AS1755-2000 Conveyors Safety Requirements

8/10/2019 AS1755-2000 Conveyors Safety Requirements

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This Australian Standard was prepared by Committee EL/23, Electrical Equipmentin Coal Mines. It was approved on behalf of the Council of Standards Australia on15 September 2000 and published on 6 November 2000.

The following interests are represented on Committee EL/23:

Australian Conveyor Manufacturers Association

Bureau of Steel Manufacturers of Australia

Department of Employment Education and Training

Department of Mineral Resources, N.S.W.

Department of Training and Industrial Relations, Qld

Metal Trades Industry Association of AustraliaMinerals Council of Australia

National Safety Council of Australia

Safety Institute of Australia

State Chamber of Commerce

Testing interests

Victorian WorkCover Authority

WorkCover New South Wales

Keeping Standards up-to-dateStandards are living documents which reflect progress in science, technology andsystems. To maintain their currency, all Standards are periodically reviewed, andnew editions are published. Between editions, amendments may be issued.Standards may also be withdrawn. It is important that readers assure themselvesthey are using a current Standard, which should include any amendments whichmay have been published since the Standard was purchased.Detailed information about Standards can be found by visiting the StandardsAustralia web site at www.standards.com.au and looking up the relevant Standardin the on-line catalogue.Alternatively, the printed Catalogue provides information current at 1 January eachyear, and the monthly magazine, The Australian Standard , has a full listing of revisions and amendments published each month.We also welcome suggestions for improvement in our Standards, and especiallyencourage readers to notify us immediately of any apparent inaccuracies orambiguities. Contact us via email at [email protected], or write to the Chief Executive, Standards Australia International Ltd, GPO Box 5420, Sydney,NSW 2001.

This Standard was issued in draft form for comment as DR 97349. A c c e s s e d b y D O W N E R E D I L I M I T E D o n 1 2 J u l 2 0 0 6


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Australian Standard

Conveyors Safety requirements

Originated as AS C2151971.Previous edition AS 17551986.Third edition 2000.

COPYRIGHT

Standards Australia International

All rights are reserved. No part of this work may be reproduced or copied in any form or by anymeans, electronic or mechanical, including photocopying, without the written permission of thepublisher.

Published by Standards Australia International LtdGPO Box 5420, Sydney, NSW 2001, AustraliaISBN 0 7337 3588 6



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PREFACE

This Standard is the result of consensus among representatives of the Standards Australia

Committee SF/25, Guarding of Conveyors and Joint Standards Australia/Standards NewZealand Committee EL/23, Electrical Equipment in Coal Mines to prepare it as anAustralian Standard. It supersedes AS 17551986, ConveyorsDesign, construction,installation and operationSafety requirements. It contains the safety measures to beimplemented for the installation and operation of conveyors and conveyor systems, bothabove ground and underground and sets out the necessary personal protective measuresagainst hazards experienced by operators of such plant.

The changes included in this Standard cover the general safety requirements for large andsmall conveyors and conveyor systems, and in particular the details for conveyor controland motor drive isolation. Technical and editorial amendments have been incorporated inline with available ISO documentation for mechanical handling equipment.

Major changes made in this edition include

(a) clarification that the Standard is applicable to both above ground and undergroundconveyor systems;

(b) adding a Section dealing with requirements for specific applications, notablyunderground coal mines; and

(c) adding, as an appendix, ergonomic data.

The term normative has been used in this Standard to define the application of theappendix to which they apply. A normative appendix is an integral Part of a Standard.



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CONTENTS

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SECTION 1 SCOPE AND GENERAL1.1 SCOPE.........................................................................................................................51.2 OBJECTIVE ................................................................................................................51.3 APPLICATION............................................................................................................51.4 SECTION REQUIREMENTS......................................................................................61.5 REFERENCED DOCUMENTS...................................................................................61.6 DEFINITIONS.............................................................................................................6

SECTION 2 REQUIREMENTS FOR DESIGN AND CONSTRUCTION2.1 GENERAL...................................................................................................................92.2 DESIGN AND CONSTRUCTION...............................................................................92.3 ACCESS TO CONVEYORS......................................................................................122.4 OPERATING CLEARANCE.....................................................................................122.5 LIGHTING.................................................................................................................122.6 ELECTRICAL REQUIREMENTS ............................................................................122.7 CONVEYOR CONTROL AND ISOLATION FACILITIES......................................132.8 FIRE PROTECTION..................................................................................................192.9 MARKINGS, SIGNS AND IDENTIFICATION........................................................19

SECTION 3 REQUIREMENTS FOR GUARDING3.1 GENERAL.................................................................................................................213.2 DESIGN AND CONSTRUCTION OF GUARDS......................................................213.3 PARTS REQUIRING GUARDING...........................................................................293.4 REMOVAL OF GUARDS.........................................................................................31

SECTION 4 REQUIREMENTS FOR SPECIFIC LOCATIONS4.1 GENERAL.................................................................................................................324.2 TUNNELS, GALLERIES OR PITS ...........................................................................324.3 CONFINED SPACES ................................................................................................334.4 HAZARDOUS AREA................................................................................................334.5 CONVEYORS FOR MINING....................................................................................334.6 UNDERGROUND COAL MINES.............................................................................33

SECTION 5 REQUIREMENTS FOR SPECIFIC CONVEYOR TYPES5.1 GENERAL.................................................................................................................375.2 SLAT CONVEYORS.................................................................................................375.3 TOWING CONVEYORS...........................................................................................375.4 ROLLER FLIGHT CONVEYORS.............................................................................375.5 OVERHEAD CHAIN OR CABLE CONVEYORS (POWER AND FREE TYPE) ....375.6 SWING TRAY CONVEYORS ..................................................................................385.7 VERTICAL CHAIN CONVEYOR (OPPOSED SHELF TYPE)................................385.8 BELT CONVEYORS GUARDING OF NIP POINTS ...............................................38

5.9 TRAVELLING TRIPPERS AND SHUTTLE CONVEYORS....................................405.10 SCREW CONVEYORS .............................................................................................405.11 DRAG CHAIN CONVEYORS ..................................................................................405.12 MOBILE AND TRANSPORTABLE CONVEYORS.................................................41 A

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SECTION 6 SAFEWORK PRACTICES6.1 GENERAL.................................................................................................................466.2 INFORMATION TO BE SUPPLIED AND MAINTAINED......................................466.3 SAFEWORK PROCEDURES....................................................................................476.4 TRAINING ................................................................................................................49

APPENDICESA GLOSSARY OF CONVEYOR TERMS ....................................................................50B REFERENCED DOCUMENTS.................................................................................78C ERGONOMIC DATA................................................................................................79



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STANDARDS AUSTRALIA

Australian Standard

ConveyorsSafety requirements

S E C T I O N 1 S C O P E A N D G E N E R A L

1.1 SCOPE

This Standard sets out the minimum safety requirements for the design, installation andguarding of conveyors and conveyor systems. It includes requirements for users andproviders of inspection, maintenance, training and implementation of safe work practicesfor such equipment. Particular emphasis is given to operational safety and the protectionafforded to operators, maintenance personnel or other persons who may be exposed to risksto health and safety associat ed with conveyors or conveyor systems.

This Standard includes requirements for

(a) specific locations such as hazardous areas, confined spaces and coal mines; and

(b) specific types such as belt conveyors and mobile or transportable conveyors.

The Standard is not intended to apply to platform elevators, moving stairways or conveyorsspecifically designed for the conveyance of people.

A glossary of conveyor terms in provided in Appendix A.

1.2 OBJECTIVE

The objective of this Standard is to enable designers, manufacturers, suppliers, employersand users of conveyors and conveyor systems to minimize the risks to health and safetywhere conveyors are used.

1.3 APPLICATION

The requirements of this Standard are intended to be used by designers, manufacturers,suppliers, installers, users and owners of conveyors or conveyor systems.

The requirements of this Standard shall apply to all conveyors or conveyor systemsinstalled or reinstalled following the publication date of this Standard. This provision neednot apply where a contract for the supply and installation of a conveyor or conveyor systemhas been entered into prior to that time.

