Protecting Employees from the Effects of Dust Explosions and Fires in the Die Casting Industry

Protecting Employees from the Effects of Dust Explosions and

Fires in the Die Casting Industry

NADCA North American Die Casting Association

Unit 2

Enabling Objectives

Explain the significance of appropriate housekeeping practices, fugitive dust control and safe handling of fine particles of alloy metals to explosion and fire safety at the die casting plant

Combustible metal dust

After completing this section of the course students should be able to:

Implement work practices and procedures recognized as necessary for explosion and fire safety by industry and fire protection experts;

Die Casting Alloy Fires and Explosions

• Key Facts You Should Know

• Emergency Plans and Procedures

• Clothing Fires• Housekeeping• Control of Ignition

Sources• Control of

Combustible Materials

• Removal of combustible metal waste

• Inspection and Maintenance

• Fire Extinguishing Agents• Controlling Metal Fires• Fire Fighting Organization• Automatic Sprinkler

Protection

This portion of the course addresses the following topics:

Key Facts You Should Know

http://www.diecasting.org/default.htm

Key Facts You Should KnowThis section presents some key information regarding combustible metal and dust operations – the materials used in the die casting industry.

Some of this information is unusual and not widely known.

Or insert photo of typical die casting plant

Key Facts You Should KnowHealth and safety depends on:• Recognition of actual or potential hazards of

combustible metals, particularly metal dusts; • Control or removal of these hazards; and, • Training of employees on safe working

procedures.

The safe way



Important guidance on health and safety is found in NFPA 484 Standard for Combustible metals.

This presentation is based on NFPA 484

Key Facts You Should Know Everyone working with combustible die casting metals, particularly in the form of dusts and fines needs to know some key facts. Emergency response and preparedness are specially important. The following slides provide a quick review


Containers for molten metal must be cleaned and dried prior to receiving the molten material. • Metal pieces charged into liquid

molten metal must be clean and dry. • Water wet containers and charge

pieces can cause a molten metal explosion

Key Facts You Should Know Die casting metal

fires are Class D fires

• Produces an intense, extremely hot, orange or orange and white flame

• May produce a large volume of white and gray smoke


Other extinguishing materials for ordinary combustibles are not effective on this type fire.

Water applied to the fire will increase:– the rate of burning;– energy output; and,– may result in an

explosion. Carbon dioxide will have a

similar effect

Key Facts You Should Know• Dusts and fines may

cause explosions, specially in confined areas and spaces.

• Chips burn with very hot flame.

• Magnesium ingots and thick, heavy wall magnesium castings are difficult to ignite.

• Ingots and similar items are are dangerous in the heat of a fire.

Dust

Ingot

Chip


May be hot enough to– draw water from

concrete and rock,– make asphalt

paving burn in fire.Small fires may be controlled using Class D extinguishing agent.

Start video manually

Fire fighter extinguishing magnesium test fire

Burning die casting metal fires produce a great deal of heat.

Key Facts You Should Know• Small fires in die

casting metals may be controlled and separated from the oxygen in air, cease burning and cool.

• This is done by applying dry extinguishing agents to completely cover the burning materials.

Cover the burning material


Unique hazards of combustible metal dusts and fines.• Finely divided die

casting alloys can produce hydrogen and oxygen when contacted by moisture. Aluminum Fines

H2 H2H2

H2

H2

O O

O

OO

H2O

If it accumulatesBOOM!

Key Facts You Should KnowUnique hazards (cont’d) Thermite sparking may occur when there is an impact between magnesium, aluminum (or a similar light metal or alloy) and rusty iron. e.g.: • Magnesium alloy dust on

a rusty steel object that impacts a concrete floor.

• An aluminum scoop or shovel scraped along a steel deck or beam.

Rusty shovel

Reaction of magnesium and iron in

powder form


In storage areas for containers of combustible metal

Material handling equipment is needed to ease removal of a container in the event of an emergency


Stored die casting metal dusts, chips and particles that contain moisture can produce hydrogen gas.

H2 H2H2

H2H2

H2 H2H2

H2 H2H2H2 H2H2

H2

H2H2

Key Facts You Should KnowThis section presented some key information regarding combustible metal and dust operations – the materials used in the die casting industry.

Some of this information is unusual and not widely known.

Or insert photo of typical die casting plant

Key Facts You Should KnowPractice Quiz1. Stored alloy dust and chips containing moisture can

produce.A. Air.B. Argon or carbon dioxide.C. Hydrogen.

2. Burning die casting metal alloy fires are hot:A. They can drive water from concrete or destroy

asphalt paving.B.But there is usually very little to be concerned

about because of it.C.This is because ingots are so easy to ignite.

Key Facts You Should KnowPractice Quiz Cont’d

3. Water applied to a burning combustible metal fire:A.Has no effect.B. May cause an explosion.C. Is not a matter of concern.

Key Facts You Should KnowPractice Quiz1. Stored die casting alloy dust and chips that contain

moisture can produce.A. Air.B. Argon or carbon dioxide.C. Hydrogen.

2. Burning die casting metal alloy fires are hot:A. They can drive water from concrete or

destroy asphalt paving.B.But there is usually very little to be concerned

about because of it.C.This is because ingots are so easy to ignite.

Key Facts You Should KnowPractice Quiz Cont’d

3. Water applied to a burning combustible metal fire:A.Has no effect.B. May cause an explosion.C. Is not a matter of concern.

Emergency Plans and

Procedures


Emergency Plans and ProceduresThis section addresses emergency plans and procedures including emergency response and preparedness issues.

The basic concepts of evacuation and to active response are discussed.

