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A User's Guide to Conveyor Belt Safety
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1. For these measures to produce the desired results and given the serious hazards associated with conveyors they should incorporate the following recommendations gt Operation control devices including two hand controls should require hold to run input gt The operation control device used by the worker should have priority over all other control devices on the machine gt When maintenance is carried out by more than one worker while some hazards may be reduced those related to machine operation controls may increase establish a clear communication procedure to ensure clear communication between workers gt Prohibit the use of remote wireless operation controls gt Control cables should be long enough to allow visual contact with the danger zone all the while making access to the danger zone impossible 5 4 Summary of Maintenance Safeguards Table 2 4 lists the safeguards required when carrying out most maintenance activities on conveyor belts or in proximity to conveyor belts They should be addressed in maintenance procedures The inching forward of an operation control should allow limited advance in separate steps no further advancement of machinery should be allowed until the operator releases the control device and then actuates the controls anew 56 Table 2 4 Safeguards for Maintenance Activities Activity Safeguards Repairs Changing mechanical electrical hydraulic or pneumatic parts on
2. 28 2 6 1 Power Transmission Moving Parts Hazards Drive shaft shaft end sprocket pulley chain drive belt gear coupling Possible Consequences Drawing in and crushing Entanglement of a loose piece of clothing in a protruding moving part Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding fixed guards figures 2 13 to 2 16 FIGURE 2 13 SURROUNDING FIXED FIGURE 2 14 SURROUNDING FIXED GUARD FOR PULLEYS AND GUARD FOR COUPLINGS POWER TRANSMISSION BELTS NYY al Je FIGURE 2 15 SURROUNDING FIXED FIGURE 2 16 SURROUNDING FIXED GUARD FOR SHAFTS GUARD FOR SHAFT ENDS Note Extend grease points and belt tension adjusters outside the guards Regulation Respecting Occupational Health and Safety specifi cations are 2 1 m but international standards specify 2 5 m 29 2 6 2 Belt Hazard Belt in good condition Possible Consequences Depending upon the speed and belt characteristics Friction burns or abrasion Impact with belt drawing in Protective Measures If hazard is less than 2 5 m from the floor or working platform Upper Strand Work station Install guard in accordance with risk analysis results Lower Strand Work station Install guard in accordance with risk analysis results Throughway parallel to conveyor figure 2 17 Install guardrail in accordance with risk analysis results Throughway passing under conve
3. General Principles In and around conveyor belts there are many danger zones as defined in section 172 of the Regulation Respecting Occupational Health and Safety Hazards are located in danger zones Sections 182 to 184 of the regulation stated above describe provisions relating to the installation of guards and protective devices on machines Section 373 of Regulation Respecting Occupational Health and Safety in Mines describes the various safety devices that must be installed on a conveyor belt Section 3 10 13 of the Safety Code for the construction industry specifies the general features of safety devices and guards According to the regulations a conveyor must be constructed in such a way as to not allow access to danger zones or by default must be equipped with guards and protective devices section 182 of the Regulation Respecting Occupational Health and Safety It is also possible to use deterrent devices Various types of protectors and deterrent devices on a conveyor belt are described below Safety requirements for conveyor sub assemblies are also described Preventative measures for hazards related to conveyor operation must be implemented when the hazard is 2 5 m or less from the floor or working platform Guards A guard is a machine element that makes the danger zone inaccessible by isolating it section 172 of the Regulation Respecting Occupational Health and Safety Guards on conveyor belts must be design
4. Gravity system a guided weight pulls the tensioning drum figure 1 1 4e to provide the required tension 5b Manual or self adjusting system adjustment screws or automatic control systems provide the required tension 6 Power Transmission Moving Parts Function To produce and transmit the required energy to the live drum for moving or restraining the belt Many combinations are possible gt A geared motor is mounted directly to the live drum shaft or is integrated into the live drum gt The motor and speed reducing units are connected by couplings gt Chains or belts are used between the motor and the live drum shaft 7 Loading System Function To guide and control the load feed on the belt figure 1 3 There are many possible systems hoppers chutes automatic loaders pushers etc Hoppers usually contain the following parts 7a Hopper assembly Guides contains and sometimes controls the bulk load feed 7b Skirtboard Centers the load on the belt or redirects the load The skirt 7c is bolted on to it 7c Skirt Stops loose material from leaking off the belt and holds fine material that can be fairly good sized grain 7 LOADING SYSTEM 7a Hooper Assembly 7b Skirtboard 7c Skirt FIGURE 1 3 TYPICAL BULK LOADING SYSTEM 8 Unloading Mechanism Function To guide the load exiting the conveyor system Various devices may be used chutes slides automated systems ejectors packagers etc 9 Be