Where a risk assessment is required by this Standard, the requirements of AS 4024.1,AS/NZS 3931 and AS/NZS 4360 or equivalent Standards shall be followed.

Alternative methods of providing safety based on risk assessment in accordance withAS 4024.1, AS/NZS 3931 and AS/NZS 4360 may be used provided that the level of safetyoffered by the alternatives is at least equivalent to that provided by the methods given inthis Standard.

In addition to the requirements of this Standard, there may be other requirements set by theregulatory authority. Users of this Standard should therefore make themselves aware of anyspecific requirements in the jurisdiction where the conveyor or conveyor system will beused.



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1.4 SECTION REQUIREMENTS

Conveyors and conveyor systems shall comply with the requirements provided for in eachrelevant section of this Standard.

1.5 REFERENCED DOCUMENTSA list of the documents referred to in this Standard is given in Appendix B.

1.6 DEFINITIONS

For the purpose of this Standard the definitions below apply.

1.6.1 Competent person

A person who has, through a combination of training, education and experience, acquiredknowledge and skills enabling that person to perform correctly a specified task.

1.6.2 Control circuit isolation

The interruption of the control circuitry of the drive motor(s) of a conveyor system(s).

1.6.3 Conveyor

Apparatus or equipment operated by any power other than manual, by which loads areraised, lowered or transported or are capable of being raised, lowered, transported orcontinuously driven by

(a) an endless belt, rope or chain or other similar means;

(b) buckets, trays or other containers or fittings moved by an endless belt, rope, chain orother similar means;

(c) a rotating screw;

(d) a vibrating or walking beam; or

(e) rollers

It includes the supporting structure and auxiliary equipment used in connection with theconveyor.

1.6.4 Conveyor system

An installation comprising one conveyor, or multiple conveyors whose control is integrated.

1.6.5 Danger zone

Any zone in or around a conveyor or conveyor system in which a person is subject to a risk

to health or safety.1.6.6 Emergency stop

A manual or automatically operated system designed to stop a conveyor system in theshortest practicable time in an emergency.

1.6.7 Energy-isolating device

Any device that physically prevents the transmission or release of energy. These mayinclude, but are not limited to, electrical isolators, disconnect switches, line valves andblocks.

1.6.8 Fail safe

The principle of failure to safety, which is any failure of the machinery, its associatedsafeguards, control circuits or its power supply that leaves the machinery in a safecondition. A c

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1.6.9 Fixed guarding

Guarding which can only be removed by the use of tools.

1.6.10 Guarded

Shielded, fenced, enclosed or otherwise protected by means of suitable enclosures, covers,casing, shield guards, trough guards or railing guards which removes foreseeable risk of personal injury being caused by accidental contact or approach, and for an under guard,removes any additional foreseeable risk of personal injury caused by contact with, orspillage of, material from the conveyor.

1.6.11 Guarded by location or position

Moving parts which are protected by their remoteness from the floor, platform, walkway orother working level or which by their location with reference to frame, foundation, orstructure remove the foreseeable risk of accidental contact by people or objects.

1.6.12 Mining

A system of obtaining and processing minerals or coal, including quarrying.NOTE: Where the general provisions of this Standard have been varied for mining applicationsthe following has been assumed:(a) Access to all conveyors by the general public is effectively controlled.

(b) Access to all conveyors is limited to persons trained in the hazards that may be associatedwith the conveyors.

1.6.13 Mobile conveyor

A conveyor whose location may be moved during its operation (see Figure 3.3).

1.6.14 Nip point

That point at which a moving conveyor element meets a fixed or moving element so that itis possible to nip, pinch, squeeze or entrap parts of the human body coming into contactwith one of the two elements.

1.6.15 Normal stop

A manual or automatically operated system designed to stop the conveyor under normaloperating conditions.

1.6.16 Protective stop control

A stop control provided for the protection of the conveyor or personnel from a hazardwhich, when activated, stops the conveyor and includes emergency stop controls.

1.6.17 Pull wireA wire connected to a device, normally provided for emergency stop control which, whenpulled, activates the device.

1.6.18 Regulatory authority

A Minister of the Crown, a government department or other public authority having powerto issue regulations, orders or other instructions having the force of law in respect of anysubject covered by this Standard.

1.6.19 Runaway

Uncontrolled movement of the conveyor in either direction.

1.6.20 SequenceA control system designed to stop or start a conveyor, depending upon the state of otherequipment. A c



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1.6.21 Shall

Indicates that a statement is mandatory.

1.6.22 Shear point

The point at which, or the line along which, a moving part meets or passes close enough toa stationary part or object so that parts of the human body can be caught, trapped or pinchedbetween them.

1.6.23 Should

Indicates a recommendation.

1.6.24 Start

A manual or automatically operated control system designed to start the conveyor undernormal operating conditions.

1.6.25 Transportable conveyor

A conveyor which is not a mobile conveyor that can be moved as a unit from one locationto another.



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S E C T I O N 2 R E Q U I R E M E N T S F O R D E S I G NA N D C O N S T R U C T I O N

2.1 GENERAL

In addition to the requirements of this Standard, conveyors and conveyor systems shall bedesigned and constructed consistent with the relevant requirements of AS 4024.1 and otherrelevant Standards.

Safety features necessary for the safe operation of the conveyors and conveyor systemsshall be included at the design stage.

2.2 DESIGN AND CONSTRUCTION

2.2.1 Selection of materials

All materials used in the manufacture of conveyors shall comply with the relevantAustralian Standards. In the absence of an Australian Standard, appropriate International oroverseas Standards may be used.

2.2.2 Design requirements

The design and construction of a conveyor shall take into full account the magnitude,incidence, conditions and manner of all loading and forces likely to be applied to theconveyor.

The slope and characteristics of the conveying system shall be designed to preventhazardous unintentional sliding of the conveyed material under operating conditions.

2.2.3 Stopping devices

2.2.3.1 Safe stopping

Conveyors shall be designed to ensure that they will stop in the shortest practicable timeconsistent with safety when the driving energy is disconnected, and remain stopped untilthe energy is restored.

2.2.3.2 Anti-runaway device

Any conveyor which can run away due to the effect of gravity shall be provided withdevice(s) which will automatically prevent run away. Where a belt, chain drive, fluidcoupling or similar device is interposed between the motor and the driven shaft, the anti-runaway device shall be installed to prevent runaway in the event of a failure of the

interposing device. More than one anti-runaway device may be required on a chainconveyor.

Where a hazard to people exists from the failure of an anti-runaway device then twoautomatically operated devices shall be provided to prevent run away. Each device shall becapable of holding the load independently. These devices should be monitored for wear andeffective operation.

Each anti-runaway device shall be rated to stop and hold at least 150% of the maximumload applied by the conveyor.

NOTE: These devices include but are not limited to brakes, anti-runback or holdbacks.



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2.2.3.3 Prevention of hazardous movement

Where an electromechanical brake is provided on a conveyor which may run away or runback, and a non-direct drive is used, e.g. a fluid coupling, brakes shall not be released untilthe torque has been applied to the main driving shaft of the conveyor. They shall be applied

automatically if the power fails or the operating control is returned to the off or stoppedposition. See also AS 4024.1.

2.2.3.4 Controlled speed of descent

Brakes which are manually released and applied by the movement of operating devicesshall be designed so that if the power is interrupted with the brakes in the release position,the load can descend only at a controlled speed.

2.2.4 Lubrication points

Where bearings or other parts are inaccessible or are in a danger zone and requirelubrication, the lubrication point should be located in a position which is both accessibleand outside the danger zone. The lubrication points should be located outside the alignmentof the carrying mechanism of the conveyor and should be accessible without the removal of any guard.

2.2.5 Take-ups and counterweights

2.2.5.1 Take-ups

All components of a take-up which can move during operation shall be guarded.

Where a take-up device can operate automatically, fixed distance guarding should beprovided to prevent access to all components of the tension carriage or balance weight.