Emergency Plans and ProceduresEvery employee

needs to know the emergency plan and procedures to be used in the event of combustible metal fires or explosions at the die casting plant.

Emergency ResponseA careful assessment (“size-up”) of the situation is important to anyone attempting to act on or suppress a combustible metal fire. • Can the fire be isolated and safely allowed

to burn out? • Small and incipient fires may be contained

using Class D extinguishing agents. • Large fires can be difficult, even impossible to

extinguish. They must be allowed to burn out.

Emergency Response• Only an organized,

trained and properly equipped fire brigade or department should attempt to respond to a large combustible metal fire.

• All others must evacuate the area.

Insert photo or tape strip of large combustible metal fire.

Emergency ResponseKnowledge and familiarity with the products involved are critical to safety, including:•The kind of materials,

e.g.:• chips, fines, dust,• light or heavy castings, • ingots; and,

•Quantity of materials involved or potentially involved in a fire.

Emergency Response

If a fire is burning in a collector or other closed container, the potential for an explosion must be considered.

Remember – dusts and fines have the potential to explode if airborne in the presence of an ignition source.

Emergency Response

• Extreme caution is necessary.

• Heat and smoke can build up more rapidly than fires in ordinary combustibles.

• Large fires are often impossible to extinguish and must be allowed to burn out.

A fire involving a large amount of product can be dangerous, specially within a building.

Chip fire out of control

Emergency ResponseIsolate the burning material as much

as possible if this can be done safely.Water in contact with molten metal

will cause hydrogen explosions and throw material about.

Emergency ResponseWater may be used with

care on products and exposures that are not involved in the combustible metal fire.

Appropriate drainage must be available to prevent water from contacting burning material.

Prevent this with water

Emergency ResponseIf the fire has been

extinguished, the temperature of burned products must be allowed to cool.

A “flare-up” may occur if the burned material is disturbed prior to complete oxidation and self extinguishment. Professional deals with

a “flare-up”

Emergency Preparedness

• Specific actions to take in the event of a combustible metals fire; and,

• Coordination of the plan between plant management and emergency responders.

A comprehensive emergency preparedness program is necessary wherever combustible metals are processed, handled, used or stored.

Safety experts have identified the need for a plan that includes:

OurBestEAPs

OurBestEAPs

OurBestEAPs

OurBestEAPs

OurBestEAPs

OurEmergency

Plan


• The location and operation of:– Electrical switches and alarms;– First-aid equipment;– Safety equipment; and,– Fire extinguishing equipment.

All employees in areas where combustible metals are handled need training regarding the following:• The hazards of their

working area;• What they need to do in

case of fire or explosion;Fire safety

cart


• How to fight incipient combustible metal fires and for isolating fires;

• Hazards of causing dust clouds;• The dangers of applying liquids to incipient

metal fires;• Safe and proper evacuation of the work area;

All employees need training regarding: (cont’d)


• Equipment operation, start-up, shut-down and how to respond to upsets;

• Need for and function of relevant fire and explosion protection systems; and,

• Details of the emergency response plan.

All employees need training regarding: (cont’d)

I’m available

ThePlan

Emergency Plans and ProceduresThis section addressed emergency plans and procedures including emergency response and preparedness issues.

The basic requirements for the ability to evacuate and to actively respond were also discussed.

Emergency Plans and ProceduresPractice Quiz1. Extinguishing a combustible metal fire usually involves

covering all the combustible metal available for burning with a suitable extinguishing agent.A. All the problems are over at that point.B. A flare-up may occur if the burned material is

disturbed.C. Most employees should be able to extinguish large

fires by this method.2. Successfully extinguishing a combustible metal fire

usually involves :A.Training and practice.B.Blind luck.C.Using the same fire extinguishing procedures used

for any other fire.

Emergency Plans and ProceduresPractice Quiz1. Extinguishing a combustible metal fire usually involves

covering all the combustible metal available for burning with a suitable extinguishing agent.A. All the problems are over at that point.B. A flare-up may occur if the burned material

is disturbed.C. Most employees should be able to extinguish large

fires by this method.2. Successfully extinguishing a combustible metal fire

usually involves :A. Training and practice.B.Blind luck.C.Using the same fire extinguishing procedures used

for any other fire.

Clothing Fires


Clothing FiresThis section discusses the basic stop, drop and roll procedure, fire blankets and safety showers. In addition, the section describes the need for:• Special flame retardant,

antistatic clothing for dusty jobs; and,

• Suitable heat resistant clothing in molten metal jobs. Flame Resistant

Cover-alls

•If your clothing catches fire, know to

•Stop;•Drop; and•Roll

to smother the flames.

• A fire blanket is very helpful

Clothing Fires

StopDropRoll

• Place fire blankets in metal dust areas.

•Deluge showers are great but must not be located in metal dust areas.

Clothing Fires

Clothing FiresAnti-static and flame retardant clothing is necessary for dusty jobs, e.g.: • bagging or loading dusts;• work with collector bags; or, • work at bag house doors or

openings. Wear cotton, not silk or wool because of their static generating properties.

Clothing FiresEmployees working with molten die

casting alloys also need flame retardant (FR) that will shed molten alloy.

Don’t wear clothing treated with “phosphate” or “ammonia cure” flame retardant often used in the iron and steel industries.

Clothing FiresThis section discussed the basic first aid procedure of stop, drop and roll, fire blankets and safety showers. In addition, the section described the need for:

• Special flame retardant, antistatic clothing for dusty jobs; and,

• Suitable heat resistant clothing in molten metal jobs.

