetstone—not a grinding wheel. (If a grinder is used, itcan destroy the temper of the cutting edge.) Be sure torestore the original contour of the cutting edge.Cold chisels, for example, are hardened on the cuttingedge. Use only a hand file or whetstone for redressing.Be sure to restore the cutting edge to its original shapeand angle of approximately 70 degrees (Figure 21.3).

HandlesHand tools such as hammers and sledgehammers shouldhave handles of straight-grained hickory, ash, or mapleand be free from slivers. It is important to ensure thathandles are attached and properly fitted to tools by anexperienced person. Poorly fitted handles can be verydangerous and make the tool difficult to control.Constant inspection is necessary for handles. Eventhough they are received in good condition, handles canloosen with use and shrinkage. In some cases, tappingthe wedges may take up the shrinkage. In other cases thehead of the tool can be driven back on the handle and thewedges reset and any protruding piece of the handle cutoff.Most wooden handles will need replacement eventually. Areplacement handle should be of correct specifications fora tight fit and be properly wedged.

Safety TipWhenever possible, pull on an adjustable wrench. Do notpush. Force should be exerted on the fixed rather thanthe adjustable jaw.

Hand ToolsUseThe misuse of hand tools is a common cause of injury inconstruction. In many cases, the injury results because itis assumed that everyone knows how to use mostcommon hand tools. This is not the case.


Figure 21.3

Fixed Jaw

Adjustable Jaw

Direction of Pull

34 – 3

It is the responsibility of the supervisor and employer toensure that workers are trained in the safe and properuse of hand tools. This section is intended to provide anoverview of hazards and safe practices in selecting andusing hand tools.Hammers, Sledges, and MaulsHammers are made in various shapes and sizes forspecific jobs. They should be selected and used only forthe purpose intended.Ballpeen hammersThese come in a variety of weights up to 3 pounds.Ballpeen hammers are designed for striking cold chiselsand punches and for riveting, shaping, and straighteningmetal (Figure 21.4).SledgesAll patterns of thisheavy-duty striking toolhave a crowned facewith bevelled edges.Sledges are forged fromhigh-carbon or alloysteel and are heat-treated. The types mostcommonly used are:Double-face — headweights from 4 to 20pounds and handlelengths from 15 to 36inches. The 8-poundsledge is heavy enoughfor most boilermakers’work, although heaviersledges may be requiredfor fairing tank seams orfor driving wedges onheavy plate work. The 4-pound maul or sledge isa favourite with fittersand is often carried ontheir belts. With ashorter handle (10 to 12inches) permitting heavy blows with a limited swing, itsweight makes it ideal for driving in full pins for lining upshelf plates (Figure 21.5).Straight or crosspeen sledges— head weights are from 2to 16 lbs. and handle lengths from 14 to 36 inches. Thesepeens are used for shaping (fullering) and bending metal(Figure 21.6).Chipping hammers— come in a variety of styles andhandles and are designed for chipping slag off welds orburned edges. These hammers have long, slender ortapered points or edges and can be resharpened manytimes.Other types of hammers— are used when required bythe tradesperson. They include carpenter’s or clawhammers for nailing; various soft-faced mallets, when asteel head might damage the work; and brass or copperheads, when non-sparking tools are required.

Basic rules for safe hammer use• Always wear eye protection.• Make sure the handle is tight. Never use a hammer

with a loose or damaged handle.• Always strike the work surface squarely with the

hammer face. Avoid glancing blows.• Hold the hammer with wrist straight and hand tightly

wrapped around the handle.• Look behind and above before swinging the hammer.• Never use a hammer to strike another hammer.• Discard any hammer with dents, cracks, chips, or

mushrooming. Redressing is not recommended.• When striking another tool (chisel, punch, wedge,

etc.), the striking face of the hammer should have adiameter at least 1/2 inch (1 cm. +) larger than thestruck face of the tool.

• Never weld or reheat-treat a hammer.Struck or Hammered ToolsThese include chisels, punches, drift pins, and wedges.General safety measures for their use include:1) Always wear eye protection. If other people are close

by, put up a screen or shield to protect them fromflying chips.

2) Strike the tool squarely and in the centre, as called forby the crow or beveled-face design. Off-centre blowscan misdirect the tool and increase the rate of wearon the head.

3) Never use a tool with a mushroomed or chippedhead. Remove it from service and destroy or repair it.

4) Keep cutting edges sharp. A dull edge increaseslabour and decreases tool durability. Failures can becaused by dullness.

Cold chisels have a cuttingedge that will cut, shape,or remove metal which issofter than the cuttingedge. Such metals includecast iron, wrought iron,mild steel, bronze, andcopper. The hardenedcutting edge should bekept sharp at a 60- to 70-degree angle. Theselection of chisel isdetermined by the materialto be cut and the size anddepth of cut. The mostcommonly used type is theflat chisel. It is used to cutrivets, split nuts, chipcastings, cut thin plate,remove burn slag and weldspatter, and cut off small rodsand wire. Other varieties of coldchisels include: cape – forkeyways, grooves, squarecorners; half round and roundnose – for round grooves and tochip inside corners; anddiamond point – for V-groovesto remove tubes from sheets


Figure 21.4Standard ballpeen hammer

Figure 21.5Double or maul-faced sledge

Figure 21.6Straight and cross-peen sledges

Figure 21.7Metal cutting chisel types

Figure 21.8

Figure 21.9

34 – 4

and for chipping tack welds and square corners. SeeFigure 21.7.A sponge rubber pad forced down over the chiselprovides a protective cushion that reduces shock for thehand, but a protective guard such as the one shown inFigure 21.8 is more effective.Bull chisels held by one worker and struck by anotherrequire the use of tongs or a chisel holder to guide thechisel so that the user will not be injured (Figure 21.9).Punches and Pins• Select punches or pins heavy enough for the work.• Avoid jamming tapered parts of punches in openings.• Avoid bending or breaking pins.• Make sure pins or punches are held firmly in position

before hitting them, especially on rounded surfaces.Hand punches have avariety of configurations forvarious purposes. Whenusing punches, hold themat right angles to thework surface to preventside-slipping. Be sure tostrike the punch squarelywith the hammer to preventits slipping off and hittingfingers. Figure 21.9a showssome types. In addition,there are blacksmith-typepunches (not shown),mounted on hammer stylehandles; a tapered roundpoint, for drifting andaligning; and a straightpunch for backing out bolts,rivets, and pins.Drift pins are used toalign holes in metal.They come in twotypes: standard andbarrel (Figure21.10).There are also special pins used largely by boilermakers(Figure 21.11) for heavy-duty steel plate. These includethe poker pin, a large diameter punch for aligning holes insteel plate; and the bull pin, a heavy-duty pin used in thefit-up of steel plate. They are inserted into holes in fit-upclamps (welded temporarily to the side of the plates) toalign the plates for welding.

Cutting Hand toolsBolt CuttersBolt cutters (Figure 21.12) typically come in lengths of 18"to 36" with the larger ones able to cut mild-steel bolts androds up to 1/2" diameter, as well other materials such aswire rope. With these tools, observe the following.• Wear eye protection.• Keep fingers clear of jaws and hinges.• Cut ends can fly and cause injury. Try wrapping

burlap or a rag around the jaws while cutting.• Keep jaws at right angles to material. Don’t pry or

twist — chips can break off and fly,causing injury or damaging the blade.

SnipsSnips (Figure 21.13) aregenerally used to cut light-gauge galvanizedsheet metal, coppersheet, and tin. Flyingmetal particles are alwaysa hazard. Safety glasses ora face shield should be wornto protect against eye injury.Always be sure to select theright size and type of snipsfor the job. Don’t cutwire with snips —use wirecutters.

HacksawsAlthough power tools willbe used wheneverpossible, hacksawsdeserve mention. They fill a gap by cutting metal tooheavy for snips or bolt cutters. The main danger fromhacksaws is hand injury due to blade breakage. Toprevent this danger:• install and keep the blade taut but not too tight• make sure that the material is held firmly in a vise or

by other devices such as clamps.

FilesThere are three standardAmerican-pattern metal file cutsas shown in Figure 21.14.Make sure that a handle isinstalled on a file before use. Thiswill prevent the chance of anuncovered tang being jammedinto your hand. A firmly attachedhandle will also improve control ofthe tool.Taps and Dies• Keep taps and dies clean and

well oiled when not in use.• Store taps and dies so that they

don’t contact each other or othertools. For long term storage coatthem with rust preventivecompound and store in a dryplace.

• Don’t attempt to sharpen taps ordies. Precise cutting is requiredto maintain the correct thread-cutting characteristics andchamfer. This work must only bedone by experienced personnel.

• Don’t use diestocks or tapwrenches as hammers orprybars.


Figure 21.9aTypes of Punches

Figure 21.10Drift Pins: A Standard; B Barrel

Figure 21.11Special Boilermaker PinsA: Poker and B: Bull

Figure 21.12 Bolt Cutter

Figure 21.13 Snips

Figure 21.14 Metal file cuts:A) single cut, B) double cut,

C) curved cut

Taper Pipe

Taper Hand ChamferLength

Plug Hand - National Course

Bottoming HandFigure 21.15 Types of

common taps.

34 – 5

ScrewdriversThis is probably the most abused of all tools. It’s used asa punch, wedge, pinch bar, and for other jobs for which itwas not designed. Broken handles, bent or chippedblades, and twisted tips may cause the screwdriver to slipand cause a serious hand injury.• Choose a screwdriver with a rectangular handle that

fits the shank tightly, with a flange to keep your handfrom slipping off the handle.

• Never get any part of your body in front of thescrewdriver. Never hold the work in your hand whileusing a screwdriver. Hold the work in a vise, with aclamp, or at least on a solid surface.

• Keep screwdriver handles clean. A greasy handle cancause an accident.

• When working around electricity, use screwdriverswith a handle insulated with dielectric material. Keepin mind, however, that this insulation is only asecondary method of protection. Always be sureelectrical power is off before beginning work.

• Don’t use screwdrivers as chisels, hammers, prybarsor for any purpose other than to turn screws.

• Be sure to use the right screwdriver for the screwbeing turned. The blade must fit the screw type, be ingood condition, and seat solidly in the screw slot(s).

• Use an offset screwdriver in close quarters where aconventional screwdriver won’t fit.

Holding ToolsWrenchesThere are hazards with all types of wrenches: the wrenchmay slip off the work, the workpiece may suddenly turnfree, the wrench or workpiece may break. The usershould always be braced to maintain balance and keep

from being injured in case the wrench slips. Alwaysinspect a wrench for flaws, damaged parts, or wear thatcan cause it to slip and damage fasteners.There is a correct wrench for every job. If the wrench istoo big, it may not grip securely. Overtorquing can causeslippage and damageof the wrench orfastener, including thestripping of threads.Where possible, usepenetrating oil toloosen tight nuts andbolts.• Always grip the wrench

so it will not cause injuryif it slips.

• Use the correct type ofjaw to avoid slippage.Box wrenches are saferthan open-endwrenches since they areless likely to slip. Solidopen-end wrenches ofthe correct size aregenerally more securethan an adjustablewrench, especially onhard-to-turn items.

• Discard any damaged box or open-end wrench. Don’tattempt to repair a wrench with rounded or damagedpoints on the box end or worn or spread jaws on theopen end.

• Face the adjustable wrench forward and turn it sopressure is against the fixed jaw (Figure 21.19).

• Always pull on a wrench whenever possible. Do notpush.

• Never overload a wrench by using a pipe extensionon the handle or by striking the handle with ahammer. This can weaken the metal of the wrenchand cause the tool to break. Heavy-duty boxwrenches with extra long handles and “hammer” orstriking-face wrenches are available for these jobs.The striking-face wrenches with 12-point box openingare designed for striking with a ballpeen or sledgehammer. Both offset and straight styles are availablebut the straight type should be used when possible.

Spud wrenches are specializedtools with a fixed or box end.The other end is long andtapered, giving extra leverage. Itcan be used to align holes andpry steel plates. These are alsoavailable in an offset (orstructural) style for clearingobstructions.Socket WrenchesSocket wrench sets come in many types and sizes ofsocket. Drivers include ratchet, universal, and speeder,along with many extensions and adapters. Be carefulwhen adapting down in size not to overtorque a smallersocket and fastener with a larger driver.


Figure 21.16Types of solid dies:

A) rethreading; B) square pipe

Figure 21.17Common adjustable dies:A) screw adjusting type;B) open adjusting type

Figure 21.18 Diestock and tap wrenches

Figure 21.20 Hammer wrenches(A) offset hammer wrench(B) straight hammer wrench

Figure 21.21Typical spud wrenches

Fixed Jaw

RIGHT WRONGFigure 21.19

34 – 6

Always use the correct size ofsocket and make sure it fitssnugly. An oversize or sloppy fitcan cause slippage and injury aswell as wear to both the socketand the fastener.Never use “hand”sockets on apower drive or impact wrench.Hand sockets are normallybrightly finished while power andimpact sockets have a dull finishand usually thicker walls.Two useful socket items are illustrated in Figure 21.22 —a universal joint with an extension and a crowfootattachment. They allow access into otherwise inaccessiblelocations.Pipe wrenches have been the cause of serious injurieswhen used on overhead jobs. Wrenches can slip on pipesor fittings, causing the worker to lose balance and fall.Pipe wrenches, whether straight or chain tong, shouldhave sharp jaws and be kept clean to prevent slipping.

PliersConsidered a general purpose tool, pliers are frequentlymisused. Pliers are meant for gripping and cuttingoperations and are not to be used as a wrench becausetheir jaws are moveable and may slip.Basic safety rules• Choose pliers with enough space between the

handles to prevent pinching of the palm or fingers.• Select pliers that have a grip span of 6 cm to 9 cm

(2-1/2"–3-1/2").• Pull on pliers — do not push.• Side cutting pliers may cause injuries when ends of

wire are cut and fragments fly into a worker’s eye. Eyeprotection should be worn when using side cutters.

• Always cut at right angles. Never rock from side toside against the cutting edges.

• Pliers used for electrical work should be insulated.Power must still be shut off first. Remember —cushion grips on handles are for comfort only and arenot intended to protect against electrical shock.

• Never expose pliers to excessive heat; this may drawthe temper and ruin the tool.

• Don’t use pliers as hammers — they might crack,break, or be nicked.

• Don’t use cheaters to extend the handles. This candamage or spring the tool, or slip and cause injury.

• Pliers should not be used to tighten nuts or bolts. Usea wrench.

Locking Wrench PliersSometimes referred to by the trade names vise grips orgrip-locks, these can be locked onto a wide variety ofobjects, leaving the hands free for other work. They areuseful as a clamp, a speed wrench, or as a portable vise.Standard types of locking wrench pliers are shown inFigure 21.23 while Figure 21.24 displays speciality styles.• Don’t use them to replace wrenches since they can

damage fittings or fasteners.• Don’t hammer or use cheaters to increase force to

tighten jaws or to cut wire or bolts.• Don’t expose to heat

from torches or contactwith welding electrodes.

• Severe vibration cancause release of thejaws accidentally; wireor tape them shut whennecessary.

• Never clamp them orattempt to use as a stepor climbing device.

ClampsClamps are anotheruseful holding tooland the C-clamp(Figure 21.25) is themost widely usedstyle. C-clamps, likeother tools, require some maintenance; lubricateperiodically, keep threads clean and free of rust, andmake sure the swivel head rotates freely.For larger clamping jobs there are bar clamps and pipeclamps, which offer a reach limited only by the pipe lengthused.The following points should be considered when usingclamps.• Choose a clamp size suited to the job; too small and

the clamp can be overloaded and bend or break thebody; too large and it can be an obstruction.

• Overextending the screw can bend it.


Figure 21.22 Useful socket items:A) Universal socket

B) crowfoot attachment

Figure 21.23 Locking wrench pliers withA) straight jaws; B) curved jaws; andC) curved jaws with wire cutters

Figure 21.24 Some special locking wrench pliers: A) C-clamp;B) sheet metal clamp; C) pinch off tool; D) welding clamp; and E) chain clamp

Figure 21.25 Typical C-clamp

34 – 7

• Don’t use wrenches onthe screws unless theclamp is designed forthis service, with a bolthead to withstandwrench tightening.

• For welding, use clampswith a shielded thread(Figure 21.26) toprevent damage to thethreads from spatter.

VisesThe types of vises likely to be used by the various tradesare shown in Figure 21.27. The most commonly used isthe “bench” vise which can come with a fixed or swivelbase. They arealso availablewith or withoutpipe holding jaws.Bench vises areusually bolt-mounted to abench but clamp-on models arealso available forlighter duty.The blacksmith’svise is useful for workwhich must be pounced; itis secured to a bench andbraced by the long legattached to a solidbase on the floor.Pipe vises are alsouseful to varioustrades. The yoke-type pipe viseusually hascapacity up toabout 8 cm. (3 in.).The chain-typevise has a larger diameter capability as well as beinguseful for irregular shapes.Safe use• Mount vise securely.• Keep work close to jaws.• Keep vise cleaned, oiled.• Support extra-long work.• Prop very heavy work in vise with wood blocks to

prevent it from falling and causing injury.• Don’t open jaws beyond their capacity; the moveable

jaw may fall, causing injury or damage.

Pipe ToolsPipe wrenches have been the cause of serious injurieswhen used on overhead jobs. Wrenches can slip on pipesor fittings, causing the worker to lose balance and fall.Pipe wrenches, whether straight or chain tong, shouldhave sharp jaws and be kept clean to prevent slipping(Figure 21.28).

• The adjusting nut of the pipewrench should be inspectedfrequently for cracks. Acracked nut may break understrain, causing a failure of thewrench and serious injury.

• Use a wrench the right lengthand size for the job. A wrenchthat is too small will notprovide enough leverage orproper grip. A wrench that istoo big is more apt to slip onthe work.

• Face the pipe wrench forward.Turn the wrench so thatpressure is against the heeljaw.

• Never use a “cheater” toextend the length of a wrenchhandle and provide moreleverage. The cheater maystrain the wrench or the workto the breaking point.

Pipe VisesPipe vises have been discussedbriefly; however, anotherconfiguration is the portabletristand equipped with either achain vise or yoke vise (Figure21.29).• Mount the vise securely to

prevent slipping or tippingover. Most tripod stands are equipped with a ceilingbrace screw.

• Keep work close to the jaws of the vise.• Support extra-long work.• Keep the vise, especially the jaws, clean and oiled.

Pipe and tube cuttersThe most common pipeand tube cutters have analloy steel cutting wheeland two adjustablerollers. The hand unitsusually come in twosizes, up to 2" and 2" to4". Usually larger tubesand pipes are cut withpower cutters. Handcutters for tubes up to 12"are available in hingeddesign as shown inFigure 21.30(b).In any case, it isimportant not to force toomuch pressure on thecutting wheel as it may shatter and cause dangerousfragments to fly off.When setting up to cut, make sure to check the cutting wheelfor nicks and make sure to keep the cutter perpendicular tothe tube or pipe to ensure accurate tracking.


Figure 21.26 Welding C-clamp

Figure 21.28 typical pipewrenches: A) Straight, B)Offset, C) Heavy-duty chainwrench, D) Compoundleverage wrench, and E)

Strap Wrench

Figure 21.29Portable tristandchain vise

Figure 21.27

34 – 8

ReamersReamers (Figure 21.31) are used to remove the burr thatresults from cutting pipe with roller pipe cutters. Be carefulwhen using this tool with apower vise. There is always thepotential for the reamer to diginto the pipe and twist the toolout of the worker’s hands.

Power ToolsBasic SafetyPower tools used in construction are driven by gasoline,electricity, compressed air (pneumatic), hydraulicpressure, and explosive powder. Regardless of the sourceof power, these tools present hazards similar to and,because of their speed, often greater than hand tools.Typical injuries include cuts, burns, strains, and sprains.Causes of injuries include electric shock, flying particlesand dust in the eye, falls, explosive atmospheres, andfalling tools. These are all acute injuries produced bysudden trauma and are identified immediately with theevent.Chronic injuries must also be guarded against; such asmusculoskeletal conditions like carpal tunnel syndrome orRaynaud’s syndrome – white finger disease. Theseconditions can develop more subtly and prevention caninvolve awareness of a variety of precautions includingtool selection, work schedules, and work practices.Always wear eye protection. Flying particles and dust arealways problems with power tools.Wear hearing protection whenever there is chance ofexcessive noise exposure. Exposure to excessive noisecan impair hearing and prolonged exposure can result inpermanent damage to the hearing and eventuallydeafness.Always disconnect the power on a portable power toolbefore changing or adjusting accessories such as drill bitsand saw blades.Never operate a power tool with the guard removed orimproperly adjusted.Power tools should not be left where there is a chancethat the cord or hose may be pulled, causing the tool tofall. Cords and hoses left on the floor in high traffic areasmay also create a tripping hazard. Cords or hoses thatmust cross access routes or roadways should besuspended above the ground or protected by woodenplanks.General Guidelines• Whenever possible, select tools with large handles

relative to the tool body, to reduce vibration.

• Select tool handles covered with cork,rubber, or plastic bonded to steel toreduce vibration.

• Use tools with two handles to makeholding and manipulation easier.

• Always refer to the operator’s manualbefore using a tool the first time.

• Choose tools with a trigger strip ratherthan a trigger button. This spreadsforce over a greater area, reducingmuscle fatigue (Fig. 21.32).

• Make sure there’s adequate lightingfor safe tool use.

Inspection and RepairFrequent inspection of power tools is essential to keephazards from developing. Inspection will also help toidentify operating defects and possibly avoid costlybreakdowns.A regular schedule for inspection — daily, weekly, ormonthly depending on requirements — will help to ensurethat all power tools are in safe operating condition.Defective tools should be removed from service, tagged,and be either repaired or replaced.Workers should be trained to inspect the tools they useand to report defects to their supervisor. The extent of theinspection and the responsibility for maintenance orrepairs must be clearly communicated so there is nomisunderstanding. Workers should not carry out makeshiftrepairs.Electric Power ToolsTypes of injuries with electrictools include:• major shocks that may

cause a fatality• electric flash burns• minor shocks that may lead

to injury from the tool itselfor from resulting falls fromladders or platforms

• eye injuries from flying chipsand cuttings

• gashes, cuts, and puncture wounds.

The potential for current to flow through a worker from afaulty tool is determined in part by working conditions.Wet or damp conditions can reduce resistance and cangreatly increase the chance of current flow and injury fromelectric shock (Figure 21.33)Grounding of electric power tools and the use of groundfault circuit interrupters (GFCIs) will protect the workerunder most circumstances. GFCIs are required by law(Construction Regulation, section 195) wherever portablepower tools are used outdoors or in wet conditions (Figure21.34). GFCIs detect current leaking to ground from anelectric tool or cord and shut off power before injury ordamage can occur.Double-insulated tools provide reliable shock protectionwithout third-wire grounding. Tools with this type ofprotection are permanently marked DOUBLEINSULATION or DOUBLE-INSULATED. These tools have


34 – 9

been tested and listed by Underwriters Laboratories andwill carry the UL symbol. Many manufacturers are alsocarrying the symbol as shown in Figure 21.35 to identifydouble insulation.On a double-insulated electric tool, aninternal layer of protective insulationcompletely isolates the electricalcomponents from the outer housing.Therefore, the third wire or ground wire isnot needed.• All tools should be tested regularly for effective

grounding with a continuity tester (Figure 21.36).• Tools should have deadfront plugs (Figure 21.37).• Make sure the casings of double-insulated tools are

not cracked or broken and are free of moisture, oil,and grease.

MultimetersMultimeters are used for testing circuits. Multimetersdesigned to meet the International Electro-technicalCommission (IEC) 101 and Category (CAT) IIIstandards, when properly operated, offer anacceptable level of protection recognized by theelectrical industry in applications under 750 volts.CAT III devices afford more protection from hightransient voltage spikes than do CAT II and CAT Idesigns.

Look for proof of independent testing, such as theCSA International (Canadian Standards Association)logo, along with CAT III on the equipment. Test levelsshould also be rated at the same or greater categoryand voltage than the multimeter.For guidelines on standards, selection, and use, referto the Electrical Hazards chapter in this manual.

Electric cords and plugs• Inspect regularly and make sure they are in good

condition.• Never cut off, bend, or cheat the ground pin on three-

prong plugs.• Use cords fitted with deadfront plugs (Figure 21.37).

These present less risk of shock and shortcircuit

than open front plugs and prevent strainon current-carrying components when the cord isaccidentally pulled.

• Check extension cords and outlets witha circuit-tester (Figure 21.36).

• Don’t use extension or tool cords that

are defective or have been improperlyrepaired.

• Don’t wire plugs into outlets.Disconnecting will take too long inan emergency.

• Protect cords from traffic.• Extension cords should be kept clear of sharp objects,

heat, oil, and solvents that may damage or soften theouter insulation. Do not use light-duty power cords.

Electric DrillsPortable hand drillscome in a variety oftypes and sizes. Figure21.39 shows a typical lightduty, variable speed drill.Electric drills can causevarious accidents andinjuries, including cuts,gashes, puncturewounds, and eyeinjuries from flyingparticles or broken bits.Proper eye protection isessential. Material beingdrilled should always beclamped or well secured to prevent whipping should the bitbind in the hole (Figure 21.40).Standing on a ladder to drill a hole in a wall or overheadcan be hazardous(Figure 21.41) as wellas hard on theshoulder. The top andbottom of the laddermust be secure toprevent the ladderfrom slipping when theoperator puts pressureon the drill. Never reachout to either side of theladder. Overreaching cancause the ladder to slide ortip. When using any powertool from a ladder, neversupport yourself by holdingonto a pipe or othergrounded object.


Double InsulatedFigure 21.35

Figure 21.36Circuit testers

Figure 21.37Deadfront plug

Figure 21.34

Figure 21.41

34 – 10

Electric current can travel from the hand holding the toolthrough your heart to the hand holding the pipe. A minorshock can make you lose your balance. A major shockcan badly burn or even kill you.Always be sure that the switch is off before plugging inthe drill.Make sure the shank of the attachment is tight and squarein the chuck and running true before starting the drill.Punch or drill a pilot holein the work so that the bitwon’t slip or slide whenyou start drilling. Align thedrill square with the hole— Figure 21.42.

Impact orHammer DrillUsing an impact orhammer drill (Figure21.43) requiresconsiderable control.Feed the attachmentslowly and carefullyinto the material or the drill may jam and stop suddenly,severely twisting or breaking your arm. When drilling intofloors, ceilings, and walls, beware of plumbing — andwiring!Drill PressesOn many jobs, either conventional drill presses or themore mobile electromagnetic drill presses are used. Theypermit more accurate drilling.• Make sure no loose hair or loose or torn clothing can

be caught in the drill bit and cause serious injury.• Before doing any drilling on a workpiece on a

conventional drill press, make sure the work issecurely clamped to the drill table.

• Electromagnetic (“mag”) drills are only “attached” ifswitched on.

• “Mag” drills if “attached” on vertical or overheadferrous surfaces must also be secured by safety chainin case of power loss.

Power SawsUsed on construction sites, power saws of all types are aregular source of injury. Basic safety considerations withany power saw include the following points.• Wear protective clothing and equipment. Eye

protection is essential — a full face shield isrecommended because of the potential for flyingpieces, not just small particles. Hearing protectionshould also be worn.

• Where ventilation is inadequate, wear a dust mask forprotection against dust. Exposure to dust from cuttingmetal, concrete, or other materials may causerespiratory problems over time.

• Electric saws operated outside or in wet locationsmust be protected with a ground fault circuitinterrupter (GFCI).

• Never wear loose clothing, neck chains, scarves, oranything else that may get caught in the saw.

• Leave all safety devices and guards in place andproperly adjusted on the saw.

• Change and adjust blades with the power OFF.Disconnect the saw from the power source.

Chop saws are becoming more popular among manytrades in construction (Figure 21.45). They provide quick,economical cutting of various materials.

As with all power equipment, chop saws pose a serioushazard for the unwary or untrained operator. Most ofthese saws are equipped with abrasive wheels for quickcutting through metal and other materials.• Select the proper abrasive cutting wheel for the

material being cut. For metals, use aluminum oxide.For masonry, stone, and concrete, use silicacarborundum.

• Position material to be cut at 90 degrees to the blade.Support the other end to prevent the blade frombinding.

• Do not rush cutting. Let the wheel cut without burningor jamming.

• When cutting is complete, let the blade stop beforemoving material.

• Keep the saw in good repair with the blade guard inplace and working properly. Tighten any loose partsand replace any broken or damaged components.

Quick-cut saws are widely used for cutting sheet metal,light steel angles, and channels as well as aluminum,concrete, and masonry products (Figure 21.46). They arehigh-powered compared to similar tools. Hazards includehigh-speed rotation, blade exposure during operation, andexhaust from the internal combustion engine — the usualpower source.


34 – 11

Quick-cut saws also create clouds of dust and hot sparkswhen dry-cutting metal products, especially steel.Injuries can result from cuts, kickback, exposure to carbonmonoxide fumes, dust exposure, burns, flying particles inthe eye, and other injuries from flying material when workis not secured for cutting or when blades fly apart.Hazards with quick-cut saws can be controlled by• operators trained to use the saws properly and to

wear the right protective equipment (full face shieldand hearing protection.)

• saws kept in good working condition, equipped withthe proper blades or abrasive disks, and used with allguards in place

• work secured to keep it from shifting during cutting.

Operators of quick-cut saws should be instructed in thecare, maintenance, and operation of the tool. Theoperating manual should be kept on the job and read byusers. Time spent on instruction will reduce accidents andinjuries as well as extend the service life of the saw.As a minimum, the operator of a quick-cut saw should beinstructed in• care of the saw• installing disks and blades• mixing fuel and fuelling the saw• starting the saw• supporting and securing the

work to be cut• proper cutting stance and grip• proper cutting techniques for

different material• respiratory protection against

dust• inspection and storage of

abrasive disks.

In confined areas, make sure thatventilation is adequate. Gasoline-driven saws release carbon

monoxide gas — odourless, colourless, and highly toxic.For safe starting, set one foot on the rear handle, put onehand on the top handle to lift the blade off the surface,and use the other hand to pull the starter cord (Figure21.47).Once the saw is running, release the throttle and makesure the engine drops to idle without the disk or blademoving.Run the engine at full throttle and let the disk or blade runfreely to make sure it turns on the arbor without wobblingor vibrating.The saw is powerful enough to throw material aroundunless it is securely held and supported. Standing onmaterial to hold it down is not recommended.Kickback can happen extremely fast and with tremendouspower. If the segment of the disk or blade shown in Figure21.48 contacts the work, the disk or blade starts to climbout of the cut and can throw the saw up and back towardthe operator with great force.

Take the following precautions• Run the saw at full throttle.• Do not cut above chest height.• When re-entering a cut, do so without causing the

blade or disk to pinch.• Secure and support material at a comfortable position

for cutting. Make sure that material will not move,


Cutting DiskDisk Guard

Cylinder Cover

Throttle Trigger

ThrottleTriggerLockout

Throttle Latch

Carburetor AdjustmentScrews

Figure 21.46

Knob for Guard

Handle Prefilter

Starter Handle

Stop Switch

Choke

Rear Handle

Starter

Fuel Tank

Muffler

Front HandleCover Prefilter

Belt Tensioner

Belt CoverCutting Arm

34 – 12

shift, or pinch the blade or disk during cutting.• Keep steady balance and solid footing when making

cut.• Use both hands to control the saw. Maintain a firm

grip with thumb and fingers encircling the handles.• Never let the upper quarter segment of the blade or

disk contact the material.• Select the right blade for the job (Figure 21.49).

Abrasive Disks - Types and UsesType Uses Materials

Concrete All-around use, most economical Concrete, stone, masonrycutting concrete and masonry. products, cast iron,Water-cooling is recommended aluminum, copper, brass,to increase disk life and cables, hard rubber,reduce cost. plastics.

Metal Primarily for steel, not suited Steel, steel alloys, otherfor masonry products. Water- hard metals such ascooling is not recommended monel and iron.with metal abrasive disks.

Figure 21.49

In addition to the protective equipment that is mandatory onconstruction sites, operators of quick-cut saws should wearsnug-fitting clothing, hearing protection, eye and faceprotection, and heavy-duty leather gloves (Figure 21.50).

For general dust hazards, ahalf-mask cartridgerespirator with NIOSHapproval for dust, mist, andfumes should provideadequate protection whenproperly fitted and worn.Power HacksawsPower hacksawscome in two types;straight blade(reciprocating saw)and continuous blade(portable band saw)as are shown inFigures 21.51 and21.52.

When using a power hacksaw, observe the following.• Wear eye protection.• When starting a cut with a hand-held saw, hold it

above the work, turn it on, and lower it carefully ontothe work (avoid plunge cuts).

• Always start the cut off an edge, never against it.• Always keep the blade guard in place and the blade

sharp.• Keep hands away from the cutting area.• Make sure the material being cut is secure to prevent

movement.• Stay clear of end pieces that may fall after being cut off.• If using the tool as a portable unit, take extreme

caution when cutting conduit or pipe blindly. Makesure it doesn’t contain electrical wires, gases, orchemicals that could produce a hazard.

Portable NibblersPortable nibblers, orpower metal shears, willcut sheet metal up toabout 1/4" thick. Eitherelectric or pneumatic,they have onestationary blade and one powerful shearingblade. Stationary tools will cut heaviersheet or plate. Always securematerial tightly before cuttingand check for clearanceunder the work. SeeFigure 21.53.Portable GrindersGrinding wheels,portable buffers, and wirebrushes are a constantsource of flyingparticles and requirespecial caution. Thestorage, mounting,and operation of grinding wheels calls for thoroughtraining. Figure 21.54 shows types of portable grinders incommon use: straight grinders, with stones half an inchwide or more, by 4 to 8 inches in diameter; and angle, orvertical, grinders with abrasive or sanding disks or cupstones.

Safety in using a portable grinder• Always wear eye protection.• Ring-test abrasive wheels before use.

Ring Test• Clean material from wheel.• Let wheel dry before testing.• Tap wheel with something non-metallic such as thehandle of a screwdriver.

• Tap 1/2" from outside edge.• Rotate wheel 45 degrees and repeat test.• A sound, undamaged wheel will give off a clearmetallic ring. A cracked wheel will give off a dullsound with little or no ring.


Figure 21.50

34 – 13

• Never exceed the safe grinding in rpm for a stone ordisk, which should be specified on the manufacturer’slabel. Make sure the maximum rpm of the grinderdoesn’t exceed the stone speed. Excessive speedcan cause disks and stones to disintegrate with thepotential for causing a serious injury.

• Always unplug the tool before making grinder/cutterinstallations.

• Make sure that the grinding wheel is installedaccording to the manufacturer’s instructions. Use theproper hardware (safety flanges, nuts and blotters) asrecommended for holding the wheel in position.

• Make sure that safety guards are in place andproperly adjusted before operating.

• If you drop a portable grinder or a wheel, inspect itvery carefully for damage.

• Wear hearing protection, especially for extendedoperation. Wear respiratory protection.

• Change disk or stone as recommended bymanufacturer. Excessively worn disks and stones canshatter in use.

• Grind only on the face or outer circumference of thegrinding wheel unless it is specifically designed forside grinding.

• Gloves, aprons, and foot protection may be advisablefor some work, especially if hot sparks are beinggenerated.

• Always stand aside when starting a grinder, especiallywith a newly mounted wheel. Hold it away from youuntil the tool has run at operating speed beforecontacting the work. This can prevent injury from afaulty wheel blowing apart.

• Use light pressure when starting the grinding,especially with a cold wheel — too much pressure ona cold wheel may cause failure.

• Don’t wear loose clothing whengrinding.

• Do not use grinders in the vicinity offlammable materials.

Pencil Grinders and Rotary FilesThese are normally straight die grinders(some have right-angle drive) whichaccept compatible cutters (files or burrs)or abrasive grinding points of smalldiameter, normally under 2 inches.Common types include pencil grindersand rotary files. These grinders operateat high speeds and must be used withcaution. The small-diameter tools run upto about 80,000 rpm and the larger atabout 20-30,000 rpm. The files or burrs are sharp and caneasily cut you, even when static.Precautions are similar to those for other grinders, butthese tools are often unguarded — an added hazard.• Use only the accessories recommended by the

manufacturer and ensure they are speed-rated atleast as high as the no-load RPM on the tool’snameplate. The wrong accessory, if rotated too fast,may shatter during use.

• Use grinding wheels when working with hardmaterials. Rotary files are used for soft materials suchas aluminum, brass, and copper. Using grinding

wheels on soft materials can cause build-up andexcessively load the wheel, with the possibility ofwheel disintegration.

• Never over-tighten the collet; it can damage the collet,cutter or wheel. If the tool doesn’t run smoothly, thecutter may be out of balance. Replace it.

• Excessive pressure can bend or break the collet,mandrel, or wheel/cutter. If the grinder runs smoothlywithout load, but not smoothly under load, too muchpressure is being used.

• Maintain a firm gripon all grinding tools.Always keep thetool pointing awayfrom you. Never usea rotary die grinderwith the cuttertowards you. A slipcould cause seriousinjury.

• Use a vise or clamp to hold the workpiece securely.Never hold a small workpiece by hand.

Air-Powered ToolsMany different types of tools are powered by compressedair. They are fast, powerful, and ideal for repetitive taskssuch as scaling, chipping, and tube shaping or fitting, aswell as a variety of general construction tasks such asbreaking concrete or nailing. There are pneumaticequivalents for most electrical tools, including grinders,drills, and impact wrenches. Some pneumatic tools haveno electrical equivalent, including needle scalers, rotaryimpact scalers, and chipping hammers.Pneumatic tools can operate (when used with a portablecompressor) in locations remote from another source ofpower. Overloading will stall the tool without damaging it;there’s no shock hazard; speed control is variable fromzero to maximum; and fire and explosion hazards can bereduced in some environments where sparking can be aproblem.Air CompressorsPowered by a combustion engine or electric motor, aircompressors supply the air for the tool. Keep the manualwith the machine and follow its directions. Check themaintenance and setup requirements and stick to aregular maintenance schedule.There are basic precautions which must be followed forcompressors.• Inspect before use, check hoses and fittings, and

never use a damaged unit.• Keep the belt guard in place.• When using a gas or diesel powered unit, make sure

there is adequate ventilation and avoid inhalingexhaust gases.

• In cold weather, moisture in the air lines can freeze,reducing the efficiency of the equipment andproducing potential hazards. Anti-freeze systems areavailable in addition to the cold weather precautiongiven below.

Air hoses should be kept clear of traffic and not presenttripping hazards. A hose that is left on the floor should be


34 – 14

protected against damage by running planks along eitherside of it. Where possible, suspend hoses over walkways,traffic routes, and work areas, but take care that hoses donot get caught on passing vehicles.Occasionally workers suffer injuries when compressed airis used to blow dust and dirt from the work area or fromclothing. Compressed air can enter the skin andbloodstream with disastrous results. It can also blowparticles and dust into the air at high velocity, endangeringeyes and lungs. To clean away dust, use a brush orvacuum instead.Always secure hose connectionswith wire, safety clips, or chain toprevent whipping, except whenautomatic couplers are used.Never kink hose tostop air flow. Turn offthe pressure tohoses when thesystem is not in use.In cold weather, after the system is shut down and bled,air hoses should be stored overnight in a warm place sothat any residual moisture cannot condense and freeze. Ifhoses are left out, ice can form inside. On startup theymay be plugged and ice chips can be fired out of the endof the hose. Injuries have resulted from workers beingstruck while looking down the plugged line, or beingstruck by objects used to clear the line. In very coldconditions, a spare set of hoses is a good idea so thatone set can always be stored and dry.

Injuries Caused by Compressed AirAir embolism can lead to death. If compressed airfrom a hose or nozzle enters even a tiny cut on theskin, it can form a bubble in the bloodstream withpossibly fatal results.Physical damage – compressed air directed at thebody can cause injuries, including damage to theeyes and ear drums.Flying particles can accelerate to well over 70 mphwhen compressed air is used to blow off dust, metalshavings, or wood chips. These particles carryenough force to penetrate the skin.Airborne contaminants can include silica and othersubstances hazardous to the respiratory system.

Pneumatic impact toolsWhen using air-powered tools, use only the attachmentsdesigned for them. For example, with impact wrenches,use only impact sockets and adapters manufactured forthis use - they are normally marked, of a dull black colour,6-point, and of heavier wall construction than handsockets. Hand sockets, if used, could shatter and causeinjury. Always check sockets for wear or damage; socketsin poor condition could also shatter.When using larger impact wrenches, don’t try to workalone; always consider whether you need help. A secondworker is often needed for the backup wrench while

tightening to avoid injury due to the torque developed byan impact wrench.Some tools have a high noise level — for instance, impactdrills. To prevent hearing loss, always wear hearingprotection.Match the speed rating of any attachments to the toolspeed. Too fast or too slow a speed can damageattachments, break off fragments, and cause injury.Before start-up, check the couplings and fittings, open thecontrol valve momentarily, connect the hose and blow itout by opening the valve momentarily to remove moistureand dirt, then clean the nipple before connecting the tool.Set air pressure according to manufacturer’sspecifications and open gradually.Make sure that attachments on pneumatic tools aresecured or locked according to manufacturer’sinstructions.Pneumatic impact tools require regular inspection byqualified persons. Replace worn-out absorption pads andsprings. Too much vibration of the tool can damagenerves in fingers, hands, and other body parts. This iscalled “White Finger disease” or Raynaud’s Syndrome.GrindersFor information on the hazards and safe use of pneumaticgrinders, refer back to the section on electric grinders.Apart from thedifferent hazardsconnected withtheir powersources, air- andelectric-poweredgrinders presentthe same basicproblems.Chipping hammers and chisels

Chipping hammers, or chippers (Figure 21.56), areversatile tools for a number of uses with a variety of chiseltips available for attachment (Figure 21.57).Safe practices for chippers include the following.• Always wear eye protection when using a chipping

hammer; make sure anybody else in the immediatearea also has eye protection.


Figure 21.56 Pneumatic chipping hammer

Figure 21.57 Chisel types

34 – 15

• When working, never point the chipper so thatanybody might be hit by an accidentally ejected bit.

• Toward the end of a cut, ease off on the throttle leverto decrease the intensity of the blows to reduce thepossibility of a chip or the tool flying.

• If the hammer has tobe laid down, removethe attachment toprevent it from beingaccidentally ejected ifthe tool isunintentionallystarted.

Air hammers are smallmulti-purpose tools. Figure21.59 shows some commonair hammer attachments.

Safety TipChoose tools with a triggerstrip rather than a triggerbutton. This spreadsforce over a greaterarea, reducing musclefatigue.Rivet gunsA plunger inside the barrel strikes the rivet tool, causing itto shape the rivet head. Since the plunger is free to comeout, it should be removed to prevent loss or dischargewhen the tool is put aside.Air ScalersThe air scaling gun is a lightweight, highspeed tool suitablefor chipping, scaling, and removing caulking, rust, scale,flux, spatter, etc. from all types of surfaces and shapes.

A needle scaler attachment iscommonly used by boilermakers(Figure 21.60). Because of itsconfiguration of many needlesrapidly impacting individually, it isuseful for cleaning all kinds ofsurfaces, including irregular ones,since it automatically fits the irregularcontours.Besides the needle scalerattachment, there are otherchisels that work well with airscalers (Figure 21.61). Some ofthese chisels have an offsetblade at an angle to enableaccess into awkward corners.These are not intended to cutand are therefore sharpenedto a dull edge to clean outslag in corners withoutundercutting.Pipe Power ToolsPower ThreadingMachines (Figure 21.62).These are designed to letthe operator cut, ream,and thread pipe ofvarious sizes all in onepower machine. Themachine must be treatedwith respect. Potentialhazards include:- catching clothing,

gloves, or cleaning rag in revolving parts- being struck by flying metal chips- using a rag to clean oil from threads while machine is

turning- wearing loose-fitting clothes- pipe wrench locking on pipe while reversing previous

operation- losing grip or footing because of oil and debris- failure to install and use the deadman switch.Roll GrooverThis machine forms standardroll grooves in steel,stainless steel, andaluminum pipe. Figure21.63 shows a heavy-dutyroll groover designed for2-inch to 8-inchschedule 40 steelpipe (up to 12-inchfor schedule 20 orlighter wall pipe).Grooves areformed by agrooving roll fed intoa drive roll to theexact specificationsrequired formechanical


coupling systems. The roll groover can be mounted on apower drive or threading machine.Set-up• Read and follow the operator’s manual and the

information on the machine.• Know the location and function of each control before

using the machine.• Wear snug-fitting clothes, safety boots, hard hat, and

eye protection. Cover or tie up long hair. Do not weargloves, unbuttoned jackets, loose sleeve cuffs,neckties, scarves, rings, watches, or other jewelry.

• Wear hearing protection — ear plugs or muffs — ifyou use the machine daily or in a noisy area.

• Use only an approved three-wire cord with a three-prong plug in a grounded receptacle. Replace orrepair any damaged, frayed, broken, or worn cords.

• If an extension cord is required, it must be three-wirewith three-prong plug and three-pole receptacle. Makesure the cord is large enough to prevent excessivevoltage drop.

• Make sure that switch is in the OFF position beforeyou plug in the power cord.

• Connect the machine to an AC power supply thatmatches the nameplate specifications.

Operation• Clear the roll groover of all objects such as tools and

material before turning it on.• Keep guards in place. Never operate the machine

with guards removed or disarmed. Your fingers canget caught between the grooving and drive rolls.

• Operate the roll groover from the switch side only.• Keep good footing and balance. Do not operate the

machine when you are tired.• Do not use the machine in damp or wet conditions.

Do not expose to rain.• Unplug power cord when you are adjusting or

servicing the machine and changing accessories.• Use the footswitch. It lets you shut off the motor

simply by removing your foot.Warning: clothing caught in the roll groover willcontinue to wind up, pulling you into the machine.Because the machine has high torque, the clothingitself can bind around your arm or other body partswith enough force to crush or break bones.

• Make sure that you can quickly remove your foot fromthe footswitch.

• Keep other workers out of the work area. Keep thearea clean, dry, and well lighted.

• Do not reach across the machine.• Properly support the work on a pipe stand.

Maintenance• Follow manufacturer’s instructions for cleaning,

servicing, and inspection.• Keep handles dry,

clean, and freeof grease.

• When not inuse, store theroll groover ina locked areasecure from

people unfamiliar with the machine.• Keep footswitch in working order. When not in use, lock

the switch to avoid accidental start-up (Figure 21.64).

Pipe Preparation ToolsSome power tools are manufactured for specific pipingsystems. Forinstance, theVitaulic PressfitSystem for joiningpipe with speciallydesignedcouplings uses apower crimpingtool (Figure21.65). It isdesigned forschedule 5 blackor galvanized steelpipe prepared tomeet Victaulicspecifications.The T-Drill T-Less tube branching system mechanicallyforms outlets in copper tubing and eliminates the need fortee and cross fittings. The T-Drill (Figure 21.66) drills therequired hole in the pipe and forms a collar to accept thebranch pipe. The tube end notcher cuts and dimples thebranch tube to limit insertion depth. The joint is thenbrazed.