Where there is access at the bottom of the gravity take-up, protection shall be provided toeliminate the hazard from descent of the weight due to failure of a component. Provision forthe removal or disposal of spillage in this area shall be provided.Suitably worded signs warning of the stored energy hazard of the take-up system, shall bevisible at each point of access to the take-up system and rope system. Such signs shouldcomply with the requirements of AS 1319.

2.2.5.2 Access to take-up

Means of access to the take-up for repair and maintenance purposes, together with provisionfor releasing or securing the stored energy shall be incorporated in the design of the system.

2.2.5.3 Control of take-up

The manual control for the take-up shall be accessible from outside the guarded area.

Where automatic control of the take-up is provided, then isolation of the automaticoperation and selection of a manual operation should be provided.

Manually operated tension devices shall not be capable of free wheeling under anycondition.

Where take-ups are remote or on a different level from the main drive, an emergency stopfacility complying with Clause 2.7.7 shall be provided at the take-up.

2.2.5.4 Wire ropes for take-ups and counterweights

All wire ropes used for take-ups and counterweights of conveyors shall have a minimumsafety factor of 4.5, relevant to the maximum static load that can be applied by the tension

system. The minimum dynamic factor of safety should be 2.25.



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2.2.6 Hinged section

2.2.6.1 General

Hinged sections of a conveyor or conveyor system used for the purpose of creating apassageway shall be designed so that when the hinged section is opened while the conveyoris in operation, it need only stop the adjacent upstream conveyor. The conveyor may berestarted automatically upon closure of the hinged section provided that compliance withthe requirements of Clause 2.7.8.2 is assured.

2.2.6.2 Manually operated

Manually operated hinged sections shall be self-locking in the open position orcounterbalanced and shall be designed so that the maximum effort required to open or closethe hinged section does not exceed 150 N.

2.2.6.3 Power operated

Power-operated hinged sections shall be provided with mechanical safety devices which

restrict their closing to a safe speed and prevent them from falling in the event of a powerfailure.

2.2.7 Raising and lowering systems

Conveyors which include an articulated or mobile part which is raised and lowered, shall befitted with devices for automatically immobilizing these parts in the event of loss of power.

The raising or lowering system shall be designed to prevent accidental movement orkickback when operated.

The system controls shall be located so their operation is clear of the underneath of theconveyor.

Stops or limiting devices shall be provided to prevent movement of the articulated ormobile part beyond its designed limits.

2.2.8 Dust generation and control

Where dusts are present or may be generated due to the operation of a conveyor, measuresshall be taken to minimize the generation and control the presence of dust. The followingrecommendations should apply:

(a) Scrapers should be provided where material may be drawn into a pulley to the beltingcontact area. The scraper should divert the material clear of the contact area.

(b) Means should be provided at the discharge point of a conveyor to minimize carryback of material.

(c) For areas of a conveyor which may generate significant dust, (e.g. transfer points orareas of high air velocity) means should be provided to collect or suppress the dust.These means may include, but are not limited to, the following:

(i) Water sprays.

(ii) Dust cover hoods.

(iii) Dust collections systems.

(d) Horizontal areas on which dust can accumulate should be minimized.



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2.3 ACCESS TO CONVEYORS

2.3.1 General

Means of access to the conveyor and its controls for the purpose of working, operating,inspecting or servicing shall be provided. Where fixed platforms, walkways, stairways orladders are used for providing access, they shall comply with the requirements of AS 1657.Operation of the conveyor shall be from floors or platforms, not from stairways or ladders.Regular work or servicing should not be undertaken from ladders.

In the design of access provided for the operation and maintenance of the conveyor orconveyor system, alternative means of exit shall be provided for personnel in the case of fire.

2.3.2 Crossovers for aisles and passageways

Where access to either side of the conveyor is required, crossovers or underpasses shall beprovided at appropriate intervals including at the head and tail end, at the drive and othertransfer points along the conveyor.

Where a conveyor crosses a walkway, aisle or passageway and the lowest part of theconveyor or material or attachment is less than 2.1 m above the floor or walkway surface, acrossover or underpass as appropriate shall be provided.

NOTE: For underground mining applications, the underpass may be a crawlway.

2.3.3 Working clearance

Where access is required along an operating conveyor, a minimum working clearance of 600 mm coupled with a minimum headroom of 2.1 m shall be provided down one side of the conveyor. The non-walk side of the conveyor should have sufficient clearance to allowany spillage of material to fall clear of the conveyor. Adequate clearance shall be providedbetween the material being conveyed and the roof.

The provision for a minimum headroom of 2.1 m need not apply to underground mines.

2.4 OPERATING CLEARANCE

Adequate clearance shall be provided to prevent inadvertent contact between the conveyedmaterial and any part of the conveyor system, including installed equipment or structures.Where it is possible to manually overload a conveyor to a point where adequate loadclearance is not maintained, a load gauge should be installed at the loading points.

2.5 LIGHTING

2.5.1 General

Suitable permanent or mobile lighting shall be provided for conveyors or conveyor systemsappropriate to their location in accordance with AS 1680.2.1.

For underground mining, a cap lamp or other portable light is acceptable for locations otherthan transfers and drive heads.

2.5.2 Emergency lighting

Emergency lighting should be provided to allow for safe egress.

2.6 ELECTRICAL REQUIREMENTS

The electrical installation, components and associated equipment of conveyors or conveyorsystems shall comply with AS/NZS 3000 and other relevant standards appropriate to thespecific location or type of conveyor as provided for in this Standard.



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2.7 CONVEYOR CONTROL AND ISOLATION FACILITIES

2.7.1 General

Control and isolation facilities required in this Standard for conveyors and conveyorsystems shall be adequately rated.

2.7.2 System integrity

Design errors which compromise the intended integrity of a system can occur during anyphase of the design process (see Figure 2.1).

The system shall be designed in a manner that will reduce the possibility of errors beingintroduced. It should be checked during all phases to confirm freedom from error. Thehigher the level of integrity required and the more complex the system, the greater will bethe extent of the check. This applies both to systems where the logic is entirely determinedby permanent connections, e.g. a hard-wired electrical relay logic system, and to softwareor other programmable systems. However, the increasing complexity of typicalprogrammable electronic systems highlights the difficulties faced by the designer whoneeds to assure system integrity.

Programmable systems shall provide a level of performance at least equal to that affordedby conventional hard-wired safety systems

FIGURE 2.1 PHASES IN THE DESIGN PROCESS

2.7.3 Main isolating device

An energy isolating device shall be installed to completely isolate the sources of driveenergy from the conveyor or conveyor system. This device shall be capable of being lockedin the isolating position, be of the manual reset type and be suitable for direct manualoperation. The main isolating device shall not be capable of being locked in the on

position. Suitable facilities shall be provided to clearly indicate the operated state of thedevice.

2.7.4 Remote isolating device

Where it is required to isolate the conveyor remotely, an energy isolating deviceconforming with the following shall be provided for this purpose:

(a) The device shall be lockable in the isolated position and be of the manual reset type.

(b) The device shall isolate the source of energy from the drive system by either

(i) direct isolation of the energy source, or

(ii) indirect isolation of the energy source via a control system.



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(c) Where indirect isolation of the energy source via a control system is used, thefollowing shall apply:

(i) The remote isolating device shall cause the isolation of the drive energy fromthe conveyor via at least two independent means to assure system integrity.

(ii) A system shall be provided to indicate at the remote isolation device, that thedrive energy has been isolated.

(d) A prestart warning in accordance with Clause 2.7.5 shall be provided.

2.7.5 Prestart warning systems

Where an otherwise uncontrolled hazard may arise when a conveyor or conveyor systemstarts, an automatically operated prestart warning system shall alert people to the fact thatthe conveyor is commencing operation and a potential danger exists. The system shall be inthe form of an appropriately timed visual or audible warning given prior to the conveyorstarting.

Where auditory or visual warnings are provided they shall not be a substitute for physicalsafeguards. Auditory or visual warnings shall be duplicated or overlapping and shall bemonitored or inspected periodically to ensure adequate levels of safety.

2.7.6 Protective stop control

The output from a protective stop control shall cause the conveyor to stop by the operationof the energy isolating device. Activation of such control shall be by one of the followingmethods:

(a) Direct operat ion.