Flame Resistant Cover-alls

Clothing FiresPractice Quiz1. It is important to wear flame retardant and anti-static

clothing (e.g.: cover-alls) while working inA. Dusty jobs like cleaning a dust collector.B. Trimming casting fins.C. Office work and computing.

2. If your clothing catches fire, it is important to:A.Run from the flames.B.Look for a fire extinguisher.C.Stop, drop and roll.

Clothing FiresPractice Quiz1. It is important to wear flame retardant and anti-static

clothing (e.g.: cover-alls) while working inA. Dusty jobs like cleaning a dust collector.B. Trimming casting fins.C. Office work and computing.

2. If your clothing catches fire, it is important to:A.Run from the flames.B.Look for a fire extinguisher.C. Stop, drop and roll.

Housekeeping


HousekeepingHousekeeping is known to be

critical to safety and the prevention of dust explosions in the die casting industry.

This section discusses preventing dangerous accumulations through systematic cleaning, some of the most hazardous areas for dust to accumulate and removal techniques.

Vacuum cleaning and collection systems are also discussed.

HousekeepingCombustible metal dust must not be allowed to accumulate on the • floor, • ledges or other

horizontal surfaces,• walls and other

vertical surfaces.Cleaning must be systematic for all parts of the building that contain dust producing equipment.

Housekeeping

The finest and most hazardous dust is located in the high places• on roof joists

and beams,• above

suspended ceilings, and

• on top of equipment.

HousekeepingInclude the following:•Roof members and structures;

•Pipes;•Conduits, similar items;•Machines and equipment;

•Dust on Ceilings, floors and walls. Dust from vertical surfaces can be most easily be dislodged.

HousekeepingA competent person must assess the entire cleaning process to make sure that cleaning methods minimize the probability of a fire or explosion.

Way too dirty

Housekeeping

Cleaning must be planned, systematic, effective and safely done. Remove all chips and powder sweepings to an identified safe area for storage and/or disposal.

Ready to cleanJust a little dust

Housekeeping

PlantAir

Never generate a cloud of small particles in the air.Do not blow down metal dust deposits.It generates dust clouds.It causes the smallest, most hazardous particles be deposited on ledges, joists and other high places – an accumulation is an explosion hazard.

Housekeeping

–All equipment must be shut down;–Any ignition sources are to be removed or

eliminated;–Collect as much dust as possible by vacuum;–In general, low pressure inert gas is to be used to

blow out the dust; and –Provide inert gas and air outlets with non-

matching fittings to prevent an interchange of gases.

If it is not possible to clean tiny particles any other way (e.g.: a narrow channel on a piece of equipment needs cleaning) an inert or other non-reactive gas stream might be used. Implement careful safety precautions:

HousekeepingFor fine combustible dust use •a natural fiber brush•a spark resistant scoop or shovel.

Gently sweep the particles down. Use vacuum cleaning equipment only after removing bulk materials with a brush and scoop

Spark Resistant

HousekeepingFires or explosions

often occur when dry collection systems are used to collect magnesium dusts.

If a dry collection system is used, it must be:– Located outside; – Safely away from

buildings or people;

– At least 50 ft clearance is required.

Housekeeping• Any bag system must

be of the anti-static type with ground wires.

• Pulse type cleaning arrangements are preferred.

• An alarm system that monitors pressure drop and temperature should be used.

• A wet collection system is preferred and considered much safer. Bag House

Pulse Jet Cleaning

Housekeeping

Portable vacuum cleaners have been the source of fires.

Only those units labeled as appropriate for combustible metal dust areas are to be used.

HAZ LOC

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HousekeepingRemember, Inside the vacuum cleaners and systems, dust particles are•concentrated into a small space •contacting each other•moving at high speed through the air

• rubbing against the molecules of the air, duct work and equipment.

Static electricity generated as a result may be energetic enough to be an ignition source

Housekeeping

Improvised venturi vacuum

This improvised vacuum is not approved for combustible dust of any kind. • It deposits fine

particles in an oxygen rich layer on the combustible bag material.

• This could easily result in a flash fire or explosion.

I need special analysis and

review

To handle combustible metal dust, special engineering analysis and review of the vacuum systems are necessary.

Housekeeping

Housekeeping

Housekeeping

Keep incompatible materials separated.

Dross

Chips

Housekeeping

Make sure that:• supplies are

stored in order

• aisles are wide enough and not obstructed.

HousekeepingIn die casting shops, it is acceptable for combustible metal waste sweepings to contain small amounts of ordinary combustible materials.

HousekeepingConduct frequent

inspections, as often as needed.•Make sure there is no accumulation of combustible metal, chips, powder or dust.

•These materials are to be cleaned on a daily basis and not allowed to accumulate.

Housekeeping

Making and retaining records relating to the housekeeping inspections is important.

Potential ignition sources of equipment that must operate during the cleaning program must be identified.

Action must be taken to isolate, eliminate or minimize any identified hazards.

HousekeepingHousekeeping is known to be

critical to explosion prevention in the die casting industry.

Preventing dangerous accumulations through systematic cleaning, areas where dust to accumulate and removal techniques were discussed. The use

Vacuum cleaning and collection systems are also discussed.

HousekeepingPractice Quiz1. It is important to clean dust deposits from ledges,

beams and other areas high up in the work room. Why?A. Better clean than sorry.B. The finest and most easily dislodged dust

particles may be deposited there.C. The heaviest and most massive particles found

there provide the most fuel for an explosion.2. The least dangerous methods of cleaning

hazardous dust include:A.Blowing down the dust with compressed air.B.Use of ordinary steel dust pans.C.Gently sweeping and vacuuming the dust.