Victaulic crimpers and T-Drills are being used more andmore in automatic sprinkler system installation. Take thefollowing precautions.• Read and understand all instructions in the

manufacturer’s operating manual before operating orservicing the tools.

• Inspect all movable parts before starting the tools.Check for obstructions and proper installation ofcomponents.

• Disconnect tools from power source before changingaccessories or servicing. Be sure switch is off beforeplugging in the tools.

• Use only replacement parts supplied by themanufacturer.

• Keep work area clean.• Guard against shock. Prevent body contact with

grounded surfaces. Always use a ground fault circuitinterrupter.

• Do not carry live tools with your finger on the switch.


Figure 21.65

Footswitch

34 – 16

34 – 17

• Keep unauthorized personnel out of the work area.• Store tools in a dry location in a locked container.• Do not force or overload the tool.• Wear adequate eye protection.• Use the tools only for their intended purpose.• Do not operate the tools while wearing loose clothing,

jewelry, or anything else that could get caught inmoving parts.

• Never carry tools by the cord or yank the cord todisconnect the tool from the receptacle. Protect cordfrom heat, pinch points, and sharp edges.

• Use clamps, vice, or secure pipe hangers to holdwork in place.

• Do not overreach. Keep proper footing and balance atall times.

• Keep tools clean and lubricated. Repairs should bedone only by an authorized service shop. Inspect andreplace damaged extension cords. Keep handlesclean, dry, and free from oil and grease.

• Do not operate tools near flammable liquids or inexplosive atmospheres.

Powder-Actuated ToolsReferred to as explosive-actuated or powder-actuated,these tools use a powder charge to fire a fastener intohard materials such as concrete, mild steel, and masonry(Figure 21.67). They provide a fast, efficient means offastening certain combinations of materials.

Used improperly, powder-actuated tools present obvioushazards. For that reason, most jurisdictions — includingOntario — require that operators be trained before usingthese tools.Flying particles are the majorhazard. On impact, materialsmay break up, blow apart, orspall off. This often happenswhen fasteners are fired tooclose to a corner of masonryor concrete (Figure 21.68) orwhen they strike materialssuch as glazed tile, hollow tile, or thin marble tile.Ricochets usually result when the tool is not at rightangles to the material or the fastener hits a particularlyhard base material such as stone or hardened steel.Always check the base material to ensure that it willsafely accept the fastening device.Noise is extreme when powder-actuated tools are fired.Operators and others in the area should wear hearingprotection. This is especially important when the tool isoperated in a confined space.Sprain and strain injuries usually result from using the toolrepeatedly in awkward, cramped, or unbalanced positions.Operators should try to work from a balanced position ona solid surface.

Explosions and fires are always a risk when the tools areused where atmospheres may be flammable. The workarea must be well ventilated, mechanically if necessary,as in confined spaces.Blow-through results when the base material does notoffer enough resistance and the fastener passescompletely through and flies out the other side. This isparticularly dangerous when fasteners blow through walls,floors, or ceilings where other trades may be working onthe opposite side. Check the other side of walls, ceilings,and floors before firing and keep people clear ifnecessary.Protective equipment for the operator of a powder-actuated tool should include hearing protection, eyeprotection, and a face shield. Heavy shirts and pantsprovide some protection against ricochets and fragmentsof material or fasteners.High velocity powder-actuated tools use the explodingcartridge to propel the fastener directly rather than by apiston. These tools are rarely used in construction, exceptin special cases to penetrate thick steel or very hardmaterial. These applications are usually military, salvage,or underwater. No one should operate high-velocity toolswithout special training.Low velocity tools are the most common for construction.The explosive charge drives a piston which in turn drivesthe fastener (Figure 21.69).

Many different low velocity tools are available. Some arespecialized for certain trades such as drywalling. Othersare fitted with various pistons, base plates, spall stops,and protective shields for heavier-duty work.Generally, low velocity tools should only be used on mildor structural grade steel no thicker than 7mm (1/4").Fasteners used withpowder-actuated toolssuch as studs and pins(Figure 21.70) are madeof special steel to allowthem to penetratematerials without breakingor bending.The fastener is fitted with a tip or eyelet as a guide. Thisaligns the fastener on the tool as it is being driven. It isalso used to retain the fastener in the tool.Generally, fasteners should not be used on hard, brittle, orglazed materials such as cast iron, marble, tiles, and moststone. The fastener will either fail to penetrate andricochet or the base material will shatter or spall.Materials whose hardness or ductility is unknown shouldbe tested first. Try to drive a pin into the material with astandard hammer. If the pin point is blunted or fails topenetrate at least 2mm (1/16"), don’t use a powder-actuated tool.


Figure 21.70

34 – 18

Cartridges are available in various powder loads.Manufacturers may recommend cartridges for certainapplications but recommendations cannot cover everypossibility and testing may be required with unfamiliarmaterial. The general rule is to start with the weakestcartridge and increase one load number at a time to reachthe penetration required.Too strong a charge may shatter material, ricochet, orblow through. Standard loads, colour coding, andvelocities for cartridges are listed in Figure 21.71.

Misfired cartridges can be dangerous. Take the followingprecautions.• Hold the tool against the material for at least 30

seconds in case firing is delayed.• Remove the cartridge from the tool with the tool

pointed toward soft material such as wood.• Regulations require that a misfired cartridge be

placed in a container of water.• Never throw a misfired cartridge in the garbage.Explosive-Actuated Tools — General Safeguards• Explosive-actuated tools should not be used, handled,

or stored carelessly.• Don’t fire fasteners through pre-drilled holes for two

reasons:1) Unless the fastener hits the hole squarely, it will

probably shatter the edge.2) The fastener gets its holding power from

compressing the material around it. A pre-drilledhole reduces this pressure and therefore thefastener’s power.

• Because pressure must be applied to the material intowhich a fastener is being driven before the tool willfire, working from a ladder is not recommended. Forwork overhead or at heights, operate the tool from ascaffold or other approved work platform.

• Do not leave the tool unattended unless it’s locked ina box.

• Load the tool immediately before firing. Don’t walkaround with the tool loaded.

• Do not use powder-actuated tools in areas where theatmosphere may be explosive or flammable.

The Regulations for Construction Projects define theminimum requirements for the operation, maintenance,storage, and training of workers. Refer to the regulationsbefore operating any powder-actuated tool.


Colour Identification of Powder Load StrengthsLoad Cartridge Powder Load Nominal VelocityNumber Case Colour Colour m/s ft/s1 Brass Grey 91.4 3002 Brass Brown 118.8 3903 Brass Green 146.3 4804 Brass Yellow 173.7 5705 Brass Red 201.2 6606 Brass Purple 228.6 7507 Nickel Grey 256.0 8408 Nickel Brown 283.5 9309 Nickel Green 310.9 102010 Nickel Yellow 338.3 111011 Nickel Red 365.8 120012 Nickel Purple 393.2 1290

Figure 21.71

35 – 1

35 WELDING AND CUTTING

Welding is a process which uses heat and/or pressure tojoin metals.Arc welding is by far the most commonly used inconstruction. Molten metal from the workpiece and a fillermetal from an electrode form a common puddle whichcools to form a weld.Flame cutting is an allied process that requires the use ofa torch, fuel gas, and oxygen to cut metals — primarilysteel.For some of the information in this chapter, theConstruction Safety Association of Ontario gratefullyacknowledges its use of the Canadian StandardsAssociation standard CAN/CSA-W117.2 Safety inWelding, Cutting and Allied Processes, copyright CSA.

Welding MethodsShielded Metal Arc Welding (SMAW) is the most commonarc welding process in construction (Figure 20.1).SMAW uses a short length of consumable electrodewhich melts as it maintains the arc. Melted metal from theelectrode is carried across the arc to become the fillermetal of the weld.The electrode is coated with a complex mix of chemicalsthat releases a shielding gas such as carbon dioxide tokeep air out of the arc zone and protect the weld fromoxidation. The composition of the coating varies with themetal being welded.

GasMetal Arc (GMAW) or Metal Inert GasWelding (MIG)uses an uncoated consumable wire that is fed continuouslydown the middle of the welding torch. A ring-like tube

around the wire transports an inert gas such as argon,helium, or carbon dioxide from an outside source to the arczone to prevent oxidation of the weld (Figure 20.2).Flux Cored ArcWelding (FCAW)is a variation ofMIG welding. Ituses a hollowconsumable wirewhose corecontains variouschemicals thatgenerateshielding gases tostrengthen theweld (Figure20.3).Gas Tungsten Arc Welding (GTAW) or Tungsten Inert GasWelding (TIG) uses a non-consumable tungsten electrodethat maintains the arc and provides enough heat to joinmetals (Figure 20.4). Filler metal is added in the form of arod held close to the arc. The rod melts and deposits fillermetal at the weld. Shielding gases may or may not beused, depending on the metal being welded.

Oxyacetylene Weldingand Cutting burns amixture of gases —oxygen and acetylene —to generate heat forwelding metals (Figure20.5). It’s the mostcommon fuel gas cuttingand welding used inconstruction. Theprocess may also employ the use of a filler metal.

ACETYLENEAcetylene is a mixture of carbon and hydrogen. Its storedenergy is released as heat when it burns. When burnedwith oxygen, acetylene can produce a higher flametemperature (3,300°C) than any other gas usedcommercially. The wide flammable range of acetylene(2.5% to 81% in air) is greater than that of othercommonly used gases, with consequently greater hazard.

OTHER FUEL GASESFuel gases for welding are used alone or with oxygen.Examples include propane, propylene, and natural gas.

WELDING AND CUTTING

Electrode Coating

Arc

Slag

Solidified Metal

Base Metal

Figure 20.1

Molten Metal

Electrode Wire

Protective Gas fromElectrode Coating

Wire Drive

Figure 20.2

PowerSource Controls

Contactor

Gas Nozzle

Current-CarryingContact Tube

Flux-CoredElectrode

MoltenWeld Metal

SolidifiedWeld Metal

Gas Shielding

Figure 20.3

Workpiece

Figure 20.4

TungstenElectrode

Power Source

Gas Shielding

Mixer

GasSupplies

Nozzle

Workpiece

Figure 20.5

35 – 2

Types of Base Metals WeldedMild Steel (an alloy of iron, carbon, silicon, andoccasionally molybdenum or manganese).Stainless and High Alloy Steels (containing iron, nickel,chromium, and occasionally cobalt, vanadium,manganese, and molybdenum).Aluminum (either pure or as an alloy containingmagnesium, silicon, and occasionally chromium).Galvanized steel (steel that has been coated with alayer of zinc to prevent corrosion).

Welding HazardsWelders in construction are exposed to a wide range ofhazards such as inhalation of toxic fumes and gases,serious burns from hot metal, and electric shocks fromwelding cable.

Welding HazardsPhysical - ionizing radiation (x-rays, gamma rays)

- non-ionizing radiation (ultraviolet, infrared)- visible light- temperature extremes- noise- electrical energy

Chemical - flammable/combustible products- welding fumes- toxic gases- dust

Biological - bacteria- fungi- viruses

Eye protection is a must for welders and others who maybe exposed to the welding process.Once a chemical from welding has entered the body itmay have a toxic effect. Effects can range from mildirritation to death and are influenced by a number offactors. Different organs may also be affected, such asthe lungs, kidneys, and brain.The two major types of effects are acute and chronic, asdescribed in the Basic Occupational Health chapter in thismanual.

PHYSICAL HAZARDSRadiationBoth ionizing and non-ionizing radiation may beencountered by welders and their helpers. Ionizing ismore hazardous because it can contribute directly tocancer.Ionizing — A common source is the emission of x-raysand gamma rays from equipment used to gauge thedensity and thickness of pipes and to check welds.Non-ionizing — A major source is ultraviolet, infrared, andvisible light radiation from sunlight or welding.Radiation produced by the welding process is mainly non-ionizing, which includes electromagnetic fields, infraredradiation, visible light, and ultraviolet radiation.

Exposure to ultraviolet (UV) radiation can result directlyfrom the arc or from a reflection off bright objects such asshiny metal or white clothing. It can cause “arc eye” whensight is not adequately protected. Eyes become wateryand painful anywhere from 2 to 24 hours after exposure.The condition may last 1–5 days but is usually reversiblewith no lasting effects. However, repeated exposure mayresult in scar tissue that can impair vision.UV exposure may also cause a temporary loss of visualsharpness called “fluorescence.”Skin reddening, commonly known as sunburn, is anotherhazard of UV exposure. Blistering may occur in extremecases. Although excessive exposure to UV radiation fromthe sun has been linked to skin cancer, there are noreports of increased skin cancer rates from weldingexposure.The intensity of UV radiation varies with the type ofwelding. Generally, the higher the temperature of thewelding process the higher the UV radiation.Infrared radiation is hazardous for its thermal or heatingeffects. Excessive exposure to the eye may causedamage.Visible light is released at high intensity by welding. Short-term exposure can produce “flash blindness” in whichvision is affected by after-images and temporary blindspots. Repeated exposure to high-intensity visible lightcan produce chronic conjunctivitis, characterized by red,tearful eyes.X-rays and gamma rays are invisible forms of ionizingradiation used to inspect welds and can be extremelydamaging to unprotected parts of the body. Keep wellaway from any area where this type of testing is underway. X-rays are also produced during electron beamwelding. The welding chamber must be completelyshielded to confine the x-rays and protect the operator.Extreme TemperaturesVery high temperatures are caused by the weldingprocess. Gas flames may reach 3,300°C. Metals melt in arange from 260°C to 2,760°C. Welded materials, the workenvironment, and weather may all be sources ofexcessive heat which can cause muscle cramps,dehydration, sudden collapse, and unconsciousness.Welders may suffer frostbite and hypothermia whenworking in extreme cold climates or with welding gasesstored at temperatures as low as -268°C. Exposure tofreezing temperatures can lead to fatigue, irregularbreathing, lowered blood pressure, confusion, and loss ofconsciousness. Heat stress and cold stress are both life-threatening and, if not treated in time, can be fatal.NoiseSound waves over 85 dBA emitted at high intensity bywelding equipment can lead to hearing loss. Noise hasalso been linked to headaches, stress, increased bloodpressure, nervousness, and excitability. See the chapteron Hearing Protection for information on maximumexposures for workers not equipped with hearingprotection.Welding noise is produced by the power source, thewelding process, and by secondary activities such as

WELDING AND CUTTING

35 – 3

grinding and hammering. Gasoline power sources maylead to sound exposures over 95 dBA. Arc gouging mayproduce sound levels over 110 dBA. Grinding, machining,polishing, hammering, and slag removal all contribute tohigh levels of noise. Substantial hearing loss has beenobserved in welders.Electrical EnergyElectrical shock is the effect produced by current on thenervous system as it passes through the body. Electricalshock may cause violent muscular contractions, leading tofalls and injuries. It may also have fatal effects on theheart and lungs.Electrical shock may occur as a result of impropergrounding and/or contact with current through dampclothing, wet floors, and other humid conditions. Even ifthe shock itself is not fatal, the jolt may still cause weldersto fall from their work positions.Electrical burns are an additional hazard. The burns oftenoccur below the skin surface and can damage muscle andnerve tissue. In severe cases, the results can be fatal.The extent of injury due to electrical shock depends onvoltage and the body’s resistance to the current passingthrough it (see the Electrical Hazards chapter in thismanual). Even low voltages used in arc welding can bedangerous under damp or humid conditions. Weldersshould keep clothing, gloves, and boots dry and stay wellinsulated from work surfaces, the electrode, the electrodeholder, and grounded surfaces.Stray CurrentStray welding current may cause extensive damage toequipment, buildings, and electrical circuits under certainconditions.

CHEMICAL HAZARDSChlorinated solvents for degreasing, zinc chromate-basedpaint for anti-corrosion coatings, cadmium or chromiumdusts from grinding, and welding fumes are all classifiedas chemical hazards.Arc welders are at particular risk since the hightemperatures generated by the arc can release heavyconcentrations of airborne contaminants.Chemical hazards may injure welders through inhalation,skin absorption, ingestion, or injection into the body.Damage to respiratory, digestive, nervous, andreproductive systems may result. Symptoms ofoverexposure to chemicals may include nosebleeds,headaches, nausea, fainting, and dizziness.Read the manufacturer’s material safety data sheet(MSDS) for information on protective measures for anychemical you encounter in the workplace.The most common chemical hazards from welding areairborne contaminants that can be subdivided into thefollowing groups:- fumes- gases/vapours- dusts.The amount and type of air contamination from thesesources depends on the welding process, the base metal,

and the shielding gas. Toxicity depends on theconcentration of the contaminants and the physiologicalresponse of individual workers.FumesSome of the metal melted at high temperates duringwelding vaporizes. The metal vapour then oxidizes to forma metal oxide. When this vapour cools, suspended solidparticles called fume particles are produced. Weldingfumes consist primarily of suspended metal particlesinvisible to the naked eye.Metal fumes are the most common and the most serioushealth hazard to welders. Fume particles may reach deepinto the lungs and cause damage to lung tissue or enterthe bloodstream and travel to other parts of the body. Thefollowing are some common welding fumes.Beryllium is a hardening agent found in copper,magnesium, and aluminum alloys. Overexposure maycause metal fume fever. Lasting for 18–24 hours, thesymptoms include fever, chills, coughing, dryness ofmouth and throat, muscular pains, weakness, fatigue,nausea, vomiting, and headaches. Metal fume feverusually occurs several hours after the exposure and thesigns and symptoms usually abate 12–24 hours after theexposure with complete recovery. Immunity is quicklyacquired if exposure occurs daily, but is quickly lost duringweekends and holidays. For this reason, metal fume feveris sometimes called “Monday morning sickness.”Long term (chronic) exposure to beryllium fumes can resultin respiratory disease. Symptoms may include coughingand shortness of breath. Beryllium is a suspectedcarcinogen — that is, it may cause cancer in human tissue.It is highly toxic. Prolonged exposure can be fatal.Cadmium-plated or cadmium-containing parts resemble,and are often mistaken for, galvanized metal. Cadmiumcoatings can produce a high concentration of cadmiumoxide fumes during welding. Cadmium is also found insolders (especially silver solder) and brazes.Overexposure to cadmium can cause metal fume fever.Symptoms include respiratory irritation, a sore, dry throat,and a metallic taste followed by cough, chest pain, anddifficulty in breathing. Overexposure may also make fluidaccumulate in the lungs (pulmonary edema) and maycause death. The liver, kidneys, and bone marrow canalso be injured by the presence of this metal.Chromium is found in many steel alloys. Known to be askin sensitizer, it may cause skin rashes and skin ulcerswith repeated exposure. Chromium also irritates mucousmembranes in areas such as eyes and nose and maycause perforation of the nasal septa. Inhaled chromiummay cause edema and bronchitis.Lead can be found in lead-based paints and some metalalloys. Lead poisoning results from inhalation of lead fumesfrom these lead-based materials. The welding and cutting oflead or lead-coated materials is the primary source of leadpoisoning for welders. Symptoms include loss of appetite,anemia, abdominal pains, and kidney and nerve damage.Under Ontario law, lead is a designated substance requiringspecial precautions for use and handling.Nickel is found in many steel alloys including stainlesssteel and monel. It is a sensitizing agent and in certain

WELDING AND CUTTING

35 – 4

forms is toxic and carcinogenic. Nickel fumes can alsoproduce cyanosis, delirium, and death 4 to 11 days afterexposure.Zinc is found in aluminum and magnesium alloys, brass,corrosion-resistant coatings such as galvanized metal,and brazing alloys. Inhaling zinc fumes during the cuttingor welding of these metals may cause metal fume fever.Vapours/GasesA gas is a low-density chemical compound that normallyfills the space in which it is released. It has no physicalshape or form. Vapour is a gas produced by evaporation.Several hazardous vapours and gases may be producedby welding. Ultraviolet radiation, surface coatings,shielding gases, and rod coatings are primary sources ofvapours and gases. Overexposure may produce one ormore of the following respiratory effects:• inflammation of the lungs• pulmonary edema (fluid accumulation in the lungs)• emphysema (loss of elasticity in lung tissue)• chronic bronchitis• asphyxiation.Hydrogen fluoride (HF) gas can be released by thedecomposition of rod coatings during welding and irritatesthe eyes and respiratory system. Overexposure can injurelungs, kidney, liver, and bones. Continued low-levelexposures can result in chronic irritation of nose, throat,and bronchial tubes.Nitrogen oxide (NOx) gas is released through a reactionof nitrogen and oxygen promoted by high heat and/or UVradiation. It is severely irritating to the mucousmembranes and the eyes. High concentrations mayproduce coughing and chest pain. Accumulation of fluid inthe lungs can occur several hours after exposure and maybe fatal.Ozone gas is formed by the reaction of oxygen in air withthe ultraviolet radiation from the welding arc. It may be aproblem during gas-shielded metal arc welding in confinedareas with poor ventilation. Overexposure can result in anaccumulation of fluid in the lungs (pulmonary edema)which may be fatal.Phosgene gas is formed by the heating of chlorinatedhydrocarbon degreasing agents. It is a severe lung irritantand overexposure may cause excess fluid in the lungs.Death may result from cardiac or respiratory arrest. Theonset of symptoms may be delayed for up to 72 hours.Phosphine or hydrogen phosphide is produced when steelwith a phosphate rustproofing coating is welded. Highconcentrations irritate eyes, nose, and skin.Asphyxiants are chemicals which interfere with thetransfer of oxygen to the tissues. The exposed individualsuffocates because the bloodstream cannot supplyenough oxygen for life. There are two main classes ofasphyxiants — simple and chemical.Simple asphyxiants displace oxygen in air, thereby leavinglittle or none for breathing. In welding, simple asphyxiantsinclude commonly used fuel and shielding gases such asacetylene, hydrogen, propane, argon, helium, and carbondioxide. When the normal oxygen level of 21% drops to

16%, breathing as well as other problems begin, such aslightheadedness, buzzing in the ears, and rapid heartbeat.Chemical asphyxiants interfere with the body’s ability totransport or use oxygen. Chemical asphyxiants can beproduced by the flame-cutting of metal surfaces coated,for instance, with rust inhibitors. Hydrogen cyanide,hydrogen sulphide, and carbon monoxide are examples ofchemical asphyxiants — all highly toxic.DustsDusts are fine particles of a solid which can remainsuspended in air and are less than 10 micrometres insize. This means they can reach the lungs. Dusts may beproduced by fluxes and rod coatings which releasephosphates, silicates, and silica. The most hazardous ofthese is silica which can produce silicosis — a disease ofthe lung which causes shortness of breath.

BIOLOGICAL HAZARDSBiological hazards are a relatively minor concern forconstruction welders. However, exposure to bacteria mayoccur in sewer work, while air handling systemscontaminated by bacteria and fungi can causelegionnaires’ disease and other conditions. A fungus thatgrows on bird or bat droppings is responsible for a diseasecalled histoplasmosis, producing flu-like symptoms.Contact may occur where buildings contaminated withdroppings are being renovated or demolished.

Fires/ExplosionsThere is always a threat of fire with welding. Fires mayresult from chemicals reacting with one another to formexplosive or flammable mixtures. Many chemicals bythemselves have low ignition points and are subject toburning or exploding if exposed to the heat, sparks, slag,or flame common in welding. Even sparks from cuttingand grinding may be hot enough to cause a fire.In welding, oxygen and acetylene present the mostcommon hazards of fire and explosion.Pure oxygen will not burn or explode but supports thecombustion of other materials, causing them to burn muchmore rapidly than they would in air.Never use oxygen to blow dust off your clothing. Oxygenwill form an explosive mixture with acetylene, hydrogen,and other combustible gases.Acetylene cylinders are filled with a porous materialimpregnated with acetone, the solvent for acetylene.Because acetylene is highly soluble in acetone at cylinderpressure, large quantities can be stored in comparativelysmall cylinders at relatively low pressures.

Preventive MeasuresWelding hazards must be recognized, evaluated, andcontrolled to prevent injury to personnel and damage toproperty.The WHMIS chapter in this manual explains the informationon hazardous materials that can be provided by WHMISsymbols, labels, and material safety data sheets.Once a welding hazard has been identified, controls can beimplemented at its source, along its path, or at the worker.

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35 – 5

EXPOSURE FACTORSTypes and effects of airborne contaminants produced bywelding depend on the working environment, the kind ofwelding being done, the material being welded, and thewelder’s posture and welding technique.The environment for welding is a very important factor inthe degree of exposure to fumes, vapours, and gases.Welding is best done outside or in open areas withmoderate air movement. Air movement is necessary todissipate fumes before they reach the welder. Enclosedareas with little ventilation can lead to very high exposurelevels because the contaminant is not dispersed. Inconfined spaces, fume, vapour, and gas levels that aredangerous to life and health may result. Welding may alsouse up the oxygen in a confined space, causing thewelder to lose unconsciousness or even die.The base metal to be welded is an important factor in theproduction of fumes, vapours, and gases. The base metalwill vaporize and contribute to the fume.Coatings such as rust inhibitors have been known tocause increased fume levels which may contain toxicmetals. All paints and coatings should be removed fromareas to be welded as they can contribute to the amountand toxicity of the welding fume.Welding rod is responsible for up to 95% of the fume.Rods with the fewest toxic substances can’t always beused because the chemistry of the rod must closely matchthat of the base metal.Shielding gas used during SMAW can effect thecontaminants produced. Using a mixture of argon andcarbon dioxide instead of straight carbon dioxide hasbeen found to reduce fume generation by up to 25%.Nitric oxide in the shielding gas for aluminum duringGMAW has been found to reduce ozone levels.Welding process variables can have a big effect on thefume levels produced. Generally, fume concentrationsincrease with higher current, larger rods, and longer arclength. Arc length should be kept as short as possiblewhile still producing good welds. Polarity is also a factor.Welding with reversed polarity (work piece negative) willresult in higher fumes than welding with straight polarity(work piece positive).The welder’s posture and technique are crucial factors ininfluencing exposure. Studies have shown that differentwelders performing the exact same task can haveradically different exposures. Welders who bend overclose to the welding location, those who positionthemselves in the smoke plume, and those who use alonger arc than required will have a much greaterexposure. The welder should try to take advantage ofexisting ventilation (cross drafts, natural, or mechanical) todirect the plume away from the breathing zone.

VENTILATIONVentilation is required for all cutting, welding, and brazing.Adequate ventilation is defined as the use of airmovement to• reduce concentrations of airborne contaminants below

the acceptable limits in the worker’s breathing zoneand the work area

• prevent the accumulation of combustible gases andvapours, and

• prevent oxygen-deficient or oxygen-enrichedatmospheres.

You need to take special steps to provide ventilation• in a space of less than 283 cubic metres per welder• in a room with a ceiling of less than 4.9 metres• in confined spaces or where the area contains

partitions or other structures which significantlyobstruct cross-ventilation.

Natural dilution ventilation— welding outside in a lightbreeze or inside with doors and windows open provideslarge volumes of fresh air which should disperse airbornecontaminants sufficiently in most cases. However, it isimportant for the welder to stay to one side of the plume.Natural dilution ventilation alone should not be used forwelding, cutting, and allied processes in confined spacesor spaces containing structural barriers that restrict naturalair movement.

Mechanical dilution ventilation is common in most weldingshops. Fans such as roof exhaust fans and wall fansforce outside air into and out of the building. Generalmechanical ventilation in most cases will deflect theplume out of the welder’s breathing zone. Welders needdifferent amounts of fresh-air ventilation depending on thespecific task and the size of rod they’re using. For airvolume recommendations, see the American Conferenceof Governmental Industrial Hygienists’ IndustrialVentilation: A manual of recommended practice.

Local exhaust ventilation consists of an exhaust fan, aircleaner, and ducted system dedicated to removingairborne contaminants at the source and exhausting themoutdoors. Local exhaust ventilation is preferred overdilution ventilation because it is better able to prevent

WELDING AND CUTTING

Natural dilution ventilation• Welding outside in light breeze• Welding inside with doors, windows open

NOTE: Weldermust stay to oneside of plume.

Mechanical dilution ventilation• Air forced into and out of work area• Roof exhaust fans• Wall fans

NOTE: Airvolume shoulddeflect plume outof welder’sbreathing zone.

35 – 6

airborne contaminants from entering the welder’sbreathing zone.Local exhaust ventilation is recommended for weldingwhere toxic airborne contaminants are produced and/orwhere a high rate of fume is produced — for instance,during GMAW in confined areas with little ventilationwhere the shielding gases can build up to toxic levels.There are three types of local exhaust ventilation systemsfor welding:1) portable fume extractor with flexible ducting

(Figure 20.6)2) fume extraction gun (Figure 20.7)3) welding bench with portable or fixed hood

(Figure 20.8).

The effectiveness of local exhaust ventilation depends onthe distance of the hood from the source, air velocity, andhood placement. Hoods should be located close to thesource of airborne contaminants. The hood is placedabove and to the side of the arc to capture airbornecontaminants.

Warning: In all processes that use shielding gas, airvelocities in excess of 30 metres/minute may stripaway shielding gas.

Ventilation RequirementsThere are two methods for determining ventilationrequirements.One uses air sampling to measure the welder’s exposureto airborne contaminants and to determine theeffectiveness of the ventilation provided. Monitoring is notwell suited to construction because site conditions areconstantly changing.The other method uses tables to select the type ofventilation according to the process, materials, productionlevel, and degree of confinement used in the weldingoperation.

Ventilation guidelines for different welding processes arespelled out in Canadian Standards Association standardCAN/CSA-W117.2 Safety in Welding, Cutting and AlliedProcesses, copyright CSA.Other ControlsAn isolation chamber is a metal box with built-in sleevesand gloves. The work is welded inside the box and viewedthrough a window. This method is used to weld metals thatproduce extremely toxic fumes. The fumes are extractedfrom the isolation chamber and ducted outdoors.Respiratory protection willnot be required for mostwelding operations ifproper ventilation isprovided. However, whenventilation or othermeasures are notadequate, or when thewelding process createstoxic fumes (as withstainless steel andberyllium), respiratoryprotection must be worn.Select respiratory protectionbased on estimatedexposure and the toxicity ofthe materials. Disposablefume respirators areadequate for low fumelevels and relatively non-toxic fumes. For higherexposures or for workinvolving toxic fumes, a half-mask respirator withcartridges suitable forwelding fume should be used (Figure 20.9).In areas where fume or gas concentrations may beimmediately dangerous to life and health, a self-containedbreathing apparatus (SCBA) or a supplied-air respiratorwith a reserve cylinder should be used (Figure 20.10).Use only supplied air or self-contained respirators inareas where gases may build up or where there can be areduction in oxygen.A welder required to wear a respirator must be instructedin its proper fitting, use, and maintenance. For moreinformation, refer to the Respiratory Protection chapter ofthis manual.

FIRE PREVENTIONSparks and slag from cutting, grinding, and welding cantravel great distances and disappear through cracks inwalls and floors or into ducts. They may contactflammable materials or electrical equipment. Fires havestarted in smoldering materials that went undetected forseveral hours after work was done.Take the following steps to prevent fires and explosions.• Obtain a hot work permit through the safety officer if

required.• Keep welding area free of flammable and explosive

material.

WELDING AND CUTTING

Local ExhaustSystems

PortableFumeExtractor

FumeExtractionGun

Bench withPortable Hood

Figure 20.6

Figure 20.7

Figure 20.8

ReplaceableFilter

Facepiece

Figure 20.9ExhalationValve

Strap

InhalationValve

Figure 20.10

ReserveCylinder

Airline

35 – 7

• Use a flammable gas and oxygen detector todetermine whether a hazardous atmosphere exists.

• Provide fire barriers such as metal sheets or fireblankets and fill cracks or crevices in floors to preventsparks and slag from passing through.

• Provide fire extinguishers suitable for potential typesof fire. Know where the extinguishers are and how touse them.

• Provide a firewatch where necessary — a worker towatch for fires as the welder works and for at leastthirty minutes afterward. The person must be fullytrained in the location of fire alarms and the use offire-fighting equipment. Some situations may requiremore than one firewatch, such as on both sides of awall or on more than one floor.

Cutting torches should be equipped with reverse flowcheck valves and flame arrestors to prevent flashbackand explosion (Figure 20.11). These valves must beinstalled according to the manufacturer’s instructions.

Drums, tanks, andclosed containers thathave held flammable orcombustible materialsshould be thoroughlycleaned before weldingor cutting. As an addedprecaution, purge withan inert gas such asnitrogen or carbondioxide and fill with water to within an inch or two of theplace to be welded or cut and vent to atmosphere (Figure20.12).Many containers that have held flammable or combustiblematerials present special problems. Consult themanufacturer or the product MSDS for detailedinformation.

Arc Welding and CuttingEQUIPMENTOnly use manual electrode holders that are specificallydesigned for arc welding and cutting and can safelyhandle the maximum rated current capacity required bythe electrodes.Any current-carrying parts passing through the portion ofthe holder in the welder or cutter’s hand, and the outer

surfaces of the jaws of the holder, should be fullyinsulated against the maximum voltage encountered toground.Arc welding and cutting cables should be completelyinsulated, flexible, and capable of handling the maximumcurrent requirements of the work as well as the duty cycleunder which the welder or cutter is working.Avoid repairing or splicing cable within 10 feet of the cableend to which the electrode holder is connected. Ifnecessary, use standard insulated connectors or spliceswhich have the same insulating qualities as the cablebeing used. Connections made with cable lugs must besecurely fastened together to give good electrical contact.The exposed parts of the lugs must be completelyinsulated. Do not use cables with cracked or damagedinsulation, or exposed conductors or end connectors.A welding cable should have a safe current carryingcapacity equal to or exceeding the maximum capacity ofthe welding or cutting machine.

Warning: Never use the following as part of thecurrent path:• cranes• hoists• chains• wire ropes• elevator structures• pipelines containing gases or flammable liquids• conduits containing electrical circuits.

The work lead, often incorrectly referred to as the groundlead, should be connected as close as possible to thelocation being welded to ensure that the current returnsdirectly to the source through the work lead.A structure employed as a work lead must have suitableelectrical contact at all joints. Inspect the structureperiodically to ensure that it is still safe. Never use anystructure as a circuit when it generates arc, sparks, orheat at any point.The frames on all arc welding and cutting machines mustbe grounded according to the CSA standard or theregulatory authority. Inspect all ground connections toensure that they are mechanically sound and electricallyadequate for the required current.

PROCEDURES• When electrode holders are to be left unattended,

remove electrode and place holder so it will not makecontact with other workers or conducting objects.

• Never change electrodes with bare hands or with wetgloves.

• Do not dip hot electrode holders in water to cool themoff.

• Keep cables dry and free of grease to preventpremature breakdown of insulation.

• Cables that must be laid on the floor or ground shouldbe protected from damage and entanglement.

• Keep welding cables away from power supply cablesand high tension wires.

• Never coil or loop welding cables around any part ofyour body.

• Do not weld with cables that are coiled up or onspools. Unwind and lay cables out when in use.

WELDING AND CUTTING

Normal Operating Condition Check Valve

Reverse Flow Condition Check Valve

Figure 20.11

Joint to be repaired

Keep air space assmall as possible

Water

Figure 20.12

35 – 8

• Before moving an arc welding or cutting machine, orwhen leaving machine unattended, turn the powersupply OFF.

• Report any faulty or defective equipment to yoursupervisor.

• Read and follow the equipment manufacturer’sinstructions carefully.

• Prevent shock by using well-insulated electrodeholders and cables, dry clothing and gloves, rubber-soled safety boots, and insulating material (such as aboard) if working on metal.

• All arc welding and cutting operations should beshielded by non-combustible or flame-proof screensto protect other workers from direct rays of the arc.

• Keep chlorinated solvents shielded from the exposedarc or at least 200 feet away. Surfaces prepared withchlorinated solvents must be thoroughly dry beforebeing welded. This is especially important when usinggas-shielded metal-arc welding, since it produces highlevels of ultraviolet radiation.

• Check for the flammability and toxicity of anypreservative coating before welding, cutting, orheating. Highly flammable coatings should be strippedfrom the area to be welded. In enclosed spaces, toxicpreservative coatings should be stripped severalinches back from the area of heat application or thewelder should be protected by an airline respirator. Inthe open air, a suitable cartridge respirator should beused. Generally, with any preservative coating, checkthe manufacturer’s MSDS for specific detailsregarding toxicity and personal protection required.

• Shut off the power supply before connecting thewelding machine to the building’s electrical power.

Oxyacetyelene Weldingand CuttingHANDLING CYLINDERS

• Do not accept or use anycompressed gas cylinder which doesnot have proper identification of itscontents.

• Transport cylinders securely on ahand truck whenever possible.Never drag them.

• Protect cylinders and any relatedpiping and fittings against damage.

• Do not use slings or magnets forhoisting cylinders. Use a suitablecradle or platform (Figure 20.13)

• Never drop cylinders or let them strike each otherviolently.

• Chalk EMPTY or MT on cylinders that are empty.Close valves and replace protective caps.

• Secure transported cylinders to prevent movement orupset.

• Always regard cylinders as full and handleaccordingly.

• For answers about handling procedures, consult themanufacturer, supplier, or the MSDS.

STORING CYLINDERS

• Store cylinders upright in a safe, dry, well-ventilatedlocation maintained specifically for this purpose.

• Never store flammable and combustible materialssuch as oil and gasoline in the same area.

• Do not store cylinders near elevators, walkways,stairwells, exits, or in places where they may bedamaged or knocked over.

• Do not store oxygen cylinders within 20 feet ofcylinderscontainingflammable gasesunless they areseparated by apartition at least5 feet high andhaving a fire-resistance ratingof at least30 minutes(Figure 20.14).

• Store empty andfull cylindersseparately.

• Prohibit smokingin the storagearea.

USING CYLINDERS• Use oxygen and

acetylenecylindersin a properbuggy equippedwith a fireextinguisher(Figure 20.15). Secure cylinders upright.

• Keep the cylinder valve cap in place when thecylinder is not in use.

• Do not force connections on cylinder threads that donot fit.

• Open cylinder valves slowly. Only use the handwheel,spindle key, or special wrench provided by thesupplier.

• Always use a pressure-reducing regulator with com-pressed gases. For more information see the boxbelow.

• Before connecting a regulator to a cylinder, crack thecylinder valve slightly to remove any debris or dustthat may be lodged in the opening. Stand to one sideof the opening and make sure the opening is notpointed toward anyone else, other welding operations,or sparks or open flame.

• Open the fuel gas cylinder valve not more than 11/2turns unless marked back-seated.

• Do not use acetylene pressure greater than 15 psig.• Never allow sparks, molten metal, electric current, or

excessive heat to come in contact with cylinders.• Never use oil or grease as a lubricant on the valves or

attachments of oxygen cylinders. Do not handle withoily hands, gloves, or clothing. The combination ofoxygen and oil or grease can be highly combustible.

• Never bring cylinders into unventilated rooms orenclosed areas.

• Do not use oxygen in place of compressed air forpneumatic tools.

• Release pressure from the regulator before removingit from the cylinder valve.

WELDING AND CUTTING

Figure 20.13

OutletPressureGauge

Cylinder Valve

PressureAdjustingScrew

CylinderContentsGauge

Hose Check(non-return)Valves

FireExtinguisher

Figure 20.15

Figure 20.14

1.5m

35 – 9

• When gas runs out, extinguish the flame and connectthe hose to the new cylinder. Purge the line before re-igniting the torch.

• When work is finished, purge regulators, then turnthem off. Use a proper handle or wrench to turn offcylinders.

Pressure RegulatorsPressure regulators must be used on both oxygen andfuel gas cylinders to maintain a uniform and controlledsupply of gas to the torch.The oxygen regulator should be designed with a safetyrelief valve so that, should the diaphragm rupture,pressure from the cylinder will be released safely andthe regulator will not explode.Each regulator (both oxygen and fuel gas) should beequipped with a high-pressure contents gauge andworking pressure gauge. Always stand to one side ofregulator gauge faces when opening the cylinder valves.To prevent regulators from being installed on the wrongcylinders, oxygen cylinders and regulators have right-hand threads while most fuel gas cylinders andregulators have left-hand threads.Internal and external threads and different diametersalso help to prevent wrong connections.

Hoses and hose connections for oxygen and acetyleneshould be different colours. Red is generally used toidentify the fuel gas and green the oxygen. The acetyleneunion nut has a groove cut around the centre to indicateleft-hand thread.• Protect hoses from traffic, flying sparks, slag, and

other damage. Avoid kinks and tangles.• Repair leaks properly and immediately. Test for leaks

by immersing hose in water.• Use backflow check valves and flame arrestors

according to the manufacturer’s instructions (Figure20.11).

• Do not use a hose which has been subject toflashback or which shows evidence of wear ordamage without proper and thorough testing.

Backfires occur when the flame burns back into the torchtip, usually accompanied by a loud popping sound.Backfires usually are caused by touching the tip againstthe work or by using pressures that are too low.Flashback is much more serious. The flame burns backinside the torch itself with a squealing or hissing sound. Ifthis happens, follow the torch manufacturer’s instructionsto extinguish the torch in proper sequence.Many different makes, models, and designs of torches areavailable. There is no single procedure or sequence tofollow in igniting, adjusting, and extinguishing the torchflame. Always follow the manufacturer’s instructions.

Oxyacetylene SummaryStartup• Keep cylinders away from sources of heat or damageand secure them upright.

• Stand to one side and slightly crack cylinder valves toblow out dust.

• Attach regulators to respective cylinders. Tighten nutswith a proper wrench.

• Release pressure adjusting screws on regulators.• Connect green hose to oxygen regulator and redhose to fuel gas regulator.

• Connect hoses to the torch — green to oxygen inletand red to fuel gas inlet.

• Connect mixer and welding tip assembly to torchhandle.

• Open oxygen cylinder valve slowly and fully.• Open fuel gas cylinder 3/4 to 11/2 turns.• Open oxygen torch valve. Turn oxygen regulatorpressure adjusting screw to desired pressure.Continue oxygen purge for about 10 seconds foreach 100 feet of hose. Close oxygen torch valve.

• Open fuel gas torch valve. Turn fuel gas regulatorpressure adjusting screw to desired pressure andpurge for about 10 seconds for each 100 feet ofhose. Close fuel gas torch valve.

• To light torch, follow the manufacturer’s instructions.DO NOT USE MATCHES.

• Adjust to desired flame.

Closedown• Close torch valves according to the manufacturer’sinstructions.

• Close fuel gas cylinder valve.• Close oxygen cylinder valve.• Drain fuel gas cylinder line by opening torch fuel gasvalve briefly. Close valve. Drain oxygen line in thesame way.

• Re-open both torch valves.• Release pressure adjusting screws on bothregulators.

Regulators and torches can now be disconnected.

SILVER SOLDER BRAZINGSilver solder brazing is used for joining metals and steeland disimilar metal combinations where it is necessary toperform the joining of these metals at low temperatures.Applications include medical and laboratory systems,refrigeration, aerospace, and electronic equipment. Inbrazing, the major hazards are heat, chemicals, and fumes.Fumes generated during brazing can be a serioushazard. Brazing fluxes generate fluoride fumes whenheated. Cadmium in silver brazing alloys vaporizes whenoverheated and produces cadmium oxide, a highly toxicsubstance. Cadmium oxide fumes inhaled into therespiratory tract can cause pulmonary distress,shortness or breath, and in cases of severe exposuremay cause death.The most serious cause of cadmium oxide fumes isoverheating the silver brazing filler metal. Care must betaken to control the temperature of the silver brazingoperation. The torch flame should never be applied directlyto the silver brazing filler rod. The heat of the base metalshould be used to melt and flow the brazing filler metal.Cadmium-plated parts can be an even more hazardoussource of cadmium fumes, since in brazing these partsthe torch flame is applied directly to the base metal.Cadmium plating should be removed before heating orbrazing. When in doubt about a base metal, check withthe supplier of the part.

WELDING AND CUTTING

35 – 10

Safe Silver Solder Brazing• Do not heat or braze on cadmium-plated parts.• Read warning labels on filler metals and fluxes and

follow instructions carefully.• Work in a well-ventilated area or use a supplied-air

respirator.• Apply heat directly to the base metal—not to the

brazing filler metal.• Do not overheat either the base metal or the brazing

filler metal.• Wash hands thoroughly after handling brazing fluxes

and filler metals.

Confined SpacesWelding in enclosed or confined areas creates additionalhazards for the welder. The employer must have a writtenrescue procedure for confined spaces.In addition to the procedures outlined in the chapter onconfined spaces in this manual, take the followingprecautions.• Inspect all electrical cables and connections that will

be taken into the confined space.• Perform leak tests on gas hoses and connections to

eliminate the risk of introducing gases into theconfined space.

• Check for live electrical systems and exposedconductors.

• Use inspection ports, dipsticks, and the knowledge ofplant personnel to evaluate hazards from any liquids,solids, sludge, or scale left in the space.

• Isolate the space from any hydraulic, pneumatic,electrical, and steam systems which may introducehazards into the confined area. Use isolation methodssuch as blanks, blinds, bleeding, chains, locks, andblocking of stored energy. Tag isolated equipment.

• A competent person must test and evaluate theatmosphere before workers enter a confined space,and at all times during work there. A hazardousatmosphere may already exist or gases and vapoursmay accumulate from cutting or welding. Oxygencontent may become enriched or depleted.

• Ventilate space with clean air before entry andmaintain ventilation as long as necessary to preventthe accumulation of hazardous gases, fumes, andvapours.

• Different gases have different weights and mayaccumulate at floor, ceiling, or in between. Airmonitoring should be done throughout the confinedspace.

• Keep compressed gas cylinders and welding powersources outside the confined space.

• Where practical, ignite and adjust flame for oxy-fuelapplications outside the space, then pass the torchinside. Similarly, pass the torch outside the space,then extinguish it.

• When leaving a confined space, remove the torch andhoses and shut off gas supply.

• If adequate ventilation cannot be maintained, use asuitable supplied-air respirator.

It is the responsibility of the employer to have a writtenemergency rescue plan and communicate the plan to allinvolved. Each person should know what do to and how

to do it quickly. See the Confined Spaces chapter in thismanual.

Personal Protective EquipmentIn addition to the protective equipment required for allconstruction workers, welders should wear flame-proofgauntlet gloves, aprons, leggings, shoulder and armcovers, skull caps, and ear protection.Clothing should be made of non-synthetic materials suchas wool. Woollen clothing is preferable to cotton becauseit is less likely to ignite. Keep sleeves rolled down andcollars buttoned up. Wear shirts with flaps over pocketsand pants with no cuffs. Remove rings, watches, andother jewelry. Never carry matches or lighters in pockets.Clothing should be free from oil and grease.Wear high-cut CSA grade 1 footwear laced to the top tokeep out sparks and slag.Protective screens or barriers should be erected to protectpeople from arc flash, radiation, or spatter. Barriers shouldbe non-reflective and allow air circulation at floor andceiling levels. Where barriers are not feasible or effective,workers near the welding area should wear proper eyeprotection and any other equipment required.Signs should be posted to warn others of weldinghazards.