(b) A non-reprogrammable interposing device (e.g. relays, including electronic relays).

(c) A programmable interposing device for other than emergency stop controls.

The defeat of protective devices which may endanger personnel shall not be permitted.

Facilities should be provided for testing the operation of protective stop controls.NOTES:

1 Where appropriate, warning of the impending operation, status and record of operation of protective devices should be included in the design of the conveyor or conveyor system, e.g.belt tracking.

2 Blocked chute, bin full and transfer overfull are typical of the stop facilities provided for thepurpose.

3 For mining applications see Clause 4.6.8.

4 Programming requires a change in function, operational logic or purpose. A change of addressor identification does not constitute reprogramming.

2.7.7 Emergency stop controls

Controls shall be provided to stop the conveyor or conveyor system in an emergency. Thesestop controls shall be of the manually operated, automatic lock-off manual reset type. Thecircuit in which emergency stopping controls are provided shall be designed fail safe andotherwise protected from faults that may defeat the operation of the facility.

Emergency stop controls shall be capable of being operated with minimal effort withoutdanger to the operator and shall be provided where the operating control is clearly visibleand readily accessible even for inaccessible conveyors.

Emergency stop controls shall be provided as follows:(a) For conveyors not greater than 2.5 m in length and located less than 2.5 m above the

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(b) For conveyors greater than 2.5 m in length and located less than 2.5 m above thefloor, walkway or platform, at the head, tail, drive and at intervals not exceeding30 m along the length of the conveyor.

(c) For conveyors positioned more than 2.5 m from the floor, walkways or platforms, at

accessible locations at intervals not exceeding 100 m along t he length of theconveyor.

(d) At positions adjacent to the conveyor at which the conveyor can be started.

(e) At every permanent working station.

Provision of a pull wire activated device is considered adequate for the purposes describedabove.

2.7.8 Stop/Start controls

2.7.8.1 General

Except for conveyors at mines, resetting of any normal stop control or emergency stopcontrol shall not restart the conveyor without the actuation of a start control(see Clause 4.5.2).

Where practical, all stop/start controls and emergency stop facilities should be uniformthroughout the conveyor or conveyor system.

Where an otherwise uncontrolled hazard could exist at a loading, unloading or transferpoint in a conveyor system, the conveyor system shall be designed to operate in sequenceand be provided with automatic stop controls which are designed to prevent the hazard fromarising.

2.7.8.2 Automatic stop controls

Automatic stop controls provided for conveyor systems for other than safety purposes, e.g.overdimensional load, tension mechanism overtravel, and temperature limit controls, shouldnot prevent the restarting of the system after r esetting, provided that

(a) the stopping device is labelled to indicate that the conveyor will restart upon resettingthe device; and

(b) where this control is in a position from which the whole of the system cannot beviewed and there is a possibility of accidents arising from the starting of theconveyor, a warning signal in accordance with Clause 2.7.5 shall be provided.NOTE: This stop control may be wired into electronic control equipment.

2.7.9 Pull wire requirements

2.7.9.1 GeneralPull wires shall not be used as substitutes for guards. Where used as an emergency stopcontrol a pull wire activated device shall comply with following requirements:

(a) Breaking, slackening or removal of the pull wire shall activate the device.

(b) Where electrical continuity is monitored in the pull wire

(i) the slackening requirement of Item (a) need not apply; and

(ii) the conveyor shall stop in the event of the pull wire being broken or removed.

(c) The force required to operate the pull wire activated device shall not exceed 70 Nwhen applied midway between supports and at right angles to the axis of a pull wirewith less than 300 mm movement and 230 N along the axis of the wire.

(d) The design and distance between pull wire supports shall be such that the wire movesfreely when pulled and does not become disengaged from the support.NOTE: A maximum spacing of 6 m should apply. A



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(e) Materials used for pull wires shall be of adequate strength, be protected againstenvironmental conditions and be suitable for handling without the need for additionalprotection being worn by operators.NOTE: Where more than one switch is used in a pull wire system, a visual indicator should beprovided to indicate which switch has been activated.

(f) The switch shall be activated when the pull wire is pulled in any direction.(See Figure 2.2).

Where an electric pull wire is used, it shall be installed as shown in Figure 2.2(c).

2.7.9.2 Location of pull wires

Pull wires should be located in such a manner that they are

(a) clearly visible;

(b) readily accessible from all areas of access to the conveyor;

(c) located external to the vertical line of any nip or shear point and no further than 1 mfrom the nip or shear points;

(d) at least 900 mm above the access floor;

(e) generally not more than 1500 mm above the access floor;

(f) where all nip or shear points are greater than 1500 mm above the access floor the pullwire requirement of Item (e) may be raised provided the pull wire is lower than allnip or shear points; and

(g) where it is possible for a person to be inadvertently on a moving conveyor, anemergency stop should be provided and be located no closer to the conveyordischarge than the maximum stopping distance of the conveyor. The emergency stop

should be accessible from the conveyor.See Figure 2.3 for the preferred location of pull wires.

NOTES:

1 The requirements of Clause 2.7.9 relating to pull wires may be replaced by an alternativeemergency stop system providing an equivalent level of safety.

2 Pull wires are not an alternative to guarding.



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FIGURE 2.2 EMERGENCY STOP PULL WIREOPERATING DIRECTIONREQUIREMENTS A



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DIMENSIONS IN MILLIMETRES

FIGURE 2.3 LOCATION OF PULL WIRES

2.7.10 Protection of controls

Where any hazard may exist due to inadvertent or unauthorized operation of any control,then facilities shall be incorporated in the design of the controls to prevent such operation.Typical facilities provided for this purpose include covers over controls, locked enclosuresand key operated switches.



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2.7.11 Protection from overload

Overloading of a conveyor or conveyor system shall be prevented by provision of suitableenergy limiting devices. These devices include but ar e not limited to

(a) electrical overload limiters;

(b) flu id couplings;

(c) shear pins; and

(d) pressure rel ief valves.

Where a shear pin is used, a description of the size and type of material of the shear pinshall be placed at an appropriate point on the conveyor to facilitate proper replacement.

All fluid couplings shall be protected from overpressure and over-temperature.

2.8 FIRE PROTECTION

2.8.1 Firefighting facilitiesWhere a fire hazard exists on a conveyor or conveyor system, firefighting facilitiesappropriate to the risk shall be provided.

2.8.2 Fire risk

Where the operation of a conveyor or conveyor system could create a fire hazard, the designof the conveyor or conveyor system shall include items to minimize the risk.

2.8.3 Fire detection

Where a hazard may be created by not detecting a fire on a conveyor or conveyor system,fire detection facilities should be incorporated in the design.

2.8.4 LubricantsOils and lubricants should be effectively contained.

Accumulated spilled oils and lubricants should be controlled sufficiently to minimize anypotential fire hazards.

2.8.5 Accumulation of combustible materials

The accumulation of combustible material resulting from the operations of a conveyor shallbe controlled to prevent contact with the moving parts of the conveyor. This may beachieved by the installation of easily maintained scrapers, loading point skirting, shedderplates and self-shedding covers over components located beneath the conveyor.

In addition, sufficient space shall be provided under moving parts for the removal of accumulated material. Generally, for bulk materials handling belt conveyors, not less than300 mm should be provided for this purpose but, in no case shall this clearance be less than150 mm.

2.9 MARKINGS, SIGNS AND IDENTIFICATION

2.9.1 General

Where appropriate, permanent markings, signs and identification plates shall be inaccordance with AS 1318 and AS 1319. Where a hazard could exist from themisinterpretation of a symbol the meaning of the symbol shall be clarified in writing.Markings, signs and labels shall be of durable corrosion resistant construction and bepermanently attached. Markings, signs and labels shall be installed or positioned so thatthey are clearly visible and do not become obscured while in service.



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2.9.2 Information plates

Where appropriate, each conveyor should be provided with an information plate located atthe drive and detailing the following:

(a) The manufacturers and supplierss name, trade name or mark.

(b) An identification number.

(c) Year of manufacture.