HousekeepingPractice Quiz3. To assure safety, the vacuum cleaner used to clean

up combustible metal dust:A. Can be a typical shop or domestic vacuum.B. Must be of the approved type for the

combustible dust at the plant.C. Can be fabricated from simple materials found at

the plant.

HousekeepingPractice Quiz1. It is important to clean dust deposits from ledges,

beams and other areas high up in the work room. Why?A. Better clean than sorry.B. The finest and most easily dislodged dust

particles may be deposited there.C. The heaviest and most massive particles found

there provide the most fuel for an explosion.2. The least dangerous methods of cleaning

hazardous dust include:A.Blowing down the dust with compressed air.B.Use of ordinary steel dust pans.C. Gently sweeping and vacuuming the

dust.

HousekeepingPractice Quiz3. To assure safety, the vacuum cleaner used to clean

up combustible metal dust:A. Can be a typical shop or domestic vacuum.B. Must be of the approved type for the

combustible dust at the plant.C. Can be fabricated from simple materials found at

the plant.

Controlof

Ignition Sources


Control of Ignition Sources

• Hot work; • Smoking;• Sparking tools and

equipment used around metal dust;

• Static electricity; and,

• Friction and bearings.

This section identifies some of the ignition sources that must be controlled at die casting facilities. Recognized prevention techniques are discussed. The following are included:

Control of Ignition Sources – Hot Work

NFPA 484 defines Hot Work

• Work involving burning, spark producing, welding or similar operations capable of producing fires or explosions.


Use of cutting torches to dismantle dust collectors is extremely hazardous if they are not free of combustible dust.

This practice is associated with fires and explosions and has frequently been cited and fined by OSHA.


Prevent explosions caused by Hot Work

Comply with NFPA 51B regarding fire prevention during welding, cutting and other hot work.

NFPA 51BHot Work Fire Prevention


Prevent explosions caused by Hot Work OSHA has very similar rules

and safe practices identified in the regulations as 29 CFR 1910.252 regarding welding, cutting, and brazing.

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A hot work permit system must be established and used in any area containing combustible metals or combustible metal turnings, dust and fines. This includes all:• Production;• Storage;• Handling and processing; or,• Disposal areas.

Hot work procedures that are approved by qualified persons, must be used.

•Relocate•Clean •Cover •Protect•Authorize•Inspect•Watch

Adapted from...NFPA 51B - Cutting and Welding Processes( Front)BASIC PERMITFOR CUTTING AND WELDINGWITH PORTABLE GAS OR ARC EQUIPMENTDate...................................................................................................................Building.............................................................................................................Dept..................................................................Floor........................................Work to be done.........................................................................................................................................................................................................................SPECIAL PRECAUTIONS..........................................................................................Is fire watch required?.....................................................................................The location where this work is to be done has been examined, necessary precautions taken, and permission is granted for this work. (See other side)Permit expires..................................................................................................

Signed...................................................................................(Individual responsible forauthorizing welding and cutting)

Time started.................................Complete.....................................................======================================================FINAL CHECK‑UPWork area and all adjacent areas to which sparks and heat might have spread (including floors above and below and on opposite sides of walls) were inspected 30 minutes after the work was completed and were found fire safe.

Signed ....................................................................(Supervisor or Fire Watcher)

(Basic Hot Work Permit - Page 2 )ATTENTIONBefore approving any cutting and welding permit, the fire safety supervisor or his appointee shall inspect the work area and confirm that precautions have been taken to prevent fire in accordance with NFPA 51 B. PRECAUTIONSSprinklers in serviceCutting and welding equipment in good repairWITHIN 35 FT OF WORKFloors swept clean of combustiblesCombustible floors thoroughly covered with dry sand or suitable shieldsCOMBUSTIBLE MATERIAL OR FLAMMABLE LIQUIDSCombustibles and flammable liquids protected with covers, guards

or metal shieldsAll wall and floor openings coveredCovers suspended beneath work to collect sparks

(Basic Hot Work Permit – Page 2 Cont’d)WORK ON WALLS OR CEILINGSConstruction noncombustible and without combustible coveringCombustibles moved away from opposite side of wallWORK ON ENCLOSED EQUIPMENT(Tanks, containers, ducts, dust collectors, etc.)Equipment cleaned of all combustiblesContainers purged of flammable vaporsFIRE WATCHTo be provided during and 30 minutes after operationSupplied with extinguisher and small hoseTrained in use of equipment and in sounding fire alarmFINAL CHECK‑UPTo be made 30 minutes after completion of any operation unless fire watch is provided.

Signed .....................................................

(Supervisor)


Before any welding, cutting, open flame or other hot work is performed, the area must be cleaned. Remove:• Combustible metals; • Combustible metal

dust;• Powder; or,• Fines.


A hot work permit is not required for any hot work processes that are a routine part of the production process.

This work must be done in a safe area as demonstrated by a hazard analysis.

Welding shop

Control of Ignition Sources - Smoking

• At die casting plants, smoking is only allowed in designated safe areas.

• When allowed in any area of the plant, no smoking signs are posted.

• Where smoking is prohibited in all areas, it may be a good idea to post no smoking signs anyway.

Smoking may be an ignition source for a disastrous explosion or fire.

Control of Ignition Sources – Spark Resistant Tools

• They are made from materials that will not generate impact sparks when they are used.

• Standards for these tools are listed in Air Movement Control Association (AMCA) Standard No. 99-1408-86.

•Risks of ignition by equipment and tools must be assessed in combustible metal areas

Use spark resistant tools when making repairs or adjustments in areas where combustible metals cannot be moved away.

