AS 1755—2000
AS 1755
Australian Standard™
Accessed by DOWNER EDI LIMITED on 12 Jul 2006
Conveyors—Safety requirements
This Australian Standard was prepared by Committee EL/23, Electrical Equipment in Coal Mines. It was approved on behalf of the Council of Standards Australia on 15 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 Australia Minerals Council of Australia National Safety Council of Australia Safety Institute of Australia State Chamber of Commerce Testing interests Victorian WorkCover Authority
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WorkCover New South Wales
Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Detailed information about Standards can be found by visiting the Standards Australia web site at www.standards.com.au and looking up the relevant Standard in the on-line catalogue. Alternatively, the printed Catalogue provides information current at 1 January each year, 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 especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. 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.
AS 1755—2000
Australian Standard™ Conveyors— Safety requirements
Accessed by DOWNER EDI LIMITED on 12 Jul 2006
Originated as AS C215—1971. Previous edition AS 1755—1986. 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 any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Published by Standards Australia International Ltd GPO Box 5420, Sydney, NSW 2001, Australia ISBN 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 New Zealand Committee EL/23, Electrical Equipment in Coal Mines to prepare it as an Australian Standard. It supersedes AS 1755—1986, Conveyors—Design, construction, installation and operation—Safety requirements. It contains the safety measures to be implemented for the installation and operation of conveyors and conveyor systems, both above ground and underground and sets out the necessary personal protective measures against hazards experienced by operators of such plant. The changes included in this Standard cover the general safety requirements for large and small conveyors and conveyor systems, and in particular the details for conveyor control and motor drive isolation. Technical and editorial amendments have been incorporated in line 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 underground conveyor systems;
(b)
adding a Section dealing with requirements for specific applications, notably underground coal mines; and
(c)
adding, as an appendix, ergonomic data.
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The term ‘normative’ has been used in this Standard to define the application of the appendix to which they apply. A normative appendix is an integral Part of a Standard.
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CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE .........................................................................................................................5 1.2 OBJECTIVE ................................................................................................................5 1.3 APPLICATION............................................................................................................5 1.4 SECTION REQUIREMENTS......................................................................................6 1.5 REFERENCED DOCUMENTS ...................................................................................6 1.6 DEFINITIONS .............................................................................................................6 SECTION 2 REQUIREMENTS FOR DESIGN AND CONSTRUCTION 2.1 GENERAL ...................................................................................................................9 2.2 DESIGN AND CONSTRUCTION...............................................................................9 2.3 ACCESS TO CONVEYORS......................................................................................12 2.4 OPERATING CLEARANCE .....................................................................................12 2.5 LIGHTING.................................................................................................................12 2.6 ELECTRICAL REQUIREMENTS ............................................................................12 2.7 CONVEYOR CONTROL AND ISOLATION FACILITIES......................................13 2.8 FIRE PROTECTION..................................................................................................19 2.9 MARKINGS, SIGNS AND IDENTIFICATION........................................................19
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SECTION 3 REQUIREMENTS FOR GUARDING 3.1 GENERAL .................................................................................................................21 3.2 DESIGN AND CONSTRUCTION OF GUARDS......................................................21 3.3 PARTS REQUIRING GUARDING ...........................................................................29 3.4 REMOVAL OF GUARDS .........................................................................................31 SECTION 4 REQUIREMENTS FOR SPECIFIC LOCATIONS 4.1 GENERAL .................................................................................................................32 4.2 TUNNELS, GALLERIES OR PITS ...........................................................................32 4.3 CONFINED SPACES ................................................................................................33 4.4 HAZARDOUS AREA................................................................................................33 4.5 CONVEYORS FOR MINING....................................................................................33 4.6 UNDERGROUND COAL MINES.............................................................................33 SECTION 5 REQUIREMENTS FOR SPECIFIC CONVEYOR TYPES 5.1 GENERAL .................................................................................................................37 5.2 SLAT CONVEYORS.................................................................................................37 5.3 TOWING CONVEYORS...........................................................................................37 5.4 ROLLER FLIGHT CONVEYORS.............................................................................37 5.5 OVERHEAD CHAIN OR CABLE CONVEYORS (POWER AND FREE TYPE) ....37 5.6 SWING TRAY CONVEYORS ..................................................................................38 5.7 VERTICAL CHAIN CONVEYOR (OPPOSED SHELF TYPE)................................38 5.8 BELT CONVEYORS GUARDING OF NIP POINTS ...............................................38 5.9 TRAVELLING TRIPPERS AND SHUTTLE CONVEYORS....................................40 5.10 SCREW CONVEYORS .............................................................................................40 5.11 DRAG CHAIN CONVEYORS ..................................................................................40 5.12 MOBILE AND TRANSPORTABLE CONVEYORS.................................................41
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Page SECTION 6 SAFEWORK PRACTICES 6.1 GENERAL .................................................................................................................46 6.2 INFORMATION TO BE SUPPLIED AND MAINTAINED......................................46 6.3 SAFEWORK PROCEDURES....................................................................................47 6.4 TRAINING ................................................................................................................49
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APPENDICES A GLOSSARY OF CONVEYOR TERMS ....................................................................50 B REFERENCED DOCUMENTS .................................................................................78 C ERGONOMIC DATA................................................................................................79
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STANDARDS AUSTRALIA Australian Standard Conveyors—Safety requirements
S E CT I ON
1
S COP E
AND
GE NE RAL
1.1 SCOPE This Standard sets out the minimum safety requirements for the design, installation and guarding of conveyors and conveyor systems. It includes requirements for users and providers of inspection, maintenance, training and implementation of safe work practices for such equipment. Particular emphasis is given to operational safety and the protection afforded to operators, maintenance personnel or other persons who may be exposed to risks to health and safety associated 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 conveyors specifically 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, employers and users of conveyors and conveyor systems to minimize the risks to health and safety where conveyors are used. 1.3 APPLICATION
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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 systems installed or reinstalled following the publication date of this Standard. This provision need not apply where a contract for the supply and installation of a conveyor or conveyor system has 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 with AS 4024.1, AS/NZS 3931 and AS/NZS 4360 may be used provided that the level of safety offered by the alternatives is at least equivalent to that provided by the methods given in this Standard. In addition to the requirements of this Standard, there may be other requirements set by the regulatory authority. Users of this Standard should therefore make themselves aware of any specific requirements in the jurisdiction where the conveyor or conveyor system will be used.
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1.4 SECTION REQUIREMENTS Conveyors and conveyor systems shall comply with the requirements provided for in each relevant section of this Standard. 1.5 REFERENCED DOCUMENTS A 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, acquired knowledge 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 are raised, lowered or transported or are capable of being raised, lowered, transported or continuously 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 or other 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 the conveyor. 1.6.4 Conveyor system An installation comprising one conveyor, or multiple conveyors whose control is integrated.
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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 the shortest practicable time in an emergency. 1.6.7 Energy-isolating device Any device that physically prevents the transmission or release of energy. These may include, but are not limited to, electrical isolators, disconnect switches, line valves and blocks. 1.6.8 Fail safe The principle of failure to safety, which is any failure of the machinery, its associated safeguards, control circuits or its power supply that leaves the machinery in a safe condition. © Standards Australia
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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, or spillage 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 or other working level or which by their location with reference to frame, foundation, or structure 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 applications the 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 associated with 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 it is possible to nip, pinch, squeeze or entrap parts of the human body coming into contact with one of the two elements. 1.6.15 Normal stop A manual or automatically operated system designed to stop the conveyor under normal operating conditions. 1.6.16 Protective stop control
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A stop control provided for the protection of the conveyor or personnel from a hazard which, when activated, stops the conveyor and includes emergency stop controls. 1.6.17 Pull wire A wire connected to a device, normally provided for emergency stop control which, when pulled, activates the device. 1.6.18 Regulatory authority A Minister of the Crown, a government department or other public authority having power to issue regulations, orders or other instructions having the force of law in respect of any subject covered by this Standard. 1.6.19 Runaway Uncontrolled movement of the conveyor in either direction. 1.6.20 Sequence A control system designed to stop or start a conveyor, depending upon the state of other equipment. www.standards.com.au
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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 to a stationary part or object so that parts of the human body can be caught, trapped or pinched between them. 1.6.23 Should Indicates a recommendation. 1.6.24 Start A manual or automatically operated control system designed to start the conveyor under normal operating conditions. 1.6.25 Transportable conveyor
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A conveyor which is not a mobile conveyor that can be moved as a unit from one location to another.