5. need to be operational Note Should the removal of material accumulation from an operating conveyor become frequent consider installing an operator work station Conveyor parts cleaning or maintenance drums rollers chassis etc Lockout procedures apply Operation authorized if housekeeping can be done gt With an automated jet air or water or gt According to section 5 3 above See also paragraph 3 4 Fire and Explosion Hazards 57 Inspection Visual and auditory inspection Permissible at all times as long as the worker remains outside the danger zone If the conveyor remains operational while the worker enters to make contact with a machine part for example to measure vibrations the point where the measurements are taken must be protected by a guard If a conveyor must remain operational while a guard is removed apply measures in section 5 3 Lockout for all other cases for example mechanical free play measurements Unclogging unjamming Lockout procedures apply Apply measures in section 5 3 should the conveyor need to be operational Maintenance activities not Lockout procedures apply at all times covered above Unclogging may create new specific hazards which must be analyzed before starting work hazard of falling in the hopper etc 58 6 6 1 6 2 Operator and Maintenance Crew Training All operators and maintenance workers who work on or
6. procedures during maintenance requiring access to danger zones For more information on the operation of emergency stop devices consult ISO Standard 13850 and NF EN 60947 5 5 53 4 4 Emergency Stop Pull Cords According to section 373 5 of the Regulation Respecting Occupational Health and Safety in Mines all conveyors must be equipped where the workers may access a conveyor while it is in operation with an emergency shut down device along its full length between the head pulley and the return pulley tail pulley Therefore for all mines the emergency shut down device must take the form of a cable spanning the full length of the conveyor In other workplaces an emergency stop cable may not be necessary where another shut down device has been installed in accordance with section 270 of the Regulation Respecting Occupational Health and Safety A sheathed metal strand cable shut down device must function as an emergency stop switch whatever direction the cable is pulled in or when it is broken A spring failure must also create an emergency stop A horizontal force of less than 125 N must be all that is needed to activate an emergency stop cable when applied midway between two support rings and perpendicularly to the cable The lateral movement of the cable between the position while at rest and the activation point must not exceed 300 mm The cable must be able to resist a tension force 10 times greater than the tens
7. 31 ONTARIO PRINTING AND IMAGING ASSOCIATION INDUSTRIAL ACCIDENT PREVENTION ASSOCIATION AND WORKPLACE SAFETY INSURANCE BOARD Printing Industry Health and Safety Guide 2002 S D lt lt Manutention en vrac des solides Technologies et crit res de choix gt gt Informations Chimie n 326 mars 1991 p 148 153 SCHULTZ George A Conveyor Safety Requirements when Using Older Equipment American Society of Safety Engineers Professional Safety May 2001 SCHULTZ George A Conveyor Safety Safety in the Design and Operation of Material Handling Systems American Society of Safety Engineers 2000 69 SCHULTZ George A What a Safety Engineer Should Know About Conveyor Safety ASSEs 2001 Professional Development Conference June 2001 SMANDYCH R Susan et al Dust Control for Material Handling Operations a Systematic Approach American Industrial Hygiene Association Journal vol 58 no 2 Febuary 1998 p 139 146 SLJOKAS Jouko Evaluation of the Effect of Safety Regulation Case Studies in Press and Conveyor Regulations Safety Science vol 16 No 3 4 1993 p 307 324 MACHINE SAFETY AFNOR NF EN 292 2 S curit des machines Notions fondamentales principes g n raux de conception partie 2 Principes et sp cifi cations techniques d cembre 1991 AFNOR NF EN 292 2 A1 S curit des machines Notions fondamentales principes g n raux de conception partie 2 Principes et sp cifications t
8. Door panel component frame Hex key hold Latch sub assembly Spring latch bolt FIGURE A 2 TYPICAL QUARTER TURN KEYED SPRING LATCH Fasteners should remain permanently connected to the guards captive fasteners This precaution prevents the loss of fasteners and the need to replace them figure A 3 Chassis Retainer washer LUI DE pea ey AZA AAA PRE Guard FIGURE A 3 CAPTIVE FASTENERS 61 Appendix B How to Use Table 2 2 Required distances for separation barrier guards Example 1 Calculating Protector Height b Initial Data Danger zone height a is 1 500 mm and the horizontal distance c from the guard to be installed is 700 mm Rationale Always select a barrier ensuring the greatest level of security Since the danger height a 1 500 mm is not listed in table 2 2 the values for the nearest upper height 1 600 mm and the nearest lower height 1 400 mm must be used in the calculation Next for each of these heights locate the corresponding horizontal distance 700 mm in column c of the table to find the appropriate protector height b gt When the danger zone height a is 1 400 mm and the horizontal distance c is between 100 mm and 800 mm the protector height b must be at least 1 800 mm gt When the danger zone height a is 1 600 mm and the horizontal distance c is between 100 mm and 800 mm the p