Spark Resistant

Control of Ignition Sources – Spark Resistant Tools

Aluminum and magnesium are not non-sparking material where they can strike or contact rusted iron or steel.This contact can generate a spark, known as a thermite reaction.

Aluminum scoop

Control of Ignition Sources – Static Electricity

Prevent accumulations of electrostatic energy. Bond and ground:

• The building structure;• All fixed equipment; and,• Equipment that may be

moved, including tools made of metal.

Failure to do this has been frequently cited and fined by OSHA.

Bonding and grounding to a

good earth ground is required.


Bearings and the belting of drive systems and conveyors are to be grounded. Belts must be •anti-static and •conductive type.

SightPort

Glass


If non-conductive equipment components create discontinuity to ground,

•Suitable bonding jumpers must be used to bridge any gaps.

•The connecting wires must be verified as conductive..

Duct sections bonded and grounded

Control of Ignition Sources – Friction and Bearings

Install and maintain equipment correctly to minimize the possibility of friction sparks.

Control of Ignition Sources - Friction and Bearings

Prevent rubbing and frictional heating of Bearings and other equipment by proper installation. • Appropriate clearances

are needed.• This type of heating is

often a source of ignition

SHAFTBUSHING

Sealed or shielded bearings look like

this

Control of Ignition Sources - Friction and Bearings

Bearings are to be sealed type or shielded against dust.• Shielded bearings have

lubrication points and must be kept properly lubricated.

• Localized frictional heating of bearings may cause hot spots and a fire hazard.

Control of Ignition Sources

• Hot work; • Smoking;• Sparking tools and

equipment used around metal dust;

• Static electricity; and,

• Friction and bearings.

This section identified some of the ignition sources that must be controlled at die casting facilities. Recognized prevention techniques were discussed including the following:

Control of Ignition SourcesPractice Quiz1. Hot work at a facility is considered a source of

ignition. Work activities that are considered hot work include:A. Nesting and stacking light castings.B. Only welding torches and arc welding.C. Any activities that causes high temperature

surfaces, arcing or sparking.2. Static electricity can result in sparking that may be a

source of ignition. The prevention of static sparks usually involves:A.Hot work permits.B.Thermite sparking.C.Bonding and grounding.

Control of Ignition SourcesPractice Quiz Cont’d

3. Steel hand tools that are dropped on concrete covered with alloy metal dust may be an ignition source. This may occur because of:A.Contact or thermite sparking due to striking the

concrete.B.Gravity.C.Friction due to the tool passing through the air of

the room.

Control of Ignition SourcesPractice Quiz1. Hot work at a facility is considered a source of

ignition. Work activities that are considered hot work include:A. Nesting and stacking light castings.B. Only welding torches and arc welding.C. Any activities that causes high

temperature surfaces, arcing or sparking.2. Static electricity can result in sparking that may be a

source of ignition. The prevention of static sparks usually involves:A.Hot work permits.B.Thermite sparking.C.Bonding and grounding.

Control of Ignition SourcesPractice Quiz Cont’d

3. Steel hand tools that are dropped on concrete covered with alloy metal dust may be an ignition source. This may occur because of:A.Contact or thermite sparking due to

striking the concrete.B.Gravity.C.Friction due to the tool passing through the air of

the room.

Combustible Materials and Metal Waste

Removal


Combustible Materials and Metal Waste Removal

In this section, the need to control flammable and combustible liquids and oils, wood, paper and metal waste is discussed.

This prevents the fire control problems of combustible metals and dusts from being increased by other materials.


Flammable and combustible liquids are hazardous and must be carefully controlled:•Spray finishing;•Open containers;•Spills;•Use around ignition sources;•Lack of ventilation.

High capacity hydraulic systems (> 50 gallons), must use hydraulic oil with a flashpoint exceeding 200° F.


Wood, paper, and other materials that will burn, must not be allowed to accumulate in processing areas. • If needed store them in

designated safe places. • Segregate combustible

metal waste and other waste products.

• Use separate waste containers.


Use closed top metal containers. • Remove containers from the processing area at

least daily. • Be sure to separate combustible metal waste

materials from metal scraps and ordinary combustible material.

Collect waste caused by cutting, machining, or grinding, e.g.: • Chips, fines, and other waste; • Swarf, paste, powder, dust and

sweepings Constant cleaning


In this section, the need to control flammable and combustible liquids and oils, wood, paper and metal waste was discussed.

This prevents the fire control problems of combustible metals and dusts from being increased by other materials.


Practice Quiz1.Combustible metal waste materials and other

ordinary combustible materials should beA.Collected and placed in the same

container.B. Kept separately because they might

produce different kinds of fires that would be difficult to control.

C. Allowed to accumulate around the work site.


Practice Quiz1.Combustible metal waste materials and other

ordinary combustible materials should beA.Collected and placed in the same

container.B. Kept separately because they

might produce different kinds of fires that would be difficult to control.

C. Allowed to accumulate around the work site.

Inspectionand

Maintenance


Inspection and Maintenance

• Inspection focus areas are outlined.

• Management of Change is identified as critical to safe operations.

• In this section, the need for a systematic inspection and maintenance program is discussed.

Inspection and MaintenanceGood maintenance will assure that

• systems,• processes and • equipment

performs in the way they were intended.

Regular, systematic plant inspections will help that occur


There are many things to check out including: • Fire protection provisions on plant

equipment meets NFPA and other requirements.

• All dust control equipment is properly installed and functioning.

• Electrical grounding meets requirements. • No dust is leaking from ducts and other

equipment.• There are no hazardous housekeeping

practices relating to metal dust.