EYE AND FACE PROTECTIONWelding helmets provide radiation, thermal, electrical, andimpact protection for face, neck, forehead, ears, andeyes. Two types are available — the stationary platehelmet and the lift-front or flip-up plate helmet.The lift-front type should have a fixed impact-resistantsafety lens or plate on the inside of the frame next to theeyes to protect the welder against flying particles when thefront is lifted. All combination lenses should have a clearimpact-resistant safety lens or plate next to the eyes.There are also special models incorporating earmuffsound arrestors and air purification systems. Specialprescription lens plates manufactured to fixed powers areavailable for workers requiring corrective lenses.The typical lens assembly for arc welding is shown inFigure 20.16.The filtered or shaded plate is the radiation barrier. It isnecessary to use a filterplate of the proper lensshade to act as a barrierto the harmful light raysand to reduce them to asafe intensity. Guidelinesfor selection are shown inFigure 20.17.In addition to commongreen filters, many specialfilters are available. Someimprove visibility byreducing yellow or redflare. Others make thecolour judgment oftemperature easier. Somehave a special gold

WELDING AND CUTTING

1st: Clear Glassor Plastic Lens

2nd: ShadeLens

3rd: ClearPlastic Lens

The arc welding lens assembly consists of3 parts. The outside lens is clear plastic ortempered glass. It protects the shade lensfrom damage. The centre lens is a shadelens that filters out the harmful light. Theinner lens is clear and must be plastic.

Figure 20.16

35 – 11

coating on the filter lens to provide additional protectionby reflecting radiation.Welding hand shields are designed to provide radiationand impact protection for the eyes and face. They aresimilar to welding helmets except that there are no lift-front models.Spectacles with full side shields designed to protectagainst UV radiation and flying objects and suitable filterlenses should always be worn in conjunction with fullwelding helmets or welding hand shields.Where only moderate reduction of visible light is required(for instance, gas welding) use eyecup or cover goggleswith filter lenses for radiation protection. Goggles shouldhave vents to minimize fogging and baffles to preventleakage of radiation into the eye cup.

Welders should not wear contact lenses becauseairborne dust and dirt may cause excessive irritationof the eyes under the lenses.

HEARING PROTECTIONSee the Hearing Protection chapter in this manual.Welders may find that ear muffs are cumbersome andinterfere with the welding helmet. Ear plugs may be abetter choice but must be properly inserted to ensureprotection.Welders should have their hearing checked every year orso. A simple test can be arranged through your doctor.Once hearing is damaged, the loss is likely permanent.Checkups can detect any early losses and help you tosave your remaining hearing.

Continue on next page for “Radiographic and X-RayTesting.”

WELDING AND CUTTING

Lens Shade Selection Guide for WeldingShade numbers are given as a guide only and may bevaried to suit individual needs.

Electrode Arc Minimum Suggested1

Size Current Protective Shade No.Operation mm (32nd in.) (Amperes) Shade (Comfort)Shielded Metal Arc less than 2.5 (3) less than 60 7 –Welding 2.5-4 (3-5) 60-160 8 10(SMAW) 4-6.4 (5-8) >160-250 10 12

more than 6.4 (8) >250-550 11 14

Gas Metal Arc Welding less than 60 7 –and Flux Cored 60-160 10 11(GMAW) >160-250 10 12

>250-500 10 14

Gas Tungsten Arc Welding less than 50 8 10(GTAW) 50-150 8 12

>150-500 10 14

Air Carbon (light) less than 500 10 12Arc Cutting (heavy) 500-1000 11 14

Plasma Arc Welding less than 20 6 6 to 8(PAW) 20-100 8 10

>100-400 10 12>400-800 11 14

Plasma Arc Cutting (PAC)Light2 less than 300 8 9Medium 300-400 9 12Heavy >400-800 10 14

Torch Brazing (TB) – – 3 or 4

Torch Soldering (TS) – – 2

Carbon Arc Welding (CAW) – – 14

Plate Thicknessmm in.

Gas Welding (GW)Light under 3.2 under 1/8 4 or 5Medium 3.2 to 13 1/8 to 1/2 5 or 6Heavy over 13 over 1/2 6 to 8

Oxygen Cutting (OC)Light under 25 under 1 3 or 4Medium 25 to 150 1 to 6 4 or 5Heavy over 150 over 6 5 or 6

Figure 20.17

1. Shade numbers are given as a general rule. It is recommended tobegin with a shade that is too dark to see the weld zone. Then oneshould go to a lighter shade which gives sufficient view of the weldzone without going below the minimum. In gas welding or oxygencutting where the torch produces a high yellow light, it is desirable touse a filter lens that absorbs the yellow or sodium line in the visiblelight of the operation (spectrum).

2. These values apply where the actual arc is clearly seen. Experiencehas shown that light filters may be used when the arc is hidden by theworkpiece.

Reproduced with the permission of the American Welding Society.

35 – 12

Radiographic and X-Ray TestingSome construction trades will encounter situations inwhich welds, metals, or special coatings require on-sitenon-destructive testing.Methods include1) radiography using a radioactive source for generalmaterials2) x-rays for testing thicker sections.Radiography is federally regulated across Canada by theAtomic Energy Control Board. Users must be licensedand operators must be trained according to a CanadianGovernment Standards Board (CGSB) program.X-ray testing is provincially regulated—in Ontario byRegulation 632/86.While many requirements apply to licensed users in bothsituations, this section will only cover the basic health andsafety guidelines for field use.

RADIOGRAPHIC TESTINGLicensed users of radiographic testing systems areresponsible for general safety in the field, transportation,emergency procedures, and record-keeping.Radiographic testing must be carried out in the presenceof persons certified to CGSB Standard 48GP4a. Ingeneral these people are employees of a recognizedtesting agency.Radiographic materials and equipment must be keptlocked up in shielded storage containers accessible onlyto certified personnel. The containers must beconspicuously marked and kept in an area not normallyoccupied by the workforce. There may be other specialrequirements which apply, depending on the strength ofthe radioactive source and the location.Radiographic cameras in the field must be used inconjunction with pocket dosimeters, survey meters,directional shields, barrier ropes, radiographicwarning signs, and an emergency source container.

General Safety Precautions• Radiographic testing should be conducted, whenever

possible, on an off-shift with as few workers aspossible in the work area. The radiographic sourceshould be no stronger than is required for the job.Determining the strength of the source is notgenerally the responsibility of construction sitepersonnel.

• Equipment should be checked before use. Theregulation includes a list of items to be checked, butdoing so is not usually the responsibility of sitepersonnel.

• After taking tests where the camera will be moved,the area should be checked using a survey meter.

• Licensed users are required to keep recordsregarding the use of sources, including dates, times,locations, and other details. These records must bemade available to inspectors from the Atomic EnergyControl Board. Users are also responsible for advisingthe local fire department when radioactive materialwill be in a municipality for longer than 24 hours.

Specific requirements for radiographic camera users arethe responsibility of the certified persons operating theequipment.• The survey meter must be checked to ensure that it is

working and calibrated properly.• Barrier ropes should be set up around the area where

testing will be carried out unless this area is isolatedand access can be controlled. Barriers must be set upaccording to the strength of the source.

• Warning signs must be posted along the barriers.• A patrol must be provided to ensure that no

unauthorized persons enter the testing area.• Before the camera shutter is opened and testing is

conducted, the area must be properly shielded.• Personnel working within the testing area should carry

personal dosimeters. Dosimeters may also beadvisable for workers in the immediate vicinity outsidethe barriers.

X-RAY TESTINGCertain basic health and safety precautions are requiredfor the x-ray testing of welds and metals.• There must be suitable means to prevent

unauthorized persons from activating the equipment.• There must be some device to indicate when the x-

ray tube is energized.• The housing must adequately shield the equipment

operator.• Employers using X-ray equipment must advise the

Ministry of Labour that they have such equipment.• Employers must designate certain persons to be in

charge of x-ray equipment who are trained andcompetent to do so, and must give the Ministry ofLabour the names of these designated persons.

Measures and procedures at the x-ray testing site aresimilar to those required for radiographic testing. Thefollowing are the employer’s responsibilities.• Test during off-shifts.• Cordon off the test area if it cannot be isolated or if

entry cannot be controlled.• Post warning signs along the barrier or at the

entrance to the room where testing is taking place.• Have a patrol to prevent unauthorized entry.• Install shielding as required before any equipment is

activated.• Ensure that employees in the controlled area wear

personal dosimeters.• Keep dosimeter records.• Keep at least one radiation survey meter of a suitable

type with each portable x-ray machine and calibrate itat least once each year.

TrainingWelders, fitters, and welding supervisors should betrained in both the technical and safety aspects of theirwork. Health and safety training should include but not belimited to the following:• hazard identification• safe welding, brazing, and cutting practices• fire and safety precautions• control methods for welding hazards

WELDING AND CUTTING

35 – 13

• use, maintenance, and limitations of personalprotective equipment.

The effectiveness of health and safety training should beperiodically evaluated through• a workplace inspection to ensure that safe working

procedures, equipment, and conditions areimplemented.

• air monitoring of common contaminants to determinethe effectiveness of controls and compliance withacceptable limits.

• an assessment of control performance (for instance,testing of the ventilation system)

• review of lost-time-injuries• discussion of the program with the health and safety

committee or representative(s).Any corrective actions necessary should be takenimmediately.

WELDING AND CUTTING

36 – 1

36 LOCKOUT AND TAGGING

CONTENTS• What is lockout and tagging?• Forms of energy• Procedure• Planning steps• Explanation of steps• Summary

WHAT IS LOCKOUT AND TAGGING?Lockout and tagging ensures that hazardous energysources are under the control of each worker. Serious orfatal accidents can occur when people assume thatmachinery is turned off or made harmless—but it isn’t.Lockout is a procedure that prevents the release ofhazardous energy. It often involves workers using apadlock to keep a switch in the “off” position, or to isolatethe energy of moving parts. This prevents electric shock,sudden movement of components, chemical combustion,falling counterweights, and other actions that canendanger lives. Lockout is a physical way to ensure thatthe energy source is de-energized, deactivated, orotherwise inoperable.Tagging tells others that the device is locked out, who haslocked it out, and why. Tagged devices and systems mustnot be re-energized without the authority of those namedon the tag.

FORMS OF ENERGYWhen most people think of uncontrolled hazardousenergy, they think of electricity. But construction crewsdoing work in industrial or office settings often have tolock out and tag a variety of energy sources. Here are themain types.• Electrical—electrical panels, generators, lighting

systems, etc.• Mechanical (the energy of moving parts)—flywheels,

blades, fans, conveyor belts, etc.• Potential (stored energy that can be released during

work)—suspended loads, compressed air, electricalcapacitors, accumulated bulk goods, coiled springs,chemical reactions, changing states (solid—liquid—gas), etc.

• Hydraulic—presses, rams, cylinders, cranes, forklifts,etc.

• Pneumatic—lines, compression tanks, tools, etc.• Thermal—steam, hot water, fire, etc.• Chemical—flammable materials, corrosive

substances, vapours, etc.

Some equipment may involve more than one type ofenergy, and pose unexpected hazards. For example, amachine may have an electrically operated component

with a hydraulic or pneumatic primary power source, or itmay become activated on a timed schedule. With someequipment, gravity and momentum can presentunexpected hazards.You must recognize and control conditions such as these.Switches, power sources, controls, interlocks, pneumatics,hydraulics, computer-controlled sources, gravity-operatedsources—all of these must be locked out andappropriately tagged by each worker involved.

PROCEDURE

Many plants or industrial establishments will have specificprocedures for lockout and tagging. This makes sensebecause the in-plant workforce will have proven itsprocedures through use on the particular system ormachine in question.Follow these procedures, but also verify that all energysources have been isolated because construction workmay differ from routine plant maintenance.Plant personnel may shut down machines, equipment, orprocesses. In other cases, plant representatives mayissue permits: 1) a work permit to allow work on theirequipment and 2) a lockout permit to ensure that alllockout procedures are followed before work begins.A written safe work procedure for lockout and tagging isessential. Once implemented and followed, a goodprocedure ensures that no form of energy can harmanyone during a lockout.A written procedure helps to ensure that lockout andtagging have been thoroughly and effectively carried outbefore work begins. It should include• training requirements for workers and supervisors• quality, type, and colour of locks, scissors, chains,

blanks, blinds, and other lockout devices• method of identifying lock owners• control of keys for locks• colour, shape, size, and material for tags• method of securing tags and information to be

included• communication and authorization procedure for

shutting down and starting up machinery andequipment

• record-keeping requirements• itemized steps to meet lockout objectives.

LOCKOUT AND TAGGING

Know the law

Section 188 of the Construction Regulation (O. Reg.213/91) lists the requirements for lockout and tagging,including the requirement that “written procedures forcompliance with this section shall be established andimplemented.”

36 – 2

LOCKOUT AND TAGGING

1. Locate area. Identify equipment, machinery, etc.

2. Identify all energy sources

3. Determine parts to be locked out

4. Determine proper lockout methods

5. Notify affected personnel

6. Shut down equipment

7. Lock out equipment

8. Tag locked-out equipment

9. Verify: zero-energy state?

12. Restore power

Work still required?

13. Return control to operating personnel

14. Record date/time lockout removed andsystem restored

11. Communicate that work is completeand all personnel are clear

10. Perform the work Hazardous energy not controlled

PLANNING STEPS

Yes

Yes

No

No

Specific lockout procedures will vary depending on the work and the processes which must be shut down.The following chart can help you develop specific procedures.

36 – 3

EXPLANATION OF STEPS

STEP 1: LOCATE WORKAREAAND IDENTIFYEQUIPMENT, MACHINERY, OR OTHER SYSTEMCOMPONENTS TO BE WORKED ONIdentify the area with references such as floor, roomname, elevation, or column number. Identify theequipment that is the subject of the work.

STEP 2: IDENTIFY ALL ENERGY SOURCESIdentify all energy sources affecting the equipment ormachinery. Identify the various energy forms to be lockedout such as electrical, momentum, pneumatic, hydraulic,steam, and gravity.

STEP 3: IDENTIFY THE PARTS TO BE LOCKED OUTOR ISOLATEDIdentify systems that affect, or are affected by, the workbeing performed. These may include primary, secondary,backup, or emergency systems and interlocked remoteequipment.Review the current system drawings for remote energysources and, where required, identify and confirm with theclient or owner the existence and location of any switches,power sources, controls, interlocks, or other devicesnecessary to isolate the system.Remember that equipment may also be affected by• time restrictions for completing the work• time-activated devices.

STEP 4: DETERMINE LOCKOUT METHODSConfirm that the lockout of all energy sources is possible.Some equipment may have to be kept operational tomaintain service to other equipment that cannot be shutdown. Take appropriate steps to provide protection forworkers while working near operating equipment.Equipment that can be locked out should be locked out bythe methods most appropriate to the hazards.

STEP 5: NOTIFY ALL PERSONNELAFFECTEDShutting down equipment may affect operations in otherlocations, incoming shifts, or other trades who may beplanning to operate the locked-out system. Beforeproceeding with the lockout, inform all personnel who willbe affected.At construction sites with a large workforce or at relativelylarge factories, you may need to have specialcommunication methods and permits or approvals.

STEP 6: SHUT DOWN EQUIPMENT AND MACHINERYQualified personnel must shut down the equipment,machinery, or other system components, placing them ina zero-energy state. Trace all systems to locate and lockout energy sources. The main source may be electrical,for instance, but pneumatic and other forms of energymay also be present. Always look for other possibleenergy sources.All equipment capable of being energized or activatedelectrically, pneumatically, or hydraulically must be de-energized or de-activated by physically disconnecting orotherwise making the apparatus inoperable.Always ensure that the client and operators are aware ofthe plan to shut down and lock out equipment, machinery,or other system components. In some cases, operationspersonnel or equipment operators may be required toshut down components because of their specialqualifications or knowledge of the system.In determining what needs to be shut down and lockedout, consider the different energy sources that may befound in the system.

STEP 7: INSTALL LOCKOUT DEVICESAfter the circuit has been de-energized and locked out bythe person in charge, each worker involved in the lockoutmust be protected by placing his or her personal lock onthe isolating device.Remember—even though the disconnect is alreadylocked out, you are not protected until you attach yourown personal safety lock.Each worker must retain his or her key while the lock is inplace. Only the worker in charge of the lock should have akey.

Remember . . .• Merely removing a fuse

doesn’t constitute lockout.The fuse could be easilyreplaced. The fuse shouldbe removed and the boxlocked out.

• The lockout devicesattached to one systemshould not prevent accessto the controls andenergy-isolating devices ofanother system.

LocksLocks should be high-quality pin-type,key-operated, and numbered to identifyusers.

Multiple locks and lockout barsWhen several workers or trades are working on amachine, you can add additional locks by using a lockoutbar. You can add any number of locks by insertinganother lockout bar into the last hole of the previous bar.

LOCKOUT AND TAGGING

In-plant procedures specified by the owner or clienttake precedence over the procedures outlined here,provided there is no contravention of existing codes orlaws.

36 – 4

Other lockout devicesScissors—have holes for locks and shouldbe made of hardened steel.Chains—should be high quality and snugfitting.Blocks or cribbing—prevent or restrictmovement of parts.Blanks or blinds—are solidmetal plates inserted at flangedconnections to prevent the flowof liquids or gases.Pins and clamps—should be ofhigh-quality materials anddesigned to fit the system.

STEP 8: TAGGINGSection 188 of the Construction Regulation (O. Reg.213/91) requires each worker involved in a lockoutoperation to attach a durable tag to his or her personallock. The tag must identify the worker’s name, theworker’s employer, the date and time of lockout, the workarea involved, and the reason for the lockout.A tag in itself offers no guarantee that a machine orsystem is locked out. It simply provides information.

Signs must be placed on the system indicating that• it must not be energized or operated• guards, locks, temporary ground cables, chains, tags,

and other safeguards must not be tampered with orremoved until

a) the work is complete, andb) each worker has removed his or her personal

lock.A record must be kept of all equipment locked out orotherwise rendered inoperable so that all of these devicescan be reactivated once the work is complete.

STEP 9: VERIFY ZERO-ENERGY STATEAfter any power or product remaining in the equipmenthas been discharged or disconnected by qualifiedpersonnel, verify that all personnel are clear of theequipment. Then try, with extreme caution, to start theequipment manually. Look for any movement or functions.If none are observed, confirm that all energy sources areat a zero-energy state.Test the system to ensure that all electrical componentsare de-energized and de-activated, including interlockingand dependent systems that could feed into the system,either mechanically or electrically.

STEP 10: PERFORM THE TASKCarry out and complete the work assignment.

STEP 11: COMMUNICATE THAT WORK IS COMPLETEAND THAT ALL PERSONNELARE CLEAR• Ensure that personnel are clear of the locked-out

equipment, machinery, or system.• Remove only your tags and locks.• Tell personnel that were originally informed of the

lockout that the equipment, machinery, or system isno longer locked out.

STEP 12: RESTORE POWERReturn systems to operational status and the switches topower ON. Have qualified personnel restart machinery orequipment.

STEP 13: RETURN CONTROL TO OPERATINGPERSONNELWhen all work is completed, the person in charge of thelockout operation should formally return control of theequipment or system to plant personnel.

STEP 14: RECORD DATE/TIME LOCKOUT REMOVEDAND SYSTEM RESTOREDThis last step is important. It saves valuable informationthat may be lost if not recorded. Staff involved in theshutdown may not remain at the same jobsite. Owners oroperators may require this information to help plan futureshutdowns.

SUMMARYLockout can ensure the safety of a single mechanicworking alone or of hundreds of workers in a factory. Ineither situation, a procedure for safe lockout and taggingmust be written, implemented, and followed step by step.Lockout and tagging procedures help to ensure that• all energy sources are identified and locked out• energy is not inadvertently restored while work is

proceeding• maintenance, repair, installation, and other jobs can

be carried out safely• records are kept.

LOCKOUT AND TAGGING

Scissors

Blank / blind

Front Back

37 – 1

ELECTRICAL HAZARDS

37 ELECTRICAL HAZARDSCONTENTS• Introduction

• Electrical injuries

• Safeguards

• Working on energized systems

• Portable tools and extension cords

• Temporary wiring and power

• Other electrical issues

• Reporting electrical accidents/incidents

INTRODUCTIONAn electrical hazard can be defined as

- a dangerous condition where a workercould make electrical contact withenergized equipment or a conductor, andfrom which the person may sustain aninjury from shock; and/or,

- there is potential for the worker to receivean arc flash burn, thermal burn, or blastinjury.

Note: An electric hazard is considered to beremoved when protective measures are putin place at the source (remove hazard or de-energize), or along the path (place electricalinsulation/barrier between the worker andthe electrical hazard). Where PPE is reliedupon for worker protection, an electricalhazard is considered to remain and it is stillnecessary to address safety requirements forother workers in the area.

Injuries resulting from a worker makingelectrical contact represent a relatively smallportion (7.7%) of the lost-time injurieselectricians experience, according to 1997–1999statistics. It is reasonable to assume that thesituation is similar today. Other mechanicaltrades that do some electrical work canprobably expect even fewer electrical injuries.

Nevertheless, working on or near electricalhazards is dangerous and can be fatal. Anywork on or near energized equipment must bedone only when measures are in place toprovide protection from electric shock and burn.With adequate safety measures in place, everyelectrical injury and fatality can be prevented.

The law requires safe work practices. Under theOccupational Health and Safety Act andRegulations for Construction Projects, employers,supervisors, and workers each have legalresponsibilities to ensure that work is beingcarried out in a safe manner.

There are also restrictions in the ConstructionRegulation (Ontario Regulation 213/91 Section182) on who can work on electrical equipment:

(1) No worker shall connect, maintain, ormodify electrical equipment or installationsunless,

(a) the worker is an electrician certifiedunder the Trades Qualification andApprenticeship Act; or

(b) the worker is otherwise permitted toconnect, maintain or modify electricalequipment or installations under theTrades Qualification and ApprenticeshipAct, the Apprenticeship and CertificationAct, 1998 or the Technical Standardsand Safety Act, 2000.

(2) A worker who does not meet therequirements of clause (1) (a) or (b) mayinsert an attachment plug cap on the cordof electrical equipment or an electrical toolinto, or remove it from, a conveniencereceptacle.

Guidelines for working on or near electricalequipment and conductors are found in severaldocuments:

• Construction Regulation (O. Reg. 213/91)

• Ontario Electrical Safety Code

37 – 2

ELECTRICAL HAZARDS

• Operating manuals for different tools andequipment.

• NFPA 70E Standard for Electrical Safety inthe Workplace

• CSA Z462 Workplace Electrical Safety*.

* CSA Z462, tentatively called WorkplaceElectrical Safety, is under development.It is a Canadian version of the USelectrical safety standard NFPA 70EStandard for Electrical Safety in theWorkplace and is anticipated to beavailable in 2008.

An important aspect of electrical work involvesisolating electrical energy. A reference fordetailed information on lockout and control ofhazardous energy is the Canadian standard CSAZ460-05, Control of Hazardous Energy—Lockoutand Other Methods.

ELECTRICAL INJURIESThere are basically two ways to be injured byelectricity. One is by electric shock and theother is by arc flash.

Electric shock is the passing of electric currentthrough the body. Electrical contact can causeinvoluntary physical movements. The electricalcurrent may

• prevent you from releasing your grip froma live conductor

• throw you into contact with a highervoltage conductor

• cause you to lose your balance and fall

• cause severe internal and external burns

• kill you.

A household 125-volt circuit can deliver15 amps. Current as low as 30/1000 of 1amp (30 mA) can cause breathing to stop.A 15-Amp circuit contains many times thecurrent needed to cause death.

An arc flash is a releaseof energy caused by anelectric arc. The flashcauses an explosiveexpansion of air andmetal. The blast produces

• a dangerous pressurewave

• a dangerous soundwave

• shrapnel

• extreme heat

• extreme light.

These dangers can resultin blast injuries, lunginjuries, rupturedeardrums, shrapnelwounds, severe burns, andblindness. Arc flash injuriescan also result in death.

A major cause of accidentsinvolving electricity comes fromthe failure to identify the hazardsassociated with live electrical

equipment and wiring.

Arc flash

Electric arc

37 – 3

ELECTRICAL HAZARDS

SAFEGUARDS

Protective tools and equipment

Workers exposed to an electrical hazard mustuse mats, gloves, shields, flame resistantclothing, and any other protective equipmentrequired to protect themselves from electricshock and burn. As part of everyday work,electrical workers should always

• remove watches, rings, neck chains, orother current-conducting apparel

• wear electric-shock-resistant footwear

• wear a CSA-approved Class E hard hat orequivalent

• wear safety glasses with side shields, and

• wear under and outer clothing that hasflame-resistance properties.

Tools, devices, and equipment — includingpersonal protective equipment — used for livework must be designed, tested, maintained, andused so as to provide adequate protection forworkers.

Where there is the potential for an arc flash, allPPE should be chosen with consideration for thekinds of hazards that can result from an arc flash.See Flash Hazard (Arc Flash) Protection below.

The following information provides guidelineson appropriate and required personal protectiveequipment. Check the reference documentsidentified at the beginning of this chapter todetermine your job-specific needs. See also thechapters on personal protective equipment inthis manual.

Clothing

Whether or not the day’s planned work involvesworking near an electrical hazard, workers thatdo electrical work should choose everydayclothing that offers some flame resistanceproperties. When work must be done in thepresence of an electrical hazard, ensure that allclothing is chosen to provide adequate

protection from the potential hazards. See FlashHazard (Arc Flash) Protection below.

Head protection

The following hard hats comply with theConstruction Regulation:

• CSA Z94.1-1992 Class E (Canadian)

• ANSI Z89.1-1997 Type II Class E (US)

• ANSI Z89.1-1997 Type I Class E. (US)

Note that under the latest ANSI standard, thereare two types of Class E hard hats: Type I andType II. Type I hats are similar to the old CSAClass B hard hats which provide limited lateralimpact protection. The Type II hats haveenhanced lateral protection like the CSA Class E.ANSI Type II Class E hard hats are clearlylabelled “Type II.” If your hard hat just says“ANSI Class E,” assume it’s a Type I.

Foot protection

Construction workers require Grade 1 toeprotection with sole protection in accordancewith the Canadian Standards Associationstandard (CSA) Z195-02. Protective footwearcompliant with the intent of the ConstructionRegulation is identified by a green triangularpatch on the tongue or the ankle of thefootwear.

Mechanical trades people exposed to electricalhazards should also wear electric-shock-resistantfootwear identified by a white rectangular labelbearing the CSA logo and the Greek letteromega in orange.

Eye protection

The Canadian Standards Association (CSA)standard CAN/CSA Z94.3-99 Industrial Eye andFace Protectors can assist you in classifyinghazards and recommending protectors.

ΩCSA logo omega

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ELECTRICAL HAZARDS

Appropriate protection chosen according to thisstandard meets with the intent of theConstruction Regulation regarding eyeprotection worn on the job.

In any case, eye protection should be ofindustrial quality eye protection in the form ofsafety glasses incorporating side-shields or awrap-around style. Arc flash protection requiresa face shield that is rated for arc flash, withsafety glasses underneath.

Regular plastic face shields do not toprovide arc flash protection. They can burnand melt in an arc flash incident. Use a faceshield that is designed and rated for arcflash protection.

Hearing protection

Hearing protection is important at work sincecontinuous exposure to excessive noise can leadto hearing loss and tinnitus. Hearing protectionis required for some arc flash hazards. Hearingprotection is available in three general types:

1. Disposable ear plugs made of pliablematerial. One size fits all, but they shouldonly be used once.

2. Reusable custom-fit ear plugs are availableto provide protection for specificfrequencies of noise. These provide a goodseal and can be washed and reused.

3. Earmuffs. They need to be fitted toprovide maximum protection.

Shock protection

The passage of electricity through the body iscalled shock. Effects can range from a tinglingsensation to death. A shock that may not beenough to cause injury can nonetheless startle aworker, causing an involuntary reaction that canresult in serious injuries or death.

A household 125-volt circuit can deliver 15amps. Current as low as 30/1000 of 1 amp (30mA) can cause breathing to stop. A 15-amp

circuit has many times the current needed tocause death.

Rubber gloves and leather protectors are themost common personal protective equipmentused for shock protection. These must beadequate to protect the worker from electricalshock or burn. The rubber gloves must havebeen tested and certified.

Class 0 and Class 00 gloves must be air-testedand visually inspected for damage and adequacyimmediately before each use. Class 0 and Class00 are exempt from regular re-certification unlesswork is carried out under the Electrical UtilitySafety Rules. Rubber gloves rated for use withvoltages above 5,000 volts AC must be regularlytested and certified to ensure that they canwithstand the voltages for which they are rated,

• at least once every three months if theyare in service, or

• once every six months, if they are not inservice.

Workers must be trained in the proper use, care,and storage of rubber gloves and leatherprotectors.

Rubber mats and shields can also be used withstandard personal protective equipment toprotect the worker from electric shock or burn.The rubber mat must have been tested andcertified.

The best shock protection is afforded by turningoff or isolating the electrical power from theworker. The Construction Regulation requires allwork to be done with the system de-energizedunless certain specified conditions are met. See“Working on Energized Systems” in this chapter.

Flash hazard (arc flash) protection

A flash hazard is defined as a dangerouscondition associated with the release of energycaused by an electric arc (NFPA 70E 2004). Therelease of energy is often referred to as an arcflash.

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ELECTRICAL HAZARDS

An arc flash produces thermal energy which ismeasured in calories/cm². Adhering to arc flashprotection calculations can still expose a workerto second degree burns, or 1.2 calories/cm².

One calorie is the amount of heat needed toraise the temperature of one gram of waterby 1°C.

Second degree burn results from exposureto 1.2 cal/cm² for more than 0.1 second.

1.2 calories/cm² is equivalent to holdingyour finger in the blue part of a butanelighter flame for one second.

These conditions can lead to arc flash:

• accidental contact between two conductors

• wiring errors

• insulation deterioration or failure

• corrosion of equipment

• contamination of the equipment (e.g., dust,moisture)

• animals, tools, or fallen parts that short-circuit the equipment

• poor maintenance

• workers using improper or non-rated tools.

If a worker is close to energized electricalequipment, the worker may be exposed to aflash hazard, even if the source of the arc flashis not being worked on. Employers andsupervisors need to ensure these workers areprotected from flash hazards, and shouldeducate workers on flash hazard recognition.

It may be possible to eliminate the electricalhazard with equipmentdesigned to offer flashprotection. The plug inthe picture at right andbelow is designed forflash protection andcan be used as adisconnect switch.

Mechanical workers that are potentially exposedto arc flash should always wear clothing thatprovides for some level of arc-flash protection.Clothing made of synthetic fibres can be readilyignited by arc flash and melt to the workersskin. Cotton or wool fabrics are more flame-retardant and are therefore recommended asouter-wear and inner-wear for work clothes.Clothing that is flame resistant (FR) and rated toprovide protection up to a specified hazardcategory must be worn when there is a flashhazard.

Protection from an arc flash is afforded byprotective clothing and equipment such as

• wearing flame-resistant clothing

• flame-resistant eye protection (flame-resistant face shield is often required aswell)

• hand protection

• hearing protection.

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ELECTRICAL HAZARDS

There are a number oflevels of flame-resistant(FR) clothing, ranging fromcotton clothes to the flashsuits and face shieldsshown in theaccompanying image. Thelevel of protectionnecessary is determined bya calculation using tablesor a computer program.

A hypothetical example:

For voltage testing on anenergized part, 240 volts orless, a worker may require

• FR-rated pants andshirt (each rated towithstand 4 calories/cm2)

• FR-rated safety goggles

• 500-volt-rated class 00 gloves (class 0gloves protect up to 1000 volts)

• 1000-volt-rated tools

• approved hard hat.

Actual calculations for this task may yielddifferent results.

Workers that encounter a flash hazard can takeadditional precautions to reduce exposure.

• Standing as far away as possible from thehazard lowers the calorie intensity of anarc flash.

• Standing to the side when openingelectrical-box doors can reduce exposureto the full force of a blast.

Information is available to assist with arc-flashenergy calculations. Here are some sources:

• The (US) National Fire ProtectionAssociation’s Standard for Electrical Safetyin the Workplace (NFPA 70E). Contact theNFPA: 1-800-344-3555, www.nfpa.org.

• The Institute of Electrical and ElectronicsEngineers’ standard 1584, Guide forPerforming Arc-Flash Hazard Calculations.Contact the IEEE: 1-800-678- 4333,www.ieee.org.

• CSA standard Z462 Workplace ElectricalSafety is currently being developed. Uponcompletion in 2008, CSA Z462 will beanother resource of information dealingwith electrical safety concerns such as arcflash. Contact the CSA: 1-800-463-6727,www.csagroup.org

WORKING ON ENERGIZED SYSTEMSWhat if there’s an electrical hazard but workmust be done on or near enough to the hazardto make electrical contact, or near enough to beexposed to injury from an arc flash? In suchcases, work while the system is energized ispermitted only if specific conditions are met.

Work on energized equipment is permitted only if

• it is not reasonably possible to disconnectthe equipment, installation, or conductorfrom the power supply,

• the equipment is rated at a nominalvoltage of 600 volts or less, anddisconnecting the equipment would createa greater hazard to workers thanproceeding without disconnecting it, or

• the work consists only of diagnostictesting.

Note: Testing with a meter is working onenergized equipment, and requiresappropriate protection including personalprotective equipment.

Unless the work consists only of diagnostictesting or involves a nominal voltage under 300volts, an adequately equipped competentworker who can perform rescue operations,including cardiopulmonary resuscitation (CPR),must be stationed where he or she can see theworkers performing the live work.

A flash suit andface shield arerequired for themore powerfulflash hazards.

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ELECTRICAL HAZARDS

Work on energized equipment nominally ratedgreater than 400 amperes and greater than 200volts, or greater than 200 amperes and greaterthan 300 volts, can only be done if

1) the owner of the equipment provides theemployer and the constructor with arecord showing that it has been maintainedaccording to the manufacturer’sspecifications

2) a copy of the maintenance record isreadily available at the project

3) the employer has determined from themaintenance record that work on theequipment can be performed safelywithout disconnecting it, and

4) before beginning live work, the workerhas verified that requirements 1), 2), and3) have been met.

Repair or permanently disconnectdefective equipment.

Section 2-300 of the Ontario Electrical SafetyCode requires operating electrical equipmentto be kept in safe and proper workingcondition.

The constructor must ensure that writtenprocedures for work on or near live equipmentare produced and implemented to protectworkers from electrical shock and burn. Theconstructor must have copies of the proceduresavailable for employers on the project.

The employer must provide and explain thewritten procedures to workers before they startwork on or near live equipment. Theconstructor and the employer both have ageneral duty to ensure that the health and safetyof workers are protected.

Operating equipment near

energized powerlines

Incidental powerline contact happens too often,especially considering the potential severity ofthe consequences. The Ministry of Labourreported 108 powerline contacts in 1998. Thatnumber rose to 196 in 2005. See Table 1.

Constructors must be aware of electrical hazardswhen equipment such as a crane, dump truck,or other vehicle is going to be operated near anenergized overhead electrical conductor, orwhen excavating equipment such as a backhoewill be operated near underground powerlines.

Table 1: Summary of Powerline Contacts

Overhead Lines Buried Cables

Year Crane Dumptruck

Treefelling Other Digging Other Total

2005 19 21 9 87 45 15 196

2004 11 16 5 57 53 9 151

2003 16 19 9 63 35 6 148

2002 16 20 4 50 36 6 132

2001 16 22 5 43 27 7 120

2000 15 10 3 59 32 3 122

1999 11 26 2 48 27 1 115

1998 10 17 8 39 27 7 108

TOTALS 114 151 46 446 282 54

(Source: Ontario Ministry of Labour)

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ELECTRICAL HAZARDS

When equipment operates within reach of, andcould therefore encroach on, the minimumpermitted distances from live overhead

powerlines (as listed inTable 2), theconstructor is requiredto have writtenprocedures in place toprevent it fromoccurring and to havecopies of theprocedure available for every employer on theproject.

Overhead powerlines are most frequently hit bydump trucks and cranes; however, elevatingwork platforms and low-tech equipment such asladders and rolling scaffolds are also involved.Keep in mind that many powerline contactsinvolve low-voltage service and buried cable.

Safety measures

Written measures and procedures required bythe Construction Regulation include thefollowing:

• Place enough warning devices in the areaof the hazard so at least one is alwaysvisible to the operator. The warningdevices must be visible to the operatorunder any conditions in which the

Table 2

Normal phase-to-phase voltage rating Minimum distance

750 or more volts, but no more than 150,000 volts 3 metres

More than 150,000 volts, but no more than 250,000 volts 4.5 metres

More than 250,000 volts 6 metres

The wind can blow powerlines, hoist lines, or your load. This can cause them to cross the minimumdistance.

POWERLINESOVERHEAD 72000 V

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ELECTRICAL HAZARDS

equipment may be operating (night, rain,fog, etc.), and must be specific about thehazard. Provide a sign meeting therequirements of the ConstructionRegulation’s section 44, stating, forexample, “Danger! Electrical power linesoverhead.” We recommend that youinclude the voltage.

• Ensure the equipment operator has beenprovided with written notification of theelectrical hazard before beginning the work.

• Ensure there is a sign warning of thehazard that is visible to the operator at theoperator’s station. This may come as asticker with the machine. Check to ensurethe sticker is still legible.

• Before the operator starts work, ensurethat the employer of the equipmentoperator provides and explains theprocedures to the equipment operator.

• A competent worker must be designated asa signaller to warn the operator when anypart of the equipment, load, or hoist linemay approach the minimum distance. Thesignaller must then be in full view of theoperator and have a clear view of theequipment and the conductor. Section 106

of the Construction Regulation also applieswith respect to the designated signaller.

An exemption to these measures is only allowedif under the authority of the owner of theelectrical conductor (typically the local utility),protective devices and equipment are installed,and written procedures are implemented (forexample, using the Electrical & Utilities SafetyAssociation (E&USA)’s Electrical Utilities SafetyRules) that are adequate to protect the equipmentoperator from electrical shock and burn.

Prevention

Ensure that contractorsand workers understandthat work should beplanned to avoidpowerlines. Prepare forwork that must be donein close proximity toenergized powerlines bydeveloping written procedures ahead of time.Have overhead powerlines moved, insulated, orde-energized where possible. Insulating or“rubberizing” powerlines offers some protectionagainst brush contact in some circumstances.The local utility may provide this service.

Identify the voltage of the service by checkingmarkings on the utility pole and calling theutility. If material must be stored underpowerlines, hang warning flags and signs toinform workers about the hazard and the needto obtain written procedures if hoisting.

Provide instruction as part of site orientation:

• Advise operators of large equipment whereoverhead and buried powerlines are andwhere overhead powerlines may be lowerthan expected.

• Remind workers not to let a ladder,scaffold, or elevated work platform lean ordrift toward overhead powerlines. Alwaysmaintain minimum allowable clearances.

Inside the limit of approach to the powerline.

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ELECTRICAL HAZARDS

• Inform all workers how powerline hazardsare identified on site and that writtenprocedures are required prior to operatingnear them.

• Review an appropriate emergencyresponse for equipment operators andworkers assisting operators, in case contactshould occur.

In the event of contact betweenequipment and overhead powerlines:

1. Stay on equipment. Don’t touchequipment and the ground at the sametime. Touching anything in contact withthe ground can be fatal. Stay on theequipment unless forced off because of alife-threatening hazard such as fire.

2. Keep others away. Warn everyone notto touch the equipment or its load. Thatincludes buckets, outriggers, load lines,and any other part of the machine. Bewareof time-delayed relays. After line damagetrips a breaker, relays may still try torestore power. They may resetautomatically two or three times.

3. Break contact. If possible, break contactby moving the equipment clear of thewires. This may not be feasible wherecontact has welded conductors toequipment, the hoist line, or the load.

4. Call the local utility. Get someone tocall the local electrical utility for help. Stayon the equipment until the utility shutsdown the line and confirms that power isoff. Report incidents of powerline contactso that the utility can check for damagethat could cause the line to fail later.

5. Jump clear. If forced to leave theequipment, jump carefully off theequipment onto the ground landing onlyon your feet, with your feet together.Touching the equipment and theground at the same time can be fatal.

Touching the ground at different pointscan also be fatal. Shuffle slowly away fromthe equipment using very small steps tominimize the contact area with the ground.

6. Report the contact. See “ReportingElectrical Accidents/Incidents” in thischapter.

Hidden power supplies

Digging into buried cable resulted in 282powerline contacts between 1998 and 2005 (seeTable 1). A great many of these resulted fromexcavating prior to getting a locate on theservice. If the electrical power cannot be shutoff during excavation, the owner (of the service)must be present to supervise the uncovering ofthe powerline.

The following are some prevention measures forhidden powerlines.

For underground powerlines:

• Before excavating, request that the ownerof the service locate and markunderground powerlines.

• Contact the utility through Ontario OneCall to locate all underground services.

• Locate and mark underground lines ondrawings that will be used for excavating.

• Post warning signs along the route ofunderground powerlines.

• When operators of excavation equipmentarrive on site, advise them whereunderground services are located and howthey are identified.

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ELECTRICAL HAZARDS

For powerlines embedded in concrete:

• Ensure various trades provide sleevingwhen concrete is poured to reduce theneed to drill.

• Try to have powerlines laid alongdedicated sections of flooring and walls.

• Mark powerline locations on drawings thatwill be referenced for drilling.

• Use a location service to ex-ray theconcrete and locate embedded powerlines.

MULTIMETERSIn the process of troubleshooting, electricalworkers face the risk of injury from impropermultimeter selection or use. Multimeters that aredesigned to meet the International Electro-technical Commission (IEC) 1010 andovervoltage category standards, when properlyused, offer the electrician an acceptable level ofprotection that is recognized by the electricalindustry. The use of fused leadsprovides additional protectionfor the worker.

Why use overvoltage

category rated multimeters?

Momentary high-voltagetransients or spikes can travelthrough a multimeter at any timeand without warning. Motors,capacitors, lightning, and powerconversion equipment such asvariable speed drives are allpossible sources of spikes.

The IEC 1010 standard defines categories I throughIV that are abbreviated as CAT I, CAT II, CAT III,etc. The higher-numbered categories represent anelectrical environment that is susceptible to higher-energy spikes. For example, multimeters that aredesigned to the CAT IV standard provide theworker more protection from high transient voltagespikes than do CAT III, CAT II, or CAT I designs.See the diagram on the next page and Table 3below for an explanation of each category.

Be sure that the multimeter model has beentested. Simply being designed to the CAT IIIstandard, for example, does not mean themultimeter was also tested to that standard.Look for proof of independent testing byan organization accredited by theStandards Council of Canada, suchas the CSA (Canadian StandardsAssociation) International logo,along with the appropriatecategory rating on the equipment. Test

Reprinted in part with permission of Fluke Electronics Canada Inc.A failed multimeter

Table 3

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ELECTRICAL HAZARDS

leads should also be rated at the same orgreater voltage than the multimeter.

Understanding overvoltage installation

categories

The division of a power distribution system intocatagories is based on the fact that a dangeroushigh-energy transient such as a lightning strikewill be attenuated or dampened as it travelsthrough the impedance (AC resistance) of thesystem. A higher CAT number refers to anelectrical environment with higher poweravailable and higher-energy transients.Therefore, a multimeter designed to the CAT IIIstandard is resistant to much higher-energytransients than one designed to the CAT IIstandard. Categories I through IV apply to lowvoltage (less than 1000 V) test equipment.

Safe use of multimeters

• Use only multimeters that display both theCSA logo (or equivalent) and the CAT (I,II, III, or IV) designation. Categories Ithrough IV apply to low voltage (less than1000 V) test equipment.

• Check to ensure that the meter’s voltagerating is appropriate for the work beingdone. Be aware of multimeters withmaximum voltage ratings typical of othercountries (550 V for example).

• Use personal protective equipment such asarc flash fire-resistant clothing; eye and

face protection; long sleeve shirts;dielectric safety boots; rubber gloves withleather protectors; and mats, blankets, orshields as required. Do not wearsynthetic inner or outer clothing thatcan melt if an arc flash occurs.

• Check the manufacturer’s manual forspecial cautions. Moisture and cold mayaffect the performance of your meter.

• Wipe the multimeter and test leads cleanto remove any surface contamination priorto use.

• Use fused test leads. Ensure fused leadsand internal probe fuses are rated as highas or higher than the equipment you aregoing to work on. A minimum of 30 kA isrecommended (200 kA is desirable).

• Ensure that test leads are in the correctinput jacks.

• When the values to be measured areuncertain, start testing with high ranges ofthe multimeter, then move to the lowerranges.

• Connect to the ground first, and disconnectfrom ground last.

• Test the multimeter on a known powersource to verify that the meter isfunctioning properly before and aftertesting the suspect circuit, using the samepower function for all three tests.

Using a meter to confirm zero energyfor a lockout

Set the meter to the power function to be usedfor validating the zero energy. Test to ensurethe meter is functioning correctly by testing ona known power source, then test the lockedout circuit to verify the power has beeneffectively isolated, and finally re-test on thesame known power supply to verify themeter’s fuse has not blown and the meter isstill functioning correctly on that power setting.

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ELECTRICAL HAZARDS

PORTABLE TOOLS AND EXTENSIONCORDS1. Unless they are double-insulated, toolsmust have:

a) the casing grounded

b) a polarized plug connection.

2. Extension cords must be of the outdoortype, rated for 300 volts, and have aninsulated grounding conductor.

3. Defective cords must not be used. Theyshould either be destroyed or tagged andremoved from the jobsite until they arerepaired.

4. Extension cords should be protectedduring use to prevent damage.

5. Extension cords should be plugged intoClass A GFCIs. When built-in GFCIreceptacles are not available, protection canbe attained with an in-line GFCI pluggeddirectly into the supply receptacle. Electrictools used outdoors or in wet locationsmust be protected by a Class A GFCI.

TEMPORARY WIRING AND POWER1. Temporary wiring for construction ordemolition projects must be installed inaccordance with the Ontario ElectricalSafety Code 23rd Edition/2002 (asamended by O. Reg. 62/07). Copies

available from Orderline at 1-888-361-0003or www.orderline.com.

2. A switch and panel board,

a) must be securely mounted on a soundlyconstructed vertical surface;

b)must have a cover over uninsulatedparts carrying current;

c) be located,

• in an area where water will notaccumulate; and

• within easy reach of workers andreadily accessible to them;

d)must be kept clear of obstructions in thearea in front of the panel board;

e) that controls a service entrance, servicefeeder or branch circuit providingtemporary power,

• must not be locked in the energizedposition; and

• must be housed in an enclosure thatcan be locked and is provided with alocking device.

f) When supplying power to tools that willbe used outdoors or in wet locations, thereceptacle must be protected by a classA ground fault circuit interrupter (GFCI).

In-line Class A GFCI.

Shelter forTemporary Panel

Lockout

GFCI in Panel Box

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ELECTRICAL HAZARDS

3. Portable generators for use as a stand-alone supply for portable electrical devicesmust be labelled “Neutral Bonded ToFrame.”

“Portable Generators for portableelectrical devices shall be a generatorwith the neutral bonded to the case tofacilitate the operation of the overcurrentprotection device(s).” Labelling on newerportable generators must indicate the status ofthe neutral conductor and shall be marked on

each machine as follows: NEUTRAL BONDEDTO FRAME or NEUTRAL FLOATING.