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S E CT I ON
2
RE QUI RE ME NT S FOR AND CONS T RUCT I ON
DE S IGN
2.1 GENERAL In addition to the requirements of this Standard, conveyors and conveyor systems shall be designed and constructed consistent with the relevant requirements of AS 4024.1 and other relevant Standards. Safety features necessary for the safe operation of the conveyors and conveyor systems shall 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 relevant Australian Standards. In the absence of an Australian Standard, appropriate International or overseas 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 the conveyor. The slope and characteristics of the conveying system shall be designed to prevent hazardous 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 time consistent with safety when the driving energy is disconnected, and remain stopped until the energy is restored.
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2.2.3.2 Anti-runaway device Any conveyor which can run away due to the effect of gravity shall be provided with device(s) which will automatically prevent run away. Where a belt, chain drive, fluid coupling or similar device is interposed between the motor and the driven shaft, the antirunaway 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 chain conveyor. Where a hazard to people exists from the failure of an anti-runaway device then two automatically operated devices shall be provided to prevent run away. Each device shall be capable of holding the load independently. These devices should be monitored for wear and effective operation. Each anti-runaway device shall be rated to stop and hold at least 150% of the maximum load 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 run back, and a non-direct drive is used, e.g. a fluid coupling, brakes shall not be released until the 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 ‘stopped’ position. 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 devices shall 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 require lubrication, the lubrication point should be located in a position which is both accessible and outside the danger zone. The lubrication points should be located outside the alignment of 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 be provided 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 to eliminate the hazard from descent of the weight due to failure of a component. Provision for the 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 be visible at each point of access to the take-up system and rope system. Such signs should comply 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 provision for releasing or securing the stored energy shall be incorporated in the design of the system. 2.2.5.3 Control of take-up Accessed by DOWNER EDI LIMITED on 12 Jul 2006
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 automatic operation and selection of a manual operation should be provided. Manually operated tension devices shall not be capable of free wheeling under any condition. Where take-ups are remote or on a different level from the main drive, an emergency stop facility 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 minimum safety 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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AS 1755—2000
2.2.6 Hinged section 2.2.6.1 General Hinged sections of a conveyor or conveyor system used for the purpose of creating a passageway shall be designed so that when the hinged section is opened while the conveyor is in operation, it need only stop the adjacent upstream conveyor. The conveyor may be restarted automatically upon closure of the hinged section provided that compliance with the 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 or counterbalanced and shall be designed so that the maximum effort required to open or close the 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 power failure. 2.2.7 Raising and lowering systems Conveyors which include an articulated or mobile part which is raised and lowered, shall be fitted 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 or kickback when operated. The system controls shall be located so their operation is clear of the underneath of the conveyor. Stops or limiting devices shall be provided to prevent movement of the articulated or mobile part beyond its designed limits. 2.2.8 Dust generation and control
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Where dusts are present or may be generated due to the operation of a conveyor, measures shall be taken to minimize the generation and control the presence of dust. The following recommendations should apply: (a)
Scrapers should be provided where material may be drawn into a pulley to the belting contact 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 carry back of material.
(c)
For areas of a conveyor which may generate significant dust, (e.g. transfer points or areas 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:
(d)
(i)
Water sprays.
(ii)
Dust cover hoods.
(iii)
Dust collections systems.
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 or ladders 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 or conveyor 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 be provided at appropriate intervals including at the head and tail end, at the drive and other transfer points along the conveyor. Where a conveyor crosses a walkway, aisle or passageway and the lowest part of the conveyor or material or attachment is less than 2.1 m above the floor or walkway surface, a crossover 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 allow any spillage of material to fall clear of the conveyor. Adequate clearance shall be provided between 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 conveyed material 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 load clearance is not maintained, a load gauge should be installed at the loading points. 2.5 LIGHTING Accessed by DOWNER EDI LIMITED on 12 Jul 2006
2.5.1 General Suitable permanent or mobile lighting shall be provided for conveyors or conveyor systems appropriate to their location in accordance with AS 1680.2.1. For underground mining, a cap lamp or other portable light is acceptable for locations other than 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 conveyor systems shall comply with AS/NZS 3000 and other relevant standards appropriate to the specific 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 conveyor systems shall be adequately rated. 2.7.2 System integrity Design errors which compromise the intended integrity of a system can occur during any phase of the design process (see Figure 2.1). The system shall be designed in a manner that will reduce the possibility of errors being introduced. It should be checked during all phases to confirm freedom from error. The higher the level of integrity required and the more complex the system, the greater will be the extent of the check. This applies both to systems where the logic is entirely determined by permanent connections, e.g. a hard-wired electrical relay logic system, and to software or other programmable systems. However, the increasing complexity of typical programmable electronic systems highlights the difficulties faced by the designer who needs to assure system integrity. Programmable systems shall provide a level of performance at least equal to that afforded by conventional hard-wired safety systems
FIGURE 2.1 PHASES IN THE DESIGN PROCESS
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2.7.3 Main isolating device An energy isolating device shall be installed to completely isolate the sources of drive energy from the conveyor or conveyor system. This device shall be capable of being locked in the isolating position, be of the manual reset type and be suitable for direct manual operation. 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 the device. 2.7.4 Remote isolating device Where it is required to isolate the conveyor remotely, an energy isolating device conforming 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)
(d)
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Where indirect isolation of the energy source via a control system is used, the following shall apply: (i)
The remote isolating device shall cause the isolation of the drive energy from the 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 the drive energy has been isolated.
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 system starts, an automatically operated prestart warning system shall alert people to the fact that the conveyor is commencing operation and a potential danger exists. The system shall be in the form of an appropriately timed visual or audible warning given prior to the conveyor starting. Where auditory or visual warnings are provided they shall not be a substitute for physical safeguards. Auditory or visual warnings shall be duplicated or overlapping and shall be monitored 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 operation of the energy isolating device. Activation of such control shall be by one of the following methods: (a)
Direct operation.
(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.
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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 the purpose. 3 For mining applications see Clause 4.6.8. 4 Programming requires a change in function, operational logic or purpose. A change of address or 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. These stop controls shall be of the manually operated, automatic lock-off manual reset type. The circuit in which emergency stopping controls are provided shall be designed fail safe and otherwise protected from faults that may defeat the operation of the facility. Emergency stop controls shall be capable of being operated with minimal effort without danger to the operator and shall be provided where the operating control is clearly visible and 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 floor, walkway or platform, a single stop control at the middle of the conveyor.
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(b)
For conveyors greater than 2.5 m in length and located less than 2.5 m above the floor, walkway or platform, at the head, tail, drive and at intervals not exceeding 30 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 the length of the conveyor.