9. S411104 ONIAYAYVI AVOT UINJaJ puens 18M07 QL GuiAue5 DEOD puens reddn ep 1134 speo7 Jing m Belt Function To convey or transport material 1a Upper strand generally the load carrying strand 1b Lower strand generally the return strand 2 Load Carrying Rollers Function To support the belt and reduce its resistance to movement of the load Some load carrying rollers may also be impact reducing self aligning trough forming figure 1 2 or be able to change the inclination of the belt 3 Return Rollers Function To support the belt and reduce resistance to movement Some return rollers may also be self aligning or be able to change the inclination of the belt 4 Drums Function To drive a belt or re orient the direction of travel Types of drums 4a Live drum drives the belt by being itself driven by a motor 4b Head drum returns the belt to the lower strand and may also serve as a live drum 4c Tail drum returns the belt to the upper strand 4d Snub drum aligns the entering or exiting strand with the lower strand or ensures the required arc of contact with the live drum 4e Tensioning drum maintains proper belt tension by way of a take up system 1 BELT 1a Upper Strand 1b Lower Strand 2 LOAD CARRYING ROLLERS 3 RETURN ROLLERS FIGURE 1 2 TYPES OF BELT SUPPORTS 5 Take Up System Function To ensure proper belt tension Types of systems 5a
10. TRAVAIL CSST ET L INSTITUT DE RECHERCHE ROBERT SAUVE EN SANT ET EN S CURIT DU TRAVAIL IRSST Am lioration de la s curit des machines par l utilisation des dispositifs de protection publication n DC 100 1313 COMMISSION DE LA SANT ET DE LA S CURIT DU TRAVAIL CSST ET L INSTITUT DE RECHERCHE ROBERT SAUVE EN SANTE ET EN SECURITE DU TRAVAIL IRSST Mode d emploi du s curim tre publication n DC 500 191 2002 GORIS Anne Marie lt lt Les dangers des points rentrant gt gt Travail et s curit n 586 587 juillet ao t 1999 p 36 LUGDUNUM Bernard lt lt Contrat de pr vention Concassage en douceur la carri re Roffat gt gt Travail et s curit n 585 juin 1999 LUPIN Henriet et Jacques MARSOT S curit des machines et des quipements de travail Moyens de protection contre les risques m caniques INRS ED 807 2000 MAUGE Michel Machines et quipements de travail Mise en conformit INRS ED 770 1998 ORGANISATION INTERNATIONALE DE NORMALISATION ISO 13853 S curit des machines Distances de s curit pour emp cher l atteinte des zones dangereuses par les membres inf rieurs 1998 PAQUES Joseph Jean et R al BOURBONNI RE Formation en s curit des machines appr ciation et r duction du risque IRSST septembre 2002 70
11. Therefore all adjustment and grease points must be accessible without having to remove guards or other protective devices When it is necessary to open or remove guards or even to neutralize protective devices in order to carry out a maintenance procedure safeguards must be implemented to ensure worker safety in the areas transformed into danger zones These measures must conform to sections 185 and 186 of the Regulations Respecting Occupational Health and Safety According to section 185 of the Regulation Respecting Occupational Health and Safety Subject to the provisions of section 186 before undertaking any maintenance repair or unjamming work in a machine s danger zone the following safety precautions shall be taken 1 turn the machine s power supply switch to the off position 2 bring the machine to a complete stop 3 each person exposed to danger locks off all the machine s sources of energy in order to avoid any accidental start up of the machine for the duration of the work Lockout Procedures The goal of lockout procedures is to allow workers to carry out their tasks maintenance repairs cleaning etc on a conveyor and its accessories bumpers ejectors etc without risk Lockout procedures involve the following basics gt Bringing the machine to a complete stop gt Disconnecting all the machine s sources of power electric pneumatic hydraulic mechanical and thermal gt Dissipating all accum
12. a conveyor the head room below the conveyor should be more than 2 m and the width of the throughway at least 600 mm For a throughway passing over a conveyor the footwalk must be equipped with a guardrail section 31 of the Regulation Respecting Occupational Health and Safety and section 373 3 of the Regulation Respecting Occupational Health and Safety in Mines Service ways can be divided into two groups gt Well marked footwalk along the conveyor single file access way under the conveyor etc the measures in paragraph 2 6 apply only to hazardous components along service ways gt Not marked or poorly marked under a conveyor to access certain machine elements the measures in paragraph 2 6 apply to all components deemed to be hazardous Falling or Projecting Objects Hazards of falling or projecting machine components or loads are created when machine parts break or there is a sudden jarring in sub assemblies 2 5 1 Conveyor Elements Hazards of falling or projecting conveyor elements can be caused by the following gt Forces during normal operating conditions centrifugal force pressure gt Exceptional forces normally foreseeable jarring ramming gt Aging material It s important to implement measures to prevent hazards such as a falling return rollers or belt breakage see section 2 6 2 5 2 Carried Loads The complete conveyor circuit specifically loading unloading and transfer points must be designed to r