2.9.3 Safe working load

The safe working load of a unit handling conveyor should be exhibited at each loadingpoint. For overhead chain type conveyors the safe working load shall be indicated as massper attachments and total mass per structure.

The load capacity of bulk handling conveyors should be exhibited on the conveyor.

2.9.4 Marking of control devices

Each manually operated stop, start or other function control shall be identified withmarkings, signs or labels in writing clearly indicating the purpose of the control. Notwithstanding the generality of this requirement, the following shall also apply:

(a) Emergency stop devices shall be indicated by a sign.

(b) Actuators of knock-off emergency stop devices shall be coloured red.

(c) Signs shall be provided at each end and every 30 m along a conveyor where a pullwire is used e.g. emergency stop.

(d) Signs shall be provided at the isolating devices provided for in Clauses 2.7.3 and2.7.4 which clearly indicate the function and purpose of the device. See Clause 6.3.3for specific requirements for remote isolating devices.



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S E C T I O N 3 R E Q U I R E M E N T S F O R G U A R D I N G

3.1 GENERAL

Guards shall be designed and provided to prevent access to danger zones unless the dangerzone is guarded by location or position. Guards shall be included in the design of theconveyor or conveyor system and shall not in themselves create a hazard.

Particular attention is drawn to the mass of guards which may need to be manually liftedinto place. Guidance on manual handling is provided in NOHSC:1001 (1990).

All guards shall be secured in position so that they cannot be removed without the use of tools unless an interlocking device is provided to automatically stop the conveyor in theevent of the removal of the guard.

For mining applications complying with Clause 4.5, guards may be of the lift-off design not

incorporating the interlocking device.Guards should be designed so that it is not necessary to remove them for servicing orinspection purposes.

NOTE: For example, interlocking may be achieved by a pull wire operated stop switch inaccordance with Clause 2.7.9, which operates automatically when the guards are removed.

3.2 DESIGN AND CONSTRUCTION OF GUARDS

3.2.1 General

Unless otherwise specified guards shall be designed and located in accordance with therequirements of AS 4024.1. Guards shall be designed to prevent

(a) persons reaching into the danger zone;

(b) clothes and hair or other body parts becoming caught;

(c) conveyed materials accidentally falling or being projected onto persons;

(d) the hazard from the failure of a component;

(e) inadvertent contact with a danger point on the conveyor; or

(f) inadvertent contact with hot or hazardous fluids from fluid couplings or torqueconverters.

3.2.2 Materials

Guards shall be made of solid material, mesh or equivalent construction. Sheet metal guardsshould not be less than 1.5 mm thick. Mesh guards should not be less than 1.5 mm wiregauge, or 3 mm wire gauge for 50 mm square mesh and above.

3.2.3 Strength

The safety distances specified in Clause 3.2.4 shall be maintained when loads are applied asfollows:

(a) A force of 450 N at a point on the guard applied over a square area of 50 mm 50 mm.

(b) For guards which can be climbed or rested upon, a mass of 90 kg placed on the guardand a simultaneous horizontal force of 220 N applied to points selected to establishthe strength of the guard. The required clearances from the danger zone shall bemaintained when a force of 450 N is applied at point on a guard over a square area of 50 mm 50 mm. A c



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3.2.4 Reach dimensions and guard placement

Except where stated elsewhere the design and construction of guards and their subsequentlocation shall be such that the safety distance from any nip point or shear point to thenearest point of access is in accordance with Appendix C.

Typically the safety distances are as follows:

(a) For square mesh with opening size up to and including 9 mm, guards shall be at least25 mm from the nip or shear point.

(b) For square mesh with opening above 10 mm and up to 50 mm, guards shall be at least200 mm from the nip or shear point.

(c) For fence type guards the maximum distance between the underside of the fence andthe floor shall be 200 mm. The location of the nip or shear point may reduce thisdimension.

3.2.5 Types of guards

3.2.5.1 General

Guards are normally provided in the form of

(a) fixed enclosure guards see Figure 3.1;

(b) fixed distance guards see Figure 3.2; or

(c) nip guards where shear hazards are not present see Figure 3.3.

3.2.5.2 Fixed enclosure guard

A fixed enclosure guard is a guard which, when in position, prevents access to a hazard orarea by enclosure. It encloses the hazard to prevent access, so far as is practicable,consistent with the passage of the conveyor, materials and spillage.

Where an opening exists for the passage of the conveyor, the guard at the opening shouldextend for a minimum distance of 1000 mm from the hazard (see Figure 3.1). This distanceshall be increased to 1150 mm when the pulley diameter is greater than 1000 mm. Wherefixed enclosure guards cannot be used, fixed distance guards or nip guards shall beinstalled.

Guarding of idler sets where required should be provided on the approach side and shouldextend for 1000 mm from the nip point. On the out-running side the guard should extend forat least 1000 mm beyond the nip point (see Figure 3.4).



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FIGURE 3.1 FIXED ENCLOSURE GUARD A c c e s s e d b y D O W N E R E D I L I M I T E D o n 1 2 J u l 2 0 0 6


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3.2.5.3 Fixed distance guards

A fixed distance guard does not completely enclose a hazard but reduces access by virtue of its physical dimensions and its distance from the hazard. It shall be designed andconstructed with the object of preventing any part of the body from reaching a hazard. It

may take the form of a fixed barrier of fence designed to such a height so as to preventnormal access to the danger zone, although climbing over this type of safeguard cannot beentirely eliminated. (See Figure 3.2.)

Where fence type guards are used they shall ensure that

(a) the access to any fenced area includes a system to automatically stop the conveyorbefore access is obtained to the danger zone; and

(b) a sign shall be provided at every access point through the fenced off area statingDANGERIsolate drive energy.

3.2.5.4 Nip guards

Nip guards shall extend for a minimum of 150 mm from the nip point and across the widthof the belt for the full length of the idler or pulley and shall be closely fitted to follow thefelt line and idler or pulley periphery approaching the nip, with gap not exceeding 4 mm.See Figure 3.3(a) and 3.3(b).

NOTE: Nip guards may not provide adequate protection from injury due to entrapment of hair,skin or clothes.

The principle of nip guards is shown in Figure 3.3(c). Examples of typical arrangements fornip guards at tail pulleys are shown in Figures 3.3(e) and 3.3(f).

Where nip guards of alternative designs are used, which do not provide adequate protect ion,they should be fitted in association with fixed enclosure guards or fixed distance guards.



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FIGURE 3.2 (in part) FIXED DISTANCE GUARD



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D I M E N S I O N S I N M I L L I M E T R E S

F I G U R E 3 . 2 ( i n p a r t

) F I X E D D I S T A N C E G U A R D



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FIGURE 3.3 (in part) NIP GUARDS



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FIGURE 3.3 (in part) NIP GUARDS



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3.3 PARTS REQUIRING GUARDING

3.3.1 Shear points and nip points

Shear points and nip points in locations less than 2.5 m above any access floor, platformlevel, stored goods or materials shall comply with the following requirements:

(a) All shear and nip points shall be guarded. Shear and nip points are created where thegap between any moving part of the conveyor and any fixed equipment is greater than4 mm and less that 120 mm.

(b) As an alternative, pop-out rollers or dead plates which, when operating, allow aminimum clearance of 120 mm to be maintained, may be provided. The force requiredto operate such devices shall not exceed 110 N. (See Figure 3.5.)

(c) Where the surface of the moving part of the conveyor is provided with projectionsexceeding 6 mm in height, or where there is any type of attachment to the movingpart, the minimum clearance of 120 mm shall be maintained between the highestpoint of the projection and the fixed equipment.

(d) The requirements of this Clause need not apply to nip points associated with thosebelt conveyor idlers which comply with the requirements of Clause 5.8.


FIGURE 3.4 IDLER SET GUARDSFIXED ENCLOSURE OR FIXED DISTANCE

3.3.2 Rotating parts

All exposed projections, gaps, shaft couplings or collars shall be guarded.

All fluid couplings fitted with a fusible plug or bursting discs shall be provided withsuitable guards to control and contain discharge of fluid in the event of the plug fusing.