(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 described above. 2.7.8 Stop/Start controls 2.7.8.1 General Except for conveyors at mines, resetting of any normal stop control or emergency stop control 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 uniform throughout the conveyor or conveyor system. Where an otherwise uncontrolled hazard could exist at a loading, unloading or transfer point in a conveyor system, the conveyor system shall be designed to operate in sequence and be provided with automatic stop controls which are designed to prevent the hazard from arising. 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, should not prevent the restarting of the system after resetting, provided that— (a)
the stopping device is labelled to indicate that the conveyor will restart upon resetting the device; and
(b)
where this control is in a position from which the whole of the system cannot be viewed and there is a possibility of accidents arising from the starting of the conveyor, a warning signal in accordance with Clause 2.7.5 shall be provided. NOTE: This stop control may be wired into electronic control equipment.
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2.7.9 Pull wire requirements 2.7.9.1 General Pull wires shall not be used as substitutes for guards. Where used as an emergency stop control 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 N when applied midway between supports and at right angles to the axis of a pull wire with 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 moves freely when pulled and does not become disengaged from the support. NOTE: A maximum spacing of 6 m should apply.
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(e)
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Materials used for pull wires shall be of adequate strength, be protected against environmental conditions and be suitable for handling without the need for additional protection being worn by operators. NOTE: Where more than one switch is used in a pull wire system, a visual indicator should be provided 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 m from 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 pull wire requirement of Item (e) may be raised provided the pull wire is lower than all nip or shear points; and
(g)
where it is possible for a person to be inadvertently on a moving conveyor, an emergency stop should be provided and be located no closer to the conveyor discharge 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.
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NOTES: 1 The requirements of Clause 2.7.9 relating to pull wires may be replaced by an alternative emergency 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 WIRE—OPERATING DIRECTION REQUIREMENTS www.standards.com.au
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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 enclosures and 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 suitable energy limiting devices. These devices include but are not limited to— (a)
electrical overload limiters;
(b)
fluid couplings;
(c)
shear pins; and
(d)
pressure relief valves.
Where a shear pin is used, a description of the size and type of material of the shear pin shall 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 facilities Where a fire hazard exists on a conveyor or conveyor system, firefighting facilities appropriate 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 design of 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 Lubricants Oils and lubricants should be effectively contained. Accumulated spilled oils and lubricants should be controlled sufficiently to minimize any potential fire hazards. 2.8.5 Accumulation of combustible materials
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The accumulation of combustible material resulting from the operations of a conveyor shall be controlled to prevent contact with the moving parts of the conveyor. This may be achieved by the installation of easily maintained scrapers, loading point skirting, shedder plates 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 than 300 mm should be provided for this purpose but, in no case shall this clearance be less than 150 mm. 2.9 MARKINGS, SIGNS AND IDENTIFICATION 2.9.1 General Where appropriate, permanent markings, signs and identification plates shall be in accordance with AS 1318 and AS 1319. Where a hazard could exist from the misinterpretation 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 be permanently attached. Markings, signs and labels shall be installed or positioned so that they 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 at the drive and detailing the following: (a)
The manufacturer’s and suppliers’s 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 loading point. For overhead chain type conveyors the safe working load shall be indicated as mass per 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 with markings, signs or labels in writing clearly indicating the purpose of the control. Not withstanding the generality of this requirement, the following shall also apply: 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 pull wire is used e.g. emergency stop.
(d)
Signs shall be provided at the isolating devices provided for in Clauses 2.7.3 and 2.7.4 which clearly indicate the function and purpose of the device. See Clause 6.3.3 for specific requirements for remote isolating devices.
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(a)
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S E CT I ON
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3.1 GENERAL Guards shall be designed and provided to prevent access to danger zones unless the danger zone is guarded by location or position. Guards shall be included in the design of the conveyor 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 lifted into 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 the event 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 or inspection purposes. NOTE: For example, interlocking may be achieved by a pull wire operated stop switch in accordance 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 the requirements 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 torque converters.
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3.2.2 Materials Guards shall be made of solid material, mesh or equivalent construction. Sheet metal guards should not be less than 1.5 mm thick. Mesh guards should not be less than 1.5 mm wire gauge, 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 as follows: (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 guard and a simultaneous horizontal force of 220 N applied to points selected to establish the strength of the guard. The required clearances from the danger zone shall be maintained when a force of 450 N is applied at point on a guard over a square area of 50 mm × 50 mm.
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3.2.4 Reach dimensions and guard placement Except where stated elsewhere the design and construction of guards and their subsequent location shall be such that the safety distance from any nip point or shear point to the nearest 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 least 25 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 least 200 mm from the nip or shear point.
(c)
For fence type guards the maximum distance between the underside of the fence and the floor shall be 200 mm. The location of the nip or shear point may reduce this dimension.
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 or area 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 should extend for a minimum distance of 1000 mm from the hazard (see Figure 3.1). This distance shall be increased to 1150 mm when the pulley diameter is greater than 1000 mm. Where fixed enclosure guards cannot be used, fixed distance guards or nip guards shall be installed.
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Guarding of idler sets where required should be provided on the approach side and should extend for 1000 mm from the nip point. On the out-running side the guard should extend for at least 1000 mm beyond the nip point (see Figure 3.4).
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AS 1755—2000
DIMENSIONS IN MILLIMETRES
FIGURE 3.1 FIXED ENCLOSURE GUARD
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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 and constructed 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 prevent normal access to the danger zone, although climbing over this type of safeguard cannot be entirely 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 conveyor before access is obtained to the danger zone; and
(b)
a sign shall be provided at every access point through the fenced off area stating ‘DANGER—Isolate 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 width of the belt for the full length of the idler or pulley and shall be closely fitted to follow the felt 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 for nip guards at tail pulleys are shown in Figures 3.3(e) and 3.3(f).
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Where nip guards of alternative designs are used, which do not provide adequate protection, they should be fitted in association with fixed enclosure guards or fixed distance guards.
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DIMENSIONS IN MILLIMETRES
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FIGURE 3.2 (in part) FIXED DISTANCE GUARD
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FIGURE 3.2 (in part) FIXED DISTANCE GUARD
DIMENSIONS IN MILLIMETRES
AS 1755—2000 26
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AS 1755—2000
DIMENSIONS IN MILLIMETRES
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
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Shear points and nip points in locations less than 2.5 m above any access floor, platform level, 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 the gap between any moving part of the conveyor and any fixed equipment is greater than 4 mm and less that 120 mm.
(b)
As an alternative, pop-out rollers or dead plates which, when operating, allow a minimum clearance of 120 mm to be maintained, may be provided. The force required to 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 projections exceeding 6 mm in height, or where there is any type of attachment to the moving part, the minimum clearance of 120 mm shall be maintained between the highest point of the projection and the fixed equipment.
(d)
The requirements of this Clause need not apply to nip points associated with those belt conveyor idlers which comply with the requirements of Clause 5.8.
DIMENSIONS IN MILLIMETRES
FIGURE 3.4 IDLER SET GUARDS—FIXED 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 with suitable 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 shall be 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 into working areas below. Open chutes should be provided with plates at the point where conveyors 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 personnel during normal operation of the plant. Where a hazard exists from moving equipment behind inspection doors, the doors shall be lockable, 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 discharge point, guards in the form of guard-rails, fences, or close fitting guards shall be installed to prevent 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 moving parts of the conveyor or into the opening, guard railing and toeboards shall be provided in accordance with AS 1657. 3.3.6 Falling materials
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Where a hazard can be created by the material being conveyed falling into or being projected into an accessible area, then guarding shall be provided. Consideration should be given 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 be avoided by making the first idle roller free to move away along an incline ‘A’ cut in the sides of the conveyor. The angle of the incline is so arranged as to prevent lateral movement of the roller during the passage of goods from the belt to the idle roller conveyor. Care should be taken to ensure that the weight and dimensions of the loads being conveyed do not prevent the roller from lifting. In some installations more 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 accordance with 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 the hazard 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
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Removable guards shall be clearly labelled as follows, at intervals not greater than 10 m: ‘DANGER—Isolate energy source before removing guard’.