13. designed to put an end to a recurring dangerous situation this is the role of an emergency stop switch A stop command must have priority over a start command Emergency Stop According to section 270 of the Regulation Respecting Occupational Health and Safety the emergency stop device of a conveyor to which workers have access comprises several control devices located at loading and unloading piers as well as at other points along the conveyor s itinerary In addition these devices have the following features 1 they are easily visible 2 one single action activates them 3 they are clearly identified 52 An emergency stop device should also be activated by a positive action and be forced to break contact type device symbol illustrated in figure 2 42 FIGURE 2 42 STANDARD SYMBOL DESIGNATING FORCED TO BREAK CONTACT DEVICES Emergency stop devices must be installed at a height between 0 6 m and 1 7 m from the floor and must include the following gt One or more push button switches installed in such a manner that at least one is accessible within a 10 m distance from any equipment access point gt One or more emergency stop pull cords along the full conveyor length compulsory measure for mines where workers may have access to conveyors in operation section 373 5 of the Regulation Respecting Occupational Health and Safety in Mines gt A conveyor power disconnect device if the distance to the disc
14. hazard is less than 2 5 m from the floor or working platform In accordance with risk analysis results barrier guard deterrent device or ground markings or signs to indicate the conveyor s operating area figure 2 41 It is also possible to use electronic safety devices surface detectors etc FIGURE 2 41 MOVEABLE CONVEYOR Note The limits of the operating area must be considered before applying protective measures 50 3 3 1 3 2 3 3 3 4 Safeguards against Other Hazards Hazards Generated by Poor Ergonomic Design Equipment must be designed so that operators and other users need not assume constraining work postures overexert themselves or carry out repetitive movements Control devices must be grouped near workstations to allow operators and other users easy access They must be located outside danger zones so that activating them does not create hazards and workers do not have to enter the danger zones to access them To prevent unexpected start ups they must be positioned and protected Every workstation or intervention area must be provided with adequate lighting for the nature of the work being done or the nature of the work environment section 125 of the Regulation Respecting Occupational Health and Safety Heat Related Hazards Where conveyed products or any part of the equipment may cause burns take the following precautions gt Prevent contact with conveyed loads and hot o
15. results the scraper protection device may be combined with the drum protection device figure 2 27 and dimensions to be defined according to the opening that is necessary to adjust the scraper Add a guard to close the opening after adjustments FIGURE 2 27 SURROUNDING BARRIER GUARD FOR DRUM AND SCRAPER PARTIAL CAGE 38 2 6 4 Curved Zone Hazards In running nip between the belt and rollers in the curved zone Possible Consequences Drawing in Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding in running nip or separation barrier guard figures 2 28 and 2 29 1 3 roller Min 620 mm ee 1 3 roller Min 1000 mm Fi Max 5 mm FIGURE 2 28 SURROUNDING aie FIXED GUARDS FOR Max 5 mm CURVED ZONE FIGURE 2 29 CURVED ZONE IN RUNNING NIP GUARD SEE TABLE 2 3 FOR C DIMENSION Note Belt edge tension is greater in the curved zones 39 2 6 5 Transition Zone Hazard In running nips between the upper strand and the load carrying rollers in the transition zone Possible Consequences Drawing in Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding or in running nip figure 2 30 First transition roller FIGURE 2 30 PROTECTORS FOR HEAD DRUM AND TRANSITION ZONE TO DETERMINE LATERAL SCREEN HEIGHT SEE TABLE 2 2 40 2 6 6 Drum
16. A Users Guide to Conveyor Belt Safety Protection from Danger Zones Gi CS IAPA m It s About Making A Difference RESEARCH AND EDITING Laurent Giraud Ph D Trainee Engineer Researcher IRSST Serge Mass Engineer Scientific Professional IRSST Julie Dub Trainee Engineer Scientific Professional IRSST Luc Schreiber Engineer M Sc Direction r gionale de la Mauricie et du Centre du Qu bec CSST Andr Turcot Engineer Direction de la pr vention inspection CSST CONVEYOR SAFETY COMMITTEE VALIDATION Laurent Giraud Ph D Trainee Engineer Researcher IRSST Serge Mass Engineer Scientific Professional IRSST Julie Dub Trainee Engineer Scientific Professional IRSST Gilles Brouard Inspector Direction r gionale de l Outaouais CSST Yves Desrochers Inspector Direction r gionale de l Abitibi T miscamingue CSST Donald Duchesne Engineer Prevention Inspection Consultant Direction de la pr vention inspection CSST Gilles Gagnon Engineer Prevention Inspection Consultant Direction de la pr vention inspection CSST Louise Gravel Engineer Prevention Inspection Consultant Direction de la pr vention inspection CSST Daniel Macleod Engineer Inspector Direction r gionale de la Chaudi re Appalaches CSST Andr Marchand Inspector Direction r gionale de la Mauricie et du Centre du Qu bec CSST Yvon Papin Prevention Inspection Consultant Direction de la pr vention inspection CSST Luc S