Electrical Safety Authority Flash notice 03-03-FL

Portable generators with no connectionbetween the neutral and the case cannot beused for a stand-alone electrical supply for theoperation of portable electrical equipment.Generators with no connection between theneutral and the case are intended to beconnected to a distribution system through atransfer switch. An example of this is a standbybackup system in a residential home whichkicks in upon failure of the utility supply. Thesegenerators will be labelled “Neutral Floating”.

OTHER ELECTRICAL ISSUES

Electromagnetic induction

Electromagnetic induction can create an electriccurrent in a dead circuit. The condition occurswhen a magnetic field from another wire,circuit, or device cuts across a wire in its pathand produces a charge in that wire. Temporarygrounding will prevent electromagneticinduction. The temporary grounding cable mustbe the same size conductor as the one foundwithin the circuit.

Grounding

A ground conductor provides a direct physicalconnection to the mass of the earth.

A grounding conductor limits the voltage orcurrent to the ground during normal operation,and also prevents excessive voltages due tolightning strikes.

A temporary ground provides a direct physicalconnection to the mass of the earth. Temporarygrounding typically involves the use of a wire orcable that has one end connected to a de-energized circuit, and the other end to a knowngrounded connection. The known groundedconnection can be the equipment frame (notethat if the equipment is electrically isolated, theframe may not provide an effective groundedLabelled “Neutral Floating”

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ELECTRICAL HAZARDS

connection), a metal water pipe, a groundelectrode, or other acceptable grounding medium.

Ground all phases. Attach a temporary groundcable to the system and keep it in place untilwork is completed.

Connecting and disconnecting conductors

Disconnect devices used to isolate electricalequipment must be certified by CSAInternational or another certification bodyaccredited by the Standards Council of Canada.It is important that the device has theappropriate rating for the available current andload it is serving. Never assume a circuit hasbeen de-energized when the disconnect is in theopen position. Check for power in allconductors, then follow prescribed lockout andtagging procedures before beginning work.

Capacitors

Isolate the capacitor by opening the circuitbreaker or the isolation device connecting it tothe circuit. Drain off the accumulated charge forfive to ten minutes with the system device. Shortcircuit and ground the capacitor using a hotstick and required personal protectiveequipment.

Electrical fires

Never put water on fires in live electricalequipment or wiring. Water is a conductor andincreases the risk of arc flash and electrocution.An electrical fire in a confined space can rapidlydeplete oxygen and may release toxic fumes. Ifpossible, switch off power. Avoid inhaling fumesand vacate the area at once. If necessary,breathe through a damp cloth and stay close tothe floor. Use a Class C fire extinguisher.Intended for electrical fires, Class Cextinguishers employ a non-conductiveextinguishing agent. An ABC fire extinguishermay also be used on an electrical fire. Everyworker who may be required to use a fireextinguisher must be trained in its use. Reportfires immediately. Wiring or equipment involved

in a fire must be inspected by the electricalutility inspector before being reactivated.

REPORTING ELECTRICALACCIDENTS/INCIDENTSAll accidents, regardless of severity, must bereported promptly to management and theimmediate supervisor, and a record should bekept at the jobsite. When a serious or fatalinjury involves a union member, the unionoffice and steward must be notifiedimmediately. Labour and management shouldcooperate fully in conducting an investigation.

Part VII of the Occupational Health and SafetyAct specifies the requirements for notification inthe event of fatalities, injuries, and accidents. Inthe event of an accident that requires reportingand investigation, care should be taken not todisturb the accident scene, nor should equipmentor tools involved in the accident be removed.

Contact with an overhead powerline

Contact with an overhead powerline must bereported to multiple parties.

If accidental contact occurs with an energizedpowerline carrying 750 V or more, report thecontact to the inspection department of theElectrical Safety Authority (ESA), and providewritten notice to the Ministry of Labour, jointhealth and safety committee or health and safetyrepresentative, and trade union.

Fatality or critical injury

A written report is required under subsection51 (1) of the Act, respecting an occurrence inwhich a person is killed or critically injured.(See box on next page.)

Section 53 of the Act: Where a notice or reportis not required under section 51 or 52, and an

• accident

• premature or unexpected explosion, fire,flood or inrush of water

• failure of any equipment, machine, device,article, or thing

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ELECTRICAL HAZARDS

• cave-in, subsidence, rockburst

• or other incident as prescribed (see boxbelow)

occurs at a project site, mine, or mining plant,notice in writing of the occurrence shall be givento a director, the joint health and safety committeeor health and safety representative, and tradeunion, if any, by the constructor of the project orthe owner of the mine or mining plant within twodays of the occurrence containing suchinformation and particulars as are prescribed.

Reporting serious electrical incidents to

the ESA

An owner, contractor, or operator of a facilitymust report any serious electrical incident to theInspection Department of the ESA within 48hours after the occurrence.

Notice of accident, explosion or fire

causing injury

If a person is disabled from performing his orher usual work or requires medical attentionbecause of an accident, explosion, or fire at aworkplace, but no person dies or is criticallyinjured because of that occurrence, theemployer shall, within four days of theoccurrence, give written notice of theoccurrence containing the prescribedinformation and particulars to the following:

1. The joint health and safety committee orthe health and safety representative, andthe trade union, if any.

2. The Director, if an inspector requiresnotification of the Director.

For the purpose of the Act, the Regulations,and the Ontario Electrical Safety Code,“critically injured” means an injury of aserious nature that,

• places life in jeopardy;

• produces unconsciousness;

• results in substantial loss of blood;

• involves the fracture of a leg or arm butnot a finger or toe;

• involves the amputation of a leg, arm,hand, or foot but not a finger or toe;

• consists of burns to a major portion ofthe body; or,

• causes the loss of sight in an eye.

Note: O. Reg. 834 and Ontario ElectricalSafety Code (OESC) (twenty third edition2002) use virtually identical wording for thedefinition of “critically injured.”

For the purpose of section 53 of the Act, aprescribed incident includes:

• accidental contact by a worker or by aworker’s tool or equipment with energizedelectrical equipment, installations orconductors. s.11 O. Reg. 213/91

• Accidental contact by a crane, similarhoisting device, backhoe, power shovelor other vehicle or equipment or its loadwith an energized electrical conductorrated at more than 750 volts. s.11O. Reg. 213/91

“Serious electrical incident” means,

a) Any electrical contact which causes deathor critical* injury to a person, or

b)Any fire or any explosion or anycondition suspected of being electrical inorigin which might have caused a fire,explosion, loss of life, critical* injury to aperson, or damage to property, or

c) Any electrical contact with electricalequipment operating at over 750 volts, or

d)Any explosion or fire of electricalequipment operating at over 750 volts.

OESC 2002

* see definition of “critically injured” under“Fatality or Critical Injury” above.

38 – 1

38 PROPANE

INTRODUCTIONPackaged under pressure, propane gas presents threehazards if misused:1. high flammability and explosive potential2. displacement of breathable air in confined spaces

(also, being heavier than air, propane will collect inlow areas)

3. contact injury from accidental exposure to asubstance under high pressure.

We will not cover the use of propane in the roofingindustry.

Propane - Physical CharacteristicsPropane or liquefied petroleum gas (LPG) is a by-productof petroleum or natural gas refiningwhich is packaged under pressure incylinders. In its stored state it is aliquid but is released from thecylinder or tank in a gaseous form.The boiling point of propane, thepoint at which the liquid converts toa gas, is -42.2°C (-44°F). If thesurrounding air temperature is abovethis, gas will form in the upper partof the cylinder (Figure 1).The pressure within the container isvariable depending on thetemperature to which the container isexposed (Table 1). The pressureincreases as the temperature rises,causing expansion of the liquid. For this reason containersare never fully charged with liquid, but have a vapourspace at the top of the tank to allow for normal expansion.Should the temperature rise above safe limits, a reliefvalve will open to allow release of the gas in a measuredamount. This release is generally over in seconds. Thevalve reseals and remains closed until the pressure buildsup again. Cylinder relief valves are set at 2585.5 kPa (375lb per square inch).Propane is packaged in a number of cylinder types andsizes to meet a variety of applications:• 100-lb cylinders for construction heaters, roofing

kettles, and other appliances that consume largeamounts of fuel. They are called 100 lb cylindersbecause they are charged with 100 lb of liquid at thepropane plant.

• 20-lb cylinders for oxypropane welding set-ups. (Thisis a familiar size that will be used on such appliancesas household gas barbecues.)

• 10 and 20 lb cylinders for soldering work.• 14 oz. throwaway containers for various hand-held

torch applications.

Propane can be easily compressed from a gaseous to aliquid state in small cylinders, making it very portable.When the liquid converts back to a gas, it expands 270times in volume. Compared to natural gas, propane has a

heating value that is 2.5 times greater. One cubic foot ofpropane converts to 2500 BTUs, while one cubic foot ofnatural gas converts to only 1000 BTUs. This explains whyso much energy (BTUs) can be contained in a smallcylinder, making it a very convenient fuel for the contractor.But the high-energy value of propane also makes it verydangerous to handle. It only takes a tiny leak to form anexplosive gas/air mixture.The high flammability of propane can be seen by comparingits ignition characteristics with those of gasoline (Table 2).

When you consider that the heat from a lighted cigaretteranges between 1000°F and 1600°F, and that a lightedmatch produces 2000°F, all that is necessary forcombustion is a sufficient quantity of propane gas mixedwith air. This is why safety procedures must be followedso that a very efficient energy source does not become ahazard to workers.

PROPANE

Cutaway viewof vapour withdrawalpropane cylinder

Figure 1 Temperature/Pressure Variables (values taken fromCSAStandard B149.2-M80)Table 1

*kilopascals *pounds per square inch

Propane GasolineMinimum ignition 493° - 549°C 427° - 482°Ctemperature range (920° - 1020°F) (800°- 900°F)

Flammability limits in air 2.4 - 9.5% 1.3 - 7.5%Vapour density (air=1) 1.52 3.50Minimum flash point -104°C (-156°F) -51°C (-60°F)

Table 2

38 – 2

Safe Handling of CylindersIn construction, most propane applications dispense thefuel in a vapour form. For this reason it is essential thatportable cylinders be transported, stored, and used in anupright position. Propane liquid must never come incontact with the cylinder relief valve. If liquid escapesthrough the valve, large volumes of gas will be released.On a construction heater, for example, this can cause aserious overburn with flames extending many feet pastthe burner tip.The simplest way to avoid the problem is to fastencylinders in an upright position with rope, wire, or othermeans. When transporting by truck, take extra care tokeep cylinders upright and stationary. Cylinders shouldnot be transported in an automobile trunk or in a closedvan. Because propane is heavier than air, escaping gascan collect in a confined space and create an explosiveatmosphere, as well as threaten life by displacingbreathable air.Store cylinders safely on the jobsite. They should bestored away from buildings, preferably in a separatecompound out of traffic areas and where they are in nodanger of being struck by falling materials or movingequipment. A simple compound can be constructed usinga length of snow fence and a few T-bars (Figure 2). Whenproperly constructed, this barrier provides a means oftying up the cylinders as well as controlling stock.Cylinders should not be stored closer than 25 feet to aproperty line. Empty cylinders should be stored on oneside, full on the other. Don't mix the cylinders.The compound should not be close to an area whereflammable liquids such as gasoline and diesel fuel arestored. Only cylinders that are in use should be inside abuilding. (“In use” means hooked up to a constructionheater or other appliance.)

Propane must not be stored inside abuilding unless in a specially constructedexplosion-proof room, which meets thepropane and fire codes. Do notlocate cylinders in stairwells andhallways. Leaking gas or theoutbreak of fire can blockexits and prevent escape.When moving cylindersof gas around thejobsite, rememberthe followingprecautions.

• Keep cylinders upright. Use a hand cart (Figure 3).Never roll cylinders.

• Use a hoisting cradle to movecylinders from one level to another(Figure 4).

• Never use a sling. This practiceis prohibited by the ConstructionRegulation under theOccupational Health and SafetyAct.

• Never hook onto the protectivecollar around the valve.

• Keep cylinders away from heat sources.

HeatersYou must have a record of training (ROT) recognized bythe Technical Standards and Safety Authority (TSSA)before you can hook up and light a propane-fired heater.When hooking up and using construction heaters, observethe following precautions.• All connections must be made by a

competent worker.• Inspect burner, controls, regulator, and

hose for defects. Have any damaged partsrepaired or replaced. Gas-burningequipment should only be repaired bylicensed service personnel.

• Make sure all hose and valve connectionsare clean.

• Use fitting wrenches to make connections.Don't use adjustable pipe wrenches.

• Cylinders should be at least 10 feet away from theheaters. The cylinder should be placed well clear ofany heat source and never at the flame end of aheater.

• Have a 4A40BC fire extinguisher on hand beforelighting the heater.

• When connections are made, slowly open the cylindervalve and check for leaks when the hose line is full ofgas. Cylinder valves in use must be fully opened.Check for leaks with soapywater (Figure 6) or a leakdetector. Sometimes you maynotice a gas odour or frostappearing on a fitting, butthese signs are not alwaysreliable. If a leak isdetected, shut off thecylinder valve and makecorrections. Fully closevalves when not in use.

• If the cylinder valve isopened too quickly it may

PROPANE

Simple but secure on-site storageFigure 2

Figure 3

Figure 4

Figure 5Secure the cylinder and keep it at least 10 feet away from the heater.

Hose lengthmust be between 15 feet and 50 feet.

Figure 6 - Soap Test for Leaks

Distance:

10 ft.min.

Hose: 15 ft. min., 50 ft. max.

38 – 3

cause closing (slugging) of the excess flow checkvalve. The purpose of this valve is to shut off gas flowshould the regulator accidentally be broken off.

• To unslug the check valve, shut off the flow at thecylinder, wait a couple of minutes for the check valve toreopen, then proceed. The cylinder valve should beopened slowly to its normal limit, approximately1-1/2 to 2 turns. Do not force the valve beyond this limit.

• Secure the cylinder by tying or wiring it to a column orother upright. Keep cylinders out of traffic areaswhere they may be knocked over.

• Cylinder and heater must always be in the same roomso that the cylinder valve can be shut down quickly iftrouble develops.

• Keep heaters away from flammable materials. Theheat from a burner is effective well past the tip.

• Watch for a drop in pressure orreduced flame efficiency. Thisindicates that gas is beingwithdrawn too quickly, and mayrequire additional cylinders tobe hooked up in manifold.Never attempt to increase theamount of vapour by applyingheat to the cylinder.

• Where possible, use only single cylinders for heaters.However, if cylinders must be manifolded, use nomore than three 100-pound cylinders (Figure 7). Ifother heaters with manifolded cylinders are to beoperated in the same area, they must be at least fiftyfeet away or be separated by a firewall.

• Remember that propane is heavier than air and willcollect in low areas such as trenches, pits, and

basements where it can create a flammable orexplosive situation (Figure 8).

• Never attempt to tie down, defeat, or bypass safetydevices on a construction heater. If the heater isdefective, replace it. If the heater is inadequate, getextra heaters or replace it with a larger one.

• If the flame goes out, act with caution. Shut off the gassupply, then determine whether escaped gas isconcentrated in the area. Because of its strong odour,you can usually smell propane. However, in a confinedspace, test with a gas detection device. If escaped gasis detected or even suspected, ventilate and purge thearea thoroughly before relighting the unit.

Warning - If the heater is in a confined or low-lyingarea, escaped gas can be hazardous. Never enter thearea without help standing by. Never attempt to relightuntil the gas is completely purged from the area.

• Never expose any part of your skin to liquid propane.Propane under pressure is extremely cold and cancause frostbite. Always wear gloves when handlingcylinders.

• Don't allow propane gas to saturate your clothing. Ahighly flammable situation can remain for some timeafter the exposure. Saturated clothing should beremoved and aired outside.

• Never operate heaters without adequate ventilation.Follow manufacturer's recommendations on the plate.

Bulk TanksPropane construction heaters that operate from a centralbulk storage tank are common on large constructionprojects. This type of installation takes planning andclose consultation between contractor and gas supplier toselect a safe, convenient tank storage area that will notinterfere with on-site traffic and materials handling, norinfringe on property line clearance requirements. The

bulk tank and feed lines are installedby licensed service personnel, buthooking up the heaters is generally leftto workers on the site. The feed linesare usually well provided with hook-uppoints called station valves. Theyconsist of a shut-off and a connectionpoint for a flexible hose. However, thesame rules for hooking up to aportable container apply here.• Check for leaks at the hook-up point

after installing flexible heater line.• Make sure the shut-off valve is in

the same room as the heater.• If heat is required in an area that is

not serviced by a valve a qualifiedservice person should extend theline, or take off a spur line usingapproved piping and install a valveat its terminus.

• Flexible hose lengths should neverexceed 25 feet between heater andstation valve.

PROPANE

Typical Manifold Set-UpFigure 7

Heavier than air,propane gas cancollect in low areasand create thepotential forasphyxiation orexplosion.

Figure 8

38 – 4

Welding and CuttingIn recent years, propane has become a popular energysource in open flame welding and cutting. Combined withoxygen in a manner similar to oxyacetylene welding, itprovides a gas mix that is considered much more stable bymany users.While welding cylinders are generally smaller than cylindersused for construction heaters, they should be treated withthe same care.• Fittings should be clean and

free of grease before hookingup.

• Fitting wrenches should beused to avoid damage toparts.

• Cylinders should be in anupright position at all times,kept in a suitable cradle whenin use, and preferably tiedupright to prevent tipping over(Figure 9).

• A fire extinguisher (4A40BCminimum) should be keptclose when using any torch.

• Regulators should beremoved and stored in aprotective case when not in use, along with hoses andtorches.

• Consult manufacturer's handbook for oxypropaneregulator settings. They are very different fromoxyacetylene settings. For more information, refer toWelding and Cutting in this manual.

SummaryThe safe use of propane depends on twelve basic rules:1) Don't store cylinders inside a building.2) Remove cylinders from the building when not in use or

when empty.3) Keep cylinders away from heat sources, and

flammables away from heaters.4) Always secure cylinders to prevent upset.5) Never transport cylinders in an enclosed vehicle or

trunk.6) Always use proper gear for hoisting or moving cylinders

around the worksite.7) Keep heaters in good condition. Repairs and

maintenance should be done only by licensed servicepersonnel.

8) Always have a fire extinguisher handy (4A40BCminimum).

9) Protect stored cylinders or bulk tanks from on-sitetraffic.

10) Don't tamper with controls or safety devices.11) Never enter an area where leaking gas is suspected.12) Don't use or store cylinders of propane in low areas

such as trenches, maintenance holes, or basements.

PROPANE

LiftRing forHoisting

Oxypropane Welding CartFigure 9

SpecialLocations

39 – 1

39 CONFINED SPACES

Complies with changes to the Construction Regulation(Ontario Reg. 213/91) implemented in 2006.

Before letting a worker enter a confined space, theemployer must develop a written confined space programmeeting the requirements of the Construction Regulation(Part II.1, Confined Spaces, sections 221.1 to 221.19).The employer must maintain the program.

CONFINED SPACE PROGRAMAmong the first requirements for employers developing aconfined space program is the need to assess whichworkers will be entering the confined space and thereforewhich workers will need a copy of the confined spaceprogram.

Employers must provide a copy of the program to theconstructor of a project. In turn, the constructor mustprovide a copy of the program to the project's joint healthand safety committee or health and safety representative,if any. A copy must also be available to other employers towhich the program relates and every worker if there is noproject joint health and safety committee or health andsafety representative.

If workers from more than one employer will be enteringthe confined space, the constructor must prepare aconfined space coordination program. A copy of theconfined space coordination document must be providedto each employer who is performing work in the confinedspace and to the project's joint health and safetycommittee or the health and safety representative.

The confined space program can apply to one or moreconfined spaces.

Program elements must include

a method of recognizing each confined space

a method for assessing the hazards to which workersmay be exposed

a method for developing plans for controlling thehazards

a method for training workers

an entry permit system setting out measures andprocedures to be followed when working in a confinedspace.

RECOGNIZING A CONFINEDSPACEA confined space is defined as a place

a) that is partially or fully enclosedb) that is not both designed and constructed forcontinuous human occupancy, and

c) where atmospheric hazardsmay occur because of itsconstruction, location, or contents, or because of workthat is done in it.

All three criteria have to be met before a space is definedas a confined space. Here is more information on each ofthe criteria.

Partially or fully enclosedBecause air cannot move freely in and out of a partially orfully enclosed space, there is a potential for a hazardousatmosphere to be generated inside. This is especially true forspaces such as vaults, tanks, pits, trenches, or manholes.

Not designed and constructed for continuous humanoccupancyConfined spaces are not designed or constructed forpeople to work in them on an ongoing basis. They areusually designed and constructed to store material,transport products, or enclose a process. Butoccasionally, some work must be done inside the space.Atmospheric hazardsA hazardous atmosphere is one which contains any of thefollowing:

an accumulation of flammable, combustible, orexplosive agents

less than 19.5% or more than 23% oxygen, or

an accumulation of atmospheric contaminants thatcould result in acute (short-term) health effects which

a) pose an immediate threat to life, orb) interfere with a person's ability to escape unaided

from a confined space.

CONFINED SPACES

CoordinationWhen workers of more than one employer performwork in the same confined space the constructormust prepare a coordination document to ensurethat the various employers perform their duties in away that protects the health and safety of allworkers. A copy of the coordination document mustbe provided to each employer of workers who perform work in

the same confined space

the project's joint health and safety committee orhealth and safety representative.

39 – 2

HAZARD ASSESSMENTBefore each time that a worker enters a confined space, acompetent workermust perform a written hazardassessment. The name of the competent worker mustappear on the assessment and the employer must keep arecord of the competent worker's qualifications.The hazard assessment must take into account

a) the hazards that may exist in the confined space

b) the hazards that may develop while work is performedinside the confined space

c) general safety hazards in the confined space.

The competent worker must sign and date theassessment and give it to the employer.If requested, the employer must give copies of theassessment and competent worker's qualifications to

the project's joint health and safety committee, or

the health and safety representative, or

every worker involved in the confined space entry ifthe project has no joint health and safety committeeor health and safety representative.

The employer must review the assessment as often asnecessary to make sure that the plans remain adequate.For example, if the potential chemical hazard changesdue to a change in process or equipment use, then theassessment must be changed.

An assessment is generally required for each confinedspace. But if there are two or more similar confinedspaces containing the same hazards then you need onlya single assessment document.

To perform a hazard assessment, you need to anticipatepotential hazards. Often, the hazards of working inconfined spaces are not recognized until it's too late.

For example:

A mixing tank was inadvertently started while aworker was inside.

A worker was killed by carbon monoxide gas from agasoline-powered pump used to drain a pit.

Because construction projects are not limited to newbuildings, confined spaces may be encountered in avariety of places. The following table describes typicalconfined spaces and the most common hazards foundthere.

Hazards in confined spaces can be divided into twodistinct categories: physical hazards and atmospherichazards.

CONFINED SPACES

If control measures (such as continuous mechanical ventilation) are used to ensure that the concentrations of anatmospheric hazard are controlled or maintained at an appropriate level (but not eliminated) then the space wouldstill be considered a confined space. If, however, measures are implemented to eliminate the possibility that anyatmospheric hazards may occur in a space, then the confined space provisions no longer need to apply.Eliminating the possibility that an atmospheric hazard will occur is different from controlling the hazard. If workersmust enter the confined space to eliminate the hazards (by steam-cleaning or vacuuming, for example), then theconfined spaces provisions apply.

EVERY CONFINED SPACE MUST BE THOROUGHLY ASSESSED AND EVALUATED BY ACOMPETENTWORKER TO DETERMINE WHETHER IT IS POSSIBLE TO ELIMINATE THE ATMOSPHERIC HAZARDCOMPLETELY.

Even if a space is not defined as a confined space under the regulations, the employer must take every precautionreasonable in the circumstances to protect workers entering the space.

COMPETENT WORKER

in relation to specific work, means a worker who

a) is qualified because of knowledge, training andexperience to perform the work

b) is familiar with the Occupational Health andSafety Act and the provisions of the regulationsthat apply to the work, and

c) has knowledge of all potential or actual dangerto health and safety in the work.

39 – 3

PHYSICAL HAZARDSPhysical hazards often present a greater danger inside anenclosed space than they do outside.Examples:

Noise and vibrationAn enclosed environment can amplify noise. Excessivenoise can damage hearing and prevent communication. Itcan affect workers' ability to hear alarms, warning shouts,or orders to evacuate.

Temperature extremesAsk plant personnel if workers could encounter dangeroustemperatures. For example, heat stress can be a hazardwhen working around boilers, hot pipe or tanks, orstructures heated by the sun. Protective clothing can alsoadd to heat stress.

Cramped work spacesCramped work spaces restrict movement and can makeusing tools and equipment difficult and dangerous.

Poor access or exitConfined space openings are generally small and notwell-located. This can make entry and exit difficult andcan interfere with rescue.

Rotating or moving equipmentBefore entry, identify any moving or rotating equipment(such as conveyors, mixers, augers, etc.) which couldbecome activated by stored pressure, accidental contact,

CONFINED SPACES

Examples of confined spaces Common hazards

Chemical and petrochemical projectsTanks, vessels, storage tanks, underground tanks, pipes,sumps, pits, any area where a worker cannot readilyescape from a toxic or explosive atmosphere; any areawhere toxic, explosive, or oxygen deficient atmospheresmay be encountered.

Toxic and explosive gases, vapours and fumes; physicalhazards of cramped entry and exit, narrow passages,and chemical spills.

Sewage handling systemsSettling tanks, sewers, manholes, pumping areas, septictanks, digesters.

Toxic and/or explosive atmospheres such as hydrogensulphide and methane; oxygen deficiencies.

Water treatment plantsSettling tanks, holding tanks, equipment and wells belowfloor level.

Oxygen deficiency, chlorine gases, ozone; also possiblymethane and hydrogen sulphide produced by decayingdebris removed from lake and river water.

Heavy industrial projectsSumps, pits, roasters, digesters, mixers, bins, flues,ducts, conveyors, elevators, bag houses.

The hazards will depend on processes and materialsinvolved but may include methane, hydrogen sulphide,oxygen deficiency, flammable agents, electrical hazards,moving parts, and engulfment due to free-flowingmaterials.

General constructionVaults, caissons.

Toxic materials such as carbon monoxide from temporaryheaters in low-lying areas; refrigerants; high-voltagetransmission equipment; physical hazards involving poorlighting and cramped working conditions.

39 – 4

or gravity action. Check with plant personnel on lockoutand tagging procedures, and review drawings, plans, andspecifications.

Electrical hazardsAny exposed conductors or energized equipment shouldbe identified before entry. The presence of water inconfined spaces may pose an additional electrocutionhazard where electrical circuits, equipment, and tools areused.

Engulfment due to uncontrolled movement of liquidsand solids

Liquids, sludge, fine solids, and other material may not becompletely removed from confined spaces and maypresent an engulfment or drowning hazard. Useinspection ports and dipsticks, and check with plantpersonnel to evaluate such hazards.

Slick or wet surfacesYou can be severely injured from a slip or fall on icy, oily,wet, or moist surfaces.

LightingConfined spaces generally have poor lighting. You oftenneed temporary lighting. In potentially explosiveatmospheres, use lighting designed for such situations.

ATMOSPHERIC HAZARDSConfined spaces can present three kinds of atmospherichazards:

flammable, combustible, or explosive atmosphere

oxygen-enriched or oxygen-deficient atmosphere

atmospheric contaminants.

The hazardous atmosphere may be due to existingconditions (e.g., residue in a tank,) or it may be created bythe work being done inside the confined space (e.g.,welding or using solvents). In some cases, removingsludge or scale can release trapped pockets of gas orvapour and create a hazardous atmosphere. Moreover,dangerous atmospheres often exist together. For instance,flammable, combustible or explosive atmospheres mayalso be toxic or cause an oxygen deficiency.

FLAMMABLE, COMBUSTIBLE, OREXPLOSIVE ATMOSPHERESFlammable atmospheres are generally caused by

evaporation of flammable liquids (e.g., gasoline)

by-products of chemical reactions (e.g.,decomposition of organic matter to form methane).

Explosive atmospheres are those in which a flammablegas or vapour is present in quantities between the LowerExplosive Limit (LEL) and the Upper Explosive Limit(UEL). These limits define the “Explosive Range” whichvaries from one substance to another. Refer to the section

“Fire and Explosion Hazard” of a material’s MSDS for fire-and explosion-related information.The LEL is the lowest, and the UEL the highestconcentration of gas or vapour that will supportcombustion. For example, gasoline has an LEL of 1.4%and a UEL of 7.6%. Below 1.4% there is not enough fuelto burn, while above 7.6% there is too much fuel and notenough oxygen to burn. (See figure above.)

The most common explosive gas likely to be encounteredin sewers and other underground structures is methane-or“natural gas”-produced by decaying garbage and sewage.

Other explosive gases and vapours may be present inconfined spaces depending on previous contents oraccidental spills and leaks (e.g., leaking fuel-storage tanksnear service stations).

Explosive ranges for common gases and vapours arelisted in Table 1. These values must be considered whenselecting and operating gas-testing equipment.

Combustible atmospheres can arise in grain elevators,feed mills, and some industrial settings such as baghouses, because of the large quantities of dust generated.The most common combustible dust is grain or flour dust-there have been several explosions in grain elevators.You need to address this issue whenever you're workingin these settings.

CONFINED SPACES

39 – 5

OXYGEN-ENRICHED AND OXYGEN-DEFICIENT ATMOSPHERESNormal outside air contains about 21% oxygen. If theconcentration of oxygen exceeds 23% it is considered“enriched”. The primary concern with oxygen-enrichedatmospheres is the increased flammability of materials.Things that would only smoulder in normal air will burnvigorously in oxygen-enriched atmospheres.

Oxygen-enriched atmospheres are fairly rare inconstruction. They are usually associated with pureoxygen escaping from leaking or ruptured oxyacetylenehoses or, on projects in industrial plants, from an oxygenline in an industrial or manufacturing process.

Oxygen-deficient atmospheres, on the other hand, arefairly common. They may result from work being done(such as welding), bacterial action (which consumesoxygen), or from chemical reactions (such as rusting).Oxygen may also be displaced by another gas or vapour(e.g., carbon dioxide or nitrogen used to purge tanks,pipe, and vessels). Table 2 lists the effects of oxygendeficiency.

ATMOSPHERIC CONTAMINANTSBecause confined spaces are poorly ventilated,atmospheric contaminants can build up to hazardouslevels very quickly. For construction in an industrialsetting, the type of airborne hazard that may beencountered depends on

products stored in the confined space

the type of work tasks performed in the confinedspace

work or processes being performed near the confinedspace.

The most common atmospheric contaminants inconstruction include hydrogen sulphide, carbon monoxide,sulphur dioxide, chlorine, and ammonia.

Hydrogen Sulphide (H2S) is a gas generated by thedecomposition of garbage and sewage. H2S can be foundin sewers, sewage treatment plants, refineries, and pulpmills. It is also found in many oil refineries since mostcrude oil in Canada has some H2S dissolved in it. H2S isvery toxic. A single breath at a concentration of about500-700 ppm (parts per million) can be instantly fatal. Atvery low concentrations, H2S has the characteristic odourof rotten eggs. However, at about 100 ppm it can deadenyour sense of smell and create the false impression thatno hazard exists.Carbon Monoxide (CO) is a very common toxic gas. It hasno odour or taste and is clear and colourless. Carbonmonoxide poisoning can be very subtle and may causedrowsiness and collapse followed by death. The majorsources of CO in construction include the internalcombustion engines powering saws, scissor lifts, powertrowellers, generators, and forklift trucks. Even theserelatively small engines produce high levels of CO.

CONFINED SPACES

Gas/vapour LowerExplosiveLimit (%)

UpperExplosiveLimit (%)

Acetone 2.6 12.8

Ammonia 16.0 25.0

Benzene 1.3 7.1

Ethyl Alcohol 3.3 19.0

Gasoline 1.4 7.6

Hexane 1.1 7.5

HydrogenSulphide 4.0 44.0

Methane 5.0 15.0

Methyl Alcohol 7.3 36.0

Propane 2.4 9.5

Toluene 1.2 7.1

Xylene 1.1 7.0

Table 1Explosive Range for

common gases and vapours

Oxygenconcentration Effect

19.5% Minimum for safe entry

Less than 18% Loss of judgment andcoordination

Less than 15% Loss of consciousness

Less than 12% Sudden collapse and loss ofconsciousness

Table 2Effects of oxygen

deficiency

Never use pure oxygen to ventilate a confinedspace. Use clean air.

39 – 6

Heating in confined areas, particularly with propane,presents special hazards and requires special safeguards.Propane is heavier than air and can collect in low-lyingareas such as trenches, basements, and shaft bottoms.Propane can also be absorbed into clothing. Workersmust therefore use extreme caution in the event ofleakage or flame-out.

Direct-fired heaters release combustion emissions directlyinto the air where people work. Although carbon monoxide(CO) is the main concern, carbon dioxide (CO2) andnitrogen oxides may also be a problem.

Traditionally, explosive blasting has been used fordemolition or breaking up rock. Blasting in a confinedspace can produce high levels of carbon monoxide. Youmust use mechanical ventilation and perform air testsbefore workers re-enter the blast area to ensure that thecarbon monoxide levels are within acceptable levels.

Sulphur Dioxide (SO2) is a very irritating and corrosivegas with a strong sulphur-like odour which can be foundin pulp-and-paper mills and oil refineries.

Chlorine (Cl2) is another irritating and highly corrosive gaswith a bleach-like odour used as a disinfectant in waterand sewage treatment plants and a wide variety of otherindustrial settings.

Ammonia (NH3) is a fairly common chemical used as arefrigerant and in making fertilizer, synthetic fibres,plastics, and dyes.Hundreds of other toxic materials may be encountered infactories, chemical plants, and similar industrial settings.The best way to obtain information regarding thepresence or absence of toxic materials is to discuss theproposed work with the client and ask for the information.

FLAMMABLE PRODUCTSWhen using flammable materials in a confined space,take these precautions:

Provide adequate ventilation.

Control sparks (use non-sparking tools) and controlother potential ignition sources

Extinguish all pilot lights.

Use specially protected lighting.

Have fire extinguishers handy.

Contact cement is an example of a product with fire orexplosion potential when used in a small area with poorventilation. Workers have been killed from explosion andfire when they finished work and switched off the light in aroom where solvent vapours from contact cement oradhesives had accumulated.

ACCUMULATION OF CONTAMINANTSBELOW GRADETrenches, manholes, and low-lying areas may becomehazardous from leaking gases heavier than air-such aspropane-or from gasses such as carbon monoxideseeping through the soil and into the confined space.

CONFINED SPACES

Adequate ventilation is absolutely essential whenyou cannot avoid using combustion engines inconfined spaces.

CO inatmosphere(parts permillion)

Signs and symptoms

10 No symptoms

25

TWAEV (Time-Weighted AverageExposure Value): The maximumaverage amount a worker isallowed to be continuouslyexposed to for a work day orwork week.

70Blood vessels widen, shortnessof breath, tightness across theforehead

100STEV (Short-Term ExposureValue): The maximum amount aworker is allowed to be exposed tofor a 15-minute period.

120 Shortness of breath, headachewith throbbing in temples

220Headache, irritability, tiredness,impaired judgment, impairedvision, dizziness

350–520 Headache, confusion, fainting,collapse

800–1220Unconsciousness, spasms,respiratory failure, death ifexposure continues

More than 2000 Rapidly fatal

Do not restrict ventilationby blocking openings

Blockedopening

39 – 7

ACCUMULATION OF CONTAMINANTS INAREAS NOT CLASSIFIED AS CONFINEDSPACESA variety of spaces can become hazardous because ofthe products being used or the work being done in them.These areas can be deadly even if they are not classifiedas confined spaces and even if the confined spaceprovisions of the Construction Regulation do not apply.

Skylights, domes, and ceilings

Work is sometimes required within newly installedskylights where lighter-than-air gases and fumes mayaccumulate.

Workers should be aware of this hazard. At the first signof discomfort or disorientation they should leave the areauntil it has been ventilated.

Workers feeling light-headed or experiencing headachesmay be inhaling these pollutants. Drowsiness ordisorientation can lead to falls. Again, leave the area untilit has been ventilated.

Underground mines, tunnels, and shafts

These spaces are intended for people to carry out work inthem-this work is covered by specific regulation. Theymay present physical or atmospheric hazards. Manyutilities are routed through tunnels or underground shaftswhere hazardous atmospheres may collect fromcontainers or operations above, or be created by utilityleaks (such as gas and oil).

Work in shafts must be carefully planned. Because thework may be of short duration and require only atemporary platform, these jobs are often not given properattention.

In addition to the areas already described, beware ofapparently harmless areas such as basements, halls, andsmall rooms that can become dangerous when a lack ofventilationandhazardousmaterials oroperationscombine tocreateatmospherichazards.

CONFINED SPACES

Case studyA construction crew finished installing a 12-foot-deepmanhole without incident. After the crew left thearea, 265 pounds of nitroglycerin-based explosive in20 boreholes, each 18 feet deep, were detonated40-60 feet from the manhole. A worker who enteredthe manhole 45 minutes after the explosioncollapsed within minutes, and two coworkersdescended into the manhole to rescue him. Onerescuer retrieved the unconscious worker beforecollapsing on the surface, and the other rescuer diedin the manhole.

An investigation determined that carbon monoxidereleased from the explosion had migrated throughthe soil into the manhole. Carbon monoxideconcentrations at the bottom of the manhole twodays after the incident were 1,905 ppm (parts permillion). This concentration was well above 1,200ppm, the concentration classified as ImmediatelyDangerous to Life or Health (IDLH). Tests followingventilation of the manhole showed that high levels ofcarbon monoxide reappeared as a result ofcontinued migration from the surrounding soil.Subsequent monitoring of the manhole showed adecline in carbon monoxide levels over the next 8days.

If a worker can be injured by inhaling a hazardousgas, vapour, dust, or fume or there is an explosionhazard then you must provide adequate ventilationby natural or mechanical means. If this is notpossible then you must provide respiratoryprotection equipment suitable for the hazard.

39 – 8

PLAN FOR CONTROLLINGHAZARDSOnce the hazards have been identified in the assessment,a competent person must develop a plan to eliminate orcontrol the hazards.

The primary objective of the plan is to eliminate thehazard before entry. If this is not possible, then controls,measures, and procedures must be put in place to ensurethat workers are not in danger.

If confined spaces are of similar construction and presentthe same hazards, a single plan can be used. Still, theindividual confined spaces must be identified in both thehazard assessment and the plan.

The Plan is the program element with the most regulatoryrequirements attached to it. The regulation outlines 11mandatory requirements that must be contained in theplan:

1) Duties of workers

2) Coordination document (prepared by the constructor)if workers of more than one contractor enter the sameconfined space

3) On-site rescue procedures

4) Rescue equipment (inspected by a competent worker)and methods of communication

5) Protective clothing and protective equipment

6) Isolation of energy and control of material movement

7) Attendants

8) Adequate means of access and egress (entry andexit)

9) Atmospheric testing (conducted by a competentworker)

10) Adequate procedures for working in the presence ofexplosive or flammable substances

11) Ventilation and purging.

We address each of these 11 mandatory requirementsbelow.

1) DUTIES OF WORKERSa) Do not enter or re-enter (if the confined space has

been left unoccupied and unattended) the confinedspace unless testing has been performed.

b) Know the hazards that may be faced upon entry.Know the route of exposure (e.g., inhalation or skinabsorption), signs and symptoms, and long-termeffects of exposure.

c) Know how to use the equipment (including personalprotective equipment and tools) properly.

d) Maintain communication with the attendant so that theattendant can monitor your safety and be able to alertworkers to evacuate the confined space.

e) Alert the attendant whenever:– you recognize any warning sign or symptom of

exposure– you see a dangerous condition– an alarm is activated.

f) Get out of the permit space immediately whenever– a warning system indicating a ventilation failure is

activated– the attendant gives an evacuation order– a worker recognizes any signs or symptoms of

exposure– a person inside detects a dangerous condition– an evacuation alarm is activated.

2) COORDINATIONWhen workers of more than one employer perform workin the same confined space, the constructor mustcoordinate entry operations. The constructor must preparea coordination document to ensure that the variousemployers perform their duties in a way that protects thehealth and safety of all workers entering the confinedspace.

A copy of the coordination document must be provided toeach employer of workers who perform work in theconfined space and the project's joint health and safetycommittee or health and safety representative.

CONFINED SPACES

COMPETENT PERSON

means a person who

a) is qualified because of knowledge, training andexperience to organize the work and itsperformance

b) is familiar with the Occupational Health andSafety Act and the regulations that apply to thework, and

c) has knowledge of any potential or actual dangerto health and safety in the workplace.

Each employer is responsible for the health andsafety of their own workers and for ensuringcompliance with the regulation.

39 – 9

3) RESCUE PROCEDURESThe confined space plan must include written proceduresfor safe onsite rescue that can be implementedimmediately in case of an emergency. An adequatenumber of people must be available to carry out therescue procedures immediately. They must be trained in

a) the onsite rescue procedures

b) first aid and cardio-pulmonary resuscitation (CPR)

c) how to use the rescue equipment necessary to carryout the rescue.

4) RESCUE EQUIPMENTThe rescue equipment must be readily available,appropriate for the confined space, and inspected by acompetent worker. The competent worker must keep awritten record of the inspection. Examples of rescueequipment include harnesses and lifelines, hoist/retrievalsystems, respirators, and other personal protectiveequipment.

NOTE: You must consider the size of the confined space'sopening when choosing rescue equipment. There is nopoint planning for a rescuer to wear a SCBA (self-contained breathing apparatus) unit if it doesn't fit throughthe opening.

All too often, inadequate or incorrect emergency rescueresponse results in multiple fatalities. Here are twoexamples:

A worker collapsed shortly after entering a degassertank. His coworker went in after him and collapsed aswell.

A contractor went to test acid-tainted water and wasdiscovered by a worker floating in a well of the above-ground pump house. The worker went to his rescueafter calling 911 but was himself overcome. Twoparamedics responding to the call were also struckdown. All four victims died.

Even with the best planned and executed entry there is achance of a sudden change in conditions. The changecould be due to factors recognized earlier but for which no“absolute” protection exists, such as the failure of arespirator, the introduction of a new hazard, or collapsefrom heart attack or illness. In such cases you need arescue plan that has been practiced and works.

5) PROTECTIVE CLOTHING ANDPERSONAL PROTECTIVE EQUIPMENTProtective clothing and equipment suitable for onematerial may not be suitable for others. For example,polyvinyl chloride (PVC) plastic is resistant to most acids,but it can be softened or penetrated by many commonsolvents such as benzene, toluene, and xylene.

For this reason, a knowledgeable person should assessthe protective clothing and equipment needed (e.g.,gloves, boots, chemical suits, fire resistant coveralls-aswell as hearing, respiratory, eye, and face protection).Don't forget that if workers need personal protectiveequipment, they must be trained in its use.

Respiratory protective equipment should be used whereventilation is impractical or inadequate. Certain basic rulesapply to the equipment.

First of all, you need to select the proper type ofrespirator. Oxygen-deficient atmospheres requiresupplied-air respirators—either airline types withemergency reserves or SCBA (self-contained breathingapparatus) as in the figures on the next page.

In toxic atmospheres, you must use supplied-airrespirators if the concentration of the gas or vapourexceeds the level considered to be ImmediatelyDangerous to Life or Health (IDLH), or if the concentrationis unknown.

CONFINED SPACES

Dialing 911 is not a sufficient rescue response.

SCBA note: Because the amount of air supply instandard SCBA cylinders is rated for a specific timeperiod, it is very important to plan your tasks,especially rescues operations, accordingly. Heavywork and stress will increase breathing rates andworkers will use up the air in less than the ratedtime. An alarm sounds when the air supply is low.

Remember, rushing into a confined space to helpyour buddy who is laying on the ground will likelyresult in your own death. Rescuers are no good tothe victim if they also become victims. Many cases ofmultiple fatalities involve would-be rescuersovercome because of inadequate preparation.

39 – 10

When the level of toxic gas or vapour is above theexposure limit but below the IDLH level, air-purifyingrespirators approved by the National Institute ofOccupational Safety and Health (NIOSH) may be usedprovided the exposure conditions do not exceed the unit'slimitations. Someone who is competent in respiratorselection must determine the appropriate type ofrespirator.

Workers required to wear respirators must be instructedhow to properly fit and maintain them. For moreinformation on respiratory protection, refer to the chapteron Respiratory Protection in this manual, or the CanadianStandards Association’s standard Z94.4-02, Selection,Use, and Care of Respirators.

6) ISOLATION OF ENERGY ANDCONTROL OF MATERIAL MOVEMENTEquipment that moves in any way (even rotation) must beisolated by disconnecting the equipment from its power source

and de-energizing the equipment, or lockout and tagging. Only workers trained in lockout

and tagging should perform such operations. Lockoutand tagging should be done even if you use the firstoption (disconnect and de-energize) to isolate theenergy.

For pneumatic or hydraulic equipment, isolate the powersource and depressurize the supply lines. Depressurizeany components that may still be pressurized after thesupply lines have been bled-hydraulic cylinders forexample. You must disconnect and drain pipes carryingsolids or liquids to or from a confined space, or insertblank flanges.

If the pipe cannot be blanked off or disconnected, thevalve may be closed, chained, locked and tagged,provided thatthis type ofcontrol—and itsimportance—have beenexplained to allworkers in thearea. Simplyclosing valvesis not generallyacceptable.

You may needblocking to prevent movement caused by gravity for someequipment (e.g., conveyors).

Electrical equipment in thespace should bedisconnected, tagged andlocked out, and groundedwhen it's practical to do so.

In the case of live electricalwork in a confined space,you need to pay specialattention to standardprocedures. A minormistake in a manhole canlead to disaster.

Cramped workingconditions can makeaccidental contact with anenergized conductor morelikely, so you may need non-conductive equipment.

You may need gloves, mats, and other insulatingequipment depending upon the type of work. Capacitorsor other components which can store a charge should bedischarged and/or grounded.

CONFINED SPACES

Do not use single-strap dust masks and surgicalmasks—they are not approved by the NationalInstitute for Occupational Safety and Health(NIOSH). NIOSH is a U.S.-based organization thatapproves respirators. Workers must be supplied withNIOSH-approved respirators only. All NIOSH-approved respirators have an approval number(always starting with the letters TC) on them.

Make sure your respirator has all the proper parts.Since each manufacturer uses different designs,parts are not interchangeable between brands. Makesure you use the correct parts (cartridges, aircylinders, etc.) for your brand of respirator. Neveruse cartridges or air cylinders from anothermanufacturer. They will not fit correctly and willendanger the life of the worker or rescuer.

39 – 11

7) ATTENDANTAn attendant must be present whenever a worker enters aconfined space. The attendant is not allowed to enter theconfined space, unless he or she is replaced by anotherattendant in accordance with the plan.

The attendant must

remain alert outside and near to the entrance be in constant communication (visual or speech) with

all workers in the confined space monitor the safety of workers inside the confined

space provide assistance as necessary be provided with a device for summoning help in case

of emergency, and initiate an adequate rescue procedure in case of an

emergency.

8) ENTRY AND EXIT (ACCESS ANDEGRESS)The means of entry and exit can be evaluated beforeentry by checking drawings, by prior knowledge, or simplyby inspection from outside the space.