Inspection and MaintenanceCheck this out (Cont’d):• All equipment and

interlocks are functioning properly.

• Grounding and bonding systems provide appropriate continuity to ground.

• There are no built up deposits of dust.

• Identify any potential ignition sources.

Really looked

high and low for

that dust!


•Comprehensive and include work practices

Inspectors must be competent and know all relevant safety equipment, practices and procedures

Inspection program must be •Complete and cover all areas

•Frequent, at least quarterly


Good records will help to make sure that recommendations are resolved in a systematic way.

Records and files must be established for all findings and recommendations.

Inspection and MaintenanceManagement of Change (MOC)•Make sure any changes are safe for fire and explosion.

• Review all operating and maintenance procedures for safety: – Whenever there

are any changes; and,

– At least annually.

MOC

Inspection and Maintenance• MOC includes

all modifications to:

–Equipment;–Procedures;–Raw materials;–Processing.

• “Replacements in kind” or same to same replacements are an exception.

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Blender

Some examples are:• Increasing the operating

temperature of the molten metal furnace;

• Implementing a new way of cleaning dust;

• Removing a dust collector.


• Inspection focus areas were outlined.

• Management of Change was identified as critical to safe operations.

• In this section, the need for a systematic inspection and maintenance program was discussed.

Metal furnace

Inspection and MaintenancePractice Quiz1. Heavy deposits of dust, built up over a long time

A. Indicate a good maintenance and inspection program.B. Indicate a maintenance and inspection program that

needs substantial improvement. C. are not an important concern.

2. If a plant is operating to safelyA.There is no need to systematically manage changes in

the operation.B. It is still important to manage any changes at the plant.C. Systematic maintenance and inspection probably won’t

improve anything.3. Anyone at the plant is competent to make a safety

inspection for combustible dust problems.A. True B. False

Inspection and MaintenancePractice Quiz1. Heavy deposits of dust, built up over a long time

A. Indicate a good maintenance and inspection program.B. Indicate a maintenance and inspection program

that needs substantial improvement. C. are not an important concern.

2. If a plant is operating to safelyA.There is no need to systematically manage changes in the

operation.B. It is still important to manage any changes at the

plant.C. Systematic maintenance and inspection probably won’t

improve anything.3. Anyone at the plant is competent to make a safety

inspection for combustible dust problems.A. True B. False

FireExtinguishing

Agents


Fire Extinguishing Agents

In this section, the classes of fire and fuels are reviewed.

Class D extinguishing agents are discussed in some detail.

Fires fueled by wood, paper and similar items, materials that leave an

Ash

Class AClass ARemember

A

Class BClass BFires that involve flammable liquids and gases, such as gasoline, grease, propane, and paint thinner, materials that Boil

Remember

B

Class CClass CFires that involve energized electrical Current

Crane contacts power line

Remember

C

Class KClass KFires that

involve vegetable cooking oil in commercial deep fat fryers,

i.e.: in the Kitchen are Class K.

Remember

K

Class DClass Dmagnesium and aluminum alloys used in die casting plants are Class D

Test magnesium chip fire

Remember

D

Fires that involve combustible metals, for example

Fire Extinguishing AgentsFor magnesium and aluminum alloy fires, extinguishing materials (extinguishing agents) are to be listed by a NRTL (a nationally recognized testing laboratory authorized by OSHA) as suitable for Class D fires, are to be used on burning combustible metal fires.

Magnesium flux

Acceptable for use on combustible metals fires at die casting shops

Aluminum alloy(NFPA484)

Magnesium alloy(NFPA484)

Zinc alloy(MSDS data)

Met-L-X Preferred Preferred Recom’dedDry flux Preferred Preferred Not addressed

Dry sand Preferred Preferred Recom’dedDry sodium chloride

Preferred Preferred Recom’ded

Argon Preferred Preferred Not addressed

Dry soda ash Acceptable Acceptable Not addressed

Coke (spheroids) Acceptable Acceptable Not addressed


Lith-XCopper powderDry lithium chlorideWaterFoamCO2NitrogenHalonHalon replacements

• These materials are not recommended for use and

• hazardous for use on combustible metal fires at die casting shops



Locate extinguishers and extinguishing materials with easy access in the event of a fire. OSHA 29 CFR 1910.157 (d)(6) requires portable fire extinguishers or other containers of Class D agent to be placed so that the travel distance from the combustible metal working area is 75 feet (22.9 m) or less.

Within 75 Feet

Metal Fire


OSHA requires portable fire extinguishers for Class D hazards where combustible metal dusts, flakes, shavings, or similarly sized products are generated at least once every two weeks or more often.

10 micronDust

Shavings and

flakes

every two weeks or

more often.


• If the agent is wet, it is not effective and is dangerous to use.

•Containers must be checked frequently to assure that the agent is dry.

•Weekly is recommended.

Containers for fire extinguishing agents that are applied by hand must be kept tightly covered to keep the agent dry.

Fire Extinguishing AgentsClass A:B:C dry chemical and B:C dry chemical extinguishers are never to be used on combustible metals. • They must be marked “Not for

Use on Combustible-Metal Fires”.

• CO2 used as an expellant in an extinguisher or as the actual extinguishing gas is hazardous around combustible metals.

• Only materials that are compatible with combustible metals may be used.


In this section, the classes of fire and fuels were reviewed.

Class D extinguishing agents were discussed in some detail.

Fire Extinguishing AgentsPractice Quiz1. A combustible metal fire is a Class ____ fire.