17. AISSE R GIONALE D ASSURANCE MALADIE D LE DE FRANCE CRAMIF Installation et utilisation des transporteurs bande dans les carri res dispositions g n rales n 4 1994 Available from the CSST Document Center English Web site under construction Belt Conveyor Installation and Operation for Quarries General Rules 4 INSTITUT NATIONAL DE RECHERCHE ET DE S CURIT INRS Consignations et d consignations ED 754 1993 Available from the CSST Document Center English Web site under construction MO 126203 Holds and Releases AMERICAN NATIONAL STANDARDS INSTITUTE ANSI Z244 1 Safety Requirements for the Lock Out Tag Out 1993 68 Bibliography CONVEYOR BELTS AFNOR NF EN 1554 Courroies transporteuses Essais de frottement au tambour ao t 1999 AFNOR NF EN 1724 Courroies transporteuses l g res M thodes d essai pour la d termination du coefficient de frottement juin 1999 AFNOR NF H 95 320 Engins de manutention continue Transporteurs courroies destin s tre quip s d un instrument de pesage totalisateur continu Caract ristiques mai 1988 BRITISH STANDARD INSTITUTE Steel Cord Conveyor Belts Adhesion Strength Test of the Cover to the Core Layer BS EN 28094 1994 ISO 8094 1984 CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION ANSI CEMA 402 2002 Conveyor belts Unit Handling Conveyors 2002 CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION ANSICEMA 502 2001 Bulk Material Conveyor Be
18. Areas Fixed barrier guard separation type or plates between rollers or deterrent device FIGURE 2 38 TYPICAL GUARD FOR INDIVIDUAL LOADS AND ROLLERS EXCEEDING BELT WIDTH 47 Moving Loads Hazard Loads falling from the belt Possible Consequences Impact with moving loads Crushed by falling loads Protective Measures If hazard is less than 2 5 m from the floor or working platform Protection plate mesh netting or guiding rail to maintain individual loads on the conveyor and prevent them from falling off in accordance with risk analysis results figure 2 39 FIGURE 2 39 TYPICAL PROTECTIVE DEVICES FOR THROUGHWAYS 48 2 6 8 Moving Sub Assemblies Hazard Pushers bumpers ejectors sorters Possible Consequences Crushing and shearing Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding fixed or barrier guards figure 2 40 LL A ES st Floor FIGURE 2 40 TYPICAL BARRIERS FOR EJECTORS Note Leave a safe distance between the load and the guard so as not to create a trapping hazard Minimum distances are If the entire body can be drawn in 500 mm minimum If arms can be drawn in 120 mm minimum If legs can be drawn in 180 mm minimum 49 2 6 9 Moveable Conveyors Hazard Vertical and or horizontal movement Possible Consequences Crushing entanglement trapping Protective Measures If
19. D FIGURE 2 9 IN RUNNING NIP FIXED GUARD FORM FITTING ELEMENT ANGLED DEFLECTOR WITH SIDE PLATES For C values see Table 2 3 23 Table 2 3 Minimum Lengths of In Running Nip Fixed Guards Drum or Roller Entrapment Zone Minimum Guard Minimum Huard Diameter d mm Length C Length from Roller Length from Drum Center C 150 mm Center C 600 mm 200 60 210 660 315 77 227 677 400 87 237 687 500 98 248 698 630 110 260 710 800 125 275 125 1000 140 290 740 1250 157 307 757 1400 166 316 766 1600 177 327 777 For roller or drum diameters not listed above C may be calculated using the formula C V d 2 d 2 20 2 2 3 Interlocking Guard fi gure 2 10 A guard equipped with an interlocking device should have the following characteristics It should gt cause the machine or the operation of its hazardous components to stop as it is slightly opened gt make it impossible to start the machine or to operate its hazardous components for as long as it is not in place gt not cause the machine or its hazardous components to restart once it is fully restored to its place This type of guard may only be used if the hazard disappears before a worker can access the danger zone low inertia conveyor with rapid stop figure 2 10 WARNING In the case of interlocking guards and interlocked guards with guard locking it must not be possible
20. IRSST makes no guarantee regarding the accuracy reliability or completeness of the information contained in this document In no case shall the IRSST be held responsible for any physical or psychological injury or material damage resulting from the use of this information Note that the content of the document is protected by Canadian intellectual property legislation TABLE OF CONTENTS INTRODUCTION APPLICATION SECTION 1 GENERAL INFORMATION 1 Context Analysis and Definitions 1 1 1 2 1 2 1 1 2 2 1 2 3 1 24 DAR ON Hazards Context Analysis Definitions Tasks Workers Areas Conveyor Components Accident Information Applicable Acts and Regulations Risk Assessment and Reduction Maintenance Information SECTION 2 SAFEGUARDS AGAINST HAZARDS 1 Risk Assessment and Reduction 2 Safeguards against Mechanical Hazards 2 1 2 2 2 2 1 2 2 2 2 2 3 2 2 4 2 3 2 4 2 5 2 5 1 2 5 2 2 6 2 6 1 2 6 2 2 6 3 2 6 4 2 6 5 2 6 6 2 6 7 2 6 8 2 6 9 General Principles Guards Allowable Dimensions for Guard Openings Fixed Guard Interlocking Guard Interlocked Guard with Guard Locking Deterrent Devices Service Ways and Throughways Falling or Projecting Objects Conveyor Elements Carried Loads Conveyor Belt Safety Requirements for Operating Conditions Power Transmission Moving Parts Belt Upper and Lower Strands in a Straight Run Curved Zone Transition Zone Drums Moving Loads Moving Sub Asse