Confined space openings are generally small and not welllocated. These small openings must be considered in therescue plan since they restrict the movement of workersand equipment in and out of confined spaces.

Entry and exit for top-side openings may require ladders.Ladders must be well secured. Performing an emergencyrescue on workers trapped in such areas requires carefulplanning and practice.

9) ATMOSPHERIC TESTINGIf the hazard assessment determines that there is anatmospheric hazard in the confined space, you mustperform atmospheric testing.

1) The employer must appoint a competent worker toperform adequate tests safely before and during thetime a worker is in a confined space to ensure thatacceptable atmospheric levels are maintained. Thecompetent worker who will perform the tests mustreceive training in the operation, calibration, andmaintenance of the instruments. Most manufacturerscan provide necessary training.

2) If the confined space has been left unoccupied andunattended, you must perform the testing again.

3) The competent worker performing the tests must useproperly calibrated and maintained instrumentsappropriate for the hazards in the confined space.

4) Results of every sample of a test must be recordedon the entry permit. If continuous monitoring isperformed, test results must be recorded at adequateintervals.

Gas detection instruments

Gas detection instruments can take many forms-“personal” or “area,” single-gas or multiple-gas detectors,detectors with dedicated sensors or those withinterchangeable sensors.

CONFINED SPACES

The attendant is not allowed to enter the confinedspace to perform a rescue even after help hasarrived unless he or she is replaced by anotherattendant in accordance with the plan.

Gas detectioninstruments

Personalmonitor

Areamonitor

Single gasmonitor

Multi-gasmonitor

Definedsensors

Interchangeable sensors

39 – 12

If a monitor is wornby the worker it isreferred to as“personalmonitoring.”Personal monitoringgives informationabout theconcentration ofhazardoussubstancessurrounding the worker. It is particularly useful when theworker is moving from place to place within the confinedspace.

Area sampling is done before entry or re-entry. As muchof the confined space area as possible should be tested,including the bottom, mid level, top, and corners.

Single-gas detectors measure only one gas while multi-gas monitors are available with several toxic sensoroptions and have the flexibility of measuring many gasessimultaneously. Most multi-gas monitors include anoxygen sensor, aflammable/combustible gassensor, and one or twosensors for detectingspecific toxic gases. Newersingle and multi-gasinstruments offer theflexibility of interchangeablesensors. You can changethe sensors to suit theapplication in hand. For example, a single-gas detectorused to check hydrogen sulphide levels can be used tomonitor carbon monoxide concentrations after you changethe sensor.

Key steps to follow when you suspect adangerous atmosphereSelect the appropriate type of calibrated instruments forthe hazards identified in the assessment.You must understand the characteristics of the work areain order to choose the right instruments. Different types ofconfined spaces present different kinds of toxic gashazards. There are hundreds of different toxics gases orvapours. You need a familiarity with the characteristics ofthe confined space in order to narrow down thepossibilities and choose equipment.

You must use a calibrated monitor that is capable ofmeasuring the hazardous atmosphere found in theconfined space. For example, if a propane heater is beingused inside a confined space, then you need calibratedmonitors capable of measuring oxygen levels, carbonmonoxide, and combustible gases.

You must calibrate, maintain, and use the equipment inaccordance with the manufacturer's recommendations.If the meter is not properly calibrated, you cannot relyupon its results. Deaths can occur if the instrumentunderestimates the atmospheric conditions.

CONFINED SPACES

WARNING: Combustible gas detectors should notbe used to assess toxic atmospheres. Mostcombustible gas detectors do not respond to lowconcentrations of gases. For example, H2S isflammable from 4.3% to 44%. But it is ImmediatelyDangerous to Life or Health (IDLH) at 100 parts permillion (0.01%) and would not be detected at thisconcentration by most combustible gas detectors.Most other toxic gases that are also flammable aredangerous in concentrations well below the LEL.

Most confined-spaceinstrumentmanufacturers nowoffer "docking"stations that canautomaticallycalibrate instrumentsand print a record ofcalibration. Thestations also rechargeand store theinstruments.

39 – 13

Perform the tests safely.Entry into a confined space must be prohibited before theappropriate tests are performed. Atmospheres should beevaluated remotely (from outside the confined space)before each entry. If possible, an extendable probe shouldbe inserted through an inspection port or other openingbefore removing large doors or covers.

Make sure that as much of the space as possible istested, including the bottom, mid-level, top, and corners,so that you don't miss layers or pockets of bad air. (Seefigure below). There are some gases that are lighter orheavier than air. Lighter gases, such as methane, willaccumulate at the top, while gases heavier than air willsink to floor level. Gases that are the same weight as air,such as carbon monoxide, will be found throughout aconfined space.

Check for oxygen content, combustible or explosive gasesand vapours, and toxic gases and vapours in that order ifyou use more than one meter.First, check for oxygen content. Checking oxygen first isimportant because you may need adequate oxygen to geta valid result from other tests.

If the oxygen level is adequate, test for explosiveatmospheres. Several different calibration gases areavailable. Methane is used most frequently since it is acommon gas found in many places. But you can getdevices calibrated for propane, hexane, heptane, or

almost any other combustible gas. These devices give aresult expressed as a percentage of the lower explosivelimit (LEL) for the calibration gas used.

The next thing to check for is the presence of toxic gasesand vapour using a calibrated instrument.

If you're using a multi-gas monitor capable of measuringoxygen, combustibles, and toxic gases simultaneouslythen the order of testing is not as critical.

All three types of dangerous atmospheres must beevaluated before entry. Users of gas detectors must becompetent workers. They must also receive training in theoperation, calibration, and maintenance of the devices.Most manufacturers can provide necessary training.

You may need to monitor the atmosphere continuously.

Continuous monitoring in a confined space is requiredwhile hot work is being performed in a potentiallyflammable or explosive atmosphere or where theflammable or explosive atmosphere has been renderedinert by adding an inert gas. It should also be consideredwhen conditions in the confined space change rapidly.

If continuous monitoring is performed then test resultsmust be recorded at regular intervals.

Most confined space instruments have data-loggingcapabilities. Data-logging is useful for compliance andrecord-keeping purposes. If an accident or unusual eventhappens, data-logging may be useful for demonstratingdue diligence.

Interpret the results.

There may be other gases present in the confined spacethat interfere with the reading for the gas you are trying tomeasure. Such gases are referred to as “interferinggases.” They can lead to misinterpretation of themonitoring results.

If the atmosphere meets acceptable exposure limits (seenext page) the confined space may be entered. If theatmosphere does not meet acceptable limits, you need toimplement controls before anyone can enter.

CONFINED SPACES

Always test for the three dangerous atmospheres:

too much or too little oxygen

combustible or explosive gases or vapours

toxic gases or vapours.

Know the limitations of your specific equipment.Consult the manufacturer's instructions for properuse.

Temperature, humidity, and interfering gases can allaffect the performance of gas monitors.

39 – 14

If measurements are within acceptable exposure limits butare approaching hazardous levels, the competentworker's decision to proceed should be based on anassessment of the source of the problem, the likelihood ofchange, and the conditions at the scene. In doubtfulcases, it is best to implement the appropriate controlsdiscussed in the following section.

Recording the results.

The test results must be recorded on the work entrypermit. The records must be kept by the constructor oremployer for at least one year after the project is finished.

10) COMBUSTIBLE, EXPLOSIVE, ORFLAMMABLE ATMOSPHERESNo worker is allowed to enter a confined space if airbornecombustible dust or mist is present in a concentrationsufficient for explosion. If an explosive or flammableatmosphere is detected, you can perform only certaintypes of work. The conditions for each type of work arespecified below the following definitions.

a) Between 0% and 5% of the LEL, you can perform hotwork. The following conditions must also be met:

The oxygen content must be maintained below23%

The atmosphere must be continuoouslymonitored.

The entry permit must include adequateprovisions for hot work, and it must specify theappropriate measures to be taken.

An alarm and exit procedure must be in place toprovide adequate warning and allow safe escapeif the atmospheric concentration exceeds 5% ofthe LEL or if the oxygen content exceeds 23%.

b) Between 0% and 10% of the LEL, you can performcold work.

c) Between 0% and 25% of the LEL, you can performinspection work.

Alternatively, work may be carried out in the confinedspace if the combustible, explosive or flammableatmosphere is rendered inert by an inert gas (such asnitrogen, argon, helium, or carbon dioxide).

The atmosphere must be monitored continuously toensure it remains inert. The worker in the confined spacemust use adequate respiratory equipment as well asadequate equipment to help people outside the confinedspace locate and rescue the worker if a problem occurs.

CONFINED SPACES

Acceptable atmospheric levels

Explosive orflammable gasor vapour

< 25% of its lower explosive limit:inspection work can be performed.

< 10% of its lower explosive limit:cold work can be performed. (Coldwork is work which does not involve– welding and cutting– the use of tools or equipment

which can produce a spark– other sources of ignition.)

< 5% of its lower explosive limit: hotwork can be performed.

Oxygen content At least 19.5% but not more than23% by volume.

Exposure toatmosphericcontaminants

Exposures to atmosphericcontaminants must not exceed whatis reasonable in the circumstances(section 221.2 (c) of theConstruction Regulation).

The exposure limits in theregulation on Control of Exposureto Biological or Chemical Agents(Ontario Regulation 833) and theDesignated Substance Regulations*are generally considered

* This is the case despite the fact that construction projects are,strictly speaking, exempt from Regulation 833 and most of theDesignated Substance Regulations. (The Designated SubstanceRegulation which does apply to construction is O. Reg. 278/05:Designated Substance–Asbestos on Construction Projects and inBuildings and Repair Operations.)

Never trust your senses to determine whetherthe atmosphere in a confined space is safe.

You cannot see or smell many toxic gases andvapours.

You cannot determine by your senses the levelof oxygen present.

Know which gases or vapours may be present inthe confined space and test for them.

Inerting is the process of replacing the potentiallycombustible atmosphere in a confined space with anoncombustible gas such as nitrogen, argon, helium,or carbon dioxide.

Hot workmeans activities that could produce asource of ignition such as a spark or open flame.Examples of hot work include welding, cutting,grinding, and using non-explosion-proof electricalequipment.

Cold workmeans activities that cannot produce asource of ignition.

39 – 15

11. VENTILATION/PURGINGThis is the most effective method of control. The spacecan be purged of dangerous atmospheres by blowingenough fresh air in, and/or by removing (or suction-venting) the bad air and allowing clean air in. Studieshave shown that the best results are obtained by blowingfresh air into a space close to the bottom. Check theefficiency of ventilation by re-testing the atmosphere withthe gas detection equipment before entry.

When ventilation is used to improve the air in a confinedspace, ensure that the toxic or flammable gases orvapours removed from the space do not pose a risk toother workers. “Exhaust air” should not be discharged intoanother work area.

In cases where theconcentration ofexplosive gas or vapouris higher than the UEL,ventilation will bring theconcentration down intothe “Explosive Range.”This is one reason whyyou should use only“explosion-proof” fans.These may be speciallydesigned fans poweredby electricity orcompressed air. Somepneumatic air moversmay also be suitable.

For manholes, you canuse portable fans. Theseusually provide around750-1,000 cubic feet ofair per minute.

A typical manhole 10 feet deep and 5 feet wide contains196 cubic feet. Blowing in 750 cubic feet per minuteshould provide an air change every 15 seconds and easilydilute or displace most dangerous atmospheres.

Fans capable of moving 5,000 cubic feet per minute areavailable for use in larger tanks and vessels.

This type of ventilation may not be adequate in situationswhere additional toxic or explosive gases or vapours maybe generated (e.g., during cleaning and resurfacing tanksor by disturbing sludge and scale).

In the case of welding or other work which generates alocalized source of toxic gas, fume, or vapour, an exhaustventilator can be used to draw out and discharge thehazard in an open area. (See figure below.)

Options must be evaluated by someone who understandsthe risks of the work being done.

CONFINED SPACES

The inert gas will replace all of the oxygen as wellas the combustible gases in the confined space.Workers entering the confined space should useNIOSH-approved air-supplied respirators. Afterwork is completed, the confined space must beproperly ventilated, and a competent worker musttest the confined space to see if it is safe.

If you use mechanical ventilation to maintainacceptable atmospheric levels by providing acontinuous supply of fresh air, you must have awarning system (i.e., an alarm) and exit procedure incase there is a ventilation failure. The alarm shouldbe activated by a pressure switch at the fan ratherthan by electrical failure. This ensures that the alarmis activated if the fan belt fails.

39 – 16

WORKER TRAININGWorkers must be trained before they enter a confinedspace. The training must include recognizing the hazards (including potential hazards)

in the confined space safe work practices, including the use of all

equipment such as ventilation equipment, airmonitors, and personal protective equipment.

It is strongly recommended that

the employer use an evaluation procedure (a test) toensure that workers have acquired the knowledgenecessary to safely perform their duties

inexperienced workers team up with experiencedworkers.

You must review the content of the training at leastannually, and whenever there is a change incircumstances such as a change in an industrial process.If the review indicates that the training is not adequate,you must provide additional training.

You must keep a record of the names of trainers, trainees,as well as the date of training. If the project's joint healthand safety committee or health and safety representativewants a copy of the record, you must provide one.

ENTRY PERMITSPermits are valuable tools for planning, evaluating, andcontrolling confined space entries.

A permit involves a formal system of procedures and isissued by the employer before any worker enters theconfined space. A competent person must verify that thepermit issued complies with the plan before every shift.The duration of an entry permit must not exceed the timerequired to complete the task. Entry permits should beunderstood by everyone involved in the job and must bereadily available to every person entering the confinedspace.

At the very least, the entry permit must include

the location and description of the confined space

a description of the work

a description of the hazards and the correspondingcontrols

the time period for which the entry permit applies

the name of the attendant

a record of each worker who enters and leaves

a list of the equipment required for entry and rescue,and verification that the equipment is in good workingorder

the results of the atmospheric testing

additional procedures and control measures if hotwork is to be done.

The entry permit may also include

a record of the hazard assessment

the hazard control plan

the training records.

See four pages ahead for a sample of an entry permitform.

CONFINED SPACES

Unauthorized entry

The constructor must ensure that each entrance tothe confined space is secured against unauthorizedentry and/or has adequate barricades or signswarning against unauthorized entry.

39 – 17

RECORD KEEPINGThe employers must keep records of every plan assessment coordination document training entry permit record of rescue equipment inspection record of tests.

The records must be kept for at least one year after theproject is finished, and they must be available forinspection.

CONFINED SPACES

See next few pages for— a decision tree for confined space entry— a sample confined space entry permit.

39 – 18

CONFINED SPACES

DECISION TREE FOR CONFINED SPACES

Is there more than oneemployer involved in

the entry?

No

Yes

The employer must give acopy to the constructor.

The constructor, in turn, must provide a copy to: • the project’s JHSC or HSR

• other employers involved • workers involved if there is no project JHSC or HSR.

Employer must ensurethat a competent workerprepares a written assessment

On request, a copy must be given to the projectJHSC or HSR, or workers if no project JHSC orHSR exists.

No

A competent person must prepare a written plan.

Constructor must prepare a coordination document

The employermust prepare awritten program

Workers must be trained to perform work in accordance with the plan.

The employer must issue an entrypermit before any worker enters the confined space.

The entry permit must beverified before each shift by a competent person.

The entry permit must be available to every person entering the confined space.

Before any worker enters the confined space written procedures and rescue equipment must be in place.

Rescue equipment must be inspected by a competent worker.

The employer must ensure that workers entering the confined space are provided with adequate protective clothing and PPE.

The employer must ensure that workers are protected against • the release of hazardous substances• contact with electrical energy • contact with moving parts • hazards associated with free-flowing material.

Before a worker enters a confined space, an attendant must be • assigned• stationed outside and near the entrance• in constant contact with the workers inside • provided with a device for summoning an adequate rescue response.

The constructor must ensure that the confined space is secured against unauthorized entry.

Before a worker enters a confined space, a competent worker must perform atmospheric testing.

Do tests indicate a hazardous atmosphere ?

Is the location a confined space?

No

Yes

Entrance permitted.

A copy of the co-ordination document must beprovided to each employer who performs work in thesame confined space and to the project’s joint healthand safety committee (JHSC) or health and safetyrepresentative (HSR), if any.

and make copies available to:

Entrance permitted provided all applicable regulations arefollowed. For example, if a worker may be injured by inhaling a hazardous gas, vapour, dust, or fume, or there is an explosion hazard, then adequate ventilation must be provided by natural or mechanical means. If this is notpracticable then respiratory protective equipment suitablefor the hazard must be provided.

Yes

Tone

xtpa

ge

39 – 19

CONFINED SPACES

The hazardous atmosphere contains or is likelyto contain an explosive, flammable, or combustible dust, mist, gas or vapour.

No worker is allowed to enter or remain in a confined space if there is an airborne concentrationof dust or mist sufficient for explosion.

The hazardous atmosphere contains or likely to contain an atmosphere where the oxygen content is less than 19.5% or greater than 23%; or there is an accumulation of gases, vapours, fumes dust, or mist that can cause an immediate threat to life or prevent unaided escape out of the confined space.

Can the hazardous atmosphere be purged and vented?

No

Yes

If mechanical ventilation is required,you need a warning system and exitprocedure in case of ventilation failure.

Yes

Can all of the following conditionsbe met? • The hazardous atmosphere

can be rendered inert by adding an inert gas and it can be continuously monitored to ensure it remains inert.

• The workers can use adequaterespiratory protective equipment.

• Adequate rescue equipment can be provided so that the person outside can locate andrescue the worker.

• Other equipment can be provided as necessary toensure the worker’s safety.

Entrance permitted.

Entrance permitted. Entrance permitted only if • workers use adequate

respiratory protective equipment

• adequate rescue equipment is provided so that the person outside can locate and rescue the worker

• other equipment is provided as is necessary to ensure the worker’s safety.

No worker is allowed to enter or remain in the confined space unless, for each of the following types of work, certain conditions are met while performing the work.

For inspection work For cold workFor hot work

Entrance permitted only if • the atmospheric

concentration is monitored continuously

• the entry permit provides for control measures for hot work

• an alarm system and exit procedures are provided.

Is the concentration of flammable or explosive gasless than 5% of its Lower Explosive Limit (LEL) and

the oxygen content less than 23%?

Yes

Entrance permitted only if • the hazardous atmosphere is

rendered inert by adding an inert gas and it can be continuously monitored toensure it remains inert

• the workers use adequaterespiratory protective equipment

• adequate rescue equipment is provided so that the person outside can locate and rescue the worker

• other equipment is providedas is necessary to ensure theworker’s safety.

No

Entrance permitted only if a worker can perform cold work that does notcreate a source of ignition.

There is an airborne concentration of dust or mist which is sufficient for explosion.

No

The hazardous atmospherecontains an explosive or flammable gas or vapour.

Is the concentration of flammable gas or vapour less

than 10% of its LEL?

Yes

Entrance permitted only if a worker canperform inspection work that does not create a source of ignition.

Yes

Is the concentration of flammable gas or vapour

less than 25% of its LEL?

NoNo

Or

Or

YesFrom previous page

39 – 20

CONFINED SPACES

Sample confined space entry permit

Employer name ____________________________ Project name __________________________________

Date ______________________________________ Permit end time ________________________________

Assessment performed by __________________ Permit start time ________________________________

Location of confined space (or spaces if they are similar)

Description of confined space (or spaces if they are similar)

Description of work to be performed

Monitoring equipment

Air testing equipment Serial # Last calibrated

Air quality results

Test # Test # Test #1 2 3 1 2 3 1 2 3

Time of test

Oxygen, %

Combustibles, %

Atmospherichazard:Atmospherichazard:Atmospherichazard:

Other:

Tester’s name ______________________________ Signature ______________________________________

Location: Location: Location:

39 – 21

CONFINED SPACES

Controls

Atmospheric hazards Hazard controls Personal protective(existing or introduced) equipment (type)

Hot temperature

Cold

Noise

Electricity

Vibration

Slippery surface

Lighting

Work at height

Moving machinery

Influx of liquid

Influx of gas

Hazard above

Other:____________

Ventilation

De-energize, lockout

Blank, disconnect

GFCI cords

Lighting

Other:_________________

Hearing protection

Anti-vibration gloves

Other gloves: ____________

Goggles

Fall protection

Other:___________________

Flammable

Toxic

Corrosive

Oxygen deficient

Oxygen enriched

Other:__________

Purge using mechanicalventilation equipped withwarning device in case offailure.

Natural ventilation(re-test / air quality)

Continuous monitoring

Other:________________

Respirator ____________________

Gloves ________________________

Boots ________________________

Coveralls ______________________

Eye protection__________________

Other: ________________________

Physical hazards Hazard controls Personal protective equipment (type)

Attendant

Attendant’s name __________________________ Signature ______________________________________

Communications

Method of communication with workers Method of communication to summon rescue

__________________________________________ ____________________________________________

39 – 22

CONFINED SPACES

Hot work (complete if hot work will be conducted)

Will space be rendered inert by adding inert gas? Yes No

If “yes,” ensure

space is monitored continuously to ensure it remains inert

worker(s) entering use adequate respiratory equipment – list equipment:_____________________

there is adequate equipment to allow persons outside to locate and rescue worker – list

equipment: __________________________________________________________________________

there is other equipment necessary to ensure safety of worker – list equipment: __________________________________________________________________________________________________

If “no,” ensure

On-site rescue

Training

Adequate number of trained persons are available to implement rescue procedures

Names ofworkers approved

for entry

Has confinedspacetraining

Trained in theentry plan

Time of entry Time of exit

Tripod Harness Winch/cable Other:_________________________________________

List of equipment required for entry

Appropriate rescue equipment has been inspected and isin good working order:

Appropriate rescueequipment is readilyavailable to be usedfor a rescue

Flammable gas ismaintained below 5% ofits LEL by purging andcontinuous ventilation

O2 content ismaintainedbelow 23%

Atmosphere willbe monitoredcontinuously

Alarm and exit procedures are inplace should the LEL exceed 5%

or the O2 exceed 23%

Supervisor’s name __________________________ Signature ______________________________________

Respirator Coveralls

40 – 1

40 PULP AND PAPER MILLS

ProcessesA number of processes, grouped by type as mechanical,chemical, and semi-chemical (or hybrid), are used inthe preparation of wood pulp. In 1990 (according toLockwood’s Directory) the distribution of pulp mills inOntario and Quebec was as follows:

In chemical pulping, the wood chips are cooked, usingheat and a chemical solution that depends on the type ofprocess being used. The lignin binder, a natural glue thatholds the wood cells (fibres) together, is dissolved.

The two common forms of chemical pulping are1) the dominant “alkaline” or “kraft” process, and2) the “acid pulping” or “sulphite” process.Acid pulping has generally declined but is still in use. Thedigester liquor is a solution of sulphurous acid, H2SO3,mixed with lime (CaO) or other base (magnesium,sodium, or ammonium) to form bisulphites.Mechanical processes produce the highest yield from thewood, but have high energy demands. Mechanical pulpinggenerally incorporates thermal or chemical pre-softeningof the wood chips, resulting in lower energy requirements.Some chemical processes include mechanical features.The division is not distinct and is generally based onefficiency of production from dry wood.Figure 22.2 provides a flow diagram for a semi-chemicalpulp mill.Of the chemical processes, alkaline pulping – the kraft orsulphite process – is the most common and is shown inFigure 22.3.

PULP AND PAPER MILLS

Chemical Processes Semi-chemical Mechanical TotalKraft Sulphite

Ontario 9 4 2 15 30Quebec 10 8 2 41 61

Figure 22.1: Number of pulpmills by type in Ontario and Quebec

Process Type

40 – 2

Kraft ProcessThe kraft process consists of three principal operations:1) cooking and washing2) evaporation and alkali recovery3) causticizing and lime recovery.Following debarking and chipping, the chipped wood is"cooked" or digested with steam at a pressure ofapproximately 150 psig (1034.1 kPa) in the digester with asolution of sodium hydroxide (NaOH) and sodiumsulphide (NaS2) known as white liquor. After cooking forabout six hours, the lignin binder is dissolved and thecellulose fibres, now called pulp or “brown stock,” areseparated from the spent cooking liquor (black liquor) inthe pulp washers. The kraft process is associated withstrong-smelling gases – organic sulphides – which are anenvironmental concern.The dilute or “weak” black liquor (10-15% solids) comesfrom the washers. After concentration by removal of waterin the multiple-effect evaporator using steam, the resulting"heavy" black liquor usually goes through furtherconcentration in a direct-contact evaporator.The concentrated black liquor then goes to the mix tankwhere the sodium sulphate (salt cake) is mixed with theliquor to make up the chemical losses in the system. The"heavy" black liquor (60-70% solids), with its salt cakeburden, is heated to lower its viscosity and pumped to therecovery furnace where it is sprayed on the walls fordehydration prior to final combustion of the dried “char” onthe hearth. Sodium sulphate dust in the boiler gases isremoved by an electrostatic precipitator.The intense heat in the furnace fuses the inorganicelements of the black liquor (mainly sodium carbonate andsodium sulphide) to form what is known as smelt. Thesmelt is tapped from the furnace and runs into a dissolvingtank where it is mixed with water to form “green liquor.”Carbon and other impurities in the green liquor are settledout in a clarifier, filtered, and sent to landfill. The clarifiedgreen liquor is subjected to a causticizing treatment withhot lime, Ca(OH)2, in a lime slaker to convert sodiumcarbonate into sodium hydroxide. The insoluble calciumcarbonate mud produced is settled out and reused. Theresulting sodium of sodium hydroxide and sodiumsulphide, now called “white liquor”, is reused as cookingliquor for the wood chips in the digester.The bleaching of brown pulp to white pulp is usuallyaccomplished with chlorine, followed by extraction withsodium hydroxide, then calcium or sodium hypochlorite,and finally a chlorine dioxide treatment.

HazardsMaintenance work in operating pulp and paper mills canpresent a number of special hazards to constructionworkers. In addition to the trade hazards associated withwhat is commonly encountered in new construction, thereare other hazards:1) hazardous process chemicals2) piping systems3) heat

4) noise5) pinchpoints and moving equipment.The following information is provided to help constructioncrews recognize, assess, and control these hazards inpulp and paper mills.1) Hazardous Process ChemicalsGeneralOf the many different hazardous chemicals used, mostare found in the parts of the mill that digest or break downthe wood fibres. The cooking liquors described above(white liquor, green liquor, and black liquor) all tend to bevery corrosive and may contain several different toxic orhazardous ingredients.Extreme precautions should be taken when working intanks or vessels used for these liquors or when working onrelated piping. Hazardous chemicals may be encounteredin storage tanks, process piping, process equipment, wastehandling systems, and environmental control systems.In addition to these "contained" sources, some processesmay emit gases, vapours, or dusts that may behazardous. Always be aware of potential emissions orleaks from adjacent operating or apparently isolatedequipment or storage facilities.Harmful residues may also be left as potential exposuresto maintenance and construction personnel. Extremeprecautions should be taken when working in tanks orvessels. During maintenance or repair operations insideproduction equipment, confined space procedures mustbe established and followed strictly.Process ExposuresFollowing are some of the potential exposures fromvarious parts of the process.DigesterPotential exposures include organic sulphur compounds,primarily methyl mercaptan, ethyl mercaptan, dimethylsulphide and dimethyldisulphide, in addition to hydrogensulphide and sulphur dioxide.Evaporator and RecoveryEvaporators are sources of hydrogen sulphide andsulphur dioxide and require precautions, especially duringmaintenance. When they become plugged, precautionsmust be taken while cleaning them with nitric acidsolutions. Repair and maintenance around digesters,evaporators, and furnaces also offer potential exposure tocaustic liquors and asbestos. Air emissions associatedwith recovery boilers contain sulphur dioxide, sodiumsulphate particulate, and salt cake (basically a nuisancedust). Duct systems, electrostatic precipitators forparticulates, and wet scrubbers for SO2 requireappropriate precautions during repairs.

Causticizing and Lime RecoveryIn addition to exposure to caustics, potential exposuresinclude calcium oxide (quicklime) and calcium hydroxidedusts, particularly during cleanups.BleachingPotential exposures include chlorine and chlorine dioxide


40 – 3

(CIO2) which is a severe pulmonary irritant even at lowconcentrations – usually encountered only during upsetsor leaks.

Paper MachinesPotential exposures include dusts from cleaners,slimicides, pH control chemicals, and off-gassing offormaldehyde and ammonia.Specific Process Chemical HazardsAlthough the kraft, or alkaline, process is the mostcommon, there are other pulping processes. The sulphiteprocess involves acid cooking in which the digester liquoris a solution of sulphurous acid mixed with lime or other

base to form bisulphites.Figure 22.4 lists some of the major chemicals used orencountered in different processes. It is not intended as acomprehensive reference to all of the major chemicals orintermediate chemicals used in pulp and paper mills. Theprecise chemicals, quantities, and processes may varyfrom one facility to another.Construction crews should obtain and review the MaterialSafety Data Sheets (MSDSs) for these and otherhazardous materials in use at the plant where work isscheduled to take place. MSDSs should be readilyavailable from the client/operator of the mill.


Acids:• sulphurous (H2SO3)• sulphuric (H2SO4)• nitric (HNO3)

Ammonia

Black liquor

Calcium bisulphite

Calcium sulphate

Caustic soda

Calcium oxide (CaO)

Chlorine (CI2)

Chlorine dioxide(CIO2)

Green liquor

Hydrogen peroxide(H2O2)

Hydrogen sulphide(H2S)

• in sulphite cooking liquor• clear & oily, biting acrid odour• used in cleaning evaporators• yellow colour, biting acrid odour

• used to digest pulp in some processes

• liquid alkali, thick and slippery likemolasses when concentrated

• in weaker concentrations is a brown-to-black, watery liquid

• slightly sickening smell, with odour ofsulphides

• used in cooking pulp in the "sulphiteprocess"

• used in finishing stages to impartspecial properties to paper

see sodium hydroxide

see lime

• toxic gas with characteristic acrid odour,like bleach, sweet-tasting

• used in bleaching pulp• gasifies immediately on contact with air• yellow-green coloured gas-cloud

• produced on site and used in thebleaching process dissolved in water

• liquid - yellow, green colour• biting, acrid odour like bleach, releasesCIO2 gas

• alkali• green colour, no odour• slippery or soapy feeling

• liquid, clear and colourless• slight pungent odour

• colourless, toxic gas, byproducts• rotten-egg odour at low concentrations• biting acrid odour

• reactive and corrosive• dehydrates skin, causes reddening, skin then turns black• severe burns – turns skin yellow.

• very irritating to eyes, nose and throat• overexposure can cause choking and difficulty in breathing

• corrosive burns• reddening of skin, burning sensation

• primarily a skin irritant• corrosive

• nuisance dust• non-corrosive

• acute exposures cause irritation, stinging of eyes, nose and throat• exposure causes coughing, chest pain, and difficulty in breathing• overexposure can be fatal• delayed acute response to overexposure is fluid build-upin the lungs

• the gas is a severe pulmonary irritant even at low concentrations• choking sensation, followed by coughing and, in heavyconcentrations, nausea and insensibility

• skin burns on contact, reddening of the skin

• corrosive burns - less corrosive than white liquor, but is scaldinghot when handled in the plant

• reddening of skin, burning sensation

• strong oxidizer, will react with organic materials and cause fire• concentrations: mild 3-5%-no danger; moderate 6-10%-minorburns, eye damage; medium 10-50%-minor burns, eye damage;high over 70%-major burns

• explosion risk if mixed with strong acids or caustics

• rotten egg smell at very low concentrations (below 100 ppm)• as concentration rises, the sense of smell is rapidly deadened• nausea, dizziness, and disorientation• toxic gas: 500-700 ppm can be instantly fatal• explosive at high concentrations

Figure 22.4: Hazardous Process Chemicals in Pulp Processing

Chemical Uses and Characteristics Hazards

40 – 4

2) Piping SystemsThe contents of piping systems, storage bins, or othercomponents should be determined. If clearly wordedcontent labels do not exist, WHMIS regulations requirethat some other warning system be in place. This mayvary from one facility to another. For example, one plantmay use a coded number system; another may use colourcoding or symbols. Construction crews working in thesefacilities must become familiar with the warning system inuse.

MSDSsMSDSs for materials that may be encountered should bereviewed with the crew to ensure that everyone is awareof the location and nature of the hazard(s).Confined SpacesEntry into vats, maintenance holes, or other enclosedwork spaces must be done in accordance with theregulations for confined spaces (refer to the chapter onConfined Spaces in this manual). Requirements include


Lime:• quickline, calciumoxide (CaO)

• slaked lime, calciumhydroxide(Ca(OH)2)

Methanol(CH3OH)

Methyl mercaptan(CH3SH)

Sodium Carbonate,solda ash: (Na2CO3)

Sodium Chlorate(NaCIO3)

Sodium Hypochlorite

Sodium HydroxideCaustic Sodaor Lye - (NaOH)

Sodium Sulphate(Na2SO4)

Sodium Sulphide(NaS2)

Sulphur (S)

Sulphur Dioxide(SO2)

White liquor

• white powder• used in sulphite pulping

• methyl alcohol or wood alcohol• colourless• when pure, has slight alcoholic odour;other grades have oily odour

• colourless gas

• used in some processes to digest pulp

• used in some bleaching processes• liquid – normally clear, colourless,odourless

• in white crystalline form when dry• used or found in some bleachingprocesses

• used in bleaching processes

• used in digesting pulp• slippery or soapy to touch on skin• clear to milky white, odourless

• make-up chemical for cooking liquor

• component of white liquor used indigesting (cooking) pulp in the kraftprocess

• yellow solid• used in some processes to producesulphur dioxide gas, which is used indigesting pulp

• used in digesting pulp• clear and colourless gas, biting acridodour

• alkali• golden colour, no odour• slippery or soapy feeling

• corrosive, alkali burns• dehydrates skin

• harmful to inhale vapour, or to allow repeated or prolonged skin contact• affects central nervous system; signs of poisoning includeheadache, nausea, vomiting, aimless erratic movement, anddilated pupils

• flammable liquid and vapour-air mixture can be explosive

• irritant causing watering of eyes and nose• headaches and nausea• high concentrations can be fatal

• primarily irritates eye, nose, throat• corrosive

• harmless when wet, except when in contact with acid – then aviolent flammable reaction

• irritating to eyes nose and throat• when sodium chlorate solutions dry to crystals, the dry form is veryunstable and can be ignited by spark or friction. Fire cannot be putout by water except by total immersion

• dust may cause irritation of eyes nose and throat• contact with water can release chlorine gas

• very corrosive material, can cause chemical burns on exposed skin• can cause irritation of skin, eyes, nose and throat• overexposure to mists or dusts containing sodium hydroxide canlead to fluid build-up in the lungs

• minor irritation of eyes, nose and throat possible• low toxicity based on animal studies• reacts dangerously when melted with aluminum

• inhalation of dust can cause irritation of nose, throat and lungs• corrosive – can cause skin burns• may react with moisture to release hydrogen sulphide gas• repeated skin contact may cause allergic skin reaction

• burns to produce sulphur dioxide

• very irritating gas: causes irritation of eyes, nose and throat• exposure can cause choking and difficulty in breathing• delayed response to overexposure can result in fluid build-up inthe lungs

• corrosive burns• reddening of skin, burning sensation, like caustic but at a highertemperature

Chemical Uses and Characteristics Hazards

40 – 5

testing atmospheres for toxic or explosive conditions aswell as oxygen deficiency or excess.LeaksWhen working on pumps, pipes, or valves where there isa danger from squirting liquids, always follow threeprecautions:1) wear goggles, a face shield, or both2) have a hose immediately available to deliver water for

immersion3) know the location of the nearest emergency shower

and eyewash station.Emergency SystemsIn addition, construction crews in pulp and paper millsshould be made aware of any emergency procedures thatare in place. For example, the plant may have some kindof alarm system to warn people of a gas leak or processproblem. If there is an evacuation plan involving specialassembly areas or the use of self-rescue equipment suchas respirators, these precautions must be fully explainedto all construction workers at the project.Pressurized SystemsConstruction crews must ensure that work on processpiping or other components is done with the system de-energized. Many processes rely on pressurized feed linesor may have pressure vessels in the process system. Allcomponents should be brought to atmospheric pressurebefore attempting to disconnect or open them. Contentsmust be determined beforehand, since some of theprocess materials or byproducts can be very toxic or verycorrosive. Small leaks under pressure can present serioushealth and safety hazards.

3) HeatHeat is used or generated in many parts of pulp andpaper mills. Refer to the chapter on Heat Stress in thismanual.4) NoiseNoise is a hazard inherent in many pulp and paper mills.In many cases, the ambient noise level may require thewearing of earmuffs and/or ear plugs. The noise hazardshould be identified by warning signs in the facility.Additional noise sources from tools and equipment usedby the construction or maintenance crew will increase thetotal noise exposure. Hearing protection is advised for alltrades working under these conditions.5) Pinch Points and Moving EquipmentConveyors, rollers, and other pieces of moving machinerypresent common hazards in pulp and paper mills.Wherever possible, de-energize systems before workingon components with moving parts.Exposed pinch points should be guarded. Wherepermanent guards have been removed in order to carryout repairs or modifications, temporary guards should beinstalled during the work. All permanent guards must bereplaced after completion.In high traffic areas, where plant personnel are movingequipment or where construction equipment mayendanger plant personnel, use signallers or lanebarricades to keep people away from moving equipment.


41 – 1

41 STEEL MILLS

Steelmaking ProcessThe conventional steelmaking process, in its most basicform, consists of the following sequence of steps.Blast furnace ironmaking – Three raw materials (iron ore,coal, and limestone) are modified, brought together, andsmelted in a blast furnace to produce iron for steelmaking.Iron, usually in molten form, is transported in hot metalcars to the steelmaking furnaces where impurities areremoved and alloying elements are added.Molten steel is then cast (usually using a continuouscasting process) in large blocks such as slabs, blooms,billets, or ingots, which are subsequently reheated,cleaned, and reshaped repeatedly, and often coated, in aseries of operations to produce the variety of steelproducts that we know.Iron ores are mined in various concentrations. All gradesrequire some improvement. High-grade ore may needonly crushing, screening, and washing for a blast furnace.Lesser grades and fines require further treatment toproduce usable ore pellets for blast furnaces. Much of thisprocessing occurs away from the steel mill so that onlyhigh grade material has to be transported. Sintering is aprocess at the steel mill which makes lump feed suitablefor blast furnaces from materials which once were wasted– ore fines, flue dust (reclaimed from blast furnacegases), coal fines, and coke breeze (dust). They arespread on a moving belt and ignite, producing sinter, aclinker-like cake, which is quenched, broken up, and fedto the blast furnaces.Coke is the strong porous form of carbon used as the fuelmixed with iron ore in blast furnace ironmaking. It isproduced by "baking" pulverized coal at hightemperatures in coke ovens, after which the hot coke isquenched with water to prevent further oxidation. Thecoke is crushed and screened to remove finer particles,which are recycled. Many volatile and toxic chemicals,unwanted in blast furnaces, are released during thecoking process. The gases are captured and passedthrough a byproduct plant which produces a number ofvaluable byproducts such as tar, ammonia liquor,ammonium sulphate, light oils, and fuel gas. The cokeoven gas is used for firing in the coke ovens and is pipedfor use around the plant. Limestone and lime, producedfrom limestone, are used as fluxes to remove impuritiesfrom iron ore and steel respectively. Limestone and limeare normally produced offsite and stored for use.In steelmaking, molten iron joins scrap steel, lime, andalloying materials in a furnace and with injected oxygenthey form a steel heat with the right recipe to meet therequired specifications. Since oxygen is needed inconsiderable quantities in steelmaking, an oxygen plant isoften associated with a steel mill. Excess carbon and otherunwanted chemicals are oxidized with the help of lime as aflux to form a floating slag of unwanted impurities.The most common steelmaking furnaces are the basicoxygen furnace (BOF) and the electric furnace.Basic oxygen furnaces (BOFs) are located close to blastfurnaces and are charged with primarily molten iron with

some scrap steel. Pure oxygen is blown into the vessel andthe resulting reaction generates a lot of carbon monoxideduring blowing time, which can be burned in a waste heatfurnace built into the hood system before the flue gases aredischarged to a precipitator and baghouse system.Electric furnaces are used in some facilities to producestainless steels and in others to produce mild steels.Electric furnaces are charged primarily with scrap iron andsponge-iron pellets or steel scrap which has been analyzedand sorted.Two types of electric furnaces are typically used:1) the electric arc furnace, generating heat from the arcs

from one carbon electrode to the metal and back to theother carbon electrode from the metal and from theresistance of the current flow through the metal itself, and

2) the induction furnace, which behaves like atransformer, in which the metal acts as the core andsecondary winding and enough heat is generated tomelt the metal.

Once steel is made, the product usually proceeds to thecontinuous casting stage. This employs a process whichutilizes oscillating, cooling molds, going directly in this onestage from molten steel to semi-finished products,including slabs, blooms, and billets.The conventional intermediate steps, in use for decades,which involved casting ingots and repeatedly passingthem through roughing mills, have largely been replacedby continuous casting. The old ingot process may remainin some mills as a backup method.By the use of reheat furnaces to bring them to hot rollingtemperatures, the slabs, blooms, or billets are shapedusing hot rolling mills – slabs into sheet and strip, bloomsinto structurals and rails, and billets into bars, rod, wire,and some pipe and tube.Beyond this the steel shapes undergo a number of coldforming processes such as cold rolling, pickling,tempering, and forging. They can undergo a number offinishing processes including electroplating, galvanizing,annealing, painting and a variety of proprietary finishesdepending on the end use of the steel.

Areas of Steel PlantRaw materials processingIron ore: - Pelletization, kilns, etc. — normally offsite

- Sinter plantCoke: - Facilities for coal storage, handling, and

preparation — coal bins, blended coalbunker

- Machinery for charging coal, pushingcoke and quenching — larry car, quenchcar and tower

- Coke ovens — banks of ovens that bakethe coal at high temperatures

- Machinery for transporting and screeningcoke-coke crusher

- By-products plantLimestone - Quarries

- Crushing and sintering

STEEL MILLS

41 – 2

Blast FurnacesStockshed — coke, iron ore, and limestone bins and

hoppersStovesCast houseGas cleaning system — dust catchers, scrubbers,

precipitators, thickenersSteelmakingSteelmakingBasic oxygen furnacesElectric furnacesTeeming and Casting

Slab castingHot rollingPickling and finishingCold rollingTinning, electroplating and galvanizing linesAcid plants and storageUtilitiesPower plants — boiler stationsWater treatment — filtration plants, clarifiers, thickeners

Pressure VesselsBoilersHeat exchangersFurnaces

DuctworkPrecipitatorsTanks— clarifiers, thickeners, holding tanks, etc.Stacks— breechingScrubbersCyclonesBins— coal and cokeChutes

Health and Safety HazardsFor construction crews working in steel plants, there aremany hazards. The following points summarize the mainhazard areas.1) Pinch points and moving equipmentTransportation equipment

Bulk material handling and transport is a major activityfor a steel mill. There are railroad systems with tracksall over the plant, hot metal cars, transfer cars,buggies, charging cars, hopper cars, scrapers, coilcarriers, slab carriers, and many others.

Overhead cranesOverhead cranes form an integral part of operatingand maintenance practice throughout a steel mill.Many hazards are associated with their use, including

overhead loads, hot metal splash, equipment failure,communication breakdown, and the fact that craneoperators may not be aware of construction workersin unexpected locations.

Operating equipmentProduction equipment may operate on a timed basis,it may be remote-controlled, or operators may notexpect non-operating personnel on site.

Construction personnel must learn plant safetypractices, alarms, access requirements and limitations,and emergency procedures for whichever section ofthe mill they must enter. They must follow theseprocedures.

2) Explosion and burn hazardsSpatters or spills of molten material are an obvioussource of burns and fires. Contact between moltenmetal or slag and moisture will result in violentexplosions and spattering of molten material.

A network of piping transports fuel gases and oxygenaround the plant – all of which have a potential forexplosion and fire. Sparks and fires around oxygen linesare especially hazardous. One area of a steel mill with ahigh fire hazard is the coke oven byproduct plant, whichshares many characteristics with oil refineries.

3) Health and hygiene hazardsPlant operating practices and precautions must befollowed at all times. The contents of all storage andpiping systems should be determined. MSDSs shouldbe obtained and reviewed in advance. Informationshould be readily available from the client/mill operators.

The table on the next page relates various locations in asteel mill to the health hazards they pose.

Chemical HazardsThe following is a list of the major chemical hazardspresent in steel mills identified in the table and theireffects. It is not intended to be comprehensive. Chemicalsand chemical processes may vary from plant to plant.Acids• pickling and tinning lines and acid regeneration plants

(hydrochloric)• hydrochloric acid or sulphuric acid• highly corrosive, can be dangerously reactive in high

concentrations

Ammonia• very irritating to the eyes, nose and throat• high exposure can cause choking and breathing

difficulties• coke oven byproducts plant.

Asbestos• can be present in blast furnace and stoves, by-

products plant, steam, generation (either central orwaste heat boilers)

• asbestosis, mesothelioma, lung cancer

Byproduct plant light oil• containing chemicals such as benzene and

naphthalene and minor amounts of toluene andxylene

• coke oven byproducts

STEEL MILLS

41 – 3

STEEL MILLS

Blast furnaces

Steelmaking

Finishingoperations

Steamgeneration

Miscellaneous - CO gas lines

Casthouse and around furnace

Stoves

Dust catcher, scrubber, precipitator

Slag Pits

General

Precipitator and baghouse

Waste heat boilers

Pickling and acid regeneration

Annealing

Cleaning lines

Tinning lines

Central boiler facility

Waste heat boilers (see alsosteelmaking)

• naphthalene• xylene - possible• toluene - possible• coal tar pitch volatiles• asbestos (insulation on pipes and tanks)• ammonia (anhydrous ammonia)

• driplegs - see above, basically naphthalene

• carbon monoxide• silica products - from furnace lining (refractory) during a reline and fromrunner lining

• noise - from blast mains & tuyeres• asbestos - possible

• asbestos• carbon monoxide, CO

• carbon monoxide, CO• confined spaces

• sulphur dioxide, SO2

• dusts - mostly iron oxides, lime, silica (during reline)• radiant heat

• dust - mostly iron oxides, including lead from leaded steels (often nolonger produced)

• confined spaces• lime in baghouse and storage shed

• mild steel tubes probable (not stainless)• asbestos

• hydrochloric (HCI) acid- acid mist and vapour- iron chloride dust (irritant)

• can be sulphuric acid

• batch anneal - ceramic fibre from blankets at base• possible carbon monoxide, CO

• sodium hydroxide - corrosive

• sulphuric acid• other acids

• usually fired by CO gas, BF gas, and/or natural gas• high noise in some areas, asbestos

• mild steel tubes probable• asbestos

Iron ore preparation

Coke ovens

Sinter plant- general- baghouse

Coal handling - coal bins- coal bunkers

Coke handling

Coke ovens (in vicinity of batteries)

Byproduct plant

• dust, primarily iron oxides• possibly silica dust• some BOF dusts may contain lead• dust, confined space

• coal dust

• coke dust• coke oven emissions from hot coke

• coke oven emissions (designated substance)• sulphur compounds (H2S)• CO

• coke oven gas• carbon monoxide, CO• Hydrogen sulphide, H2S• benzene

AREA UNIT HEALTH HAZARDSPRIMARY HYGIENE HAZARD LOCATIONS IN STEEL MILLS

41 – 4

• acute effects - typical solvent effects, central nervoussystem depression

• chronic effects - carcinogens (cancer-causing agents);some cause liver and kidney damage.