A. B. C. K. D. 2. Bulk containers of combustible metal fire

extinguishing agent should be keptA. Open to the air of the plantB. Tightly coveredC. Outside the plant

3. Lith-x, Copper power, or chemical foam may be used on combustible metal fires at die casting plants.

A. True B. False

Fire Extinguishing AgentsPractice Quiz1. A combustible metal fire is a Class ____ fire.

A. B. C. K. D. 2. Bulk containers of combustible metal fire

extinguishing agent should be keptA. Open to the air of the plantB. Tightly coveredC. Outside the plant

3. Lith-x, Copper power, or chemical foam may be used on combustible metal fires at die casting plants.

A. True B. False

ControllingMetalFires


Controlling Metal FiresControl of combustible metal fires requires careful planning and training. • Small or incipient fires

are discussed in contrast to large or advanced fires.

• The effects of water use in a class D environment and

• Some specific details on control of these fires are presented.

Controlling Metal Fires

Experts define a small fire as an incipient fire. It is in the beginning stage and small enough to be safely suppressed without wearing special protective clothing or breathing apparatus.

Controlling Metal FiresAn incipient fire is a small fire. It is not small if you need • thermal

protective clothing; or,

•Breathing apparatus; or,

•Crawl on the ground or floor to stay below smoke or heat.

Small fireThey can do it!

Big fireHe and his crew can handle it!

Controlling Metal FiresAn incipient fire may be controlled or extinguished • using small

extinguishers and hand scoops and

• relatively small amounts of dry extinguishing agent.

An incipient fire

Not a lot of agent

Controlling Metal FiresPlans must be prepared for any fire fighting – large or small. This must include:

•specific actions to take in the event of a combustible metal fire;

• specifying what the safety limits are regarding attempts to extinguish combustible metal fires.

Industrial fire brigade requirements are discussed in detail in NFPA 600.

Controlling Metal Fires• Water must not be

applied to combustible metal fires or molten metal.

• water may be used to– protect, – cool and/or – extinguish other

materials, structures or equipment to prevent fire spread

• Not on the burning or molten metal.

Water on magnesium test fire


A fire in a significant quantity of burning combustible metal may grow large and dangerous.

Controlling Metal Fires Fires in combustible metals that have developed beyond the incipient stage are to be fought by •professional fire

fighters and/or •specially trained

fire brigade members.

Turn out gear for larger metal fire

Controlling Metal Fires Metal fire fighting beyond the incipient stage requires:• Eye protection that

includes attention to radiant light from metal fire;

• Protective equipment including clothing intended for metal fire fighting with heavy quilted lining and aluminized coating or equivalent;

• Self contained breathing apparatus.

Controlling Metal FiresEmployees dressed in ordinary work clothing, must not attempt to suppress a fire beyond the incipient stage.

Most companies have the policy encouraging and trained, capable employee to attempt to suppress a small or incipient fire.


•Proper training and information will allow employees to know the answer to this question.

•Can the fire can safely be suppressed, extinguished, isolated or contained, given existing training and and resources?

An employee must know the answer to this question about a combustible metal fire:

What should we do?

Don’t ask me!

I don’t know.


Do not cause a cloud of combustible metal particles to form.• It is critical to

avoid this in the presence of a fire. An ignition source is present.

• An explosion may result.

Exploded dust collector and scarred walls


A trained, skilled combustible metal fire fighter may do this in special circumstances if:• The risk is low; and • There is a greater hazard

to not moving the burning material to a safe area.

Don’t move, carry or disturb a pan or tray of burning metal chips, turnings or other small particles. You may:

• spread the fire or • cause an explosion.

Chip fire extinguished

on its panSTILL HOT

Controlling Metal Fires If it can be done safely, drums or tote bins of burning materials should be moved outside as rapidly as possible.

Controlling Metal FiresHow to suppress a small fire in burning die

casting metal alloy:1. Surround the fire with dry extinguishing

agent.2. Never allow a dust cloud.3. Apply agent gently 4. Don’t spread the fuel around or form a

cloud.5. Cover the burning material with Class D

extinguishing agent.

Controlling Metal Fires Once a fire has been extinguished and a crust is

formed by the extinguishing agent, don’t disturb the crust until the residue has cooled to room temperature.

Protect residues from water and other materials that could cause an adverse reaction.

Crusty


Appropriate extinguishers, compatible with any hazards in the area, must be provided and available in combustible metal scrap storage areas.

Class D

Class ABC


An incipient (small) fire in solvent or oil coated alloy dust, chips or turnings may be fought with a class B extinguisher and then • Treated as a combustible

metal fire,• Covered in, • Allowed to cool and • Disposed of in covered

metal containers.


Solvent or oil coated alloy fires (cont’d)Make certain the fire is a solvent or oil fire before a Class B fire extinguisher.Combustible metal fires emit an intensity of light not present in Class B fires.Use of extinguishers intended for Class B fires may be dangerous on a burning combustible metal fire.


• The effects of water use in a class D environment and

• Some specific details on control of these fires were explained.

Control of combustible metal fires was discussed in this section. Careful planning and training are required. • Small or incipient fires were discussed in

contrast to large or advanced fires.

Magnesium Fins

Controlling Metal FiresPractice Quiz1. An incipient combustible metal fire is a

A. Small fire that may be extinguished by any capable, trained employee.

B. Large fire that requires properly protected fire crews to extinguish.

C. A conflagration. 2. At die casting plants, water is often used to protect, cool

and/or extinguish materials located away from burning combustible metal.

A. TrueB. False

3. High Pressure flows from fire extinguishers may be used to extinguish small combustible metal fires.

A.TrueB.False

Controlling Metal FiresPractice Quiz1. An incipient combustible metal fire is a

A. Small fire that may be extinguished by any capable, trained employee.

B. Large fire that requires properly protected fire crews to extinguish.

C. A conflagration. 2. At die casting plants, water is often used to protect, cool

and/or extinguish materials located away from burning combustible metal.