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4.1 GENERAL The additional requirements below are relevant to the specific location in which the conveyor is to be installed or used and shall be included 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 or other 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, an appropriately located device providing visual indication as to the depth of any water or other 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 may become flooded. 4.2.5 Ventilation Tunnels, galleries and pits shall be adequately ventilated. Where ventilation is provided by mechanical means, systems shall be incorporated in the design to manage any risk arising from 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, an alternative means of egress shall be provided.
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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, the opening shall be guarded in accordance with AS 1657. Where it is not practical to have fixed barriers or guardrails fitted to a temporary opening, then temporary barriers or guardrails shall be provided. 4.2.8 Accumulated material Pits shall have adequate space for the accumulation of spilled material and means for the ready 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 provisions contained 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 are greater than 60 m in length; © Standards Australia
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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 permit transport 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 hazardous area in accordance with AS 2430 (all Parts), the electrical equipment used in the hazardous area 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 need for separate actuation of a start control, provided that a prestart warning in accordance with Clause 2.7.5 has been given. 4.5.3 Prestart warning
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A prestart warning system in accordance with Clause 2.7.5 shall be installed on every conveyor. This provision need not apply to conveyors controlled by a single operator who can readily see the full length of the conveyor and has access to a manually operated prestart 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 or conveyor 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 and non-metallic materials that may contact the conveyor belting shall be manufactured from material that has anti-static properties. These items include but are not limited to, scraper blades, ploughs, skirt rubber, pulley and idler lagging, skid bars and spliced joints. Anti-static properties shall conform with the requirements of AS 1333 or AS 1332, electrical resistance (Grades E and S belts). The electrical resistance shall be measured in accordance with AS 1334.9. 4.6.3.2 Anti-static measures Where a conveying system can introduce a risk arising from static electricity, for example from pneumatic bulk transfer conveyors, they shall be provided with means of static discharge. Guidance may be found in AS/NZS 1020. 4.6.4 Hazardous zone electrical equipment Where a regulatory body or user establishes a hazardous zone or area in underground working 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 fireresistant 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 lining.
(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. Accessed by DOWNER EDI LIMITED on 12 Jul 2006
NOTES: 1 2
Guidance on the selection of fire-resistant hydraulic fluids may also be found in ISO 7745. 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 drive locations and other areas where the risk of fire warrants this equipment. These are additional 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. The requirements are summarized in Table 4.1. © Standards Australia
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TABLE 4.1 PROTECTIVE STOP CONTROLS Parameter
Mandatory
Belt slip
x
Fluid coupling over-temperature
x
Brake over-temperature
Recommended
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 the belt. When the slip exceeds 10% the conveyor shall stop. This device may be over-ridden during 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 high temperature 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 stop the conveyor. 4.6.8.5 Brake release
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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 brake failing 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 side movement of the conveyor belt while operating. As a minimum, these devices shall be installed within 30 m of either side of any transfer point, drive head, loop take-up or place where a significant change in belt elevation occurs. NOTE: A timer may be fitted to prevent nuisance trips of the conveyor which may occur due to momentary tracking problems or to a small protrusion to the side of the belt. A self-resetting override 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 where the 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, devices should be installed to detect the overheating. The detection system shall not be selfresetting. 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 overtemperature monitoring device, hence, the use of a device which detects and stops inadvertent shaft rotation may prevent a fire.
4.6.8.9 Blocked chute Devices shall be installed to detect blockage of chutes incorporated in a conveyor or conveyor systems. 4.6.9 Accumulation of combustible materials
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In addition to the requirements of Clause 2.8.5, a space of not less than 300 mm shall be provided below the lowest part of the lowest belt surface except that at the first loading end of each conveyor system where the clearance shall be sufficient to prevent contact between the belt surface or any rotating element and any spillage.
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5.1 GENERAL The additional requirements below shall be included in the design and construction relevant to the specific conveyor type detailed 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 allowance for wear. 5.2.2 Spacing between slats The distance between slats when travelling in a straight line along a slat conveyor should be 25 mm, except that this gap may be increased in accordance with the safety distances given in AS 4024.1, or where alternative forms of guarding are provided in accordance with AS 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, and any other truck or fixed object. 5.3.3 Guarding of wheels
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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 CONVEYORS The distance between rollers of a roller flight conveyor shall not be greater than 25 mm except that this gap may be increased where the entire space under the top of the carrying rollers is a solid smooth bed eliminating any shear hazard or where shear and nip points are guarded. 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 within 2.5 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 provided for maintenance, yokes need not be specifically guarded provided that the clearance between 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 following free trolley from entering the open section of track. and the free trolley in the drop section shall be positively retained on the track. Means shall be provided to stop the descent of any drop section or to control its speed to not more than 125% of its normal operating speed; in any event its speed shall not exceed 500 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 its controls shall be designed to ensure that the trays cannot be at the loading points at the same time. Loading and unloading points shall be guarded by fixed guards extending a distance 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 loading and unloading point shall be provided with doors interlocked to stop the conveyor when the doors 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
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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 the conveyor 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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FIGURE 5.1 BELT CONVEYOR NIP POINT—GUARDING
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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 provided between a moving tripper, shuttle conveyor or radial conveyor and other objects likely to cause entrapment along the length of travel and at either end. Guards shall be provided to prevent any trapping between the travelling wheels and the rails. See Figure 5.2 for typical requirements. Where access is provided to, or across a travelling tripper, guards shall be provided to prevent any trapping between any fixed or moving object. Where a crossover or underpass is attached to a travelling tripper a suitable boarding switch should be provided. For a manually positioned tripper, a travel-locking device shall be provided.
DIMENSIONS IN MILLIMETRES
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FIGURE 5.2 TYPICAL GUARDS FOR TRAVELLING TRIPPER
5.10 SCREW CONVEYORS All casings, loading, delivery, drainage and inspection apertures or chutes of screw conveyors 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, a wire mesh screen shall be provided under the door or panel; such screens shall be designed and 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 stable under the stated loads and operating conditions. The design and construction of mobile and transportable conveyors shall take into account the magnitude, incidence, condition and manner of loading, including possible overloads and all other forces likely to be allied to the conveyor under the operating conditions. 5.12.2 Margin of stability The margin of stability shall be determined for mobile and transportable conveyors under the combined effects of— (a)
wind loading;
(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 the following equation: ⎛a ⎞ m = 100 × ⎜ − 1⎟ ⎝b ⎠ 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 metres
b=
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, stability shall be maintained in a condition of under-inflation or loss of air in one or more of the tyres.
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5.12.4 Boom mounting The boom or trunking shall be mounted on the chassis, base or wheels. The plan distance at right angles to the boom or trunking between the chassis, base, or wheels shall not be less than 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 prevent unwanted 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 and transportable conveyors. NOTE: Reference should be made to traffic rules for transporting or operating conveyors on public 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 the power is removed from the raising or lowering medium. A screw or helix type brake fulfils this 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 requirements of AS 3569 and AS 2759 with respect to the minimum factor of safety and ratio of rope diameter 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 the rope 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 shall be 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 to the ground or floor level, unless measures are taken to ensure that the elevated boom or trunking has its descent controlled to a safe regulated speed. The boom raising frame shall not 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 lowered elevation or being transported, it cannot rest upon the conveyor drive.
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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 the driving controls of a mobile conveyor. This applies to mobile or transportable conveyors which have any parts that can be raised in excess of 2000 mm. See Figure 5.3 for a typical sign. 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 distribution lines carrying up to 132 kV on poles
.................
(b)
For transmission lines carrying greater than 132 kV on towers
...........
3 m. 8 m.