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3.3.3 Hoppers and chutes

All openings to hoppers and chutes shall be suitably guarded where there is a risk of contacting dangerous parts or of personnel falling into the opening. Hoppers or chutes shallbe provided with access or openings so that, as far as possible, any necessary cleaning or

inspection may be carried out from outside the hopper or chute.The sides of open hoppers or chutes shall be high enough to prevent material falling intoworking areas below. Open chutes should be provided with plates at the point whereconveyors discharge into them to prevent materials from bouncing out of the chute.

Chute doors shall be located so that when open they do not create a hazard to personnelduring normal operation of the plant.

Where a hazard exists from moving equipment behind inspection doors, the doors shall belockable, or interlocked to the conveyor controls.

3.3.4 Loading, unloading and discharge points

Wherever a person has access to a loading, unloading, work station, transfer, or dischargepoint, guards in the form of guard-rails, fences, or close fitting guards shall be installed toprevent injury to that person.

3.3.5 Guarding of openings in floors

In locations where conveyors pass through a floor or where it is possible to step on movingparts of the conveyor or into the opening, guard railing and toeboards shall be provided inaccordance with AS 1657.

3.3.6 Falling materials

Where a hazard can be created by the material being conveyed falling into or beingprojected into an accessible area, then guarding shall be provided. Consideration should begiven to the height, mass and speed of the material being conveyed. (See Figure 3.6.)

NOTE: The possibility of trapping at the junction of a powered conveyor and an idle roller conveyor can beavoided by making the first idle roller free to move away along an incline A cut in the sides of theconveyor. The angle of the incline is so arranged as to prevent lateral movement of the roller during thepassage of goods from the belt to the idle roller conveyor. Care should be taken to ensure that the weightand dimensions of the loads being conveyed do not prevent the roller from lifting. In some installationsmore than one free roller may be required. This solution is not effective where the rollers are powered.

FIGURE 3.5 POP-OUT ROLLER



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FIGURE 3.6 GUARD TO PROTECT FROM FALLING MATERIAL

3.4 REMOVAL OF GUARDS

3.4.1 General

Where work requires the removal of guards, the conveyor shall be isolated in accordancewith Clause 6.3.2.

3.4.2 Inspection doors in fixed guards

Where required for inspection, maintenance, cleaning, or operational purposes, inspection

doors may be provided in a fixed guard. These openings shall not expose a person to thehazard being guarded.

3.4.3 Removal of guards and opening of inspection doors

Lifting handles or lugs shall be provided for the safe removal of guards and opening of inspection doors.

3.4.4 Labelling of guards

Removable guards shall be clearly labelled as follows, at intervals not greater than 10 m:DANGERIsolate energy source before removing guard.



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S E C T I O N 4 R E Q U I R E M E N T S F O R S P E C I F I CL O C A T I O N S

4.1 GENERAL

The additional requirements below are relevant to the specific location in which theconveyor is to be installed or used and shall be inc luded in the design.

4.2 TUNNELS, GALLERIES OR PITS

4.2.1 Materials inflow

The entrance to a tunnel, gallery or pit shall be designed to prevent any inflow of water orother materials.

4.2.2 Drainage facilities

Drainage facilities shall be provided in a tunnel, gallery or pit.

4.2.3 Depth indication

Where a risk exists of an accessible area in a tunnel, gallery or pit becoming flooded, anappropriately located device providing visual indication as to the depth of any water orother material in the area shall be provided.

4.2.4 Location of controls

Manual controls for any pumping systems shall be located outside any area which maybecome flooded.

4.2.5 Ventilation

Tunnels, galleries and pits shall be adequately ventilated. Where ventilation is provided bymechanical means, systems shall be incorporated in the design to manage any risk arisingfrom the failure of the ventilation.

4.2.6 Alternative egress

Where there is a risk of the normal access to a tunnel, gallery or pit becoming blocked, analternative means of egress shall be provided.

4.2.7 Openings to pits or sumps

Where there is a risk of falling into a temporary or permanent opening of a pit or sump, theopening shall be guarded in accordance with AS 1657. Where it is not practical to havefixed barriers or guardrails fitted to a temporary opening, then temporary barriers orguardrails shall be provided.

4.2.8 Accumulated material

Pits shall have adequate space for the accumulation of spilled material and means for theready removal of such accumulation.

4.2.9 Additional requirements

4.2.9.1 General

A risk assessment shall be conducted which includes but is not limited to the provisionscontained in Clause 4.6 for the areas given in Clauses 4.2.9.2 to 4.2.9.5.

4.2.9.2 Tunnels, galleries or pits

All tunnels, galleries or pits which are enclosed to a major degree on all sides and which aregreater than 60 m in length; A



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4.2.9.3 Confined spaces

All confined spaces as nominated in Clause 4.3;

4.2.9.4 Hazardous areas

All hazardous areas as nominated in Clause 4.4;4.2.9.5 Underground mines

All underground mines including the areas nominated in Clause 4.2.9.2 require that

(a) consideration shall be given to ensuring that sufficient space be provided to permittransport of a stretcher patient along at least one side of the conveyor; and

(b) at least two means of egress shall be provided.

4.3 CONFINED SPACES

Where a working area in or about a conveyor installation is considered as a confined space

as defined in AS 2865, the provisions of that Standard shall be applied to the installation.

4.4 HAZARDOUS AREA

Where the area in which a conveyor is to be installed or used is classified as a hazardousarea in accordance with AS 2430 (all Parts), the electrical equipment used in the hazardousarea shall be selected, installed and maintained in accordance with AS/NZS 2381.1.

4.5 CONVEYORS FOR MINING

4.5.1 Emergency stop

In addition to the requirements of Clause 2.7.7 a pull wire system shall be installed in

accordance with Clause 2.7.9 on every belt conveyor.4.5.2 Restart

Resetting alone of any protection or stop control may restart the conveyor without the needfor separate actuation of a start control, provided that a prestart warning in accordance withClause 2.7.5 has been given.

4.5.3 Prestart warning

A prestart warning system in accordance with Clause 2.7.5 shall be installed on everyconveyor. This provision need not apply to conveyors controlled by a single operator whocan readily see the full length of the conveyor and has access to a manually operatedprestart warning system.

4.6 UNDERGROUND COAL MINES

4.6.1 Maximum surface temperature

In underground workings at a mine the surface temperature of any part of the conveyor orconveyor system shall not exceed 150 C under operating conditions.4.6.2 Light metals

In underground workings in a mine, light metals shall not be used for the construction of external surfaces of conveyor equipment. Light metals are aluminium, magnesium,titanium, or an alloy containing an aggregate of more than 15% by mass of aluminium,

magnesium and titanium, or an alloy containing an aggregate of more than 6% by mass of magnesium and titanium.



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4.6.3 Control of static electricity

4.6.3.1 Anti-static materials

In underground mines where explosive atmospheres may be present, conveyor belting andnon-metallic materials that may contact the conveyor belting shall be manufactured frommaterial that has anti-static properties. These items include but are not limited to, scraperblades, ploughs, skirt rubber, pulley and idler lagging, skid bars and spliced joints.

Anti-static properties shall conform with the r equirements of AS 1333 or AS 1332,electrical resistance (Grades E and S belts). The electrical resistance shall be measured inaccordance with AS 1334.9.

4.6.3.2 Anti-static measures

Where a conveying system can introduce a risk arising from static electricity, for examplefrom pneumatic bulk transfer conveyors, they shall be provided with means of staticdischarge. Guidance may be found in AS/NZS 1020.

4.6.4 Hazardous zone electrical equipmentWhere a regulatory body or user establishes a hazardous zone or area in undergroundworking at a mine, the electrical equipment used in those areas shall comply with AS 2380(all Parts).

4.6.5 Fire resistant materials

4.6.5.1 Non-metallic materials

Non-metallic materials used in the construction of conveyors, shall comply with the fire-resistant requirements of Grade S belting, as defined in AS 1333 or AS 1332, as applicable,for the following items:

(a) All conveyor belting and spliced joints.(b) Items in contact with or in close proximity to the belt, e.g. pulley and idler lagging,

scraper blades, impact bars, skirting rubber.