21. Strands in a Straight Run Hazard In running nips between lower strand and return rollers in a straight run only 3 of 3 This deterrent device can be used only with a belt no higher than 700 mm from the floor and when housekeeping is done while the conveyor is not operating Min 400 mm A a i S a G i S a Fi i l C ds LS hee ie ye a L di ki dy L C A Note Safety devices are not shown foi ki dit a the sake of clarity of the illustration kan a 7 4 A 3 AV a 5 a 4 FIGURE 2 25 DETERRENT DEVICE SIDE PLATE FOR RETURN ROLLERS LOCATED LESS THAN 700 MM FROM THE FLOOR NOTE THE RESTRICTIONS ON USE aan 36 Upper and Lower Strands in a Straight Run Hazard Return rollers Possible Consequences Impact with rollers Crushed by falling rollers Protective Measures Throughway under conveyor more than 2 5 m Retaining device for return rollers figure 2 26 according to risk analysis results It is possible to reduce the risk with a preventative maintenance program which should be taken into account when doing the risk analysis FIGURE 2 26 RETURN ROLLER RETAINING DEVICE 37 Upper and Lower Strands in a Straight Run Hazard Bottom strand scrapers Possible Consequences Trapping and crushing Abrasions from the belt Protective Measures If hazard is less than 2 5 m from the floor or working platform In accordance with risk analysis
22. allation 185 Making Secure 186 Adjustment Repair Unjamming Maintenance and Apprenticeship 187 Characteristics of a Protector 188 Spare Parts 189 Control Devices and Switches 190 Start and Stop Switches 191 Warning Devices 192 Emergency Stop 193 Groups of Machines 265 Carrying Elements 266 Transmission Devices 267 Protection from Falling Objects 268 Arial Conveyors 269 Safety Precaution 270 Emergency Stop 323 Tasks Involving Maintenance or Repairs Safety Code for the construction 371 Climbing on Conveyors Prohibited industry R S Q c S 2 1 372 Cleaning While all Movement has Ceased 373 Conveyor Protector 374 Underground Mine Conveyors Regulation Respecting Occupational 3 10 13 Safety and Protective Devices Health and Safety in Mines 3 16 9 Conveyors c S 2 1 r 19 1 Enginners Act R S Q c 1 9 More recent versions of the statutes in French are available from the following site www csst gc ca The French and English versions can be purchased from Publications du Qu bec There are as well many standards relating to conveyor belts and machine safety Refer to the list at the end of the Guide in the REFERENCES and BIBLIOGRAPHY Sections 12 5 Risk Assessment and Reduction Once hazards have been identified they must be eliminated or controlled by applying and implementing the appropriate safeguards and other control measures It is necessary to carry out a risk assessmen
23. area inside or around equipment that presents a risk to worker s health safety or physical integrity gt WORK STATION an operating area specifically set up for one or more workers the work station may also be the control station gt SERVICE WAY an area reserved for conveyor or other equipment operations and maintenance gt THROUGHWAY a passage way for all persons It is not part of the equipment area and may run along or cross over or under the equipment gt LOADING AND UNLOADING ZONES areas where loads are picked up for and deposited after conveyance either manually or automatically 1 2 4 Conveyor Components The principal conveyor components are defined below and illustrated in figures 1 1 to 1 3 The numbers in the figures correspond to the numbers in the legend and in the following definitions More detailed definitions can be found in S curit des convoyeurs a courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety INOZ NOILISNVAL LL INOZ G3AYND OL INFLSAS ONINV312 INNYA ANY 1144 6 INSINVHIDJIN ONIGYOINN 8 WALSAS DNIGVOT L SLUVd DNIAOIN NOISSIINSNV AL 41MOd 9 uopensniji ay yo MUSI jo ayes ayi 10 UMOUS JOU ale sadIAap ALES 810N uonensni i ayi yo Aep Jo ayes ayi 10 UMOUS JOU ale sadjAap Ajajes a10N Gunsnfpe yas Jo enue qs Ajinel6 10 2510 Ag eg WALSAS di FAVI dn aye et qnus pr ep IP peoH Av CAP SAT eh SNNYA s431108 NANLIY
24. ations Hazardous Events Damages COMMISSION DE LA SANT ET DE LA S CURIT DU TRAVAIL CSST Guide de pr vention en milieu de travail l intention de la petite et de la moyenne entreprise Publication Number DC 200 16082 2 2000 A Guide to Prevention in the Workplace for Small and Medium Sized Businesses QUEBEC GOVERNMENT Regulations Respecting Occupational Health and Safety Decree 885 2001 5 2 1 r 19 01 July 2001 Available from the CSST Document Center English Web site under construction RJ 510071 QUEBEC GOVERNMENT Mines Occupational Health and Safety Regulations 5 2 1 r 19 01 June 2002 Available from the CSST Document Center English Web site under construction RJ 510068 QU BEC GOVERNMENT Safety Code for the construction industry 5 2 1 r 6 August 2001 Available from the CSST Document Center English Web site under construction RJ 530000 CANADIAN STANDARDS ASSOCIATION CSA Z432 94 Machine Safety 1994 Available from the CSST Document Center English Web site under construction NO 001570 AFNOR NF EN 620 Continuous handling equipment and systems Safety and EMC requirements for fi xed belt conveyors for bulk materials 2002 Available from the CSST Document Center English Web site under construction NO 003033 BRITISH STANDARD INSTITUTE BS 7300 Code of Practice for Safeguarding of the Hazard Points on Troughed Belt Conveyors 1990 Available from the CSST Document Center English We