Carbon monoxide (CO)• odourless, colourless, poisonous gas• makes up a large part of fuel gases (22-30% of blast

furnace gas, 5-10% of coke oven gas)• many hazardous locations, especially around blast

furnaces – also coke ovens and steelmaking• can leak out from tops of blast furnaces, around hot

stoves, pipelines; can occur due to sudden shutdownof blowing engines, boiler rooms, ventilation fans, andfrom insufficient gas removal during electrostaticprecipitator cleaning.

Coal tar pitch volatiles• coke oven byproducts plant• skin irritant, cancer of the lung, skin, scrotum• photosensitive dermatitis.

Coke oven emissions• in the vicinity of the coke oven batteries• a “designated substance” in Ontario, carcinogenic• there must be a control/monitoring program.

Coke oven gas• high in carbon monoxide and may contain trace

amounts of carcinogens• contents can include benzene (0.4%), H2S, and

hydrogen cyanide.Dusts• Iron oxide: (found in sinter plant, before blast

furnace, and around steelmaking) inaddition to being irritating to eyes, thiscauses ciderosis, which is a specificallynamed type of pneumoconiosis orobstructive lung disease; i.e., dustbuildup, not fibrosis

• coal: - irritant to the eyes, etc.- pulmonary fibrosis, pneumoconiosis

• coke: - there is some suspicion that coke is acarcinogen

• silica: - silicosis- refractory brick lined furnaces and ladles- may occur as dust at sinter plant,primarily during furnace repair

• iron chloride - around hydrochloric acid regenerationdust: plant

- respiratory tract irritant to some people.

Hydrogen Sulphide (H2S)• around coke oven batteries• toxic gas (500-700 ppm can be instantly fatal)• rotten egg smell at very low concentrations - below 100

ppm• explosive at high concentrations.Sodium hydroxide (NaOH)

- cleaning lines (tinning)- corrosive.

Sulphur dioxide (SO2)• blast furnace slag pits• gas irritating to eyes, nose, and throat

• overexposure can cause choking and breathingdifficulties

• delayed reaction to overexposure can be fluid buildupin the lungs.

Other Health HazardsHeatHeat is generated and used all over a steel plant. Caremust be taken to control overexposure. This can come inthe form of extreme radiant heat in many locations wherethere are hot or molten materials. Care must be exercisedin these places. There are also many locations wherestrenuous work may have to be done in hot locations.Heat stroke can be a constant risk, especially duringwarm weather. See the chapter on Heat Stress in thismanual.NoiseNoise is a hazard at many locations in a steel mill.Hearing protection is often required and warning signs areposted. High noise levels exist, for example, around thetuyeres in the blast furnaces or any rolling mills. Forguidelines on noise exposure and hearing protection, referto the chapter on Personal Protective Equipment in thismanual.GeneralBefore work begins, crews should receive training in thehazards existing in the work area and obtain and reviewthe material safety data sheets for any hazardousmaterials to which they may be exposed. These should bereadily available from the client or owner and, in fact,should be obtained at the time of bidding to facilitate jobplanning. Any protective equipment used should at leastequal that worn by the client's workers in the area.

Piping systemsThe contents of piping systems, storage bins, and tanksshould be known and identified. Know the system ofidentification and warning used by the owner. These mayvary from one plant to another.Confined spacesSpecial attention must always be paid to confined spaceentry. Always comply with the Construction Regulation(Ontario Regulation 213/91) as a minimum. The steel millwill usually have an entry permit system and requirementsfor entry and work in confined spaces. Welding in anyconfined space must be done with precautions. Payspecial attention in cases where welding is being done onstainless steel, since the chromium released is a possiblecause of lung cancer.Emergency ProceduresThe steel mill will have emergency procedures in place.Know the warning alarm signals and follow theprocedures.Electromagnetic fieldsOne controversial topic is the potential for health hazardsin the vicinity of high electromagnetic fields. This concernshould be monitored for future information and raisedwhen construction crews work near electric furnaces.

STEEL MILLS

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42 MINERAL PROCESSING PLANTS

IntroductionThe following is a brief overview of the processes involvedin mineral production in Ontario.During extraction and refining, the valuable metals areseparated from the worthless materials by a series ofphysical and chemical operations. In Ontario the primarymetals extracted using these methods are nickel, copper,zinc, cobalt, and lead. Other metals such as gold, tin,silver, and indium are usually extracted as byproducts.Sulphide ores are most common and there are varioushealth and environmental hazards associated with them.Chemical metallurgical extraction processes are usuallydivided into two types:1) pyrometallurgical methods (requiring high

temperatures), and2) hydrometallurgical methods (leaching).

This chapter focuses primarly on the pyrometallurgicalmethods.

ProcessesThe sequence of processes used in extracting andrefining metals from ores varies according to a number offactors: the metal being extracted, the ore type, themineral content, and the mineral concentrations.Because the metal concentration is usually quite low innonferrous ores, the first stage in mineral production at themine is ore beneficiation, usually consisting of the processesofmilling (crushing and grinding) and concentrating (usuallyconsisting of a series of steps including flotation anddewatering by thickening and filtering).The concentrate goes to the thermal pre-treatment orpyrometallurgical processes. These require very high

temperatures and include the following procedures.SinteringOften used in lead production to reduce the sulphurcontent of the concentrate, sintering involves feeding amix of moistened concentrate, flux, and fuel (coke) to anendless belt. The charge is ignited and burns below themetal melting point to become a fused mass (sinter)which drops off the end of the machine and goes tocrushers. The ventilation and production gases go tobaghouses or electrostatic precipitators for dust recovery.RoastingThis is usually the initial step in the smelting process. Theore concentrate is roasted at about 550°C to dry it andremove much of contaminants such as sulphur. Roastingis typically used in the production of copper, nickel, cobalt,and zinc, although some smelters bypass this step andadd the charge directly to the smelting furnace. Thematerial produced is calcine.SmeltingThe extraction of metals from their ores is usuallyaccomplished by the chemical reduction of the oxides ofthe metal with carbon in a furnace. The purpose ofsmelting sulphide ores is to produce a valuable metalconcentrate, called matte.In copper and nickel production, this is a mixture of metallicswith sulphide compounds. The cold concentrate or hotcalcine charge is melted at above 1000°C by burning fossilfuels, or in an electric furnace or, in the case of flashsmelting, by oxidizing the sulphur in the concentrate.In lead production, sinter and coke are charged to a blastfurnace for smelting and the lead is reduced to metalliclead and cast as bullion.The bullion is further purified byadding sulphur to form a copper sulphide matte fromwhich copper is recovered.

MINERAL PROCESSING PLANTS

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ConvertingThe matte from the smelting furnace in copper productionusually goes to a converter, where iron and sulphur areremoved by oxidation with the addition of a flux and lowpressure air (sometimes oxygen). In copper production, thisprocess produces blister copper, usually about 98% copper.Anode production/fire refiningBlister copper is further refined in a gas-fired furnacewhere oxidation removes remaining sulphur and soda ashis added to the molten bath to remove arsenic andantimony in a slag which is skimmed off. The blistercopper is now cast into shapes called anodes which areabout 99.5% copper.RefiningLead - Lead bullion is from 95% to 99% pure but containsvaluable impurities such as gold, silver, tin, and antimony.These are removed by treating molten lead bullion inkettles with various reagents.Copper - After casting, the blister copper anode (positiveelectrode) is refined by electrolysis in an aqueous solutionof copper sulphate and sulphuric acid using a pure coppercathode. The copper from the anode is deposited duringelectrolysis on the cathode. Impurities such as gold, silver,and selenium drop to the bottom of the tank as a blackmud called slimes. Other impurities, such as arsenic andnickel, remain in solution and are treated separately.Nickel - Matte is refined by electrolysis or by the Mondprocess, in which the matte is ground, calcined, andtreated with carbon monoxide at 50°C to form gaseousnickel carbonyl (Ni(CO)4), which is then decomposedabove 60°C to deposit pure nickel powder.Figure 24.1 shows a flow diagram for a typical coppersmelting operation.

Health Hazards – Copper and LeadProductionThe tables below indicate hazardous exposure potentialsfor copper smelting and lead production.

Other Health Hazards in Mineral ProcessingMany hazards can be encountered during construction ormaintenance in mineral processing plants. Industry andplant orientation and training programs must be identifiedand planned for at the time of contract bidding so thatthey can be delivered to the necessary personnel on time.The contents of all storage and piping systems should bedetermined. MSDSs should be obtained and reviewed inadvance. Information should be readily available from theclient/mill operators.Plant operating practices and procedures must befollowed at all times. Confirm with operating personnelpotential problems in your working area such as thefollowing:1) potential sources of air contaminants needing

isolation2) areas where sudden unexpected exposures might

occur3) pinch points and moving equipment. Several

categories of equipment can present these kinds ofhazards, such as transportation equipment, bulkloading equipment, overhead cranes, and operatingequipment.

4) explosion and burn hazards — spatters or spills ofmolten material are an obvious source of burns andfires. Contact between molten metal or slag andmoisture will result in violent explosions andspattering of molten material. A network of pipingtransports fuel gases and oxygen around the plant –all of which have a potential for explosion and fire.Sparks and fires around oxygen lines are especiallyhazardous.

5) health and hygiene hazards – acids, carbon monoxide(CO), sulphur dioxide (SO2), matte fume, and dustssuch as arsenic (As), lead (Pb), and silica (SiO2).

MINERAL PROCESSING PLANTS

Roasting

Smelting

Converting

Refining

Dries ore concentrateControls silica contentProduces calcineProduces Cu-Fe sulfide matte and silaceous slag. Charge isconcentrate or calcine, recycled precipitates, converter slag,flux dust, limestone, and silica fluxProduces blister copper (95.8%).Charge is matte and silica flux.Produces domestic copper (>99.5%)

Ore dust, SO2, CO, lead & arsenic, heat, andparticulate

Lead-containing dust, flux dust, CO, matte dust &fume, SO2, noise

Lead-containing dust, flux dust, SO2, noise, metaldust/fumeH2SO4 mist, noise.Arsine gas can occur without precautions

Operation Purpose Potential ExposuresCOPPER SMELTING

SinteringSmelting

Drossing

Convert sulphides to oxides and sulphatesRemoves impurities, reduces compounds to lead (bullion)containing 94-98% lead and slag.Remove copper, silica, arsenic, antimony and nickel fromsolution

SO2, lead-containing dustCO, SO2, silaceous dust, lead dust, othermetallic oxidesCO, SO2, lead dust

Operation Purpose Potential ExposuresLEAD PRODUCTION

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43 OIL REFINERIES ANDPETROCHEMICAL PLANTS

Oil RefineriesBecause of their inherent hazards, especially fromexplosion, fire, and chemicals, oil refineries are tightlyregulated places in which to work. Work permits mustalways be obtained and followed. Plant practices,warnings, and emergency procedures must be observedat all times. When in doubt, remember to exercise your“right to know” under WHMIS legislation. Check labelsand MSDSs. Any required protective equipment andprocedures must be explained and available whenhazardous exposure is possible.IntroductionCrude oil is a complex mixture of thousands of differenthydrocarbons and varying amounts of other compoundscontaining sulphur, nitrogen, and oxygen as well as salts,trace metals, and water. Crude oils can vary from a clearliquid, similar to gasoline, to a thick tar-like materialneeding to be heated to flow through a pipeline.A petroleum refinery's main job is to split crude oil into itsmany parts (or fractions) which are then reprocessed intouseful products. The type, number, and size of processunits required at a particular refinery depends on a varietyof factors including the type of crude oil and the productsrequired. The interconnected units making up a refineryare a maze of tanks, furnaces, distillation towers(fractionating columns), reactors, heat exchangers,pumps, pipes, fittings, and valves.Products of crude oil refineries include• fuels such as gasoline, diesel fuel, heating oil,

kerosene, jet fuel, bunker fuel oil, and liquifiedpetroleum gas

• petroleum solvents including benzene, toluene, xylene,hexane, and heptane, which are used in paint thinners,dry-cleaning solvents, degreasers, and pesticidesolvents

• lubricating oils produced for a variety of purposes, andinsulating, hydraulic, and medicinal oils

• petroleumwax• greases, which are primarily a mixture of various fillers• asphalt.These products can be hazardous not only in their finalstate but as they are being processed and refined.Health and Safety HazardsThe plant and equipment of refineries are generallymodern, and the processes are largely automatic andtotally enclosed. Routine operations of the refiningprocesses generally present a low risk of exposure whenadequate maintenance is carried out and proper industrystandards for design, construction, and operation havebeen followed. The potential for hazardous exposuresalways exists, however.Because of the wide variety of hydrocarbon hazards andtheir complexity, it is impossible to identify all of the hazardshere – and impossible for construction crews to know

everything they may need for protection when performingmaintenance, repair, or installation work in an oil refinery.As a worker you must depend on the knowledge availablefrom the plant operating and maintenance staff, normallyavailable through your employer. If there is reasonabledoubt about a situation in which you find yourself,exercise your “right to know” and make use of WHMIS toobtain the information, equipment, and proceduresnecessary to protect yourself and your fellow workers.Hazardous ChemicalsIn a refinery, hazardous chemicals can come from manysources and in many forms. In crude oil, there are notonly the components sought for processing, but impuritiessuch as sulphur, vanadium, and arsenic compounds. Theoil is split into many component streams that are furtheraltered and refined to produce the final product range.Most, if not all, of these component stream chemicals areinherently hazardous to humans, as are the otherchemicals added during processing.Hazards include fire, explosion, toxicity, corrosiveness, andasphyxiation. Information on hazardous materialsmanufactured or stored in a refinery should be supplied bythe client's representative when a work permit is issued.Fire and ExplosionThe principal hazards at refineries are fire and explosion.Refineries process a multitude of products with low flashpoints. Although systems and operating practices aredesigned to prevent such catastrophes, they can occur.Constant monitoring is therefore required. Safeguardsinclude warning systems, emergency procedures, andpermit systems for any kind of hot or other potentiallydangerous work. These requirements must be understoodand followed by all workers.The use of matches, lighters, cigarettes, and othersmoking material is generally banned in the plant exceptin specially designated areas.Health and Hygiene HazardsTable 1 highlights major potential air contaminants whichcan escape from a typical refinery operation and theirmajor sources. It does not attempt to identify all suchpossible hazards.Table 2 reviews common hazardous chemicals andchemical groups typically present and their mostsignificant hazards to workers.Care should be exercised at all times to avoid inhalingsolvent vapours, toxic gases, and other respiratorycontaminants. Because of the many hazards from burnsand skin contact, most plants require that you wear long-sleeved shirts or coveralls.Major Shutdown and MaintenanceThe principal exposures to hazardous substances occurduring shutdown or maintenance work, since these are adeviation from routine operations. Plant turnaroundsrequire careful planning, scheduling, and step-by-stepprocedures to make sure that unanticipated exposures donot occur. Any plant shutdown requires a complete plan inwriting to cover all activities, the impact on other

OIL REFINERIES AND PETROCHEMICAL PLANTS

43 – 2

operations, and emergency planning. Plans are normallyformulated by plant personnel in conjunction withcontractors.Construction personnel should always keep in mind theresponsibilities of the various workplace parties under theOccupational Health and Safety Act, the regulations forconstruction projects, and WHMIS legislation. This shouldespecially be considered in the bidding and planningstages of any contract to ensure that the refinery providesall of the required health and safety information.

Common Hazardous MaterialsTable 2 lists common hazardous materials that may beencountered on a refinery site. Note, however, that thetable is not all-inclusive. See the chapters on WHMIS andBasic Occupational Health in this manual. WHMIS labelsand MSDSs provide detailed information for specificproducts.

Maintenance Hazards and PrecautionsTank CleaningHydrogen sulphide is a potential problem in the transportand storage of crude oil. The cleaning of storage tankspresents a high hazard potential. Many of the otherclassic confined-space entry problems can occur here,including oxygen deficiency resulting from previousinerting procedures, rusting, and oxidation of organiccoatings. Carbon monoxide can be present in the inertinggas. In addition to H2S, depending on the characteristicsof the product previously stored in the tanks, otherchemicals that may be encountered include metalcarbonyls, arsenic, and tetraethyl lead.

“Alky” (Alkylation) UnitThe lightest fraction from the crude unit is first processedin the gas plant. Some of the liquid hydrocarbons from thewet gas are run straight to the gasoline blending plant, butothers go through the alkylation process. These light partsare put together using hydrofluoric acid or sulphuric acidas catalysts.The main hazards in this process come from possibleexposure to the catalysts, hydrofluoric acid or sulphuricacid, and their dusts, byproducts, and residues as well ashydrogen sulphide, carbon monoxide, heat, and noise.Other processes utilize acid catalysts and caustic“washes.” These can lead to hazardous situations,especially in shutdowns where a contractor's personnelmay be exposed to residues or other contaminants.Information is required from refinery personnel andspecialized training is required in the necessary


Material Dominant HazardAdditives – usually skin irritantsAmmonia – toxic on inhalationAsbestos – designated substance under construction

regulations. See chapter on asbestos in thismanual.

Asphalt – dermatitis (can be photosensitizer)Benzene – designated substance under industrial

regulationsCarbon monoxide – toxic on inhalationCaustic soda – corrosive to skin and eyesChlorine – corrosive to skin and tissue on contact or

inhalationHBAHs (high boiling – potential carcinogensaromatic hydrocarbons)Hydrofluoric acid – corrosive to skin and tissue on contact or

inhalationHydrogen sulphide – toxic on inhalationMEK (methyl – corrosive to skinethyl ketone)Nitrogen – asphyxiantPAHs (polynuclear – potential carcinogensaromatic hydrocarbons)Phenol-acid – corrosive to skin and tissueSilica – designated substance under industrial

regulationsSulphuric acid – corrosive to skin and tissue on contact or

inhalationSulphur dioxide – toxic on inhalation

Table 2: Common Hazardous MaterialsTable 1 – Major potential air contaminents

Air Contaminants Major SourcesHydrocarbon • transfer and loading operationsvapours — • storage tankscompounds of • crude unit, atmospheric, and vacuum towerscarbon (C) and • cracking units (“cat”, hydrocracking, coking–hydrogen (H) polynuclear aromatic hydrocarbons [PAHs]

and high-boiling aromatic hydrocarbons[HBAHs] are of concern because of theircarcinogenic potential)

• rearranging and combining processes suchas reformers and alkylation units

• treating operations• cracking unit regeneration• heat exchangers• boilers and heaters• pumps, valves• cooling towers

Sulphur dioxide • boilers(SO2) • cracking unit regeneration

• treating operations• flares

Carbon monoxide • rearranging and combining processes such(CO) as reformers and alkylation units

• catalyst regeneration• flares• boilers• furnaces

Nitrogen dioxide • flares(NO2) • boilersHydrogen sulphide • sour crudes(H2S) • liquid wastes

• pumps• crude tower• cracking operations• rearranging and combining processes such

as reformers and alkylation units• hydrogeneration

Particulates • catalyst dusts – cracking units, catalystregeneration, and rearranging andcombining processes such as reformers andalkylation units

• petroleum coke dust – cracking unitsChlorine (CI or CI2) caustic unitAmmonia (NH3) compressors

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procedures and personal protective equipment, includingits care and use.Confined SpacesOn most jobsites there are potential confined spacehazards. These hazards are multiplied, however, on arefinery site because of the complex collection of tanks,reactors, vessels, and ducts combined with a wide varietyof hazardous chemicals and emissions, often in enclosedareas. Many of these chemicals can produce oxygen-deficient, toxic, or explosive atmospheres. Knowledge ofgeneral confined space procedures and specific in-plantrequirements are both critical in refinery work. For moreinformation, refer to the chapter on Confined Spaces inthis manual.

Safe Work Practices and ProceduresPersonnel• Hearing protection and safety glasses must be worn

in all operating areas or as posted.• Respiratory protection or equipment must be fit-

tested. Facial hair is unacceptable where the maskmust make an airtight seal against the face.

• Shirts must be long-sleeved and worn with full-lengthpants or coveralls.

• Clothing must not be of a flammable type such asnylon, Dacron, acrylic, or blends. Fire-resistant typesinclude cotton, Nomex, and Proban.

• Other PPE required may include acid hood,impervious outerwear, rubber boots, face shields,rubber gloves, disposable coveralls, monogoggles,and fall-arrest equipment.

• Smoking is allowed only in designated areas.

Vehicles• Vehicle entry is by permit only and keys are to be left

in parked vehicles.• Vehicles must be shut down at the sound of any

emergency alarm.• Vehicles must be equipped with ground straps or

cables.

Permit SystemsNo work takes place in a refinery without a safe work permit.A safe work permit is a document issued by an authorizedrepresentative of the client permitting specific work for aspecific time in a specific area. Work permits should indicatethe date and time of issue, the time of expiry, a descriptionof the work to be done, and the name of the companyperforming the work. Permits also specify any hazards andcontrolled products under WHMIS and any protectiveequipment needed for the job. The permit will advise you ofany steps required to make the area or equipment safe forwork, tell you the results of any gas tests, advise you of anyelectrical lockouts that have been done, and tell you of anywork practices required for the specific job.Safe work permits are valid only for a limited time andmust be renewed following expiry or normally after anyone-hour stoppage, after an emergency warning on thesite, or for other safety reasons. After such an event, anyrequired gas testing or other testing must be repeated toensure a safe return to the work.

The types of safe work permits required typically includethe following. Specific categories may vary from site tosite.• Hot work – covers any work that involves heat or an

ignition source, including welding, grinding, and theuse of any kind of motor. In high-risk areas, a sparkwatch may be required.

• X-ray and radiation• Benzene – required when a benzene exposure

hazard exists.• Confined space entry hot work – involving potential

ignition hazards.• Confined space entry cold work – involving work that

will not produce a spark.• Hoisting – permit.• Electrical – for other than routine work.• Camera – typically requires a hot work permit when

lighting is required.• Asbestos – required whenever an asbestos exposure

hazard exists.• Vehicle movement• Hydrant – permits the use of plant fire hydrants.Special Authorization PermitsIn addition to safe work permits, special authorizationpermits are normally required for the following operations:• excavation• hoisting with major mobile equipment• hot tap and non-conventional repairs• opening live flare lines• temporary electrical facilities.Emergency Warning System and ProceduresIn oil refineries there will be both plant alarms or whistlesand individual unit alarms. All workers must receivetraining in recognizing and responding to these alarms.Verbal messages usually accompany the alarms.There will be different alarms for a fire emergency andtoxic alarms.• When an alarm sounds, secure all equipment and

shut down all vehicles.• Note the wind direction (wind socks) and proceed to

the appropriate assembly area (or safe haven).• Do a head count to make sure all personnel are

accounted for and report the result to a client contactperson.

• Know the local designated safety areas or safehavens and emergency phone number(s).

If you are the one who is first aware of an emergency,then call the emergency number.• Report your name.• Describe the emergency.• Identify its location.• Indicate whether anyone is injured.• Proceed to the assembly area.

Electrical Precautions• Electrical tagging and lockout procedures must be

understood and followed by all workers.• All electric tools, cords, and equipment must be

grounded or double-insulated.• Use explosion-proof fixtures where required.


43 – 4

Sewers• Sewers must be covered when hot work is being

done in the vicinity.• Sewer covers must be in good condition with no

openings for vapour flow.• Sewer covers are to be removed when hot work is

discontinued at the end of the job or overnight toaccommodate drainage.

Blinding or Blanking-off• Piping connected to a work area from vessels,

pumps, and other sources is isolated or blinded with asolid plate prior to the start of work.

• Blanking can sometimes be done with two valves anda bleeder valve between them. In this case the valvesshould be closed, chained, locked, and tagged.

Petrochemical PlantsPetrochemicals refers to a group of chemicals that aremanufactured using crude petroleum and natural gasfeedstocks as raw materials.Petrochemicals are versatile starting points for theproduction of thermoplastic and thermosetting materials.Thermoplastics are materials that can be softenedrepeatedly by the application of heat. The most importantthermoplastics are high and low density polyethylene,polypropylene (polyolefins), polyvinyl chloride, andpolystyrene.Thermosetting materials are those that undergo achemical change when heated and shaped and thereforecannot be reshaped by another application of heat. Somethermosetting plastics are thermosetting resins (includingphenol and urea formaldehydes), epoxy resins,unsaturated polyesters and polyurethanes, andengineered plastics such as polyacetyls, polyamides, andpolycarbonates.The hazards of the petrochemical industry are closelyrelated to those of oil refining, particularly in the rawmaterial stages.Atmospheric contamination hazards in the petrochemicalindustry can be complex, particularly when substances orprocesses combine. These combined effects are oftenmuch more toxic and dangerous than individual effects.As they do in oil refineries, construction crews inpetrochemical plants must comply with regulations as wellas in-plant procedures. Cooperation between contractorand client is essential for safe work, from the biddingstage until the contract is completed.


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44 THERMAL POWER PLANTS

Thermal Power GenerationThis process involves the generation of electricity from theburning of fossil fuel in a large industrial furnace. In verysimple terms, in a coal-fired station (Figure 1) the coal ispulverized and blown into the furnace where it burns,much like a gas flame, to heat water and generate steam,which moves at high speed to a turbine. The turbine spinsand drives a rotor attached to a magnet in a generator.The rotating magnetic fields moving across coils in thegenerator produce electric currents.The thermal machines used to convert the stored energyin the fuels to the kinetic energy of the rotor are complexunits. Each consists of two principal parts: boilers andturbines. They also include a variety of auxiliaryequipment to provide fuel and water to the unit and toeliminate waste gases and products of combustion.The basic operations are mechanical and highlyautomated. In a coal-fired power station, where boilersand turbines are combined, there is automatic control ofcoal pulverization, of supplied water and fuel, ofcombustion, and of superheating. The elimination of ashin the auxiliary processes is also automated.

Plants Fired by Fossil FuelMost construction, repair, and maintenance work is doneduring unit shutdowns or periods of extensiverehabilitation. This could involve working on one of thefollowing system components:• steam drum• primary steam piping• boiler feedwater• superheater• reheater• economizer• downcomers• feeder and riser tubes

The sources of energy created by normal boiler operationare not usually present during major reconstruction work.However, units adjacent to the shutdown unit are usuallyrunning, which can cause other hazards such as heat andnoise.

Common Hazards of Shutdown andRehabilitation Work1) Conventional Construction Hazards

• falls, either people falling or things falling onpeople

• electrical contact – see proximity requirements towork around overhead powerlines

• working on or near live equipment – workers whoare asked to work on or near energized equipment(regardless of the energy source) must comply withplant requirements to be applied in all worksituations where systems are to be deenergized andlocked out by devices such as switches or valves

• rigging and hoisting hazards• site-specific hazards — to be identified by the

plant representative.2) Industrial Hygiene HazardsChemical HazardsBefore work begins, crews should receive training in thehazards existing in the work area and obtain and reviewthe Material Safety Data Sheets (MSDSs) for anyhazardous materials to which they may be exposed.These should be readily available from the facility and, infact, should be obtained by contractors andsubcontractors at the time of bidding to facilitate jobplanning. Any protective equipment used should at leastequal that worn by plant personnel in the area.See Table 1.Reported Health ProblemsSome workers in boiler rooms may suffer from diseasesof the upper respiratory tract such as bronchitis, and fromconjunctivitis caused by vanadium compounds (dust givenoff by oil combustion) and SO2.

THERMAL POWER PLANTS

• waterwalls• boiler hanger rods• mud drum• boiler casing• condensate system• electrostatic precipitators• sulphur dioxide scrubbers• stacks.

Figure 1 – Thermal (Coal-Fired) Generating Station

44 – 2

Flue cleaners and cinder removers may, after some years,suffer from chronic bronchitis and rhinopharyngitis as wellas pneumosclerosis caused by cinder dust and sulphurdioxide and trioxide.The residues of oil combustion are more harmful than thedust given off after the combustion of other fuels.Dermatitis can develop from ashes contacting damp skin.Eczema may result from the combined action ofcompounds of nickel, vanadium, and sulphuric acidpresent in the residues.3) Other Health Hazards

For information on other health hazards, refer to thechapters on WHMIS and Basic Occupational Health inthis manual. One controversial topic is the potential healthhazard of being in the vicinity of high electromagneticfields in thermal generating plants. This concern shouldbe monitored for future information.

THERMAL POWER PLANTS

Substance Characteristics and Dominant Hazard

Asbestos – Designated substance under construction regulations– Diseases include asbestosis and cancer. See chapter on asbestos in this manual.

Lead – Designated substance under industrial regulations– Can cause kidney and brain damage

Fly ash – Coal ash contains oxides of silica, aluminum, and iron, with traces of manganese, lime, sodium, andunburnt fuel (carbon). Also identified are trace elements such as arsenic and selenium

– Oil ash can contain pentoxide, other vanadium oxides, and soluble nickel compounds– Respiratory tract irritation, dermatitis, and possible eczema with extended skin contact

Silica – Designated substance under industrial regulations– Can cause silicosis

Carbon monoxide (CO) – Clear, colourless, odourless, tasteless toxic gas– Causes drowsiness leading to death

Sulphur dioxide (SO2) – From sulphur content in oil– Very irritating and corrosive gas, sulphur-like odour, forms an acid on contact with moisture

Coal dust – In fuel supply and transport areasWelding fumes – Hazards vary depending on type of metal, type of welding, and coatings

– Health effects can include metal fume fever and respiratory irritation.

Table 1 – Hazardous Substances

Trade-SpecificInformation

45 – 1

45 IRONWORKERS:STRUCTURAL STEEL

Contents- Personal protective equipment (PPE)

- Cold stress and heat stress

- Lead exposure

- Tools of the trade

- Site preparation and steel erection

- Safe access and fall protection

- Mobile welding rigs

Personal protectiveequipment (PPE)Clothing: Many injuries can be prevented bychoosing the right clothing. Don’t have cuffs onyour pants or sleeves because they can getcaught on something and cause you to fall.Cuffs can also catch sparks and cause a burn.

Hearing protection: Hearing protection is amust for today’s ironworker. Hammering,reaming, and equipment all produce noise atlevels that can harm your hearing. Wearappropriate hearing protection. It should filterout noise above 85 decibels but still allow youto communicate with your co-workers and hearany alarms or warnings. Reduce the risk ofinfection: Make sure that your hands are cleanbefore using expanding foam hearingprotection.

Eye protection: Wear proper eye protectionwhen reaming drilling, grinding, burning,welding—or whenever hazards require it. Theright eye protection can be different for differentactivities. For example, it’s common forironworkers to perform activities such as gascutting and stud welding. These activities wouldrequire the use of Class 2C goggles for radiationprotection. It is also common for ironworkers tobe grinding and cutting. These activities would

require the use of a full face shield to reduce therisk of injury from flying objects and particles. Atsome jobsites, eye protection is mandatory.Always wear eye protection as required. Forfurther information, refer to the chapter on PPEin this manual for a list of activities withrecommended eye and face protection.

Skin protection: Ironworkers must protecttheir skin against burns from hot metal,ultraviolet (UV) radiation from the sun, weldingradiation, and other hazards. Skin protectionincludes

• clothing that is flame-resistant and providesUV protection

• long sleeved shirts

• full-length pants

• leather-faced gloves

• sunscreen with a sun protection factor(SPF) of 15 or higher.

Leather-faced gloves provide protection fromhot steel and resistance to abrasion.

Head protection: A hard hat complying withthe Construction Regulation (Ontario Regulation213/91) is required on construction projects at

IRONWORKERS: STRUCTURAL STEEL

Figure 1. Ironworkers at work

45 – 2

all times. A CSA Type 2 Class E or equivalenthat with chinstrap is recommended becauseironworkers

• work at elevations in windy conditions

• have increased risk of a lateral impact dueto the specific nature of their work.

Please note that hard hats must be worn withthe brim forward unless the hat has been testedand the manufacturer confirms that it can beworn with the brim pointing backwards. (Thehard hat will have an embossed symbolindicating that it has been certified as safe to beworn backwards.)

Foot protection: Workers must wear CSAcertified Grade 1 boots. Boots should also beresistant to electric shock (certified by a whitelabel with the Greek letter omega Ω).Ironworkers should wear boots with slipresistant soles because of the time spentwalking on smooth beams.

Hand protection: Gloves are an essential partof everyday PPE. Select your gloves based onsite conditions such as temperature, the workbeing performed, the chance of getting cuts andabrasions, and the dexterity required.

For more information, see the chapter on PPE inthis manual.

Cold Stress andHeat StressCold Stress

Working in cold environments presents healthrisks. The cold can be caused naturally by theweather or be created artificially, as inrefrigerated environments. You can get seriouscold-related illnesses and injuries, leading topermanent tissue damage and even death.

Exposure to cold causes two major healthproblems: hypothermia and frostbite.

For more information, see the chapter on ColdStress in this manual.

Heat Stress

Heat stress can occur wherever constructionoperations take place in hot, humidenvironments. The locations may be indoors oroutdoors.

Works that requires you to wear semi-permeableor impermeable protective clothing cancontribute significantly to heat stress. Heat stresscauses the body's core temperature to rise andcould lead to confusion, irrational behaviour,loss of consciousness and even death.

For further information please see the chapteron Heat Stress in this manual.

Lead exposureThis section supplements the chapter onOccupational Health in this manual withmaterial of particular importance to ironworkers.

The fumes from welding and cutting are thegreatest health hazards for ironworkers.Exposure to welding by-products such as fumes,radiation, noise, or vibration is covered in thechapter on Occupational Health. The risk toyour health is worse when there is a lead-basedpaint on the metal being cut or welded.

The following sections deal with the hazard oflead exposure during welding and cuttingprocesses. For further information refer to theMinistry of Labour’s guideline Lead onConstruction Projects. We have excerpted achart from that guideline at the end of thissection.

HOW CAN I GET LEAD POISONING?Lead poisoning can occur when you inhale oringest lead dust and fumes during burning orwelding of steel structures coated with lead-containing paints.

WHAT ARE THE HEALTH EFFECTS?Common symptoms of acute lead poisoning areloss of appetite, nausea, vomiting, stomachcramps, constipation, difficulty in sleeping,


45 – 3

fatigue, moodiness, headache, joint or muscleaches, anaemia, and decreased sexual drive.Severe health effects include damage to thenervous system, including wrist or foot drop,tremors, and convulsions or seizures.

The frequency and severity of medicalsymptoms increase with the concentration oflead in the blood.

Chronic lead poisoning may result after lead hasaccumulated in the body over time, mostly inthe bone. Long after exposure has ceased, somephysiological event such as illness or pregnancymay release this stored lead from the bone andproduce health problems such as impairedblood synthesis, alteration in the nervoussystem, high blood pressure, effects on maleand female reproductive systems, and damageto the developing fetus.

APPLICABLE REGULATIONSRegarding regulations governing lead exposureon construction projects, the Ministry of Labourreferences Designated Substances—Lead(Regulation 843) and makes it relevant forconstruction projects with section 25(2)(h) ofthe Occupational Health and Safety Act, Thefollowing excerpt regarding lead exposure wastaken from the Ministry of Labour’s guidelineLead on Construction Projects:

“The Ministry’s designated substance regulation(DSR) for lead, Regulation 843, specifiesoccupational exposure limits (OELs) for lead,and requires assessment and a control programto ensure compliance with these OELs. The OELfor inorganic lead is 0.05 milligrams per cubicmetre (mg/m3) of air as an 8-hour daily or40-hour weekly time-weighted average.”

“Measures and procedures that ensureconstruction workers receive the same standardof protection as workers covered by Regulation843 should therefore be implemented onconstruction projects where exposure to lead isa hazard. Such measures and procedures aredeemed to be in compliance with section25(2)(h) of the OHS, as taking “every precaution

reasonable in the circumstances for theprotection of a worker.”

WELDING, CUTTING, OR BURNINGBefore welding, cutting, or burning any metalcoated with lead-containing materials, removethe coating to a point at least four inches fromthe area where heat will be applied. Whenremoval of lead-containing paint is not feasible,use engineering controls (e.g., local exhaustventilation) to protect workers. The controls

should remove fumes and smoke at the sourceand keep the concentration of lead in thebreathing zone below the exposure limit.

REMOVAL OF LEAD PAINTLead-based paint can be removed by a varietyof methods, including

• chemical stripping (do not use chlorinatedsolvents for stripping paint because theycan lead to toxic fumes being producedduring welding)

• wet scraping using a paint scraper

• mechanical stripping if the sander orgrinder is equipped with a High EfficiencyParticulate Air (HEPA) filter.

• heat stripping if the temperature is below600°C. Above 600°C lead fumes becomeairborne creating a significant inhalationhazard.


Figure 2. Portable fume extractor

45 – 4

Use protective sheeting to collect debris that hasbeen sanded, grinded, or stripped away.

Do not do any of the following activities whenworking in areas that might contain lead-basedpaint because they can create dangerous levelsof lead dust or fumes.

• Open flame burning or torching (includingpropane-fuelled heat grids) and heat gunsoperating above 600°C. These activitiesrelease toxic fumes.

• Machine sanding or grinding without aHEPA filter. These activities create leaddust.

• Uncontained hydroblasting, high-pressurewashing or abrasive blasting, or sandblasting.These activities create lead dust.

• Using methylene chloride paint removalproducts. These products release toxicfumes.

• Extensive dry scraping creates lead dust.

PERSONAL HYGIENEPersonal hygiene is an important element of anyprogram for protecting ironworkers fromexposure to lead dust. Employers should provideadequate washing facilities at the jobsite so thatworkers can remove lead particles thataccumulate on the skin and hair. For certain high-hazard operations, decontamination facilities withshowers may be required.

All workers exposed to lead should wash theirhands and faces before eating, drinking, orsmoking, and they should not eat, drink, or usetobacco products in the work area. Tobaccoproducts (cigarettes, cigars, chewing tobacco,etc.) and food items should not be permitted inthe work area. Contaminated work clothesshould be removed before eating.

Workers should change into work clothes at thejobsite. Work clothes include disposable orwashable coveralls. Street clothes should bestored separately from work clothes in a clean

area provided by the employer. Separate lockersor storage facilities should be provided so thatwork clothing and shoes do not contaminateclean clothing.

Workers should change back into their streetclothes after washing or showering and beforeleaving the jobsite. Doing so will prevent theaccumulation of lead dust in workers' cars andhomes and protect their family members fromexposure to lead. Separate laundering ofwashable coveralls can help prevent take-homeexposures.

WARNING SIGNSPost warning signs to mark the boundaries oflead-contaminated work areas. These signsshould indicate that there is a lead hazard andprohibit eating and drinking in the area.

PERSONAL PROTECTIVE EQUIPMENT(PPE)Use engineering controls and good workpractices to minimize worker exposure to lead.PPE should supplement the engineering controlsand good work practices.

PROTECTIVE CLOTHINGWorkers who are welding, cutting, or burningshould wear non-flammable clothing.

Protective clothing not only shields workersfrom the hazards of welding, but it alsominimizes the accumulation of lead on theworkers’ skin and hair. Workers should changeinto washable coveralls or disposable clothingbefore entering the contaminated work area.

Wearing protective equipment or clothing cancontribute to the development of heat stress.Take steps to prevent heat stress. See thechapter on Heat Stress in this manual.

To reduce the amount of lead that couldaccumulate in a worker’s car and home, and toprotect the members of the worker's household,lead-contaminated clothing (includingworkboots) should be left at the jobsite.


45 – 5

RESPIRATORY PROTECTIONThe best way to minimize worker exposure tolead is “control at the source” (such ascontainment or local exhaust ventilation).Control at the source, however, is oftenimpractical at construction sites, where airbornelead concentrations may be high or may varyunpredictably. Therefore, respiratory protectionis also necessary for operations such as sandingor grinding. A respirator is the last resort, butsometimes it’s your only choice.

When respirators are used, the employer mustestablish a comprehensive respiratory protectionprogram as outlined in the CSA standard Z94.4-93: Selection, Use, and Care of Respirators.Important elements of the CSA standard are:

• an evaluation of the worker's ability toperform the work while wearing arespirator

• regular training of personnel

• periodic environmental monitoring, and

• respirator fit testing, maintenance,inspection, cleaning, and storage.

The employer should evaluate the respiratoryprotection program regularly.

Respirators should be selected by the person who

• is in charge of the program

• is familiar with the workplace

• knows about the limitations of each typeof respirator.

The amount of lead released during constructionand can vary substantially, so use the highestanticipated exposure to determine theappropriate respirator for each job.

Respirator selection should be made accordingto the guidelines in the table below, which is anexcerpt from the Ministry of Labour’s guidelineLead on Construction Projects. Employers mustuse respirators that are approved by the

National Institute of Occupational Safety andHealth (NIOSH).

Medical Monitoring

The level of lead in the blood is currently thebest indicator of a person’s exposure to lead.Workers who can potentially be exposed to leadshould be monitored for the presence of lead intheir blood and for any effects of lead on theblood-forming system. This assessment isnecessary to ensure that engineering controls,personal hygiene practices, and PPE arepreventing lead exposure. Workers are notrequired to participate in a medical monitoringprogram if they don’t want to.

TRAININGWorkers should receive training that includes

• information about the health effects of leadexposure

• information about how to recognize leadpoisoning early

• description of proper personal hygienepractices that reduce the risk of leadpoisoning

• instruction on the use and care ofprotective equipment (including protectiveclothing and respiratory protection)

• instruction on specific practices forworking safely with lead-containing paints.


45 – 6


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45 – 7


OP

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don

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next

pag

e

45 – 8


OP

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ith

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ldbe

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lity

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erto

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ade

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ork

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carr

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ns:

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rasi

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lead

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lead

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ater

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usin

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wer

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ith

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e re

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hen

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Tools of the TradeHand Tools

Ironworkers normally carry their hand tools ontheir belt or in a pouch on their belt. Load yourbelt so that it does not hinder your movements.Balance the tools on the belt so one side is notloaded more than the other. Place commonlyused tools such as a spud wrench on yourdominant side, i.e., on your right if you areright-handed. Don’t carry tools by slipping themunder your belt and make sure that your toolsare secure and cannot fall.

Regularly inspect all hand tools for:

• split or loose handles

• mushroomed heads

• sprung parts.

Stop using unsafe tools immediately and tagthem to identify the defects. Turn them in forrepair or replace them.

Don’t leave tools on ledges, ladders, beams, ornear the edges of scaffolds or other worksurfaces where they can be knocked off orwhere workers can trip over them. Store tools inappropriate containers away from edges.

Don’t carry anything in your hands while usinga ladder. Use hand lines for lifting tools orequipment.

Wrenches

When working with a wrench, there is alwaysthe hazard that it can slip off the work, or thatthe object may suddenly turn free. There is alsothe chance that the wrench or bolt will break.Always brace yourself so you won’t lose yourbalance or be injured. Inspect your wrenchesfor flaws that could cause them to slip.

The spud wrench is the ironworker’s mostcommon wrench. It should have a roundtapered handle forged at an angle to provideample clearance for the hand yet keep the headin proper position for maximum power. The

tapered end is used for aligning bolt holes inadjacent members. Spud wrenches are availablein different sizes, so it is important to know thesize of bolt being used before beginning work.Don’t use a shim to make a wrench fit.

• Always grip the wrench so you won’t beinjured if it slips.

• Discard any damaged box or open-endwrench.

• Don't try to repair a wrench with roundedor damaged points on the box end, orworn or spread jaws on the open end.

• Wrenches are made from tempered steeland should not be welded.

• Face an adjustable wrench forward andturn the wrench so pressure is against thepermanent jaw.

• Always pull on a wrench toward yourtorso, this will reduce the chance of fingerinjuries if the wrench slips.

• Handle stops on channel locks or plierswill prevent pinching injuries to the handand fingers.

• Never overload a wrench by using a pipeextension on the handle or by striking thehandle with a hammer. This can weakenthe metal of the wrench and cause the toolto break. Heavy-duty box wrenches withextra long handles and "hammer" orstriking-face wrenches are available forthese jobs. The striking-face wrenches with


Figure 3. SpudWrench

45 – 10

12-point box openings are designed forstriking with a ballpeen or sledge hammer.Both offset and straight styles are availablebut the straight type is safer.

Socket Wrenches

Socket wrench sets offer a multitude of optionsin both the types and sizes of the sockets, andthe variety of drivers available for themincluding ratchet, universal, speeder, and theirmany extensions and adapters. When usingadapters and adapting down in size, be carefulnot to over-torque a smaller socket and fastenerwith a larger driver.

Always use the correct size of socket; make sureit fits snugly. An oversized or sloppy fit can leadthe wrench to slip and injure you, as well ascausing wear to both the socket and the fastener.

Never use "hand" sockets on a power drive orimpact wrench. (Hand sockets normally have abright finish, while power and impact socketsusually have a dull finish and usually havethicker walls.)

Hickey Bars

Hickey bars are used to position steel forconnection, or while shaking out or sortingsteel. They provide the extra leverage requiredfor a worker to move steel members which areheavy and awkward. When using a hickey bar,

• inspect it before using it

• position your feet and body so that youwon’t lose your balance

• avoid pinch points

• ensure that there is enough clearance forthe member to move

• stand to the side and turn the beam awayfrom you.

Drift Pins and Punches

A drift pin is a tool tapered at one or both endswhich is used to align holes before connecting.When striking drift pins, wedges, punches, orchisels with a hammer, hold them with tongs toprevent injuries to hands. Bull pins are taperedat one end with a striking head on the other.Using this type of drift pin reduces the chancesof hand injury.

Don’t use the tool if a mushroom headdevelops. If you hit a mushroom head, particlescan fly off.

Power tools

• Inspect and maintain power tools on aregular basis. Repair or discard defectivetools.

• Power tools should have a “dead man”trigger or switch to prevent accidentalactivation.


Figure 4. Correct use of adjustable wrench

Moveable Jaw

Direction of Pull

Figure 5 Hickey bars or beam turners

Figure 6: Bull Pin Figure 7: Reamer Figure 8: Drift Pin

45 – 11

• All portable electric hand tools must begrounded or double-insulated. The groundwires must be continuous from the toolhousing to the power-source ground. Makesure that the casing on double-insulatedtools are not cracked or broken.

• Use only those electric hand tools bearingCanadian Standards Association (CSA)approval.

• Safety guards should be kept in place ongrinders and other power tools.

• Do not use a rotary screw with aprotruding set screw that can catch ongloves or clothing.

• Use proper pins and o-rings to securesockets to impact wrenches. Do not relyon rods, wire, or other makeshift materials.

• To thaw pneumatic tools place them in awarm area. Do not use direct heat. Properuse of a de-icer will keep pneumatic toolsfrom freezing.

• All moving parts need to be guarded toprevent loose clothing or hair frombecoming entangled in them.

• Use only the right tool for the job.

Gas- or Diesel-Driven Equipment

• Do nor refuel or lubricate an engine whileit is running. Stop the motor and allow itto cool. Plan to refuel equipment first thingin the morning or at the beginning of theshift.