A. True B. False3. High Pressure flows from fire extinguishers may be used

to extinguish small combustible metal fires.A. True B. False

FireFighting

Organization


Fire Fighting Organization

Those who will handle the problem must be capable and practiced. Everyone else must be evacuated so they do not become part of the problem.

The keys to success for fire fighting crews are:

• Planning;• Good management; • Training and drills;• Equipment ;and, • Use of the incident

command system.

Fire Fighting OrganizationCombustible metal fire fighting and control

requires training. Personnel who have not been trained must be

evacuated from the area.

Fire Fighting OrganizationCombustible metal fire

fighting training programs need to emphasize• The different types

of fires that may occur;

• Extinguishing agents that are appropriate for use; and,

• Fire fighting techniques.

Incipient Fire

Not Incipient

Fire Fighting OrganizationConduct training for

combustible metal fires at a safe location away from buildings or in other safe area.

Guidance for plant fire fighting crews is listed in:• OSHA 29 CFR 1910.156

Fire Brigades; and,• NFPA 600 Standard on

Industrial Fire Brigades.Practice outside

or other safe location

Fire Fighting OrganizationTraining for combustible metal fire fighters includes:• The types of fires and other events that may

occur;• Fire fighting techniques; • Appropriate agents to be used;• Prevention of dust explosions during a

response;•How things can go wrong and what to do

about it.

Fire Fighting OrganizationA unified incident command system is necessary for any organized fire fighting.• This system includes

qualified plant safety personnel.

• The local fire department is given the opportunity to participate in practice and familiarization drills.

Fire Fighting Organization

It was indicated that those who will handle the problem must be capable and practiced. Everyone else must be evacuated so they do not become part of the problem.

In this section we discussed the keys to success for fire fighting crews are:

• Planning;• Good management; • Training and drills;• Equipment ;and, • Use of the incident command system.

Fire Fighting OrganizationPractice Quiz1. Organized fire fighting crews need good training,

organization and protective equipment.A. TrueB. False

2. There are OSHA and NFPA standards regarding organized fire brigades or crews.

A. TrueB. False

3. It may be a good idea to involve public emergency response agencies in plant emergency plans.

A.TrueB.False

Fire Fighting OrganizationPractice Quiz1. Organized fire fighting crews need good training,

organization and protective equipment.A. TrueB. False

2. There are OSHA and NFPA standards regarding organized fire brigades or crews.

A. TrueB. False

3. It may be a good idea to involve public emergency response agencies in plant emergency plans.

A. TrueB. False

AutomaticSprinklerProtection


Automatic Sprinkler Protection

• Sprinklers provide no protection from explosions.

• Sprinklers should not be used in areas where the only significant fire potential results from combustible metals or molten metal.

• It must be determined if other combustibles present a greater hazard.

Sprinkler protection is desirable as fire protection for facilities and greatly assists in protecting personnel from fire. It should be noted however:

Automatic Sprinkler ProtectionAutomatic fire sprinklers •Not suitable for use

where combustible metals are used or handled unless

•Other combustibles create a more severe hazard.

A systematic hazard analysis process will determine the hazard.

Automatic Sprinkler ProtectionWater coming into contact with combustible metal dust may generate hydrogen, oxygen and heat. It is possible that significant amounts of hydrogen may accumulate and explode. Molten metal is likely to be thrown and splashed around.

Automatic Sprinkler ProtectionStored light castings, specially those with thin metal sections, may produce a significant metal fire. Design of fire protection arrangements for these areas requires special attention for:• detection, alarm and

suppression systems and • the use of fast acting

response sprinkler heads.


Magnesium castings are packed in combustible crates or packaging; or, Where other combustible storage is located within 30 ft or 9 m of the castings.

Sprinkler systems are to be used to protect light casting storage areas where:The volume of storage exceeds approximately 1000 ft3 or 28 m3; or,


• Sprinklers provide no protection from explosions.

• Sprinklers should not be used in areas where the only significant fire potential results from combustible metals or molten metal.

• It must be determined if other combustibles present a greater hazard.

In this section, the use of automatic fire sprinklers to protect plant areas was discussed. Sprinkler protection is desirable as fire protection for facilities and greatly assists in protecting personnel from fire. It was noted that:

Automatic Sprinkler ProtectionPractice Quiz1. Fire sprinklers provide explosion protection.

A. TrueB. False

2. Water should be used on burning combustible metal.A. TrueB. False

3. Stored light castings with thin metal sections may produce a significant metal fire. Automatic sprinklers may be very useful for the protection of storage of light castings in a mixed warehouse area with ordinary combustible storage.

A.TrueB.False

Automatic Sprinkler ProtectionPractice Quiz Answers1. Fire sprinklers provide explosion protection.

A. TrueB. False

2. Water should be used on burning combustible metal.A. TrueB. False

3. Stored light castings with thin metal sections may produce a significant metal fire. Automatic sprinklers may be very useful for the protection of storage of light castings in a mixed warehouse area with ordinary combustible storage.

A.TrueB.False

PROGRAM SUMMARY

The intent is to assist in implementing work practices and procedures necessary for dust explosion and fire safety at the plant.

Of greatest concern are appropriate housekeeping, fugitive dust control and safe handling of fine particles.

This program describes the prevention and/or control of fires and explosions when working around die casting facilities producing white metal castings.

Documents

Protecting Employees from the Effects of Dust Explosions and Fires in the Die Casting Industry