5.12.9.5 Movement of transportable conveyors Transportable conveyors shall be moved to another location only after the boom or trunking has been lowered into its transportable position. A warning notice advising this requirement shall be prominently displayed on the conveyor. © Standards Australia
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FIGURE 5.3 TYPICAL WARNING SIGN FOR OVERHEAD POWER
5.12.10 Internal combustion engine drive
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Where an internal combustion engine is used as the conveyor drive power, the following shall apply: (a)
The conveyor shall be fitted with overspeed protection designed to stop the drive in the event of the maximum design speed being exceeded.
(b)
The conveyor shall be fitted with a fire extinguisher of suitable capacity and type to extinguish a fire arising from the combustion of fuel.
(c)
The conveyor shall be fitted with a sign, in a conspicuous position, warning of the hazard arising from the exhaust fumes of the engine. This warning shall include particular reference against use of the conveyor in non-ventilated or confined spaces.
(d)
Due consideration should be given to the control of static electricity (see AS/NZS 1020).
(e)
Where manual starting mechanisms are fitted to the motor, the design shall not create a hazard to the operator. NOTE: It is recommended that impulse, spring or permanently attached cord type starters be provided for this purpose.
5.12.11 Electrical cables Where electrical cables are subject to movement or vibration, such cables shall be of the flexible type and be— (a)
protected to prevent damage; and
(b)
attached to the conveyor to prevent undue strain on the electrical connections or cable.
Residual current devices should be provided to circuits feeding mobile conveyors. www.standards.com.au
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A sign shall be attached to the conveyor stating—‘This equipment should be connected only to 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 not less than four teeth or dogs. Tooth or dog type clutches shall be designed and constructed to prevent inadvertent disengagement. 5.12.13 Guarding In addition to and in accordance with the requirements of Section 3, mobile and transportable conveyors shall be fitted with guards on— return side idlers less than 2.5 m from any access floor or platform level or at any other 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 guards or aprons extending to an effective height of 100 mm;
(e)
exposed screws, chains or flights in hoppers designed to prevent contact with moving parts;
(f)
return side chains with flights, typically by positioning the chain to prevent contact by 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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(a)
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DIMENSIONS IN METRES
FIGURE 5.4 CLEARANCES FROM OVERHEAD POWER LINES
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S E CT I ON
6
S AFE WOR K
P R ACT I CE S
6.1 GENERAL This Section deals with safework practices to be developed, implemented and maintained by owners and users to ensure the safe installation, operation, maintenance and dismantling of conveyors and conveyor systems. The minimum requirements for safework practices are detailed in this Section. However, the owner should also carry out appropriate risk assessments to establish the safework practices for the activities associated with the conveyor or conveyor systems under the owner’s control. In addition, a comprehensive system of audits and checks shall be introduced to measure the effectiveness of the safework practices. Where these practices are found to be deficient the owner shall implement changes to correct the deficiency. 6.2 INFORMATION TO BE SUPPLIED AND MAINTAINED 6.2.1 General Documentation shall be provided, used and maintained for the operation of the conveyor or conveyor system provided for in this Standard. Documentation shall include but be not limited to synopses of plant, installation, commissioning, dismantling, operating and maintenance instructions. In each area where information is required, identification of potential hazards and their control shall be included. All information shall be presented in English (and other languages where necessary) and be in a logical sequence with clear illustrations. Where risk assessments are undertaken, documented evidence of such assessment shall be recorded and maintained. 6.2.2 Synopsis of plant The owner shall maintain information regarding the synopsis of plant supplied by the manufacture and designer of the conveyor or system or system components.
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The following information shall be included in the synopsis of plant: (a)
Design capacities and criteria of the conveyor system and its components.
(b)
General arrangement drawings including identification of system components.
(c)
Schematic and logic drawings of power and control facilities.
(d)
Parts identification including reorder details.
(e)
Lubrication requirements.
6.2.3 Installation, commissioning and dismantling The owner shall maintain information regarding the installation, commissioning and dismantling of the conveyor or conveyor system including requirements of the manufacturer and designer. The following information shall be provided and maintained: (a)
Installation procedures.
(b)
Dismantling, transport or removal procedure.
(c)
Pre-operational servicing procedures including lubrication requirements.
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(d)
Procedures for the adjustment and setting of controls.
(e)
Commissioning and testing procedures.
(f)
Records of data collected during commissioning.
(g)
A copy of each programmable logic controller program.
(h)
Transport weights and identification of lift points.
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6.2.4 Operating and maintenance instructions The owner shall maintain information regarding the operation and maintenance of the conveyor or conveyor system including requirements of the manufacturer and designer. The following information shall be provided and maintained: (a)
Loading and unloading instructions including ergonomic requirement.
(b)
Maintenance instructions and schedules which include lubrication testing, inspection and repair procedures.
(c)
Operating instructions which incorporate clear instructions for the operation of the conveyor system from start up to shut down including all possible sequences of control.
(d)
Emergency procedures.
6.3 SAFEWORK PROCEDURES 6.3.1 General Safework procedures shall be developed by the owner and incorporated into the operation of the conveyors or conveyor systems. 6.3.2 Access or work in a danger zone Access to, or work in, a danger zone shall not be permitted while the conveyor is running. Where any access or work, except in accordance with Clause 6.3.3, is to be undertaken in a danger zone, the procedures shall include energy isolation of the conveyor by operation of the main isolation device (see Clause 2.7.3). All other sources of energy associated with the conveyor and which may create a hazard shall also be isolated in an appropriate manner.
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6.3.3 Work using remote isolating device When using a remote isolating device (see Clause 2.7.4) to isolate the conveyor, before any work is undertaken in a danger zone a specific risk assessment shall be carried out to establish whether this isolation method is appropriate for the work to be undertaken and safe work procedures shall be established. The risk assessment undertaken for this purpose shall have due regard to the limits of the work to be undertaken, consequence, hazard exposure time and the potential for failure of the isolation or pre-start warning systems. Where work using a remote isolating device is undertaken on a conveyor, a sign clearly stating the work that can be undertaken and a warning that the device is not to be used for other purposes, shall be placed in a conspicuous position affixed to the device. 6.3.4 Isolation systems The system of isolation adopted should incorporate a tagging system, a locking system or permit system and in any case shall also include a method for ensuring that isolation is effectively established.
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6.3.5 Installation, commissioning and dismantling procedures These procedures shall cover all work to be undertaken by trained and competent personnel involved with the installation, commissioning and dismantling of conveyors and shall include— (a)
site establishment including induction and training;
(b)
materials handling;
(c)
work methods;
(d)
minimum acceptance standards;
(e)
emergency plans;
(f)
documentation; and
(g)
modifications or repairs.
6.3.6 Operating procedures These procedures shall cover all work to be undertaken by trained competent operators and shall include— (a)
pre-checks;
(b)
hazard control;
(c)
isolation;
(d)
loading and unloading;
(e)
emergency;
(f)
shutdown; and
(g)
normal start/stop.
6.3.7 Maintenance procedures
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These procedures shall cover all work to be undertaken by trained competent maintenance personnel and shall include operating aspects contained in Clause 6.3.5 and the following: (a)
Isolation requirements for the type of maintenance being undertaken.
(b)
Access incorporating the removal and replacement of guards.
(c)
Competent replacement and repair.
(d)
Use of materials.
(e)
Use of tools and test equipment.
(f)
Housekeeping.
(g)
Inspection and periodic adjustments.
(h)
Breakdown activities.
(i)
Recording and documenting activities.
6.3.8 Maintenance management A maintenance management program shall be incorporated into the operation of conveyors or conveyor systems to ensure satisfactory operation while in service. The program shall include but is not limited to the following: (a)
Pre-operational servicing including lubrication requirements.