25. b site under construction NO 002753 AFNOR NF EN 294 S curit des machines Distances de s curit pour emp cher l atteinte des zones dangereuses par les membres sup rieurs September 1992 Available from the CSST Document Center English Web site under construction NO 120491 Safety of machinery Safety distances to prevent danger zones being reached by the upper limbs COMIT EUROP EN DE NORMALISATION EN 81 1 S curit des machines Distances de s curit pour emp cher l atteinte des zones dangereuses par les membres inf rieurs 1996 Available from the CSST Document Center English Web site under construction NO 002202 Safety of machinery Safety distances to prevent danger zones being reached by the lower limbs AFNOR NF EN 953 S curit des machines Protecteurs Prescriptions g n rales pour la conception et la construction des protecteurs fi xes et mobiles December 1997 Available from the CSST Document Center English Web site under construction NO 002266 Safety of machinery Guards General requirements for the design and construction of fixed and moveable guards INTERNATIONAL STANDARDS ORGANISATION ISO 14119 S curit des machines Dispositifs de verrouillage associ s des protecteurs Principes de conception et de choix 1998 Available from the CSST Document Center English Web site under construction NO 120715 Safety of machinery Interlocking devices associated with guards Pri
26. chreiber Engineer M Sc Inspector Direction r gionale de la Mauricie et du Centre du Qu bec CSST Andr Turcot Engineer Prevention Inspection Consultant Direction de la pr vention inspection CSST Joseph Wigorski Inspector Direction r gionale de l Abitibi T miscamingue CSST Lyne Beaul Communications Consultant Direction des communications CSST PROJECT MANAGER Donald Duchesne Engineer Prevention Inspection Consultant Direction de la pr vention inspection CSST PROJECT PRODUCTION AND DESIGN SUPERVISOR AND COORDINATOR Lyne Beaul Communications Consultant Direction des communications CSST TRANSLATION Goodwill Vezina PROOFREADING Claudette Lefebvre Direction des communications CSST GRAPHIC DESIGN AND COMPUTER GRAPHICS Eykel Design and David Gillis ILLUSTRATIONS Steve Bergeron ORIGINAL TITLE S curit des convoyeurs courroie guide de l utilisateur Commission de la sant et de la s curit du travail du Qu bec 2 dition revue et corrig e Copyright Deposit Biblioth que nationale du Qu bec 2003 ISBN 2 550 42283 X DC 200 16227 1 04 01 ACKNOWLEDGEMENTS We wish to thank all company and union representatives from the following establishments and organizations Les gravi res de Beauce Abitibi Consolidated Belgo Division and Laurentides Division Produits forestiers Domtar Val d Or Division Uniboard Canada Val d Or Division Mine Jeffrey ASSIFQ ASSPPQ CIFQ and AMQ The
27. conveyors or related accessories Lockout conveyor or related accessory Belt replacement and splicing Lockout and application of a written safety procedure See S curit des convoyeurs courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety section 4 1 1 for required tools and facilities Welding and cutting Lockout if conveyor is located under the welding area Lockout if the closed unprotected danger zone is less than 2 500 mm from the work area Adjustment and fit Greasing and oiling lubrication around conveyor disposal of material recovered on the belt Authorized at all times provided adjustment points for example scraper drum and take up system adjustment are outside the danger zone Lockout if adjustment points are inside the danger zone Application of stipulations in section 5 3 drum and scraper restrictions Authorized at all times where grease points are outside the danger zone Lockout if grease points are inside the danger zone Housekeeping under and Authorized at all times as long as the danger zone remains protected by a guard Particular attention should be paid to the space under an inclined belt located less than 2 5 m from the floor belt risk analysis Reminder A 300 mm high opening measured from the floor will help in housekeeping Lockout if the danger zone is not protected with a guard Apply measures in section 5 3 should the conveyor