• Do not refuel while welding or burning istaking place in the area. Hot slag canbounce over a wide area.

• When using cold-weather starting fluids,such as ether, take extra care and followthe manufacturer’s instructions. Too muchether can damage the engine.

• If a gasoline line or any part of an enginefreezes, do not use a torch to thaw it out.

Use gas-line antifreeze or a heating pad, orwrap the frozen part in a cloth and pourhot water over it. In sub-zero weather, skincontact with gasoline increases the risk offrostbite. Protect your hands from contactwith gasoline or similar fluids.

• Provide proper ventilation if you’reoperating engines in an enclosed orunventilated area.

• At the start and end of each shift—and atleast once during the day—bleedcompressors (release air from thechamber) to blow off any condensationthat has collected.

• Check to ensure that all gauges areworking properly and report anymalfunction.

• Use only non-flammable solvents to cleanan engine.

Propane-driven equipment: Follow themanufacturer’s instructions for checkingregulators, fittings, cylinders, and othercomponents. Only workers who have receivedtraining in handling propane are allowed tohandle propane bottles or equipment. Forpropane training, contact the Construction SafetyAssociation of Ontario or other certified trainers.

Electrically Driven Equipment

Wired electrical connections must be made byonly qualified electricians and must conform toall applicable regulations.

Assume that all wires and switches areenergized until proper inspection can proveotherwise.

When working on or near electrically drivenequipment, follow appropriate lock-outprocedures. Turn off the equipment, then closedown and lock the switch box. See the chapteron Lockout and Tag in this manual for moreinformation on procedures.


45 – 12

On grounded electrical machines or motors, theground wire should be continuous from thehousing to the power source.

Only explosion-proof motors and switchesshould be used in locations where ignition cancause a fire or explosion.

Site Preparation andSteel ErectionHoisting Equipment

Cranes are used primarily to hoist steel intoposition. The crane operator must have thecorrect licence for the type of crane beingoperated and be familiar with the crane.

See the chapter on Rigging in this manual forcomplete information on rigging.

Before any steel structure can be erected safelyand efficiently, the sequence of erection must beplanned in advance and the structural memberslaid out in the order of their erection. Workareas for cutting should be laid out in advanceto ensure safe and efficient operation. Whenstockpiling steel for on-site fabrication, ensurethat a good solid base is provided for storage. Ifthe steel is to be piled high, use long sleepers toensure a level and safe storage area.

Keep work areas clear of clutter, debris, andscrap material. Keep a box or barrel close by forthe disposal of scrap.

Preparing On-Site Storage Areas

The area where the material is to be storedshould be as level as possible, well-drained and

with good access. Storage areas should be asclose to the work area as possible. Storage areasshould be well laid-out with clear and directaccess to work areas. Store the material so that itwill be kept free from mud, oil, grease, etc. Ingeneral, a clean work area is a safe work area.Store materials away from travelled walkways.

Avoid storing materials under powerlines,especially if using hoisting equipment to move it.

4x4 sleepers should be used to keep the steeloff the ground and to allow slings to pass freelyunder the load. Make sure there is adequateblocking available before steel is delivered.

The general contractor should be consultedbefore setting up storage areas so that thegeneral is aware of potential weights to bestored in each area. Ensure that steel stored onfloors does not overload the structure, and thatreshoring is in place if necessary.

Material should be stored at least 1.8 metres (6feet) away from all slab edges and openings.

Normally, members are laid down on site andsorted after they arrive. Plan the job well so thatmembers can be laid out in sequence. This willavoid moving the steel repeatedly.

Unloading and Storage Precautions

Post “DANGER” signs and cordon offunloading areas as required. Always keeppeople who are not directly involved with off-loading out of the area.

Be sure to communicate with the driver aboutunloading procedures.

Serious accidents can occur if tie-downs arereleased without the load being contained toprevent materials from spilling over. It is veryimportant to check if the load has shifted beforeyou off-load it. If it has shifted, the weight onthe trailer may not be evenly distributed and thestraps may be over-tensioned. Many workershave been struck by shipping straps uponrelease.


Figure 9: Grinder Figure 10: Impact Gun

45 – 13

When unloading the trailer always watch forloose or small pieces. Sometimes, steel suppliersor delivery companies place small pieces eitheron or in-between larger pieces. These smallpieces can cause serious injury if they shift orfall while being lifted. Always walk to the endsafter hooking up and examine the blocking thatwas used. Blocking should be hardwood, but itcould be something else. Don’t assume that thesupplier’s delivery company has used hardwoodwhen loading the trailer.

Land and block the load before unhooking it.Lower loads onto adequate blocking to preventdamage to slings.

Make sure identification marks are clearly visibleto avoid extra handling.

Space the members so that they can be pickedin sequence without having to move othermembers. If members must be stacked in layers,put sleepers between each layer.

Near openings, arrange material so that itcannot roll or slide in the direction of theopening.

Positioning the Truck

• The truck should be positioned on a levelarea as close to the crane as possible toprevent the crane from overreaching.

• Keep the truck and crane away fromoverhead powerlines.

• Trucks backing up must be directed by acompetent signaller.

• The supervisor should tell the truck driverwhere to wait during loading andunloading.

• Always stake loads before unloading.

• Unload the truck in such a way to preventuneven weight distribution. Uneven loaddistribution could cause the truck bed toshift, resulting in material spill over.

High-Visibility Clothing

The Construction Regulation (Ontario Regulation213/91) requires that any worker who may beendangered by vehicles on a project must wearhigh-visibility clothing.


Figure 11. Picture of steel laid out

Timber Blocking

Timber

Timber Blocking

Method ofPiling Beams

Methodof Piling

Channels

Methodof PilingAngles

Methodof PilingPlates

Figure 12. Hand Signals for Traffic Control

Back up

Clearance

Stop

Change direction

45 – 14

Unless stated otherwise, the high-visibilityclothing described in this section applies tosignallers and workers directing traffic.

High-visibility clothing has two main

features:

• Background material — The fabricmust be fluorescent orange or brightorange and provide the wearer withincreased daytime visibility. Werecommend fluorescent orange because itprovides a higher level of daytimevisibility.

• Retroreflective stripes or bands —The stripes or bands must be

- yellow, fluorescent, and retroreflective

- arranged in two vertical stripes downthe front, and in an “X” on the back

- 50 mm wide

These retroreflective stripes give the workerboth low-light and nighttime visibility. For nightwork, you also need stripes or bands on thearms and legs. One way to meet thisrequirement is to dress workers in fluorescentorange coveralls with retroreflective bands orstripes attached.

Risk Assessment

Before selecting high-visibility clothes, assess therisks you need to control. Workers who needgreater visibility, such as roadway constructionworkers, should wear clothing that is verynoticeable under the conditions expected.

For further recommendations on high-visibilityclothing, consult CSA standard Z96-02.

Mounting and Dismounting Truck Beds

Many accidents have occurred as the result ofworkers getting on or off a flatbed truck.

• Before getting on the truck, clean off yourboot soles to avoid slips.

• Mount the truck platform in full view ofthe crane operator or signaller. This will

prevent you from being struck by the loador the crane hook.

• Climb up and down facing the truck,maintaining 3-point contact at all times(two hands and one foot, or two feet andone hand on the trailer).

• If steps and handrails are provided, usethem. Tires or hubs don’t give you stablefooting.

Safe Rigging and Slinging

There are times when workers who are notprofessional riggers must rig loads. Ironworkersare often involved, not only in handling, but inhoisting and receiving material. When in doubtabout rigging consult an experienced rigger or aprofessional engineer. Information in this sectioncan only provide the basics of rigging. Moreinformation is contained in the Rigging chapterof this manual or the Hoisting and RiggingSafety Manual (M035) published by theConstruction Safety Association of Ontario.

Safe rigging basically depends on knowing

• the weight of the load to be lifted

• the capacity of the hoisting device

• the safe working loads of ropes andhardware.

MAJOR HAZARDSThe most frequent cause of rigging accidents islack of knowledge. In rigging, experience is notnecessarily the same thing as knowledge. Sinceironwork involves a lot of materials handling,the methods and equipment used to rig, lift, andmove materials are important for the trade.

Overhead powerlines — Most lifting devicesand all wire rope hoist lines and slings areexcellent conductors of electricity. No part of alifting device or its load must come closer thanone boom length to a live overhead powerline,unless a signaller directs the operator. No partof a lifting device or its load must come closerto live powerlines than the minimum distances


45 – 15

listed in the table below unless the powerlinehas been insulated by the owner of thepowerline and procedures are in place toprotect the workers from electrical shock.


750 or more volts, but not 3 metres (10')more than 150,000 volts

more than 150,000 but 4.5 metres (15')not more than 250,000 volts

more than 250,000 volts 6 metres (20')

Load too heavy for rigging equipment orrigging arrangement — This problem maybe related to

• planning

• the selection, condition, and inspection ofequipment

• improper estimates of the load to bemoved or lifted.

Weather — Weather conditions such as rainand ice can affect the rigging, control, andhandling of loads as well as the lifting devicesinvolved. Visibility and wind can also createproblems in hoisting and landing loads.

Unexpected loads – Loads can suddenlymove or slip because of

• weather conditions

• travel or swing that is too fast or abrupt

• inadequate support under lifting devices

• unexpected drifting.

These and other conditions can create additionalloads on rigging components, and lead to failureor collapse.

Inadequate components — Slings, shackles,hooks, and other equipment must be in goodcondition and properly sized, configured, andload-rated for the job.

Failure to keep hoist lines vertical —When hoist lines are not vertical, loads canswing unexpectedly. In particular, loads that

must be drifted into position can pull lines outof vertical. The load may slip, come apart, andstrike workers or the lifting device.

Toppling, shifting, or falling material —These problems can be caused by

• improper use of slings

• using slings not suited to the size, weight,and shape of the load

• inadequate attachment of load to liftingdevice.

Loads must be secure before, during, and afterthe lift. Pipe, in particular, is very likely to shiftor roll unless properly secured. The criticalmoment often comes when the hoist line istensioned up or slacked off. That's whenworkers should stand clear.

Lifting overhead — The dangers of standingdirectly under a load being lifted or lowered areobvious. Although it is sometimes difficult to doon crowded construction sites, workers andoperators should avoid situations where loadsare hoisted over people. Connectors must beextra diligent when they are receiving loads.

Inadequate landing surface — Loads mustsometimes be lifted to scaffolding, plankedplatforms, or other temporary structures. Thesesurfaces must be able to support whatever loadsare applied. In some cases, a knowledgeableperson may have to assess the load-carryingcapacity of the temporary structure.

Determining Load Weights

The most important step in any riggingoperation is determining the weight of the loadto be hoisted. If this information cannot beobtained from shipping papers, design plans,catalogue data, or other dependable sources, itmay be necessary to calculate the weight. Moststructural steel is classified by size and weight.For example, a W310 x 79 beam means that thebeam is 310 mm deep and 79 kg per linearmetre. Therefore a beam of this size that is 10metres long weighs 790 kg. Remember: The


45 – 16

weight of all rigging equipment must beincluded as part of the load to be lifted.

The time taken to calculate the approximateweight of any load is time well spent. It mayprevent a serious accident from a failure oflifting gear or crane collapse.

Inspection

It is important to inspect rigging, before eachuse, for damage or excessive wear. The capacityof a worn or damaged fibre rope, metal sling, orsynthetic sling can be greatly diminished,making them unsafe to use. More information iscontained in the Rigging chapter of this manual,and in the Hoisting and Rigging Safety Manual(M035) published by the Construction SafetyAssociation of Ontario.

MULTIPLE LIFTS (TIERED LIFTS)Multi-tiered lifts may be performed under certainconditions to hoist structural members intoposition. This method can reduce the potentialfor some accidents by reducing the number oftimes the crane must swing when loaded.However, the practice is highly specialized andmust be carried out only by trained workers,using established procedures and dedicatedrigging assemblies.

Inspection and capacity requirements for

rigging equipment

Before hoisting any structural members, therigging equipment must be inspected by acompetent worker at the beginning of eachshift. Removal criteria must be established. Ifthere is any doubt about the integrity of therigging components, the component in questionmust be replaced. Remember, the rigging mustbe able to support the total load attached to it,not just individual beams.

The following conditions must be met to safelyhoist multiple lifts.

• A complete inspection of all riggingequipment must be carried out daily.

• An engineered, dedicated, multiple-riggingassembly must be used. This assembly isnot to be used for other hoistingoperations.

• All hooks must have safety catches.

• Only workers directly involved in hookingon the steel, or connectors who arereceiving the loads, can be involved.

• Three members is the maximum that canbe hoisted at any time.


Fig. 13. Rigging assembly with 3 chokers of different lengths.

Fig. 14. Three beams hanging in an assembly

45 – 17

• The members must be aligned so that aminimum clear distance of 2.1 metresexists between rigged members. This givesclearance so workers hooking up orconnecting will not be struck by membersoverhead.

• Members are to be connected with a tagline at one end in order to prevent rotation.

• All workers involved in the process,including the crane operator, must betrained in the specific procedure beingused. Records of training including namesof workers and their responsibilities mustbe kept on site.

• Only structural members can be lifted.Bundled loads cannot be lifted.

• Routes for suspended loads must be pre-planned to ensure the load does not passover other workers.

• A copy of the engineered liftingprocedures and any alterations to theprocedures must be kept on site.

• Before any multiple lifts, the nearestMinistry of Labour office must be notified.

Methods of rigging multiple loads

There are several methods of rigging multipleloads. One method is to use chokers of differentlengths as shown in Figure 13. Another methodis to string chokers end-to-end with membersattached by slings to the chokers. Thesemethods are acceptable if they have beendesigned by a professional engineer.

CHOOSING THE HARDWAREKnow the safe working loads of slings andrigging hardware. Never exceed the limit of theweakest device.

Rigging equipment must be inspected beforeuse. If you have any doubt about a piece ofequipment, change it, or consult with somebodymore experienced in rigging.

Workers involved in offloading steel must becompetent through training and experience.When staking is required, stake the load beforereleasing binders.

Softener such as wood or split pipe should beused on the sharp edges of a load to protect thesling from being cut. Secure the softeners to thesling to prevent them falling off.

Keep your hands away from the load and slingswhile the load is being lifted.

Use tag lines to guide suspended loads. Coil theends of tag lines to prevent snagging ortripping. Do not stand in the coils of a tag lineor wrap a tag line around your hand.

Do not take hold of the hoist cable close to asheave or block. Your hand may be drawn in tothe block.

Do not climb on to a vehicle or crane while it ismoving or operating.

Before lifting the load make sure that it is clearof other material or obstructions.

Hooking On

• Normally two workers are involved in thehooking-on process.

• Rig the steel so that it will not shift duringhoisting yet it will be relatively easy tounhook.

• Do not stand under a load or boom.

• Keep your eyes on the entire load as it isbeing hoisted to ensure that nothing shifts.

Hooking on multiple lifts (tiered lifts)

• Workers hooking on the steel must knowthe sequence of connecting so that the firstmember to be connected is the lastmember to be hooked on.

• The centre of each piece should be markedbefore being hooked up. When it is lifted itmust hang level. It should be raised slightlyoff the ground to ensure that it is level. If


45 – 18

not, it must be put down and the chokeradjusted. When rigging long members, usetwo chokers to keep the beam balanced.

• As the load is being hooked, take care toprevent the remaining hooks fromsnagging other beams.

• A tag line must be attached at one end ofeach member, connecting all the membersto be hoisted. It will ensure that themembers do not rotate independently. Thistag line can be left to hang. Workersreceiving the load can use it to guide theload into position.

Connecting

A connector is a trained ironworker who makesthe initial connection of structural steelmembers. The supervisor should designate theconnectors in the crew. There should normallybe two connectors for each crane working.

Connecting steel members comes with manyhazards. Falls are the greatest hazard becausethis work is done mainly at heights. It’s difficultto find adequate lifeline anchors, particularlybecause members are not fully connected. Seethe chapter on fall protection in this manual.

Other common injuries are being struck by steelmembers and having hands and fingers pinchedbetween members. These injuries can often leadto falls and more serious injuries. To preventthem, follow these precautions:

• Connectors must be ready for a member asit approaches. Don’t do any other work atthe time. Keep your eyes on the steel as itapproaches and guide it into position.

• Use a drift pin or wrench to match upholes. Don’t use your fingers. Manyworkers have lost fingers this way.

• Before being cut loose, the beam must bebolted so that it will not rotate. At leasttwo or more bolts should be put inposition, depending on the engineer’srequirements. Do not rely on a drift pin ora wrench placed in a hole.

• Columns, trusses, and beams that are notproperly tied-in should be guyed beforeyou cut them loose.

• When working above reinforcing steel ordowels, ensure that the ends of the rods arecovered to protect you from being impaled.

• Use extra care while working on a beamfitted with shear connectors or NelsonStuds. Grip the beam, not the studs. Tuckin or tape your pant cuffs to avoid trippingon the studs.

Connecting multiple lifts (tiered lifts)

When the beam is lowered into position, it mustbe connected with a minimum number of boltsin the usual way. After is has been unhookedfrom the crane, position the next member. Theconnectors must be aware of the overheadmembers at all times. When all the membershave been released from the crane, the riggingassembly is lifted clear by the crane. Theconnectors must ensure that the riggingassembly does not snag a piece of the structureas it is being lifted clear. These chokers caneasily trip a worker or become snagged in othermembers.

Bolting Up

The bolting up crew follows the erection crew.Their role is to install the remaining bolts ateach connection. They normally work from atemporary platform such as a scaffold, anelevating work platform, or from the steel itself.Fall protection is easier to achieve for this workbecause the structural members are secure atthis stage, or fall arrest anchors have alreadybeen installed.

Tools and equipment should be carried incontainers. Do not leave bolts, washers, driftpins, or empty bolt cans lying around on beamsor work platforms.

Do not allow air hoses or cables to clutterwalkways, platforms, or ladders where someonecould trip. When it is necessary to work with a


45 – 19

long lead or hose be sure that it is tied off atseveral points to prevent whipping if the hosewas cut or disconnected.

Reaming and drilling

Reaming and drilling is often necessary toproperly align holes for connection. Basicprecautions include eye and hearing protectionbecause flying particles and noise areunavoidable.

In two-person operations, workers shouldstand on the same level and coordinate theirmovements. When reaming or drillingvertically, workers should stand on oppositesides of the tool and face each other. Whenreaming or drilling horizontally, workersshould keep the tool between them, preferablyat waist level and face the material. Avoidreaming or drilling overhead as controlling theequipment is difficult. Make sure that youhave enough space, secure footing and properbalance when reaming or drilling, especiallywhen you’re above floor or ground level.

Do not use an electric reamer or drill on a steelbeam that is being welded unless the membersare grounded.

When using a magnetic base drill, secure it tothe structure in case of a power failure.

Use the right size of bit for the job. Keep the bitstraight when reaming or drilling. Take extracare with bits having two or three flutes becausethey tend to bite or stick. Make sure drill bitsare sharp and true. Bits should be reconditionedregularly by a qualified person.

When drilling a deep hole beyond the flutes ofthe bit, clean out the chips by removing andreinserting the bit several times with the poweroff. Don’t let the chips or shavings build up ina hole because the bit may become tight orjam up.

Lightweight or small pieces of steel should beclamped, bolted, or tack welded so they will notbind on the bit and whip around.

Riveting

Although riveting is no longer used extensivelyon structural steel, the following tips on saferiveting are still useful for renovations,maintenance, and demolition work and fordriving drift pins with rivet guns.

• Snaps must be wired to the riveting gunbridle.

• Remove snaps and plunger when leavingthe job for any length of time.

• The riveting gun should not be left in aposition such that the trigger could bereleased unintentionally.

• When cutting or backing out rivets, useshields to stop rivets from flying andinjuring someone.

• When rivets are driven out with a punch,the helper should hold the punch with atongs or another suitable tool—not withtheir hands.

Q Decking and Floor Openings

The hoisting and installation of Q-Deck is acommon job for many ironworkers. Each taskcomes with its own set of risks. Here are someprecautions to help reduce the hazards.

• Never use bundle packaging or strappingto hoist the deck to upper floors.

• If loose items are placed on top of abundle for hoisting they must be securedto the bundle.

• Bundles must be landed on framingmembers so that the bundles aresufficiently supported to allow un-bandingwithout dislodging the bundles.

• Depending on weather conditions, such aswind, all decking must be secured so thatit doesn’t fly off and hit someone.

• Confirm with the steel erector that the steelis plumb and torqued before hoistingbundles to the upper levels.


45 – 20

• All floor openings must be coveredimmediately. This includes small holes, ifany part of a worker can go through them.The covers must be secured and markedwith a warning sign or marking.

• Holes and openings must not be cut unlessthey are essential to the constructionprocess. If cut, they must be immediatelycovered.

• The spaces around columns must becovered or blocked to prevent objects fromfalling.

Due to the nature of Q-Decking installations,access to the floor where the decking is beingplaced and the area below it must be limited topersons performing the work. Remember,proper fall protection is required until the deckis complete and guardrails are installed.

Take special care when weather conditions arepoor. For example, during winter months, thedecking can become very slippery. Wear propersafety boots with slip-resistant soles.

Safe Access and FallProtectionThe main areas of concern are fall protectionwhile working at heights and access to elevatedwork areas. The fundamentals are covered inthe chapter on fall protection, and aresupplemented by the following information.

General requirements

Fall protection must be used wherever workersare exposed to the hazard of falling:

– more than 3 metres (10 feet)

– more than 1.2 metres if the work area isused as a path for a wheelbarrow orsimilar equipment

– into operating equipment

– into water or another liquid

– into a hazardous substance or object

– through an opening in a work surface.

Where it isn’t practical to install guardrails, youmust employ fall protection measures which caninclude:

1) Fall prevention, such as

• protective covers over floor and roofopenings

• warning barriers and bump lines

• travel restraint.

2) Fall arrest, such as

• fall restriction

• fall arrest

• safety nets.

Regardless of type, every fall protection systemin Ontario construction must meet therequirements of the Occupational Health andSafety Act and the Construction Regulation(Ontario Regulation 213/91).

An integral part of fall protection is planning forwork access before you begin erecting steel.Improper access leads to workers walking longdistances on the steel. The longer you walk onthe steel, the greater your risk of falling.

The employer must also develop writtenprocedures for rescuing a worker whose fall hasbeen arrested. Workers using fall protectionmust be trained in its use, and a written recordof training must be kept.


Fig. 15: Q-Decking

45 – 21


Travel-Restraint Systems

A travel-restraint system lets a worker go just farenough to reach the edge but not far enough tofall over it.

The basic travel-restraint system consists of

• CSA-approved full-body harness

• lanyard

• lifeline

• rope grab to attach harness or lanyard tolifeline

• adequate anchorage, capable of supportinga static load of 2 kilonewtons (450 pounds)with a recommended safety factor of at least2, that is, 4 kilonewtons or 900 pounds.

Travel-restraint arrangements must bethoroughly planned, with careful considerationgiven to

• selection of appropriate components

• location of adequate anchor points

• identification of every fall hazard in theproposed work area.

Try to select an anchor point that is as close aspossible to being

• perpendicular to the unprotected edge,and

• at the centre of the work area.

You must identify all fall hazards in the workarea. Pay special attention to work areas withirregularly shaped perimeters, floor openings, orlocations near corners. A fully extended lifelineand/or lanyard that keeps a worker away from afall hazard in one section of the work area maybe too long to provide the same protection inanother section.

Two methods of travel restraint are commonlyused in construction.

• Connecting an adequately anchored lifelinedirectly to the D-ring of the worker’s fullbody harness. It’s absolutely critical that

the length of the lifeline, measured fromthe anchor point, is short enough to keepthe worker away from any fall hazard.

• Attaching a lanyard to the D-ring of theworker’s full body harness and then to arope grab on an adequately anchoredlifeline. There must be some means—suchas a knot in the lifeline—to prevent therope grab from sliding along the lifeline toa point where the worker is no longerprevented from falling.

Regardless of the method used, the system mustbe adjusted so that when all the componentsare fully extended, they prevent the workerfrom reaching a fall hazard. The system mustalso be securely anchored.

FALL-ARREST SYSTEMSWhere workers cannot be protected from fallsby guardrails or travel restraint, they must beprotected by at least one of the followingmethods:

- fall-restricting system

- safety net

- fall-arrest system.

In the event of a fall, these systems must keep aworker from hitting the ground, the next levelbelow, or any other objects below.

A fall-restricting system is designed to limit aworker’s free fall distance to 0.6 metres (2 feet).One type uses a belt grab or belly hook thatattaches to a safety rail on a fixed ladder.

A safety net system must be designed by aprofessional engineer. The system is installedbelow a work surface where a fall hazard exists.

A fall-arrest system

• must include a CSA-approved full bodyharness

• must include a lanyard equipped with ashock absorber unless the shock absorbercould cause a falling worker to hit the

45 – 22

ground or an object or a level below thework

• must include an adequate fixed support;the harness must be connected to it via alifeline, or via a lanyard and a lifeline

• must prevent a falling worker from hittingthe ground or any object or level belowthe work

• must not subject a falling worker to a peakfall-arrest force greater than 8 kilonewtons.

The construction regulation (O. Reg. 213/91)requires that

• all fall protection equipment must beinspected for damage, wear, and obviousdefects by a competent worker beforeeach use

• any worker required to use fall protectionmust be trained in its safe use and propermaintenance.

Any defective component should be replaced byone that meets or exceeds the manufacturer’sminimum performance standards for thatparticular system.

The regulation also requires that any fall-arrestsystem involved in a fall be removed fromservice until the manufacturer certifies allcomponents safe for reuse.

For any worker receiving instruction in fallprotection, the manufacturer’s instructions foreach piece of equipment should be carefullyreviewed, with particular attention to warningsand limitations.

ANCHOR SYSTEMSThere are three basic types of anchor systemsfor fall protection.

1) Designed fixed support: Load-ratedanchors specifically designed andpermanently installed for fall protection

purposes as an integral part of the buildingor structure (for example, roof anchors onhigh-rise buildings).

2) Temporary fixed support: Anchor systemsdesigned to be connected to the structureusing specific installation instructions (forexample, stanchions for horizontallifelines).

3) Structural features or equipment notintended as anchor points but verified by aprofessional engineer or competent personas having adequate capacity to serve asanchor points (for example, structural steelor reinforced concrete columns).

Designed fixed support can be used to anchor afall-arrest system, fall-restricting system, ortravel-restraint system if the support has beeninstalled according to the Building Code and issafe and practical to use.

Temporary fixed support can be used asanchorage if, without exceeding the allowableunit stress for each component used,

• it can support at least 8 kilonewtons (1800pounds), or

• when used with a fall-arrest systemincorporating a shock absorber, it cansupport at least 6 kilonewtons (1350pounds), or

• when used with a travel-restraint system, itcan support at least 2 kilonewtons (450pounds).

In all cases, use a safety factor of at least twowhen calculating the minimum load that ananchor point must support.

As a general rule with fall-arrest systems, choosean anchor capable of supporting the weight of asmall car (about 3600 pounds).

When structural features or equipment are usedas anchor points, avoid corners or edges thatcould cut, chafe, or abrade fall-protectioncomponents. Where necessary, use softeners


45 – 23

such as wood blocking to protect connectingdevices, lifelines, or lanyards from damage.

Beam Clamps

Beam clamps can make effective anchors whenused properly with a correct lanyard. There aremany different types of beam clamps. The mostcommon are plate clamps, trolley clamps, orglider clamps. The pin set must be inserted thefull length of the pin, or if the clamp has alocking device, the device must be in the lockedposition. Always check that the clamp is set forthe correct beam size and that it is tight. Alwayscheck the manufacturer’s instructions beforeuse.

Before using a beam clamp, check forcoped ends on the beams. A beam clampcould easily slide off the end of a copedbeam through the gap between the twomembers.

Lifelines

There are three basic types of lifelines.

1) vertical

2)horizontal

3) retractable.

All lifelines must be inspected daily to ensurethat they are free of

• cuts, burns, frayed strands, abrasions, andother defects or signs of damage

• discolouration and brittleness indicatingheat or chemical exposure.

Vertical lifelines

Vertical lifelines must comply with the currentedition of the applicable CSA standard and thefollowing minimum requirements:

• Only one person at a time may use avertical lifeline.

• A vertical lifeline must reach the ground ora level above ground where the workercan safely exit.

• A vertical lifeline must have a positive stopto prevent the rope grab from running offthe end of the lifeline.

Vertical lifelines are typically 16-millimetre (5/8-inch) synthetic rope (polypropylene blends).


Fig. 16. Danger: Beam clamp near coped end

Fig. 17.Vertical Lifeline

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CLIMBING THE COLUMNS FOR STEELCONNECTIONSThe first choice of a means of access for makingsteel connections must be a ladder, poweredelevating work platform, or a crane with aplatform suspended from the boom. You shouldonly climb columns when these options are notpractical due to

• characteristics of the location

• poor soil conditions.

Further to this, written notice must be given tothe Joint Health and Safety Committee or Healthand Safety Representative on the project beforea worker can climb the column. The workermust also be competent to climb and must beprotected by a fall arrest system at all times.

Horizontal Lifelines

The following requirements apply to anyhorizontal lifeline system.

• The system must be designed by aprofessional engineer according to goodengineering practice.

• The design can be a standard design orspecifically engineered for the site.

The design for a horizontal lifeline systemmust

• clearly indicate how the system is to bearranged, including how and where it is tobe anchored

• list and specify all required components

• clearly state the number of workers thatcan safely be attached to the lifeline at onetime

• provide instructions for installation,inspection, and maintenance

• specify all of the design loads for thesystem.

The system must be installed, inspected, andmaintained in accordance with the professionalengineer’s design.

Before each use, the system must be inspectedby a professional engineer or competent workerdesignated by a supervisor. A complete andcurrent copy of the design must be kept on siteas long as the system is in use.

CAUTION: The construction regulation requiresthat "a horizontal or vertical lifeline shall be keptfree from splices or knots, except knots used toconnect it to a fixed support." Knots along thelength of either a horizontal or vertical lifelinecan reduce its strength by as much as 40%.

Retractable Lifelines

Retractable lifelines must comply with thestandard CAN/CSA-Z259.2.2-M98. In general,retractable lifelines

• are usually designed to be anchored abovethe worker

• employ a locking mechanism that lets lineunwind off the drum under the slight

Fig.18. Horizontal Lifeline

Fig.19. Retractable lifeline

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tension caused by a user’s normalmovements

• automatically retract when tension isremoved, thereby preventing slack in theline

• lock up when a quick movement, such asthat caused by a fall, is applied

• are designed to minimize fall distance andthe forces exerted on a worker’s body byfall arrest.

Anchor your lifeline as close to overhead aspossible. This will minimize swing distance ifyou fall.

Always refer to the manufacturer’s instructionsregarding use, including whether a shockabsorber is recommended for the system.

A retractable lifeline that has stopped a fall mustbe removed from service until the manufactureror a qualified testing company has certified itfor reuse.

Lifeline Hazards

Ultraviolet (UV) light — Exposure to the sunmay damage or weaken lifelines. Ensure thatmaterial being considered for lifelines is UV-resistant.

Temperature — Extreme heat can damagelifelines, and extreme cold can make thembrittle. Ensure that the material being consideredfor lifelines can stand up to the most extremeconditions expected.

Friction and abrasion — Normal movementmay wear, abrade, or otherwise damage lifelinesin contact with sharp or rough surfaces. Useprotection such as wood softeners or rubbermats can at contact points to prevent wear andtear.

Sparks or flame — lifeline can be damagedwhen hot work such as welding or flame cuttingis done nearby. Sparks, flame, or heat can melt,burn, cut, or otherwise damage the lifeline.Ensure that material being considered for

lifelines is flame-resistant or provide appropriateprotection when hot work is done nearby.

Chemicals — Chemical exposure can burn ordegrade a lifeline very quickly. Ensure thatmaterial being considered for lifelines will resistany chemicals encountered on the job.

Storage — Always store lifelines separately.Never store them where they may contacthazards such as sharp objects, chemicals, orgasoline.

Ladders

Ironworkers use ladders extensively to accesselevated work areas, and in some cases they’reused for short-duration work. Portable extensionladders are the most common in the ironworkertrade, but they have been responsible fornumerous injuries. Falls, electrical contact andmaterial handling are the main injuriesassociated with ladders. If ladders are beingused as work platforms, check the ConstructionRegulation for whether fall protectionrequirements apply in your case. For example,you may require a method of fall protectionsuch as the vertical lifeline shown in Figure 17.

See the chapter on Ladders in this manual formore information.

Construction Hoists

Construction hoists are used on constructionsites to move workers and light materials toupper floors. Normally they are operated by adesignated operator, but all workers shouldfollow some basic safety precautions.

The landing gates on hoists are for yourprotection. Make sure that the gates are closedproperly before the car leaves the floor. Don’ttry to bypass gate contacts.

Removable guardrails at landings are animportant safety feature. If they must beremoved at any time during construction,replace them before you leave the area. Whenyou’re working in an area where guardrails havebeen removed, you must have another methodof fall protection.


45 – 26

Landing areas must be kept clear of materials,tools, and debris to ensure safe access to thehoist entrance.

Do not tamper with shoring under ramps orother parts of the hoist. In particular, shoringunder the hoist must be kept intact until thetower is removed.

Don’t remove a brace or anchor connecting thetower to the structure unless it’s absolutelynecessary. It must be replaced immediately. Thehoist must be taken out of service whenever abrace is removed.

Angel Wing Scaffolds

Angel wing scaffolds are a lightweightconstruction platforms used for applicationssuch as steel erection, bridgework, shipbuilding,welding and cutting, and tank inspection andrepair. They are normally made from a lightaluminum alloy that is easily installed,dismantled, and carried by one person. Angelwings have a compact, folding design. Eachcomponent must be designed so that the stagecan hold the minimum load for a work platformas specified in the Construction Regulation.They normally accommodate one or twoworkers—but all workers on the platform mustwear fall protection.

Mobile Welding RigsThis section describes some basic requirementsfor drivers of mobile welding rigs. If you haveany questions or concerns, speak with theappropriate association or ministry to ensurethat you understand the responsibilities of allpersonnel.

Legislation

Highway Traffic Act

On public roads and highways all vehicles mustoperate in compliance with the Highway TrafficAct. The Transportation Health and SafetyAssociation of Ontario (THSAO) providesinformation and training on the Act.

Commercial Plates

You need commercial plates on any motorvehicle having a permanently attached truck ordelivery body. The requirement for commercialplates on a van or pickup, however, does notautomatically classify them as commercialvehicles.

Commercial Vehicles

Loading a vehicle with equipment and suppliescan increase its weight. Whenever the grossvehicle weight rating, registered gross weight, oractual weight, loaded or empty, exceeds 4500kilograms, the vehicle and operator are subjectto the regulations under the Highway Traffic Actapplying to commercial motor vehicles andcommercial motor vehicle operators. You mustadd a trailer’s weight to the weight of thevehicle when determining total weight.

Under the Highway Traffic Act, commercialvehicle operators must obtain a CommercialVehicle Operator’s Registration (CVOR). Theymust also comply with the additional restrictionsand obligations (such as annual inspections)described in the Act.

According to the Highway Traffic Act, theoperator is the "person responsible for theoperation of a commercial motor vehicleincluding the conduct of the driver and thecarriage of goods or passengers, if any, in thevehicle or combination of vehicles." Theoperator does not have to be the vehicle owner.If the vehicles are leased or contracted, theoperator must hold a valid CVOR.

If you have any questions about how theHighway Traffic Act is applied, contact thelocal Ministry of Transportation enforcementoffice. For a CVOR application form, contactthe Carrier Sanctions and Investigation Office.

Gross Axle Weight

For any commercial or passenger vehicle, thegross weight of the vehicle or combination ofvehicles (e.g., van and trailer) must not exceedthe manufacturer’s gross axle weight rating. This


45 – 27


rating is usually written on a sticker on thedriver’s door.

There are two consequences of exceeding themanufacturer’s gross axle weight rating. First, itis an offence under the Highway Traffic Act.Second, if the gross weight is more than 4500kilograms, the vehicle can be classified as acommercial vehicle.

Trailers

If a vehicle is towing a trailer such as a utilitytrailer, the trailer’s weight must be added to theweight of the vehicle when determining totalweight. Add the highest weight of the vehicle tothe highest of the trailer’s gross vehicle weightrating (if provided on trailer) or the actualweight, empty or loaded, to determine whetherthe combined weight exceeds 4500 kilograms.

Transportation of Dangerous Goods Act(TDG Act)

The Transportation of Dangerous Goods Act(TDG Act) applies whenever hazardous materialis transported on a road or highway. Learnabout the dangers involved. Learn also aboutthe restrictions and obligations that the TDG Actapplies to the driver and owner of the vehicle.

This section only identifies some of theregulations and exemptions which apply tomobile welding rigs, vehicle owners, and driversunder the TDG Act. For more information,contact the Transportation Health and SafetyAssociation of Ontario (THSAO)—whichprovides training—or the local Ministry ofTransportation Enforcement office.

When transporting propane, drivers must alsofollow the Propane Storage and Handling Code.

Read the material safety data sheet (MSDS) ofeach product you’re transporting. It maydescribe specific information about transportingthe product.

Special Provisions of the TDG Regulations

under the TDG Act

Regulations under the TDG Act always applywhen you’re transporting dangerous goods such

as compressed gases. There are, however, someexemptions.

You may, for example, be exempt from drivertraining, documentation, and placarding of thevehicle. (Placarding means putting signs on thevehicle to identify the material beingtransported.) There may also be exemptionswhen propane, acetylene, or oxygen is beingtransported in an open vehicle, and the amountis less than 500 kilograms gross mass or iscontained in not more than five cylinders. Inthis situation, the TDG Act does require thelabel on the cylinder to be visible from outsidethe vehicle. Also see the Propane Storage andHandling Code. In all cases the cylinders mustbe securely stowed in the vehicle to preventmovement. You should have in the vehicle adry-chemical fire extinguisher of at least 10BCrating — one that’s listed by the Underwriters’Laboratories of Canada.

Depending on the hazardous material, the TDGAct could require the driver and others toreceive training in the transportation ofdangerous goods.

GENERAL PRECAUTIONS

Defensive Driving

Defensive driving means being prepared. Donot simply focus on getting to your destination.Think also about actions and events that caninfluence the way your trip unfolds. Beprepared to avoid or control hazards. Followcommon-sense rules for defensive driving.

1. Understand the rules and regulations thatapply to the vehicle and to driving.Ignorance of the law is not a valid defencein court.

2. Understand that human physical andemotional factors influence drivingperformance.

3. Ensure that the vehicle is well maintainedand operating properly.

45 – 28

4. Consider how weather, road, and trafficconditions will affect driving abilities.

5. Assess how well you understand theprevious four topics. Take steps such asenrolling in a defensive driving course toattain and maintain a level of knowledgenecessary to practice defensive driving.

Trailer Safety

Before using a trailer, be sure it is in safeoperating condition. Inspect

• lights

• tires

• brakes

• bearings

• safety chains

• hitch.

Use the correct class of trailer hitch on yourvehicle.

• Class I – up to 2,000 lb

• Class II – up to 3,500 lb

• Class III – up to 5,000 lb

• Class IV – up to 10,000 lb

A trailer requires two separate means ofattachment to the vehicle. A typical arrangementincorporates a ball hitch with two safety chains.The capacity of each chain should be equal tothe gross weight of the trailer and should crossunder the tongue to connect to the hitch.

Loose objects must be covered with a tarp. Allloads on trucks and trailers must be secured orplaced so that no portion of the load canbecome dislodged of fall from the vehicle.

Anchor points, rope, and slings used for tie-downs must be in good condition. Inspect thembefore each use. See CSAO’s Hoisting andRigging Safety Manual (M035) for moreinformation.

Maintenance

Every employer should establish a system forperiodical inspection, repair, and maintenanceof all motor vehicles and trailers operated onthe highway.

An employer must not permit a motor vehicle tobe driven, or a trailer to be towed, on ahighway if there is reason to believe that thevehicle or trailer will not meet safety standards.

A driver who reasonably believes or suspectsthat a vehicle or trailer does not meet safetystandards should advise the employer.

Inspections

Before each shift, perform a basic vehicleinspection. The following “Daily Circle Check” isa good example:

Parking brake – adequate to hold vehicle.

Fluid levels – oil, gas, brakes. Check for leaks.

Lights and turn signals – functioning.

Visibility check – mirrors properly adjusted,windows clean and intact.

Wiper/washer – functioning.

Tires – pressure, tread depth, damage.

Wheels and fasteners – defects in rim, looseor missing fasteners.


Fig. 20. Daily Circle Check

45 – 29

Seat belts – you must always wear them.

Load – secure.

Emergency equipment – install and inspectas required by law or company policy.

A more detailed inspection may be requiredfor commercial vehicles.

Record and report any defects to yoursupervisor immediately!

Users should consult the Transportation ofDangerous Goods Act, applicable highway trafficacts, provincial regulations, local bylaws, etc.,which may contain additional safetyrequirements.

Vehicle Layout

CSA standard CAN/CSA-W117.2 providesguidance for mobile welding rig design.

When a mobile oxygen/fuel gas welding systemis assembled as a cutting/welding or heatingunit, a person capable of competently operatingthe equipment should accompany the vehicle.This person must ensure that the system isbeing transported in compliance with theTransportation of Dangerous Goods Act andwhere applicable, the Highway Traffic Act.

When designing and laying out a welding rig,do the following.

• Secure any cargo that could shift duringtravel. Set up strong storage racks for tools

and supplies to distribute the weightevenly and prevent shifting during suddenstops or sharp turns.

• Do not let scrap and debris accumulateinside the vehicle.

• Set up a designated location for the firstaid station, MSDS information, and fireextinguisher.

• Install a strong reinforced divider toseparate the driver compartment from theback.

Compressed gases

• Ensure that cylinders are supported solidlyand fit snugly into their designatedlocations. Restrain cylinders in a way thatprevent them from rotating. Provide acylinder-mounting location that is easilyaccessible, minimizes lifting, and permitsthe cylinders to be installed or removedwithout dragging or scraping them.

• Ensure that all cylinders are standingupright.

• Do not store fuel gas cylinders in cabinets.Ventilation holes in a cabinet may not beadequate to vent leaking fuel gas. Forexample, acetylene has an explosive rangestarting at 2.5%, so an explosiveatmosphere can develop quickly.

Warning

Gas can leak from stored fuel hoses andgauges, causing an explosive atmosphere.

• If you’re concerned about theft orvandalism, you can build a screened cageto contain the cylinders. At least two sidesof the cage must have an 80% or greaterfree area.

• Mount all cylinders vertically unless themanufacturer’s MSDS says otherwise.

• Before you operate your vehicle on publicroadways, or park it on publicly accessible


Fig. 21

45 – 30

property, disconnect the regulators andhoses from the cylinders and put themaway in storage. The valves must beclosed on all cylinders and the protectioncaps must be in place.

• Close the cylinder valves when theequipment is unattended.


46 – 1

SHEET METAL

46 SHEET METALContents- Accident Investigation

- Material Handling

- Welding and Soldering

- Ventilation

- Fire Safety

- Shop Safety

Accident InvestigationPurpose

Accidents that injure people or damage propertyon construction sites should be investigated. Insome cases, investigation is required by law.Refer to sections 51-53 of the OccupationalHealth and Safety Act.

The purpose of accident investigation is toidentify causes and prevent the accident fromoccurring again. The objective is not to blameanyone. The method is fact-finding.Investigation looks beyond the obviousimmediate causes to determine what other,underlying causes may have contributed to theaccident.

All concerned parties should be involved inaccident investigation. Depending on the sizeand duration of the project, that may include thehealth and safety representative, the joint healthand safety committee, the projectsuperintendent, and foremen.

Investigators understand that accidents don’t justhappen. They are caused by some failure inplanning, procedures, equipment, instruction,communication, or training. If the causes offailure aren’t identified and corrected, they canlead to similar accidents in the future.

It is recommended that accident investigationresults be discussed with all employees—in

particular, the steps being taken to prevent arecurrence.

What to investigate

After an accident, employers need to

• record the facts

• determine the immediate and underlyingcauses

• identify possible accident or illness trendsin order to counteract them

• substantiate a worker’s claim in the case ofpersonal injury

• take the steps necessary to prevent arecurrence.

When to investigate

Investigations should be conducted as soon afterthe accident as possible. There are severalreasons for doing this.

• With the passage of time the accidentscene will change, evidence may beremoved, and immediate and underlyingcauses will become harder to pinpoint.

• Details are quickly forgotten.

• Witnesses may move on to other sites.

• Employers need to demonstrate promptlytheir commitment to determine causes andprevent accidents from recurring.

How to investigate

An investigation is usually conducted right atthe accident scene. That helps to develop aclear picture and allow witnesses to show andpoint out things as well as describe and explain.

Witnesses should be interviewed separately.This helps to ensure that each witness recallsevents without being influenced by hearingsomeone else’s version. Investigators don’t wanteveryone buying into a newspaper version.They look for facts, evidence, and areconstruction of events that fits the differentpoints that witnesses recall.

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SHEET METAL

For instance, one witness may state, “There wasa sharp snap,” while another remembers “aripping noise.” The two reports are notnecessarily contradictory. The sharp snap mayindicate the sudden structural failure of anoverloaded component while the ripping noiseindicates a cable tearing apart following thefailure.

Investigators try to establish

• conditions before, during, and after anaccident

• activity being performed

• role of workers, supervisors, and witnesses

• involvement of machines or equipment

• factors such as weather, work surface, andground conditions

• the sequence of events

• any deficiencies or breakdowns in thesystem that allowed the events to occur

• how the system can be corrected toprevent the accident in future.

Investigators establish these facts by

• keeping an open mind and never jumpingto conclusions

• avoiding witch hunts, fault-finding, andblaming individuals

• contacting everyone involved

• sticking to the facts

• determining both immediate andunderlying causes

• recording the details and recommendationsso follow-up action can be taken

• ensuring that everyone understands thatthe purpose of the investigation is to gainthe knowledge and understanding neededto prevent a recurrence.

The worker’s role

Without the cooperation of workers,investigation will likely fail to disclose whatcaused the accident and how it can beprevented. Digging into the facts can be painful,but labour and management must work togetherto establish what happened, determineimmediate and underlying causes, and take theaction necessary to eliminate such accidents inthe future. The full cooperation of all parties istherefore essential.

For more information, contact the ConstructionSafety Association of Ontario at 1-800-781-2726and order the data sheet Accident Investigation(DS029), poster P103, and sticker S008.

Material HandlingWork areas

• Work areas should be laid out in advanceto ensure safe and efficient operation.

• When stockpiling material for fabricationor installation ensure that a good solidbase is provided for storage.

• If material is to be piled high, use sleepersto ensure a level and safe storage area.

• Keep work areas clear of clutter, debris,and scrap.

• Keep a box or barrel close by to disposeof scrap.

Preparing storage areas

• The area where the material is to be storedshould be as level as possible, dry, well-drained and with good access.

• Avoid storing materials under powerlines,especially if hoisting equipment is beingused to move it (O. Reg. 213/91, section37).

• Sleepers should be used to keep thematerial off the ground and to allow slings

46 – 3

SHEET METAL

to pass freely under the load. Make surethere is adequate blocking available beforematerial is delivered.