(c) Structural components.

(d) Chutes and l ining.

(e) Guards/covers/hoods.

4.6.5.2 Fluids

Fluids used in fluid couplings and torque converters shall be fire resistant to AS 3997.2.NOTES:

1 Guidance on the selection of fire-resistant hydraulic fluids may also be found in ISO 7745.2 Phosphate ester based hydraulic fluids may not be suitable for some underground situation.

4.6.6 Bearing cage materials

Non-metallic bearing cages for anti-friction bearings should not be used.

4.6.7 Firefighting facilities

Provision for automatic fire suppression facilities should be considered at conveyor drivelocations and other areas where the risk of fire warrants this equipment. These areadditional to the requirements of Clause 2.8.

4.6.8 Protective stop controls

4.6.8.1 General

Protective stop controls shall be provided in accordance with Clauses 4.6.8.2 to 4.6.8.9. Therequirements are summarized in Table 4.1.



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TABLE 4.1

PROTECTIVE STOP CONTROLS

Parameter Mandatory Recommended

Belt slip xFluid coupling over-temperature x

Brake over-temperature x

Brake release x

Belt tracking x

Fire detection x

Bearing over-temperature x

Blocked chute x

4.6.8.2 Belt slip

A protective stop control shall be fitted to detect slippage between the drive pulleys and thebelt. When the slip exceeds 10% the conveyor shall stop. This device may be over-riddenduring start-up of the conveyor for a maximum period of 35 seconds.

4.6.8.3 Fluid couplings over temperature

Fluid coupling shall be fitted with an overtemperature device which operates before

(a) the coupling surface reaches 150 C; or(b) the fluid reaches the maximum operating temperature as recommended by the

manufacturer of the fluid, whichever is the lesser.NOTE: Fluid couplings should be fitted with a high-temperature trip device and a hightemperature thermal plug (see Clause 3.3.2).

4.6.8.4 Brake overtemperature

Braking systems should have an over-temperature protective stop control arranged to stopthe conveyor.

4.6.8.5 Brake release

Mechanical brakes shall be fitted with a device designed to detect the released position of the brake. The device shall be arranged to stop the conveyor in the event of the brakefailing to release when required.

4.6.8.6 Belt tracking

Devices shall be provided to detect and stop the conveyor in the event of excessive sidemovement of the conveyor belt while operating. As a minimum, these devices shall beinstalled within 30 m of either side of any transfer point, drive head, loop take-up or placewhere a significant change in belt elevation occurs.

NOTE: A timer may be fitted to prevent nuisance trips of the conveyor which may occur due tomomentary tracking problems or to a small protrusion to the side of the belt. A self-resettingoverride device may be provided for belt tracking purposes.

4.6.8.7 Fire detection

Devices should be installed to detect fire at conveyor drive locations and other areas wherethe risks of fire warrant these devices.



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4.6.8.8 Bearing over-temperature

Where a hazard may result from the overheating of a pulley or gearbox bearing, devicesshould be installed to detect the overheating. The detection system shall not be self-resetting. The system provided shall latch off and be of the manual reset type.

NOTE: Dead shaft bearing seizure may not necessarily be prevented by a bearing over-temperature monitoring device, hence, the use of a device which detects and stops inadvertentshaft rotation may prevent a fire.

4.6.8.9 Blocked chute

Devices shall be installed to detect blockage of chutes incorporated in a conveyor orconveyor systems.

4.6.9 Accumulation of combustible materials

In addition to the requirements of Clause 2.8.5, a space of not less than 300 mm shall beprovided below the lowest part of the lowest belt surface except that at the first loading endof each conveyor system where the clearance shall be sufficient to prevent contact betweenthe belt surface or any rotating element and any spillage.



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S E C T I O N 5 R E Q U I R E M E N T S F O R S P E C I F I CC O N V E Y O R T Y P E S

5.1 GENERAL

The additional requirements below shall be included in the design and construction relevantto the specific conveyor type deta iled in this Section.

5.2 SLAT CONVEYORS

5.2.1 Slat load design

Slats shall be designed, to accommodate live loads. The design shall include an allowancefor wear.

5.2.2 Spacing between slats

The distance between slats when travelling in a straight line along a slat conveyor should be25 mm, except that this gap may be increased in accordance with the safety distances givenin AS 4024.1, or where alternative forms of guarding are provided in accordance withAS 4024.1.

5.3 TOWING CONVEYORS

5.3.1 Truck release mechanism

A device shall be provided to automatically release a towed truck from the towing chain of a towing conveyor in the event of the truck or load becoming obstructed.

5.3.2 Clearances

There shall be at least 500 mm clearance between any towed truck, including its load, andany other truck or fixed object.

5.3.3 Guarding of wheels

Tow truck wheels shall be guarded by one of the following methods:

(a) By guards on the wheels to within 20 mm of the floor.

(b) By a skirt guard on the truck to within 20 mm of the floor.

(c) Any other means which provides equivalent protection for personnel.

5.4 ROLLER FLIGHT CONVEYORSThe distance between rollers of a roller flight conveyor shall not be greater than 25 mmexcept that this gap may be increased where the entire space under the top of the carryingrollers is a solid smooth bed eliminating any shear hazard or where shear and nip points areguarded.

5.5 OVERHEAD CHAIN OR CABLE CONVEYORS (POWER AND FREE TYPE)

5.5.1 Guarding yokes

Where the underside of the free track of an overhead chain or cable conveyor is within2.5 m of the floor level, the power chain and trolley shall be suitably guarded where they

pass through the yokes. Where, however, access to the trolley is from walkways providedfor maintenance, yokes need not be specifically guarded provided that the clearancebetween the trolley bracket and the yoke is not less than 30 mm.



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5.5.2 Drop sections

Where drop sections are used, suitable means shall be provided to prevent the followingfree trolley from entering the open section of track. and the free trolley in the drop sectionshall be positively retained on the track.

Means shall be provided to stop the descent of any drop section or to control its speed tonot more than 125% of its normal operating speed; in any event its speed shall not exceed500 mm/s.

5.6 SWING TRAY CONVEYORS

5.6.1 Fork tray type

Where there is more than one loading point in a fork tray conveyor, the conveyor or itscontrols shall be designed to ensure that the trays cannot be at the loading points at thesame time. Loading and unloading points shall be guarded by fixed guards extending adistance of at least 1000 mm from the sill line of the loading or unloading point.

5.6.2 Solid tray type

Where the loading or unloading of a solid tray type conveyor is not automatic, the loadingand unloading point shall be provided with doors interlocked to stop the conveyor when thedoors are open.

5.7 VERTICAL CHAIN CONVEYOR (OPPOSED SHELF TYPE)

On a vertical chain conveyor means shall be provided to stop the conveyor in the event of any portion of the load projecting beyond the door head or sill line.

5.8 BELT CONVEYORS GUARDING OF NIP POINTS

On belt conveyors, unless guarded by position, the following nip points shall be guarded(see Figure 5.1):

(a) Drive pulleys.

(b) Head and tail end pulleys.

(c) Bend and snub pulleys.

(d) Take-up pulleys.

(e) Transition idlers adjacent to pulleys.

(f) Carrying and return idlers at convex curves (brow position).

(g) Carrying and return idlers beneath feed hoppers and skirt plates.

(h) Carrying and return idlers at positions where the lift of the belt is restricted.

(i) Idlers accessible from underpasses, crossovers and crawlways.NOTE: There may be a nip point created in the opposing direction to the normal operation of theconveyor by either of the following:

(a) Reversing of the belt by design.(b) Reversing of the belt due to forces within the system, e.g. changes in the conveyor tension

system.



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F I G U R E 5 . 1 B E L T C O N V E Y O R N I P P O I N T G U A R D I N G



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5.9 TRAVELLING TRIPPERS AND SHUTTLE CONVEYORS

Where there is a risk of trapping a person, a working clearance of 500 mm shall be providedbetween a moving tripper, shuttle conveyor or radial conveyor and other objects likely tocause entrapment along the length of travel and at either end.