(b)
Periodic and or condition based servicing.
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(c)
Periodic inspections.
(d)
Testing and inspection of safety equipment.
(e)
Records, including but not limited to reporting overloads and damage.
(f)
Compliance auditing.
AS 1755—2000
6.4 TRAINING Competency based training shall be provided for installers, commissioners, dismantlers, operators and maintenance personnel and other persons exposed to a hazard from a conveyor. Such training shall be relevant to the procedures associated with installation, commissioning, dismantling, operating and maintenance of the conveyor or conveyor system. This training shall include but is not limited to the following: Safework practices including isolation procedures.
(b)
Emergency procedures.
(c)
Correct operation of the conveyor.
(d)
Hazard identification, reporting, control and management.
(e)
Reasons for protective devices including guards.
(f)
Selection and care of personal protective equipment.
(g)
Need for good housekeeping.
(h)
Statutory requirements.
(i)
Electrical and mechanical safety.
(j)
Document management and control.
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(a)
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APPENDIX A
GLOSSARY OF CONVEYOR TERMS (Normative) NOTE: The terms and definitions applicable to conveyors and conveying systems set out in this Appendix are accompanied by typical configurations for the purpose of clarity. However, this does not exclude other arrangements that achieve the same effect.
A1 ANTI-RUNBACK DEVICES A1.1 Anti-runback device for belt conveyors Consists of a full complement of shaped steel sprags or wedges, located in the annular space between concentric inner and outer races. Power is transmitted from one race to the other by the wedging action of the sprags between them. Rotation of one race in the ‘driving’ direction causes the sprags to tilt, thus transmitting the torque in full from one race to the other. Conversely, rotation of the race in the other direction frees the sprags and permits overrunning between the races (see Figure A1).
FIGURE A1 ANTI-RUNBACK DEVICE
A1.2 Anti-runback device for overhead chain conveyor
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A mechanical device to prevent reversal of a loaded conveyor under action of gravity when forward travel is interrupted (see Figure A2).
FIGURE A2 UPHILL SAFETY STOP © Standards Australia
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A1.3 Anti-runaway device for overhead chain conveyor A mechanical safety device to lock or catch the conveyor and prevent running away in the direction of travel in the case of failure (see Figure A3).
FIGURE A3 DOWNHILL RUNAWAY STOP
A2 APRON CONVEYORS A2.1 Apron conveyor
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A conveyor composed of interlocking or overlapping, flat or shaped plates, carried on chains and running on tracks (see Figure A4).
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FIGURE A4 APRON CONVEYOR
A2.2 Apron conveyor with pans
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An apron conveyor in which the sides and ends of the plates are turned upwards to form open pans (see Figure A5).
FIGURE A5 APRON CONVEYOR WITH PANS
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A3 BELT CONVEYORS A3.1 Belt conveyor A conveyor using a moving belt for the conveying medium. The belt is usually driven by a drum at one end, passing over a free-running drum at the other end. The upper portion of the belt may be supported by free-running idlers or suitable flat surfaces. This type of conveyor can be arranged for horizontal or inclined travel, the angle of slope depending on the character of the goods conveyed and the type of belt surface (see Figure A6).
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FIGURE A6 BELT CONVEYOR
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A3.2 Fixed belt conveyor A stationary mechanical item of plant designed for the conveying of materials and fitted with an endless belt of fabric, rubber, plastics, leather, or metal (see Figure A7).
FIGURE A7 FIXED BELT CONVEYOR
A3.3 Mobile belt conveyor
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A mobile conveyor with either adjustable or non-adjustable heights on wheels which is not self-propelled but carries continuous handling equipment (see Figure A8).
FIGURE A8 MOBILE BELT CONVEYOR © Standards Australia
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A3.4 Portable belt conveyor A portable conveyor with adjustable heights on stands, carrying continuous handling equipment (see Figure A9).
FIGURE A9 PORTABLE BELT CONVEYOR
A3.5 Belt conveyor, thrower or spreader A short high-speed belt conveyor, capable of throwing loose bulk material into otherwise inaccessible areas (see Figure A10).
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FIGURE A10 THROWER OR SPREADER
A3.6 Closed belt conveyor A conveyor composed of a moving belt capable of being formed into a closed tubular shape. While in motion the belt opens to receive the load, closes to convey it, and opens to discharge it (see Figure A11).
FIGURE A11 CLOSED BELT CONVEYOR www.standards.com.au
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A3.7 Telescopic belt conveyor A continuous belt consisting of a series of pulleys which permit extension or retraction of the conveyor length (see Figure A12).
FIGURE A12 TELESCOPIC BELT CONVEYOR
A3.8 Chain or wire rope belt conveyor
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A conveyor composed of a belt secured to transverse supports carried by moving wire ropes or chains. The chains or wire ropes transmit the driving force, the belt forming the loadcarrying medium (see Figure A13).
FIGURE A13 BELT CONVEYOR SUPPORTED AND MOVED BY WIRE ROPES OR CHAINS
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A3.9 STEEL BAND CONVEYOR A belt conveyor in which the carrying medium is a thin flexible steel band (see Figure A14).
FIGURE A14 STEEL BAND CONVEYOR
A3.10 WALLED BELT CONVEYOR
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A conveyor consisting of a moving belt having a flat carrying face extended to form side walls of limited height (see Figure A15).
FIGURE A15 WALLED BELT CONVEYOR
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A4 BARREL OR DRUM CONVEYOR A conveyor with arms fixed to the chains which may be set at a moderate angle to the vertical. Loading can occur at any intermediate floor but unloading can only occur as the arms pass over the top of the chain sprockets and discharge the load (see Figure A16).
FIGURE A16 BARREL OR DRUM CONVEYOR
A5 BUCKET CONVEYORS A5.1 Bucket elevator
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A conveyor for loose bulk materials with buckets as the carrying medium attached to a belt or chains as the driving medium (see Figure A17).
FIGURE A17 BUCKET ELEVATOR © Standards Australia
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A5.2 Gravity bucket conveyor A conveyor consisting of freely swinging buckets carried between parallel endless chains, the buckets being tipped to discharge contents. The centre of gravity of the bucket is below the centre-line of the chain pivot and thus the chain may follow any path from horizontal to vertical with the buckets continuing to hang vertically. Feeding of the buckets may be either by gravity or by means of a suitable rotary feeder (see Figure A18).
FIGURE A18 GRAVITY BUCKET CONVEYOR
A5.3 Pivoted bucket conveyor A conveyor using pivoted buckets attached between two endless chains. The buckets remain in a carrying position until tipped or inverted to discharge (see Figure A19).
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FIGURE A19 PIVOTED BUCKET CONVEYOR
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A5.4 Vertical internal discharge chain and bucket conveyor A totally enclosed continuous bucket conveyor with the bucket carried between two chains and having inner openings. The material is fed in at the foot of the conveyor and discharge occurs when the buckets are inverted while passing over the head sprockets, the material being delivered by means of a chute passing through a conveyor casing (see Figure A20).
FIGURE A20 INTERNAL DISCHARGE CHAIN AND BUCKET CONVEYOR
A6 CHAIN CONVEYORS A6.1 Chain conveyor A conveyor for unit loads, with an endless driving medium, e.g. chain or cable, and a series of trolleys supported by an overhead track. A6.2 Chain conveyor with driving dogs
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A chain conveyor with pusher dogs driving load-carrying trucks on a separate track or floor (see Figure A21).
FIGURE A21 CHAIN CONVEYOR
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A6.3 Drag chain conveyor A conveyor having one or more endless chains which drag bulk materials in a trough (see Figure A22).
FIGURE A22 DRAG CHAIN CONVEYOR
A6.4 Overhead chain conveyor (open track type) A conveyor which uses a biplanar chain suspended by wheeled trolleys which run on an overhead track (see Figure A23).