• Storage areas should be as close to thework area as possible, whether materialwill be handled by crane or carried byworkers.

• The mechanical contractor and/or generalcontractor should be consulted beforesetting up site storage areas so that theyare aware of potential weights to be storedin each area. Ensure that material storedon floors does not overload the structure,and that sufficient support is in place onnewly poured slabs.

• To prevent accidents, all material shouldbe stored at least 1.8 metres (6 feet) awayfrom all open edges.

• Wherever practical, storage areas shouldbe well laid-out with clear and directaccess to work areas.

• Store so that material is free of mud, oil,grease, etc.

• In general, a clean work area is a safework area. Store materials away fromtravelled walkways

Ventilate storage areas

Storage areas need to be well ventilated. Thefumes given off by paint thinners, epoxies,acids, and other materials may be toxic orflammable.

Unloading and storage precautions

• Post DANGER signs and cordon offunloading areas as required.

• Serous accidents can occur if banding ortie-downs for bundles are released withoutcontainment and materials spill over.

• Be sure to communicate with the driverabout unloading procedures.

• Land and block the load before unhookingand unslinging it. Lower loads ontoadequate blocking to prevent damage toslings.

• Make sure identification tags are clearlyvisible in order to avoid extra handling.

• Space material so that it can be picked upwithout having to move other material. Ifmaterial must be stacked in layers, putsleepers between each layer.

• Immediately after cutting, dispose ofbanding material, waste wire, or any othergarbage in proper containers so that itdoesn’t become a hazard.

• Near openings, arrange material so that itcannot roll or slide in the direction of theopening.

Positioning the truck

• Position the truck as close to the craneunloading area as possible to avoidoverreaching by the crane.

• The truck should be positioned on terrainas level as possible.

• Keep the truck and crane away fromoverhead powerlines.

• A truck backing up should be directed bya competent signaller using establishedsignals (Figure 1).

• Truck wheels should be blocked orchocked during unloading.

Figure 1. Hand Signals for Traffic Control

Back up

Clearance

Stop

Change direction

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SHEET METAL

Mounting and dismounting from truck

beds

• Many accidents have occurred as the resultof workers getting on or off a flatbedtruck. Situations will vary, but acommonsense approach should befollowed.

• Before mounting the truck, scrape off yourboot soles to avoid slips.

• Mount the truck platform in full view ofthe crane operator or signaller so that youwill not be struck by the load or the cranehook.

• Climb up and down facing the truck,maintaining 3-point contract at all times(two hands and one foot, or two feet andone hand).

• If step and handrails are provided, usethem. Stepping on tires or hubs affordspoor footing.

Welding and SolderingThe following guidelines apply to welding,cutting, and brazing. For soldering, see the boxentitled “Soldering” a few pages ahead.

Wear protective clothing

• Cotton or wool fibres if possible. Syntheticfibres are flammable.

• High-top safety shoes laced up, with pantleg covering top of shoe. A spark inside ashoe can cause a serious burn.

• Welding gloves.

• No cuffs on pants or shirt to catch sparks.

• Long hair tucked under a cap.

• Long-sleeve shirt to protect your skin fromsparks and rays.

• Welding leathers if welding at highamperage for a long time.

• A welding cap and jacket if you arewelding overhead.

• No jewelry.

• Use the right shade number for weldinglenses. See Table 8.1. Both the welder andanyone assisting the welder must wear eyeprotection.

Table 8.1

Lens Shade Selection Guide for WeldingShade numbers are given as a guide only and may bevaried to suit individual needs.

Electrode Arc Minimum Suggested1

Size Current Protective Shade No.Operation mm (32nd in.) (Amperes) Shade (Comfort)Shielded Metal Arc less than 2.5 (3) less than 60 7 –Welding 2.5-4 (3-5) 60-160 8 10(SMAW) 4-6.4 (5-8) >160-250 10 12

more than 6.4 (8) >250-550 11 14

Gas Metal Arc Welding less than 60 7 –and Flux Cored 60-160 10 11(GMAW) >160-250 10 12

>250-500 10 14

Gas Tungsten Arc Welding less than 50 8 10(GTAW) 50-150 8 12

>150-500 10 14

Air Carbon (light) less than 500 10 12Arc Cutting (heavy) 500-1000 11 14

Plasma Arc Welding less than 20 6 6 to 8(PAW) 20-100 8 10

>100-400 10 12>400-800 11 14

Plasma Arc Cutting (PAC)Light2 less than 300 8 9Medium 300-400 9 12Heavy >400-800 10 14

Torch Brazing (TB) – – 3 or 4

Torch Soldering (TS) – – 2

Carbon Arc Welding (CAW) – – 14

Plate Thicknessmm in.

Gas Welding (GW)Light under 3.2 under 1/8 4 or 5Medium 3.2 to 13 1/8 to 1/2 5 or 6Heavy over 13 over 1/2 6 to 8

Oxygen Cutting (OC)Light under 25 under 1 3 or 4Medium 25 to 150 1 to 6 4 or 5Heavy over 150 over 6 5 or 6

Figure 20.17

1. Shade numbers are given as a general rule. It is recommended tobegin with a shade that is too dark to see the weld zone. Then oneshould go to a lighter shade which gives sufficient view of the weldzone without going below the minimum. In gas welding or oxygencutting where the torch produces a high yellow light, it is desirable touse a filter lens that absorbs the yellow or sodium line in the visiblelight of the operation (spectrum).

2. These values apply where the actual arc is clearly seen. Experiencehas shown that light filters may be used when the arc is hidden by theworkpiece.

Reproduced with the permission of the American Welding Society.

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Protect others

• Position yourself so that sparks go in thesafest direction.

• Warn others in the area before striking anarc.

• Set up a screen to protect others from thewelding flash.

• Check to see if sparks or molten particlescould fall to a lower level or roll along thefloor. Be especially careful about this whenyou are welding from a scaffold or ladder.

Avoid burns and fires

• Use a striker to ignite a torch flame. Usingmatches or a cigarette lighter can burnyour fingers.

• Don’t carry a butane lighter in your shirt orpants pocket. It may be ignited by sparks,splatter, or high heat.

• Clear the work area of flammable materialsor debris.

• Never lay down a torch while the flame isburning.

GAS SOURCE EFFECTS

Acetylene From acetylene not completely In very high concentrations, usually inused up in oxyacetylene welding. confined spaces, replaces oxygen in the

air possibly causing suffocation

Argon/Helium Used in gas-metal arc welding Same as above(GMAW) and gas tungsten arcwelding (GTAW) to shieldelectrode from oxygen.

Arsine Possible contaminants of Anemia (from breaking up red bloodcommercial acetylene cells), jaundice, pulmonary edema

Carbon Monoxide Welding arc changes carbon dioxide Headache, dizziness, concentrationin the air to carbon monoxide, problems, anemia, heart disorders,GMAW can be a primary source. and (in high enough concentrations)From incomplete burning during coma and deathwelding or soldering.

Nitrogen Oxides Welding arc changes nitrogen in Respiratory irritant, pulmonary edema(NO2) & NO in air to nitrogen oxides. (delayed onset)

GMAW and plasma arc weldingcan be a primary source.

Ozone Ultraviolet light caused by the Irritant to eyes, nose and throat, chestwelding arc changes oxygen in air pains, wheezing. Can lead to pulmonaryto another form of oxygen, edemacalled ozone. GMAW and plasma arcwelding can be primary sources.

Phosgene Ultraviolet radiation from welding Respiratory irritant, chest pains,arc decomposes chlorinated solvents pulmonary edema, death (if(degreasers) such as trichloroethylene concentrations are high enough)and 1,1,1, trichloroethane

Phosphine Possible contaminant of Fatigue, tremors, coma, convulsions,commercial acetylene pulmonary edema, and (with long-term

exposure) anemia, problems with thegastrointestinal system

Table 8.2WELDING EXPOSURES

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• If welding has to be done within 10 metres(30 feet) of flammable materials, provide afire watch with fire extinguishers. The firewatch must stay at the location for half anhour after welding is completed.

Use oxygen safely

• Never use oxygen to blow dust from yourclothes. It’s a fire hazard.

• Never oil the oxygen regulator.

• Never use any grease or oil around oxygen.Oxygen mixed with the slightest trace ofgrease or oil can cause a violent explosion.

Avoid toxic fumes

• Make sure you have proper ventilation.Keep as much distance as possiblebetween the welding plume and your face.Table 8.2 shows the effects of variousgases used for or produced by welding.

• Check the MSDS for the welding rod andcomponents to be used.

• Find out if the metal you are weldingcontains zinc, lead, cadmium, chromium,or nickel. These give off toxic fumes.

• Clean off any paint before welding,especially if it might be lead-based. Beforeremoving lead, see the Ministry of Labour’sguideline Lead on Construction Projects,available on www.labour.gov.on.ca.

• Remove any degreasers. When welded,chlorinated degreasers can producephosgene gas, which is extremely toxic.

Other hazards

• Never weld or cut directly on a concretefloor. The combination of heat andmoisture in the concrete can cause a smallarea of the concrete to spatter.

• Know the special hazards for each weldingprocess. See ITI Welding Book One formore information.

Electric arc welding/carbon arc welding

• Any moisture—even sweat—aroundelectric welding machines can cause ashock. Wear dry gloves and shoes withinsulated soles. Dry off the workbench orfloor if either is wet.

• Use the proper amp rating and duty cyclerating for the electric welding machine youare using. Overheating can damageinsulation and lead to shock.

• Make sure the grounding cable is properlyattached to the work or worktable.

• The leads that carry the welding currentshould not come in contact with chains,wire ropes, hoists, and elevators.

• Disconnect the power supply whenmoving the welding machine.

• Remove the electrode from its holderwhen the welding machine is not in use.

• Place electrode holders so that they do notcome in contact with people or flammablematerials.

• Never cool electrode holder by putting itin water.

• Make sure that the polarity switch, rangeswitch, or both are not moved while thepower source is being used. This cancause a fire and damage the machine.

Oxyfuel welding, cutting, and brazing

The compressed gas cylinders used for oxyfuelprocesses can be a hazard. They must be stored,handled, and used properly to avoid accidents.

Storing cylinders

Many gas cylinders, such as oxygen cylinders,are under high pressure. Damage to the valvecan turn the cylinder into a rocket.

• Avoid any sudden shock to cylinders.

• Store all compressed gas cylinders upright

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in a clean dry area away from oil, grease,flames, and flammable materials.

• Store cylinders upright and hold them inplace with chains or cables. Use a cylindercap to protect the valve, when applicable.

• Do not store oxygen cylinders within 20feet of fuel gas cylinders such as acetylene,propane, or butane unless they areseparated by a partition at least 5 feet highand having a fire resistance rating of atleast 30 minutes (Figure 8.1).

Handling cylinders

• Cylinders being transported should besecured in an upright position.

• Cylinder valves must be closed before thecylinder is moved.

• Never use cylinders as rollers or assupports, whether they are full or empty.

• Never remove cylinder caps with a pry bar.

Using cylinders

• Cylinders should be secured in an uprightposition while in use.

• Use positive action check valves at boththe regulators and torch. These valvesprevent the gas from flowing in reverse.

• Always use a regulator on a cylinder toreduce the pressure, unless the equipment isdesigned to withstand full cylinder pressure.

• Never force regulator fittings if they do notmatch the cylinder threads. Some regulatorfittings (such as acetylene) have left-handthreads.

• Before connecting a regulator to a cylindervalve, open the valve briefly to blow awayany dust.

• Never stand in front of the regulator whenturning on the cylinder valve. In case of amalfunction, the explosion or fire willblow out the front of the regulator.

• Before removing a regulator, close thecylinder valve and release the gas from theregulator.

• Never allow any oil on an oxygenregulator. Oxygen under pressure canexplode when it contacts oil.

• Use black iron pipe and fittings foracetylene. Never use copper pipe orfittings with acetylene. Copper andacetylene form acetylides which explodeviolently.

• Make sure that the fuel gas hose is red, theoxygen hose is green, and the inert gashose is black (U.S. only). Acetylene hosesusually have left-hand threads.

• Open the valve on oxygen cylinders all theway to prevent leakage around the valvestem.

• Close all cylinder valves when you areaway from work for any length of time.

Using acetylene

• Always keep acetylene hose pressure atless than 15 psi (pounds per square inch).Higher pressure creates a risk of fire.

• Leave a wrench on the acetylene cylindervalve for emergency turnoff.

• Open the acetylene cylinder valve only 1/4turn so that if can be turned off quickly incase of an emergency.

Figure 8.1

30 Minute Fire Rating

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• Breathing acetylene gas can causedizziness, a light-headed feeling, or loss orconsciousness. Acetylene is highlyflammable. You can recognize acetylene byits garlic-like odour.

Soldering

• Wear eye protection because flux orsolder can splatter.

• Ensure good ventilation while solderingor tinning a soldering iron. The salammoniac gives off irritating toxic fumes.

• Keep away from the soldering plume asmuch as possible because of the leadcontent in the plume.

• Rest a hot soldering iron in a holder. Donot put it on a workbench or onflammable material.

• When soldering outdoors, make sure thefirepot is clear of any combustiblematerial and is level and stable.

• Fill the propane tank for the firepotcarefully and away from open flames.The tank is full when gas begins escapingfrom the relief valve.

• Use a damp cloth to clean a solderedjoint. If water drops on the hot metal itcould cause the flux to splatter.

Working with acid

• Acid can blind you. Acid fumes cancause breathing problems. Acid on yourskin can burn. Use acid or other fluxcarefully.

• If acid gets in your eyes, wash immediatelywith cold running water. See a doctorimmediately.

• If acid gets on your skin, wash it off withcool tap water right away, until the

burning sensation subsides. See a doctorimmediately.

• Ensure good ventilation while you workwith acids.

• Acid on your clothing will rot the fabricand could contact your skin.

• Do not make cut acid near an open flame.The process gives off hydrogen gas thatcan explode.

• Do not fill a container for making cut acidmore than half full. The hydrogen gas cancause the acid to bubble vigorously.

• Never add water to raw acid (hydrochloricacid) when making a solution. Add theacid to water, and add it slowly over a 10or 15 minute period in a ceramic crockthat can stand the heat produced.

Plastic welding

Sheet metal workers make ductwork out ofplastic as well as sheet metal.

• PVC (polyvinyl chloride) ductwork iswelded using a PVC filler rod heated witha hot-air gun. The filler rod is used like thefiller for oxyacetylene welding.

• FRP (fibre-reinforced plastic) is chemicallywelded. A solvent dissolves the twosurfaces so that they melt together. Theprocess involves mixing a resin, promoter,and catalyst, which react together. Thereaction produces heat over 360° F. That’senough to start a fire.

• Follow safety precautions for FRP welding:

– Read the MSDS on any chemical or othermaterial you use.

– Check all chemical containers for leaksor cracks.

– Wear proper protective equipment whenworking with any chemical.

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– Follow the manufacturer’s guidelines formixing chemicals and their catalysts. Forsafety, many components must bemixed in a specific sequence.

• Make sure you have good ventilationwhen opening and using chemicals.

• When transferring resins from 55-gallondrums, make certain the drums areelectrically grounded to reduce sparkingfrom static electricity.

• When you transfer resin to a smallercontainer, label the new container with theproduct name, chemical family,flammability, and use.

• Never experiment with the chemicals,catalysts, or their mixing ratios.

• Make certain that the proper class of fireextinguisher is available.

• A sign should identify the area where FRPmaterials are being prepared.

• Never dispose of a mixing container untilthe reaction has been completed and is nolonger producing heat.

For more information, refer to the chapteron Welding and Cutting in this manual. Safepractices are also explained in the AmericanWelding Society’s ANSI Z49 publicationSafety in Welding and Cutting and in theCanadian Standards Association standardSafety in Welding, Cutting and AlliedProcesses (CAN/CSA-W117.2).

VentilationWhether you’re welding, cutting, fabricating, orinstalling, you need clean air on the job.

Air polluted by toxic gases and particles canmake breathing hazardous. If you work indoors,

you could be trapped in bad air if there is notenough ventilation.

Air may be a hazard even though there are nodanger signs. A toxic gas may be odourless (ascarbon monoxide is).

Some hazards have short-term effects that youfeel immediately such as burning eyes,dizziness, coughing, and headaches. Other airhazards have long-term effects that you mightnot feel for 20 years or more, such as cancer orasbestosis.

The first step is to control the source of aircontamination. Changing a process or using asafer material might do this.

If the air pollution cannot be avoided, someother step is needed to make breathing safe.One solution is better ventilation. Another is towear a respirator.

Ventilation takes care of most jobsite air hazards.It removes contaminated air and replaces it withoutside air. Ventilation may use natural airmovement or forced air.

Local exhaust ventilation

Local exhaust ventilation means removing air atthe source of the contaminant. Figure 9.1 showsthree different methods. A filter is added if theair contains solid particles such as dust, paints,or oils. Local exhaust is usually more effectivethan general ventilation, but it is not 100%effective.

• The process or equipment should beenclosed as much as possible.

• The airflow rate has to be high enough topull the contaminant into the airstream.

• Intake air must be equal to the air beingexhausted.

• Intake air must be free of contamination.Intake vents should not be close toexhaust vents.

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• Exhaust air must be filtered or otherwisetreated so that clean air is exhausted to theatmosphere. Filters should be cleaned orreplaced regularly.

Hazardous fumes

• Zinc from welding galvanized sheets cancause metal fume fever. Symptoms aresimilar to flu. Metal fumes can causenausea, fever, and shaking chills andshould be avoided.

• Welding stainless steel creates chromiumfumes, which can be hazardous.

• Hydrochloric acid used as a soldering fluxreleases chlorine gas when applied tometal. Chlorine is hazardous.

• Lead, found in solder and certain alloys,causes serious health problems. It is storedin the body for a long time.

• Solvents used for many operations can alsobe hazardous.

Ventilate storage areas

Storage areas need to be well ventilated. Thefumes given off by paint thinners, epoxies,acids, and other materials may be toxic orflammable.

Portable FumeExtractor

FumeExtraction Gun

Bench withPortable Hood

Figure 9.1: Local exhaust ventilation for welding

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Fire SafetyImportant!

• If your clothing catches fire, STOP, DROP,and ROLL.

• If you suspect a fire, sound an alarm.

• Applied as soon as possible, smotheringcan usually put out a small fire.

• Know the location of fire extinguisherswherever you work.

The construction regulation (O. Reg. 213/91)requires that workers be trained to use fireextinguishers.

Information in this chapter has been taken fromthe Occupational Health and Safety Act andRegulations for Construction Projects. Theintention is to provide a general summary of theduties required of various personnel.

Fire basics

• The words flammable and inflammableboth mean the same thing—burning easily.

• Some materials may have labels thatindicate a fire hazard Figure 11.1

• A fire needs three ingredients—fuel,oxygen, and heat.

• Most fires at a sheet metal shop or jobsiteare due to

–flammable vapours from solvents,adhesives, and fuel gas

–sparks and hot metal form grinding,cutting, welding, brazing, and soldering

–electrical overloads.

• These common causes of fire can beeliminated by good housekeeping, propermaintenance, and safe work practices.

• Know the four basic types of fire (Table11.1).

Table 11.1 – Classes of Fire

CLASS TYPE OF MATERIALSFIRE

A Common Wood, paper,

materials fabric, grass, grain, coal,rubbish

B Flammable Gasoline, oil, paint,

liquids and varnish, solvents,

vapours grease, wax, fat, oil

C Electrical Motors, switch boxes,

transformers,generators, wiring

D Combustible Magnesium, titanium,

metals zirconium, sodium,lithium, potassium

Fire classification

Fires are broken down into four different classes(Table 11.1). You should be familiar with eachclass in order to know which fire extinguisherto use and in order to take proper precautions.

Figure 11. 1 Hazardous materials should be identified

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Class A – Common materials such as wood,paper, fabric, grass, grain, coal, and rubbish.

• Keep storage and work areas free ofdebris.

• Do not leave portable heaters unattended.

• Do not block the sprinkler system withstacked goods.

• Use care when welding and cutting.

Class B – Flammable liquids and vapours suchas gasoline, oil, paint, varnish, solvent, grease,wax, fat, and oil.

• Store flammable liquids in tightly closedapproved containers.

• Keep these materials away from sparks.

• Spray cans, paint cans, and othercontainers for flammable liquids must bedisposed of as hazardous materials.

• Follow all safety procedures for gascylinders.

• Clean up flammable liquid spills promptly.

• Put rags used to clean up spills (andother oily rags) in airtight containersand dispose of them daily.

• Do not refuel gasoline-poweredequipment in confined spaces orwhile the equipment is hot.

• Use non-flammable solventswhenever possible.

• Do not weld near flammable liquids.

• Do not turn on electric switches oroperate electrical equipment if thereare vapours or unidentifiable odours.An electric spark can cause anexplosion.

• Check the MSDS to find the flash point —the temperature at which vapours willcatch fire.

Class C – Electrical equipment such as motors,transformers, switch boxes generators, andwiring.

• Do not overload fuses, circuits, motors, oroutlets.

• Do not install a fuse rated higher than thatspecified for the circuit.

• Clean and lubricate motors regularly.

• Inspect electrical equipment for old wiring,damaged insulation, and looseconnections.

• Install a wire guard around utility lights.

• Investigate strange smells around electricalequipment or appliances.

Class D – Combustible metals such asmagnesium, titanium, zirconium, sodium,lithium, and potassium (these are rarely aproblem for sheet metal workers)

ABC

D

Class “A”Extinguishers

For fires in ordinary combustiblematerials such as wood, paper, andtextiles where a quenching, coolingeffect is required.

Class “B”Extinguishers

For flammable liquid and gas fires, suchas oil, gasoline, paint and grease whereoxygen exclusion or flame interruption isessential.

Class “C”Extinguishers

For fires involving electrical wiring andequipment where the non-conductivity ofthe extinguishing agent is crucial.

This type of extinguisher should bepresent wherever functional testing andsystem energizing take place.

Class “D”Extinguishers

For fires in combustible metals such assodium, magnesium, and potassium.

How to Use the Extinguisher

Aim the extinguisher at the base of the fire to extinguishthe flames at their source.Figure 11.2

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• Use MSDSs to determine the hazards andstorage requirements of combustiblemetals.

• Place metal shavings in proper containers.

Fire extinguishers

Check the fire extinguisher label to see whichclass(es) of fires it can be used for (Figure 11.2).Some fire extinguishers can be used for morethan one class of fire. The label also coversoperating instructions and recharge procedures,first aid information, and general guidelines.

• Let your employer know if an extinguisheris damaged.

• One component of fire-extinguishertraining is the PASS procedure (Figure11.3):

– Pull the pin and break the seal.

– Aim the nozzle at the base of theflame.

– Squeeze the lever while holding theextinguisher upright.

– Sweep the nozzle from side to side.

• Do not try to fight a fire if

– the fire is spreading rapidly

– the fire is blocking the path of escape

– adequate fire-fighting equipment is notavailable.

P Pull the pin

A Aim the nozzle

S Squeeze the lever

S Sweep the nozzleFigure 11.3 Learn the PASS procedure for using a fire extinguisher.

Evacuation procedures

To evacuate a burning building safely:

• Sound the alarm.

• Turn off electrical equipment (if safe to doso).

• Close windows that do not lead to fireescape routes.

• Close the door after everyone has left aroom. Do not lock the door.

• Notify anyone who may not have heardthe alarm.

• Leave the area quickly. Do not panic.

• Leave by an appropriate route. More firedeaths are caused by smoke and gasesthan by flames. Follow these rules:

– Feel a door to see if it is hot beforeyou open it.

– Stay low to avoid smoke and toxicgases; crawl if necessary.

– Cover your nose and mouth with adamp cloth.

– Use stairs instead of elevators.

– Report to an assigned, pre-determinedlocation outside the building.

• If you have no safe escape route:

– Seal cracks around doors, windows,and vents with wet towels.

– If a telephone is available, tell the firedepartment your exact location.

– Wait by the door or a window for firedepartment to arrive.

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Shop SafetySheet metal shops do not fall under theConstruction Regulation (O. Reg. 213/91).They are governed by the regulation forIndustrial Establishments (Reg. 851). Forresponsibilities of workplace parties andprocedures to follow, refer to theOccupational Health and Safety Act andRegulations for Industrial Establishments.

SAFETY BASICSAccidents are waiting to happen in a sheetmetal shop. The sharp edges of sheet metal canscratch you, gouge you, and even amputatefingers and hands. Equipment can easily crushyour hands or blind you if you don’t use itcarefully.

By following some simple safety rules, you cankeep yourself and your fellow workers safefrom most hazards.

• Watch your step! The shop has manythings you can trip on.

• Pick up scrap or other materials on thefloor before you or someone else tripsover it.

• Wear goggles or safety glasses as needed,especially around welding, grinding, orpolishing operations.

• Watch out for heavy moving carts. Don’tlet yourself get caught between a cart anda solid obstacle, such as a wall or piece ofmachinery.

• Don’t try to carry more than you can safelyhandle. Get help. You can avoid injury toyourself and to others as well. A largepiece of sheet metal that you drop couldinjure someone.

• Don’t try to catch falling materials.

• Don’t distract someone who is operatingmachinery. Don’t let yourself be distracted.

• Don’t wear loose clothes or jewelry on thejob. These items can easily get caught inpower equipment. Long hair should betied up or tucked under a cap.

SPECIFIC GUIDELINESAccess

Keep permanent aisles and passageways clean,clear, and in good repair. Aisles andpassageways should be marked by paintedlines, curbings, or other methods to distinguishthem from work areas.

Permanent roadways, walkways, and materialstorage areas in yards should be maintained freeof dangerous depressions, obstructions, anddebris.

Work areas

Permanent floors and platforms should be freeof dangerous projections or obstructions andshould be kept in good repair and reasonablyfree from oil, grease, or water. On slipperysurfaces, workers should be protected againstslipping by mats, grates, cleats, or equivalentmeasures. Floors and platforms should beconstructed and maintained to support the loadsto which they are subjected.

Storage

The maximum weight of materials stored ontemporary floors or load-carrying platformsshould not exceed their safe carrying capacity.

Wherever stored, material should be piled,stacked, or racked in a manner to prevent itfrom tipping, falling, collapsing, rolling, orspreading. Racks, bins, planks, sleepers, bars,strips, blocks, and sheets should be used wherenecessary to make the piles stable.

Sanitation

Safety devices, including protective clothing,should not be interchanged among employees

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unless the equipment is properly cleaned.Exception: safety devices worn over shoes orouter clothing, no part of which contacts theskin of the wearer, such as metal foot guards.

Toilets

Every place of employment should be providedwith a sufficient number of conveniently locatedwater closets for the use of employees. Toiletsshould be clean and provided with an adequatesupply of toilet paper.

Compressed air or gases

Compressed air or other gases should not beused to blow dirt, chips, or dust from clothingor protective equipment while it is being worn.

Compressed air or gases should not be used toempty containers of liquids where the pressureexceeds the safe working pressure of thecontainer.

The use of compressed air for cleaning machinesand tools should be controlled—or proper safetydevices or safeguards should be applied—toreduce or eliminate hazards to the eyes.

Flying particles or substances

Wherever the danger of injury from flyingparticles or substances cannot be eliminated bythe use of personal safety devices andsafeguards, then adequate shields, screens, chipguards, or enclosures should be provided. Theseshould be designed and constructed to deflector confine the flying particles or substances andthereby prevent injury to employees.

MACHINES AND EQUIPMENT — GENERALManagement must ensure

• that all supporting structures, foundations,and fastenings for machines andequipment are designed, constructed, andmaintained to support expected loadssafely and without dangerous vibration

• that equipment is of adequate design forexpected use

• that equipment isnot operated athazardous speeds,loads, or stresses

• that defective partsare repaired orreplaced

• that a record ofrepairs, replacements, and othermaintenance is kept for each machine andpiece of equipment

• that all machine operators and assistantsare properly trained in safe use of theequipment and conduct regularmaintenance checks

• that fire extinguishers are provided asrequired

• that personal protective equipment (PPE)to be used with machines and equipmentis available

• that periodic safety talks or meetings areheld for employees.

Operators must

• never eliminate or bypass any safetydevices installed on the machine

• wear all PPE required by law and by theemployer

• keep work areas clean, safe, anduncluttered

• report any defect or malfunctionimmediately

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• never operate equipment or machinery inexcess of capacity

• be certain that equipment is properlygrounded where required

• avoid becoming careless, overconfident, orcaught up in the rhythm of the operationat the expense of health and safety

• never remove warning plates or operator’sinstructions from machines and equipment

• never store anything in machines orequipment that may fall out into the workarea

• never stand or sit on anything whilefeeding machines that could cause you tofall, slip, or stumble into bending area

• never tie down or otherwise disarmactuating devices to provide continuousoperation.

MACHINES AND EQUIPMENT —LOCATIONPermanently installed machines should bearranged or guarded so that

• they and their operators cannot be struckby moving equipment and material

• product, waste stock, or material beingworked or processed will not endangeremployees.

Skirt guards or similar devices should be usedwherever there are shear hazards between pitedges and the machinery or equipment installedand operating there.

CLEANING, REPAIRING AND ADJUSTINGPRIME MOVERS1)Use extended swabs, brushes, scrapers,and other tools where machinery cannotbe locked or blocked against movementduring cleaning, adjusting, and otheroperations.

2)Every machine driven by a prime moverand equipped with lockable controls, orreadily adaptable to lockable controls,should be locked in the OFF positionduring repair work.

3)Machines or prime movers not equippedwith lockable controls, or readily adaptableto lockable controls, should bedisconnected from the power source toprevent inadvertent start-up and operation.

4) In all cases, warning signs or tags withadequate wording should be placed on thecontrols of machines and prime moversduring repair work.

5)The employer must provide enough signs,padlocks, and similar devices for useduring emergency repairs. Signs must beequipped with a means of attachment thatcan be secured to the control.

MACHINE GUARDSGuards are required on any shop equipmentthat could cause injury or accident.

• Never remove a guard unless it isnecessary to adjust the machine.

• If you must remove a guard, never do sowhile the machine is running.

• Never start a machine if the guards are notin place.

• Protect the treadle on foot-controlledpresses. Use a guard designed to preventaccidental tripping or a specially designedtreadle.

• Make sure that openings in treadle guardsaren’t more than twice the width of thefoot. The only exception is for the longbar that extends across the machine.

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SHOP EQUIPMENT — SPECIFIC TYPES

Press Brakes

Power press brake – This is a power-drivenmachine fitted with rams or dies for the purposeof blanking, trimming, drawing, punching,stamping, forming, or assembling cold materials.

• Post a sign on the front of every powerbrake. “Warning: Never place your handsor any part of your body under the ramwithin the point of operation.”

• Many operations performed on powerbrakes in sheet metal shops allow the useof point-of-operation guards and/or two-handed actuators. Use them wheneverpossible.

• Where no point-of-operation guard (two-handed actuating devices, presence-sensingdevices, etc.) can be used, it is still yourresponsibility to see that safe operatingprocedures are followed.

• Presence-sensing guards are available forpower brake operations.

• Where thenature of theworkprevents theapplication ofguards, usehand toolsappropriateto the job.

• Keep a safedistance from the point of power brakeoperation.

• Never place fingers, hands, arms, elbows,head, or feet in the dangerous bendingarea or near any moving part.

• Guards and area obstructions should beplaced over various power brakecomponents such a flywheels, gears,

sprockets and chain belts, or other movingparts.

• Always use safety tools, fixtures, andsupporting devices for loading andunloading.

Hand brake – This is a machine actuated byhand power only. It is used for formingmaterials.

• Take precautions to prevent injury tohands and fingers.

• When more thanone person isworking on thisequipment,coordinate theoperation. Makesure your partner’shands are clearbeforeclamping thehandles.

• Never put yourhand betweenthe upper leafand the bending leaf.

• Place safety barriers to limit access aroundcounterbalance weights.

Bar folder – This machine is actuated by handpower only and used for forming materials.Take precautions to prevent injury to hands andfingers.

Shears

Power shear –This is a power-driven machineused to shearplate and sheetmetal.

• Post a signon every

Power Press Brake

Hand Brake

Bar Folder

Power Shear

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power shear. “Warning: Do not extendfingers or hands beyond guard or barrier.”

• Power shears must be equipped withguards to keep hands and fingers out ofthe point of operation and the materialhold-down.

• Place personnel barriers with warningsigns at the rear of the machine to preventanyone from entering this area duringoperation.

• Never place fingers, hands, arms, elbows,head, or feet in the dangerous cutting areaor near any moving part.

Foot shear – This is a manually poweredmachine.

• Never try to hold narrow pieces of materialat the front ofthe shear.

• Do not holdshort pieces ofmetal in back ofthe blade.

• Keep your footout from underthe treadle soyou don’t stepon your own toes.

• No one should stand behind the shearunless necessary. A worker behind theshear should

– know when the shear is coming down

– stand clear of the shearmechanism and gauge bar

– watch out for the shear metalas it falls.

Beverly shear – This is hand-operated equipment used to cut ornotch light gauge metal. Takeprecautions to prevent injury tohands and fingers.

Forming Rolls

Power rolls – These are power-drivenmachines used to form round shapes of sheetmetal.

• The feed side of the rolls should beprotected with a fixed or self-adjustingbarrier to prevent the operator’s fingersfrom getting caught between the rolls orbetween the guard and the rolls. Thecontrol device should be of the constant-contact type, located to keep the operatorout of danger.

• The prime mover should be equipped withan effective brake. Across the front of therolls at knee height, a control bar, lever, orother device should be installed. Whenactivated, this device should stop themotor and apply the brake.

• Never wear gloves or loose clothingaround a power roll.

BeverlyShear

Foot Shear

Power Roll

TurningMachine

Easy Edger

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SHEET METAL

Hand rolls – These are hand-operated machines used to form andshape sheet metal. Operators shouldnot wear gloves or loose clothingand should take precautions toavoid injury to fingers and hands.

Cutting Equipment

Plasma cutter

• Ensure the area is properly exhausted.

• Take care when lifting to load the table.

• Ensure that all scrap pieces are removedbefore starting a new operation.

• Shield the cutting head.

• Wear gloves when loading and removingmaterial.

Laser cutter




• Shield the cutting head.


Water cutter





• Keep hands well clear of the water jet.

• Do not put hands in waste water.

Slitter – This is a power-driven machine usedto cut strips of sheet metal. When you run metalthrough the slitter, don’t let the metal slidethrough your hands.

Laser Cutter

Water Cutter

Slitter

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SHEET METAL

Saws

Cut-off saw – This device is a powered circularsaw that normally uses a friction cut-off wheel.It comes in both stationary and portable models.

Band saw – This is a power-operated saw thatuses a continuous circular band blade forcutting.

Power hack saw – This device is powered,base-mounted, and usually self-oiling to easecutting.

• Before using, make sure that

– all guards are in place

– blade travels true

– guard comes to within 1/4" of metalbeing cut

– tension control device is properly set.

• Never load stock while the blade isoperating.

• Always support long and heavy stock infront of and behind the saw.

• Never attempt to dislodge or move stockwhile the blade is operating.

• Always wear eye protection.

• Always hold the workpiece firmly againstthe table.

• Do not remove jammed cut-off pieces untilthe blade has stopped.

• Never wear loose clothing and gloveswhile operating the saw.

Ironworker –This poweredmachine is used tocut, punch, andform steel angle,channel, and barstock of all shapes.

• Take care toprevent injuryto hands andfingers.

• Always wear safety goggles.

• Make sure that punch and die are aligned.

Other Equipment

Power roll-former– A power rollformeris used to form locksand seams on sheetmetal.

• When you runmetal throughthe former,don’t let themetal slidethrough yourhands. Sharp edges and fishhooks cancause deep punctures.

Spiral pipe machine – This powered machineis used to form spiral duct.

• Take precautions against flying debris.

• Wear safety goggles and leather gloves.

PortableChop Saw

StationaryCut-off Saw

BandSaw

Power Hack Saw

Power Roll-Former

Ironworker

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SHEET METAL

Decoiling machine – This powered machineuncoils steel coils to produce sheets.

• Never stand under or in front of a coilwhile it is being moved.

• Do not stand in front or in back of a coilwhile aligning the coil roller onto the take-off holder.

• Hold the coil band firmly so that it cannotsnap out and cut you.

• Wear leather gloves.

Drill press – a power drill is bolted to a benchand the chuck is lowered by an operating wheelor lever.

• Centre-punch the work to keep the bit inplace when starting to drill.

• Remove chuck key beforedrilling.

• Always where safetygoggles.

• Never wear gloves whendrilling.

• Securely clamp short piecesof material before drilling.

Stationary grinders – A powered machineused to grind or de-burr metal components asrequired.

• Secure to prevent dangerous vibration.Mount on substantial floors, benches,foundations, orother solidstructures.

• Equip grinderwith adjustablework rest ofrigidconstruction.Adjust workclose to wheelwith maximumclearance of1/8".

• Always wear hearing protection, gloves,and goggles.

• Provide abrasive wheels with protectivehoods designed and constructed to protectemployees against flying fragments from aburst wheel.

• Never use defective wheels.

• Only use wheels clearly marked withspeed limitations.

• Dress wheels on a regular basis.

Spot welders – These devices use electricalresistance to generate theheat necessary to spot-weldmaterial. Always weargloves, face shield, andclothing that will protectyou from sparks. Makeevery effort to screenoperations from otherworkers.

Pneumatic riveter –This air-driven tool isused to draw rivets.

Spiral PipeMachine

DecoilingMachine

StationaryGrinder

DrillPress

Hand-controlledSpot Welder

StationarySpot Welder

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SHEET METAL

• Take care to prevent injury to hands andfingers.

• Always wear safety goggles.

• Ensure that rivet is properly set.

Paint shop – This is a separate building ordesignated area of an occupied building usedspecifically for painting.

• Ensure that paint shop is well ventilated.

• Wear adequate and proper clothing,respirators, and eye protection.

• Secure and check all couplings.

• Ensure that paint operations are a safedistance away from sparks or other sourcesof ignition.

Power forklifts – The operator must becertified.

Manual forklifts – With hand-operated palletlifters, make sure the load is centred and thefloor free of debris.

Overhead Cranes

Overhead cranes are generally used for indoorhoisting. They are often installed for specific

repetitive tasks. The capacity of these cranes iswide ranging. Contractors may use them forspecialized hoisting operations such asremoving or installing major plant equipment.

Safe operation of overhead cranes requiresoperators to have the knowledge andcompetence to employ safe rigging practices.The rigger must rig the load to ensure itsstability when lifted.

Power drive runway or monorail cranes areused to move heavy materials and to holdmaterials during the fabrication process. All suchequipment must be maintained in good workingorder and inspected annually to ensure that allcomponents operate properly and show nosigns of undue wear or damage.

All overhead cranes must be inspected annuallyby a competent person.

Ensure that the load is free to move. If itbecomes stuck and the crane begins orcontinues to lift, the crane may reach its fullcapacity quickly. There may be little or nowarning of this condition and riggingcomponents may fail.

PneumaticRiveter

Paint Shop

Paint Shop

PowerForklift

ManualForklift

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SHEET METAL

• The operator must be a competent person.

• Ensure that the sound alarm worksproperly.

• Before use, ensure that the crane issuitable for the planned hoisting task(s).Confirm it has appropriate travel, lift, andcapacity.

• Inspect the crane before use. Check fordamage, wear, and proper operation of allfunctions.

• Confirm the load weight. Check thecapacity of all equipment includinghardware, rope, and slings. Do not exceedthese capacities.

• Select the right sling for each lift. Beforeuse, inspect slings and other rigginghardware for wear, stretch, or otherdamage. Do not use damaged or defectiveslings. Use softeners around sharp corners.Do not splice broken slings.

• When communicating with a craneoperator, use clear agreed-upon signals.Except for the stop signal, the craneoperator should follow instructions onlyfrom a designated signaller. Where a wired

or remote controller is used, the operatorshould become familiar with all of itsfunctions before lifting the load.

• Warn all people in the lift area beforestarting the lift. Ensure that the path of theload is clear of persons and obstructions.Do not lift a load over anyone.

• Centre the crane hoist over the load beforehoisting to prevent the load from swinging.

• Slide the sling fully onto the hoisting hookand ensure the safety catch is fully closed.Do not load the hook tip or hammer asling into place.

• Secure unused sling legs. Do not dragslings or leave loose material on a loadbeing hoisted.

• Keep hands and fingers from beingtrapped or pinched between the sling andthe load when the slack is taken out of thesling. Step away before the lift is made.

• Move the load and controls smoothly.Minimize load swing.

• Walk ahead of the load during travel andwarn people to keep clear. Use a tag lineto prevent rotation or uncontrollablemotion. Raise the load only as high asnecessary to clear objects. Do not ride onthe hook or the load.

• Set the load down on blocking, neverdirectly on a sling. Do not pull or push theload out from under the hoist.

• Do not leave the load or the craneunattended while a load is suspended.

• Where crane operation by other personnelmust be restricted, employ tag and lockoutprocedures.

• Store slings off the floor in a clean drylocation on hooks or racks. Do not leaveslings, accessories or blocking lying on thefloor.

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SHEET METAL

HAND AND POWER TOOLSChainsaws

Each year in Ontario, construction workersare injured while using chainsaws. Generallythe injuries result from two types ofaccidents:

1) the operator makes accidental contactwith the revolving chain

2) the operator is struck by the object beingcut, usually a tree or heavy limb.

Many of these injuries are serious.

While the chainsaw is relatively easy tooperate, it can be lethal. As with all high-speed cutting tools, it demands the fullattention of even the trained andexperienced operator.

Requirements

Chainsaws can be powered by electric motors(Figure 155) or gasoline engines (Figure 156).

Both saws are designed to provide fast cuttingaction with a minimum of binding in the cut,even though wood may be sap-filled or wet.Both afford about the same performance interms of horsepower and they are equippedwith similar controls and safety devices.

Regulations require thatchainsaws used in constructionmust be equipped with achain brake. Make sure thatthe saw is equipped with achain brake mechanism, andnot simply a hand guard,which is similar in appearance.

Regulations require thatchainsaws used in constructionmust be equipped with “anti-kickback” chains. Called safetychains (Figure 157) by themanufacturers, these chainsincorporate design features

intended to minimize kickback whilemaintaining cutting performance.

Protective clothing and equipment

• Eye protection in the form of plasticgoggles is recommended. A faceshieldattached to the hard hat will not providethe total eye protection of close-fittinggoggles.

• Leather gloves offer a good grip on thesaw, protect the hands, and absorb somevibration. Gloves with ballistic nylonreinforcement on the back of the hand arerecommended.

• Since most chainsaws develop a highdecibel rating (between 95 and 115 dBAdepending on age and condition),adequate hearing protection must be worn,especially during prolonged exposure.

• Trousers or chaps with sewn-in ballisticnylon pads provide excellent protection,particularly for the worker who regularlyuses a chainsaw.

Kickback

Kickback describes the violent motion of thesaw that can result when a rotating chain isunexpectedly interrupted. The cutting chain’sforward movement is halted and energy is

Front HandleFront Hand Guard

(activates chain brake)

Guide Bar

Chain

Drive Sprocket

Rear Handleand Guard

Scabbard-TypeChain Guard

TriggerLock

Throttle TriggerFuel CapFigure 156

Gasoline Chainsaws

Figure 157Safety ChainDrive Tang

Low-Profile Cutter

Guard Link

DepthGauge

Figure 155 — Electric Chainsaw

Figure 158 — Kickback Zone

46 – 25

SHEET METAL

transferred to the saw, throwing it back from thecut toward the operator.

The most common and probably most violentkickback occurs when contact is made in the“kickback zone” (Figure 158).

Contact in this zone makes the chain bunch upand try to climb out of the track. This mostoften happens when the saw tip makes contactwith something beyond the cutting area such asa tree branch, log, or the ground.

To minimize the risk of kickback

- use a low-profile safety chain

- run the saw at high rpm when cutting

- sharpen the chain to correct specifications

- set depth gauges to manufacturers’ settings

- maintain correct chain tension

- hold the saw securely with both hands

- don’t operate the saw when you are tired

- know where the bar tip is at all times

- don’t allow the cut to close on the saw

- make sure the chain brake is functioning.

Starting

When starting, hold the saw firmly on theground or other level support with the chainpointing away from your body and nearby

obstructions. Use a quick, sharp motion on thestarter pull (Figure 159). Never “drop start” thesaw. This leaves only one hand to control arunning saw and has resulted in leg cuts. Usethe proper grip (Figure 160).

Site hazards

• Take extra care when making pocket cuts(Figure 161). Start the cut with theunderside of the chain tip, then work thesaw down and back to avoid contact withthe kickback zone. Consider an alternativesuch as a sabre saw.

• Be particularly careful to avoid contactwith nails, piping, and other metallicobjects.

Maintenance

Well-maintained cutting components areessential for safe operation. A dull or improperlyfiled chain will increase the risk of kickback.

• Inspect and maintain your saw accordingto the manufacturer's recommendationsregarding chain tension, wear,replacement, etc. Check for excessivechain wear and replace chain whenrequired. Worn chains may break!

Saw withStep-In Handle

Figure 159 — Correct Starting Position

Note thumbposition

Figure 160 — Proper Grip

Note thumbposition

Before moving from placeto place, shut off the sawand walk with the guide barpointed backwards. A tripor a stumble with a runningsaw can cause seriousinjury.

RIGHT WRONGFigure 161 — Pocket Cuts

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SHEET METAL

• Select the proper size files for sharpeningthe chain. Two files are necessary:

1) a flat file for adjusting depth gauge

2) a round file of uniform diameter forsharpening cutters and maintainingdrive links.

• You must choose the correct round file foryour chain to avoid damaging the cutters.Consult the owner's manual or the supplierto be sure of file size.

• A round file used in combination with afile holder or, better yet, a precision filingguide will give the best results (Figure162).

Adjusting chain tension

• Follow the manufacturer's instructions onchain tension.

• In general, the chain should move easilyaround the bar by hand without showingnoticeable sag at the bottom (Figure 163).

• Be generous with chain lubricating oil. It isalmost impossible to use too much. Mostlate model saws have automatic oilers. Butoperators must still remember to fillthe chain-oil reservoir.

Bench Stakes

• Lift safely to place the stake on the table.

• Make sure that stake is secure.

Slating Hammer

Safe practices withslating hammers aresimilar to those withother hammers (see thechapter on Hand andPower Tools in thismanual).

Precision Filing GuideChain

File HolderCheck the owner's manualfor recommended filingangle

Figure 162 — Sharpening Tools

RoundFile

Too Tight

Too Loose

Correct Tension

1/8 inch

Figure 163 — No Noticeable Sag

BenchStake

SlatingHammer

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SHEET METAL

Riveters

Lazy tong riveters and pop riveters (hand andair) are used to insert fasteners (rivets) betweentwo or more pieces of material to hold themtogether. Pop riveters are generally used forlighter-gauge material while lazy tongs are usedfor heavier-gauge material.

When using these tools, keep hands and fingersaway from hinged parts (pinch points) andareas around the rivet.

For more information on a variety of tools, seethe chapter on Hand and Power Tools in thismanual.

Hand Pop Riveter

Lazy Tong Riveter

Air Pop Riveter

Documents

Construction Multi-Trades Health and Safety Manual - 2009