Guards shall be provided to prevent any trapping between the travelling wheels and therails. See Figure 5.2 for typical requirements.

Where access is provided to, or across a travelling tripper, guards shall be provided toprevent any trapping between any fixed or moving object.

Where a crossover or underpass is attached to a travelling tripper a suitable boarding switchshould be provided.

For a manually positioned tripper, a travel-locking device shall be provided.


FIGURE 5.2 TYPICAL GUARDS FOR TRAVELLING TRIPPER

5.10 SCREW CONVEYORSAll casings, loading, delivery, drainage and inspection apertures or chutes of screwconveyors shall be guarded or interlocked to prevent contact with the screw and nip point.

5.11 DRAG CHAIN CONVEYORS

Where inspection panels are used in the top of a trunking which encloses a drag chain, awire mesh screen shall be provided under the door or panel; such screens shall be designedand constructed in accordance with the requirements of Clause 3.2.3.

The flights and chain of a drag chain conveyor shall be guarded where a hazard exists.



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5.12 MOBILE AND TRANSPORTABLE CONVEYORS

5.12.1 General design and construction

Mobile and transportable conveyors shall be designed and constructed to remain stableunder the stated loads and operating conditions. The design and construction of mobile andtransportable conveyors shall take into account the magnitude, incidence, condition andmanner of loading, including possible overloads and all other forces likely to be allied tothe conveyor under the operating conditions.

5.12.2 Margin of stability

The margin of stability shall be determined for mobile and transportable conveyors underthe combined effects of

(a) wind loa ding;

(b) design live and dead loads;

(c) design live load and dynamic effects; and

(d) tilting due to terrain or flat tyre where applicable.

The margin of stability expressed as a percentage shall be calculated in accordance with thefollowing equation:

= 1100ba

m

where

m = margin of stability, in percent

a = stabilizing moment about the axis of tipping of the conveyor due to the

worst case design loads, in newton metresb = overturning moment about the axis of tipping of the conveyor due to the

worst case design loads, in newton metres

The margin of stability for mobile or transportable conveyors shall not be less than 50%.

5.12.3 Pneumatic tyres

Where pneumatic-tyred wheels are used on a mobile or transportable conveyor, stabilityshall be maintained in a condition of under-inflation or loss of air in one or more of thetyres.

5.12.4 Boom mounting

The boom or trunking shall be mounted on the chassis, base or wheels. The plan distance atright angles to the boom or trunking between the chassis, base, or wheels shall not be lessthan 25% of the elevated height of the boom or trunking.

5.12.5 Locking against movement

Suitable locking devices or brakes shall be provided on transportable conveyors to preventunwanted movement while the conveyor is in use.

5.12.6 Attachment points for towing

Suitably designed points of attachment shall be provided for towing mobile andtransportable conveyors.

NOTE: Reference should be made to traffic rules for transporting or operating conveyors onpublic roadways.



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5.12.7 Loss of power

Suitable means shall be provided to maintain the conveyor boom in any position when thepower is removed from the raising or lowering medium. A screw or helix type brake fulfilsthis purpose. Ratchet and pawl type winches without brakes shall not be used.

5.12.8 Wire ropes

5.12.8.1 Safety factors and diameter ratios

Wire rope, where used for elevating booms, shall comply with the appropriate requirementsof AS 3569 and AS 2759 with respect to the minimum factor of safety and ratio of ropediameter to drum and sheave diameter.

5.12.8.2 Attachment criteria

Attachment of the ropes shall be made in such a manner that will ensure the strength of therope is maintained in the connection.

5.12.8.3 Minimum diameter

Ropes of less than 6 mm diameter shall not be used.

5.12.8.4 Load equalization

Where more than one rope or fall is used, a means of equalizing the load on each rope shallbe provided.

5.12.8.5 Anchorage

Rope anchorages shall have a minimum safety factor of 4.5.

5.12.9 Boom or trunking

5.12.9.1 Minimum approach

The boom or trunking shall be designed so that it cannot approach closer than 2500 mm tothe ground or floor level, unless measures are taken to ensure that the elevated boom ortrunking has its descent controlled to a safe regulated speed. The boom raising frame shallnot become detached from the boom trunking or base.

5.12.9.2 Separation from drive

The boom or trunking shall be attached and supported so that, when it is at its most loweredelevation or being transported, it cannot rest upon the conveyor drive.

5.12.9.3 Warning sign Overhead Power

A permanent sign warning of the hazard from overhead powerlines, shall be installed in a

conspicuous position at each towing point on a transportable conveyor and adjacent to thedriving controls of a mobile conveyor. This applies to mobile or transportable conveyorswhich have any parts that can be raised in excess of 2000 mm. See Figure 5.3 for a typicalsign.

5.12.9.4 Safety distances from overhead power lines

The conveyor shall not approach any closer to overhead power lines than the following(see Figure 5.4):

(a) For distr ibution l ines carrying up to 132 kV on poles . . . . . . . . . . . . . . . . . 3 m.

(b) For transmission lines carrying greater than 132 kV on towers . . . . . . . . . . . 8 m.

5.12.9.5 Movement of transportable conveyorsTransportable conveyors shall be moved to another location only after the boom or trunkinghas been lowered into its transportable position. A warning notice advising this requirementshall be prominently displayed on the conveyor.



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FIGURE 5.3 TYPICAL WARNING SIGN FOR OVERHEAD POWER

5.12.10 Internal combustion engine drive

Where an internal combustion engine is used as the conveyor drive power, the followingshall apply:

(a) The conveyor shall be fitted with overspeed protection designed to stop the drive inthe event of the maximum design speed being exceeded.

(b) The conveyor shall be fitted with a fire extinguisher of suitable capacity and type toextinguish a fire arising from the combustion of fuel.

(c) The conveyor shall be fitted with a sign, in a conspicuous position, warning of thehazard arising from the exhaust fumes of the engine. This warning shall includeparticular reference against use of the conveyor in non-ventilated or confined spaces.

(d) Due consideration should be given to the control of static electricity (seeAS/NZS 1020).

(e) Where manual starting mechanisms are fitted to the motor, the design shall not createa hazard to the operator.NOTE: It is recommended that impulse, spring or permanently attached cord type starters beprovided for this purpose.

5.12.11 Electrical cables

Where electrical cables are subject to movement or vibration, such cables shall be of theflexible type and be

(a) protected to prevent damage; and

(b) attached to the conveyor to prevent undue strain on the electrical connections orcable.

Residual current devices should be provided to circuits feeding mobile conveyors. A c c e s s e d b y D O W N E R E D I L I M I T E D o n 1 2 J u l 2 0 0 6


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A sign shall be attached to the conveyor statingThis equipment should be connected onlyto a power circuit equipped with residual current devices.

5.12.12 Tooth or dog clutches

Where used on a mobile or transportable conveyor tooth or dog type clutches shall have notless than four teeth or dogs. Tooth or dog type clutches shall be designed and constructed toprevent inadvertent disengagement.

5.12.13 Guarding

In addition to and in accordance with the requirements of Section 3, mobile andtransportable conveyors shall be fitted with guards on

(a) return side idlers less than 2.5 m from any access floor or platform level or at anyother position that is not guarded by position or location;

(b) flywheels, coupling and starter mechanisms of petrol engines;

(c) exposed or extended shafts of crank type starting mechanisms;

(d) bag and bale conveyors to prevent dislodgment of the load in the form of side guardsor aprons extending to an effective height of 100 mm;

(e) exposed screws, chains or flights in hoppers designed to prevent contact with movingparts;

(f) return side chains with flights, typically by positioning the chain to prevent contactby a person, enclosing in a duct or other similar barrier; and

(g) power take off drives and shafts shall be guarded in accordance with AS 1121.



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DIMENSIONS IN METRES

FIGURE 5.4 CLEARANCES FROM OVERHEAD POWER LINES



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S E C T I O N 6 S A F E W O R K P R A C T I C E S

6.1 GENERAL

This Section deals with safework practices to be developed, implemented and maintainedby owners and users to ensure the

Documents

AS1755-2000 Conveyors Safety Requirements