FIGURE A23 OVERHEAD OPEN TRACK CHAIN CONVEYOR
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A6.5 Overhead chain conveyor (enclosed track) A chain conveyor which uses a biplanar articulated chain which serves to transmit driving tension and carries the weight of the load. It has rollers disposed in the vertical and horizontal planes running in an enclosed track (see Figure A24).
FIGURE A24 OVERHEAD ENCLOSED TRACK CHAIN CONVEYOR www.standards.com.au
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A6.6 Single chain or crate conveyor A conveyor with a centrally located chain as the driving medium (see Figure A25).
FIGURE A25 SINGLE CHAIN OR CRATE CONVEYOR
A6.7 Swing chain conveyor, fork tray type
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A conveyor consisting of freely swinging finger type trays carried between parallel endless chains which swing at the change of direction to pick up on the feed side and discharge the feed on the downward side. The drive is generally at the head of the conveyor, the chains passing over sprockets of considerable diameter. Loading or unloading can be made automatic and can occur at any intermediate floor level (see Figure A26).
FIGURE A26 FORK TRAY SWING CHAIN CONVEYOR
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A6.8 Swing tray conveyor, solid tray type A vertical conveyor having one or more endless chains with suitable pendant trays, or carriers which receive and deliver packages or objects at one or more elevations (see Figure A27).
FIGURE A27 SOLID TRAY SWING CHAIN CONVEYOR
A6.9 Roller flight conveyor (accumulating)
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A conveyor having double strands of chain connected by spindles supporting freely rotating load-carrying rollers (see Figure A28).
FIGURE A28 ACCUMULATING ROLLER FLIGHT CONVEYOR
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A6.10 Vertical chain conveyor, opposed shelf type Two or more elevating conveying units opposed to each other. Each unit consists of one or more endless chains whose adjacent facing runs operate in parallel paths so that pairs of opposing shelves or brackets are synchronized to receive packages or trays and deliver them at any number of elevations. (The auto-unload type is illustrated in Figure A29.)
FIGURE A29 OPPOSED SHELF VERTICAL CHAIN CONVEYOR
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A6.11 Flight conveyor (push-type) A conveyor comprising one or more endless chains or links to which flights are attached (see Figure A30).
FIGURE A30 PUSH TYPE FLIGHT CONVEYOR © Standards Australia
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A6.12 Pallet type conveyor A conveyor assembled from a series of flat or shaped wheelless carriers propelled by and attached to one or more endless chains or other linkage (see Figure A31).
FIGURE A31 PALLET CONVEYOR
A7 CROSS-BAR CONVEYOR A conveyor consisting of two strands of chain connected together by fixed bars from which unit loads are suspended (see Figure A32).
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FIGURE A32 CROSS BAR CONVEYOR
A8 DISC OR BUTTON CONVEYOR A conveyor composed of a wire rope or chains carrying discs or buttons and operating in a V-shaped trough (see Figure A33).
FIGURE A33 DISC OR BUTTON CONVEYOR
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A9 FLIGHT CONVEYOR (RECIPROCATING) A conveyor consisting (see Figure A34).
of
a
reciprocating
beam
with
attached
hinged
flights
FIGURE A34 RECIPROCATING FLIGHT CONVEYOR
A10 POCKET CONVEYOR A conveyor consisting of a series of pockets made of flexible materials and festooned between cross-rods carried by two endless chains or other linkage (see Figure A35).
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FIGURE A35 POCKET CONVEYOR
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A11 TRUCK-TOWING CONVEYORS A11.1 Floor truck-towing conveyor A moving endless chain or wire rope carried in a trench and mounted above or below floor level, to which load carrying tow trucks are attached by means of a retractable pin (see Figure A36).
FIGURE A36 FLOOR TRUCK-TOWING CONVEYOR
A11.2 Single strand floor-mounted truck conveyor
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A conveyor for unit loads with a single strand chain or wire rope under or above floor level as the driving medium (see Figure A37).
FIGURE A37 SINGLE STRAND FLOOR-MOUNTED TRUCK CONVEYOR
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A12 MAGNETIC CONVEYOR A conveyor having a flexible rubber or canvas belt moving adjacent to a static magnetic field which imparts a retaining influence or pull to any magnetizable article and so allows the belt to move the article through vertical and horizontal planes (see Figure A38).
FIGURE A38 MAGNETIC CONVEYOR
A13 OSCILLATING CONVEYOR A conveyor similar to a vibrating conveyor but of the slow-speed type, using an eccentric crankshaft to move the trough or tube (see Figure A39).
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FIGURE A39 OSCILLATING CONVEYOR
A14 PLATE CONVEYOR A continuous conveyor for loose bulk materials or unit loads (see Figure A40).
FIGURE A40 PLATE CONVEYOR
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A15 POWERED ROLLER CONVEYOR A series of rollers over which packages or objects are moved by the application of suitable power means to all or a part of the rollers (see Figure A41).
FIGURE A41 POWERED ROLLER CONVEYOR
A16 RECIPROCATING BEAM CONVEYOR
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A conveyor assembled with one or more reciprocating beams with tilting dogs or pushers (see Figure A42).
FIGURE A42 RECIPROCATING BEAM CONVEYOR
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A17 SCREW CONVEYORS (See Figure A43) A17.1 Screw conveyor A conveyor for loose bulk materials with a trough or tube as the carrying medium, the material being transported by the action of a rotating helix or broken screw (paddle type). A17.2 Screw tube conveyor A screw conveyor for transporting bulk materials by means of a close-bladed screw.
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FIGURE A43 SCREW CONVEYOR
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A17.3 Vertical screw tube conveyor A screw conveyor for transporting bulk materials vertically (see Figure A44).
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FIGURE A44 VERTICAL SCREW TUBE CONVEYOR
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A17.4 Screw conveyor, trough type A revolving pipe or shaft on which is mounted helically shaped flighting which serves to convey bulk materials along the trough or a defined path (see Figure A45).
FIGURE A45 TROUGH TYPE SCREW CONVEYOR
A17.5 Screw conveyor, paddle type A screw conveyor which is similar to the full-bladed type, but the conveying elements are in the form of separate paddles of various shapes attached to the central shaft in a helical pattern, allowing mixing of the material during conveying (see Figure A46).
FIGURE A46 PADDLE TYPE SCREW CONVEYOR
A17.6 Screw conveyor, ribbon type
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A screw conveyor which is similar to the full-bladed type except that the helix is in the form of a ribbon attached to the central shaft by ‘palm-bolts’ (see Figure A47).
FIGURE A47 RIBBON TYPE SCREW CONVEYOR
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A18 SHUTTLE CONVEYOR Any conveyor such as a belt, chain, pan, apron, screw and the like in a self-contained structure movable in a defined path parallel to the flow of the material (see Figure A48).
FIGURE A48 SHUTTLE CONVEYOR
A19 SLAT CONVEYORS A19.1 Slat conveyor One or more endless chains to which non-overlapping, non-interlocking spaced slats are attached to form a moving support for the packages or objects being conveyed (see Figure A49).
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FIGURE A49 SLAT CONVEYOR
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A19.2 Slat conveyor with pushers A slat conveyor for loose bulk materials or unit loads with slats and pushers as the carrying medium and with chains as the driving medium (see Figure A50).
FIGURE A50 SLAT CONVEYOR WITH PUSHERS
A19.3 Slat band conveyor
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A light duty flat top conveyor in which small hinged plates serve as both the chain and the work carrying plates. This conveyor provides a flat, smooth and level surface commonly used to transport cans and bottles (see Figure A51).
FIGURE A51 SLAT BAND CONVEYOR
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A20 TWIN FLAT TOP CONVEYOR A conveyor which utilizes two heavy duty flat top lines commonly set flush in the floor and driven by a single head shaft to transport large, heavy, or wide objects such as a complete motor vehicle, rolls of paper or sheet steel (see Figure A52).
FIGURE A52 TWIN FLAT TOP CONVEYOR
A21 HINGED SECTION A hinged section, inserted in a roller conveyor, and counterbalanced to facilitate the upward tilting of the section to produce a clear way through the conveyor track (see Figure A53).
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FIGURE A53 HINGED SECTION
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A22 TRIPPER A moveable part of a conveyor, typically mounted on wheels, used for discharging material at selected locations along its length (see Figure A54).
FIGURE A54 TRIPPER
A23 TROLLEY CONVEYOR
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A conveyor consisting of a series of trolleys supported from or within an overhead track connected by an endless chain, cable, or other linkage with loads suspended from the trolleys (see Figure A55).
FIGURE A55 TROLLEY CONVEYOR
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A24 VIBRATING CONVEYOR A trough or tube flexibly supported and vibrated to convey bulk material or objects (see Figure A56).
FIGURE A56 VIBRATING CONVEYOR
A25 WIRE MESH BELT CONVEYOR A conveyor in which the carrying medium is of mesh construction, either flat or troughed, while the conveyor itself may be straight or curved (see Figure A57).
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FIGURE A57 WIRE MESH BELT CONVEYOR
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APPENDIX B
REFERENCED DOCUMENTS (Normative) The following documents are referred to in this Standard:
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AS 1121
Guards for agricultural tractor PTO drives
1318
Use of colour for the marking of physical hazards and the identification of certain equipment in industry (known as the SAA Industrial Safety Colour Code)
1319
Safety signs for the occupational environment
1332
Conveyor belting—Textile reinforced
1333
Conveyor belting of elastomeric and steel cord construction
1334 1334.9
Methods of testing conveyor and elevator belting Part 9: Determination of electrical resistance of conveyor belting
1657
Fixed platforms, walkways, stairways and ladders—Design, construction and installation
1680 1680.2.1
Interior lighting Part 2.1: Circulation spaces and other general areas
2380
Electrical equipment techniques (all Parts)
2430
Classification of hazardous areas (all Parts)
2759
Steel wire rope—Application guide
2865
Safe working in a confined space
3569
Steel wire ropes
3997 3997.2
Fluid power—Fire resistant hydraulic fluids Part 2: Guidance on the selection, use and storage
4024 4024.1
Safeguarding of machinery Part 1: General principles
AS/NZS 1020
The control of undesirable static electricity
2381
for
explosive
atmospheres—Explosion-protection
2381.1
Electrical equipment for explosive atmospheres—Selection, installation and maintenance Part 1: General requirements
3000
Electrical installations (known as the Australian/New Zealand Wiring Rules)
3931
Risk analysis of technological systems—Application guide
4360
Risk management
ISO 7745
Hydraulic fluid power—Fire resistant (FR) fluids—Guidelines for use
Worksafe Australia NOHSC:1001 (1990)
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National Standard for Manual Handling
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APPENDIX C
ERGONOMIC DATA (Normative) C1 GENERAL The data below are for users who need to design and build guards that prevent persons from encroaching into a danger zone associated with a machine. They are taken from AS 4024.1—1996, and the most recently published version of that Standard should be used, except for the specific variations detailed in Figure C4 herein. Users should carefully consider whether the data are appropriate for use with the specific workforce which may be taller, shorter or thinner than the population from which the data were taken. Where doubt exists, measurements of the workforce may be taken and careful trials made to ensure that the danger points are beyond reach. Where such trials are made, the machinery shall be in a safe condition during the trials. C2 REACHING UP
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With the body upright and standing at full height, the minimum safety distance when reaching upward is 2500 mm (see Figure C1).
FIGURE C1 SAFETY DISTANCE FOR REACHING UP
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C3 UPPER LIMB REACH DISTANCE WITH FIXED FENCES C3.1 General Selection of the appropriate safety distance for reaching over a fixed fence shall depend on a risk assessment. The assessment shall be based on the probability of occurrence of injury and the likely severity of that injury. C3.2 Reaching down and over When reaching down over an edge, e.g. on machine frames or barriers, the safety distance is found from Figure C2. NOTE: Attention is drawn to the increased danger of overbalancing when reaching over a 1 m high barrier.
C3.3 Reaching under
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Where clearance is provided under a guard for cleaning spillages, swarf and similar, the clearance should not exceed 200 mm. (See also Figure C3.)
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Height of danger zone ( h)
Horizontal distance to danger zone ( s) Height of protective structure ( u)* 1 000†
1 200†
1 400†
1 600†
1 800
2 000
2 200
2 400
2 500
2 500
—
—
—
—
—
—
—
—
—
2 400
100
100
100
100
100
100
100
100
—
2 200
600
600
500
500
400
350
250
—
—
2 000
1 100
900
700
600
500
350
—
—
—
1 800
1 100
1 000
900
900
600
—
—
—
—
1 600
1 300
1 000
900
900
500
—
—
—
—
1 400
1 300
1 000
900
800
100
—
—
—
—
1 200
1 400
1 000
900
500
—
—
—
—
—
1 000
1 400
1 000
900
300
—
—
—
—
—
800
1 300
900
600
—
—
—
—
—
—
600
1 200
500
—
—
—
—
—
—
—
400
1 200
300
—
—
—
—
—
—
—
200
1 100
200
—
—
—
—
—
—
—
0
1 100
200
—
—
—
—
—
—
—
* Protective structures less than 1000 mm height are not included because they do not sufficiently restrict movement of the body. †Protective structures having a height of 1600 mm and less should only be used where a risk assessment indicates low probability and low severity of injury. NOTES: 1
There should be no interpolation of the values in the Table.
2
Barriers are not foolproof and they cannot prevent access to persons intent on gaining access. Therefore, as a person's intent on reaching a dangerous part increases, e.g. by climbing on chairs, ladders or the barrier itself, the protection provided by a barrier decreases. DIMENSIONS IN MILLIMETRES
FIGURE C2 GUARD DISTANCES
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C4 REACHING AROUND WITH UPPER LIMBS When reaching around edges in any position, the safety distance of freely articulating upper limbs is given in Figure C3. The radius of the movement about a fixed edge is determined by the reach of given body parts. The safety distances assigned should be respected as a minimum if the body part concerned is not to be allowed to reach a danger point. Of special importance is the danger area which can be reached when these body parts are introduced through slots. When applying safety distances, it is to be assumed that the basic joint component of the relevant body part is in fixed contact with the edge. The safety distances apply only if it is ensured that further advance or penetration of the body part towards the danger point is excluded.
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Limitation of movement
Safety distance (sr)
Limitation of movement only at shoulder and -armpit
≥ 850
Arm supported up to elbow
≥ 550
Arm supported up to wrist
≥ 230
Arm and hand supported up to knuckle joint
≥ 130
Illustration
* Either the diameter of a round opening, the side of a square opening or the width of a slot opening. DIMENSIONS IN MILLIMETRES
FIGURE C3 SAFETY DISTANCES FOR REACH ROUND
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C5 REACHING IN AND THROUGH REGULAR OPENINGS WITH UPPER LIMBS Safety distances are as given in Figure C4. The dimension of openings (e) correspond to the side of a square opening, the diameter of a round opening or the narrowest dimension of an elongated opening or slot. Should any opening allow access past the shoulder, safety distances shall be selected using Figure C2.
Part of body
Fingertip
Finger up to knuckle joint or hand
Arm up to junction with shoulder
Illustration
Safety distance ( sr )
Opening Slot
Square
Round
e≤4
≥2
≥2
≥2
4