28. ding enclosure figure 2 6 For this guard to be effective it must be placed at a safe distance in accordance with NF EN standard 294 and there must be no willful act to reach the danger zone table 2 2 For examples illustrating use of this table see Appendix B 25 m An opening of not more than 300 mm from the floor should be allowed for housekeeping If the vertical distance from the hazard and bottom edge of the guard is less than 550 mm the opening for housekeeping under the guard must be in accordance with Te specifications in table 2 1 FIGURE 2 6 TYPICAL BARRIER GUARD DANGER ZONE IS AT LEAST 100 MM FROM THE GUARD 21 Table 2 2 Required Distances for Fixed Barrier Guards Based on NF EN Standard 294 Protective Structure Height b mm 1400 1600 1800 2000 2200 2400 2500 Horizontal Distance from the Danger Zone c mm 2400 100 100 100 100 100 100 EE 500 500 400 350 250 MENN o 600 500 350 PO 1800 900 900 600 PO 1600 900 900 500 1400 o 800 100 MWEN o 500 PO 1000 900 300 PO 800 Eoo EA 400 Ta Er Notes gt No interpolation from the above values is allowed gt If a measured distance falls between two values select the safer value ANN gt Structures less than 1 400 mm high ay are considered to be deterrent Hl devices see section 2 3 FIGURE 2 7 ILLUSTRATION FOR TABLE 2 2 2 2 2 3 In Running Nip Fixed Guards EN Standard 620 sections 3 4 17 and 5 1 4 2 A f
29. dual Loads and Fixed Obstacles Typical Hazards of Moving Sub Assemblies Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 Figure 2 10 Figure 2 11 Figure 2 12 Figure 2 13 Figure 2 14 Figure 2 15 Figure 2 16 Figure 2 17 Figure 2 18 Figure 2 19 Figure 2 20 Figure 2 21 Figure 2 22 Figure 2 23 Figure 2 24 Figure 2 25 Figure 2 26 Figure 2 27 Figure 2 28 Figure 2 29 Figure 2 30 Figure 2 31 Figure 2 32 Figure 2 33 Figure 2 34 Figure 2 35 Figure 2 36 Figure 2 37 Figure 2 38 Figure 2 39 Figure 2 40 Figure 2 41 Figure 2 42 Figure A 1 Figure A 2 Figure A 3 Figure B 1 Figure B 2 REFERENCES Risk Assessment and Reduction Flowchart Typical Surrounding Fixed Guard Partial Cage Surrounding Barrier Guard for Load Carrying Rollers and Return Rollers Curved Zone Surrounding Fixed Guard Typical Surrounding Fixed Guards Side Screens with No Protection Underneath Typical Barrier Guard Danger Zone is at least 100 mm from the Guard Illustration for Table 2 2 In Running Nip Fixed Guard Form Fitting Element In Running Nip Fixed Guard Angled Deflector with Side Plates Operating Principle of Interlocking Guards Operating Principle of Interlocked Guard with Guard Locking Typical Deterrent Devices Surrounding Fixed Guard for Pulleys and Power Transmission Belts Surrounding Fixed Guard for Couplings Surrounding Fixed Guard for Shafts Surrounding Fixed Guard
30. echniques juin 1995 AFNOR NF EN 349 S curit des machines cartements minimaux pour pr venir les risques d crasement de parties du corps humain septembre 1993 AFNOR NF EN 894 2 S curit des machines Sp cifications ergonomiques pour la conception des dispositifs de signalisation et des organes de service partie 2 dispositifs de signalisation avril 1997 AFNOR NF EN 954 1 S curit des machines Parties des syst mes de commande relatives la s curit Partie Principes g n raux de conception f vrier 1997 AFNOR NF EN 999 Positionnement des quipements de protection en fonction de la vitesse d approche des parties du corps d cembre 1998 AFNOR NF EN 1037 S curit des machines Pr vention de la marche intempestive mars 1996 AFNOR NF EN 1050 S curit des machines Principes pour l appr ciation du risque janvier 1997 AFNOR NF EN 1088 S curit des machines Dispositifs de verrouillage associ s des protecteurs Principes de conception et de choix juin 1996 AMERICAN NATIONAL STANDARDS INSTITUTE ANSI RIA R15 06 1999 American National Standard for Industrial Robots and Robot Systems Safety Requirements June 1999 AMERICAN SOCIETY OF MECHANICAL ENGINEERS ASME B15 1 2000 Safety Standard for Mechanical Power Transmission Apparatus 2000 BRITISH STANDARD INSTITUTE PD 5304 2000 Safe Use of Machinery 2000 COMMISSION DE LA SANT ET DE LA S CURIT DU
31. ecurity related control system malfunctions electricity heat fire and explosions For more information on hazards refer to the CSST document DC 900 337 S curit des machines ph nom nes dangereux situations dangereuses v nements dangereux dommages Machine Safety Hazards Hazardous Situations Hazardous Events Damages gt Power transmission moving part hazards figures 1 4 and 1 5 These hazards are associated mainly with the power transmission parts between the motor and the live drum They include shafts couplings pulley belts chain and sprockets Dragging crushing or entanglement on contact with rotating parts or pinch points can result in serious injuries FIGURE 1 4 TYPICAL POWER TRANSMISSION MOVING PART HAZARDS gt Other conveyor moving part hazards figure 1 5 These are associated with the moving conveyor belt and in running nips when in contact with rollers and drums and to falling return rollers dislodged from worn fasteners These hazards can result in injuries from being dragged into in running nips in abrasion and friction burns from rubbing against the belt and injuries from being struck by a ruptured belt or a falling roller the sake of clarity of the illustration Note Safety devices are not shown for gt Confinement zone hazards those related for example to hoppers skirtboards skirt Injuries result from shearing and crushing between the load and a fi
32. ed with operating conditions in mind They must be capable of resisting the loads to which they will be subjected These devices must not create additional hazards or tempt workers to bypass their use The dimensions and weight of movable guard components must be designed to allow for easy handling To this end it is preferable to have articulated or hinged guards Guard removal and reinstallation must be quick and easy Ideally guards should be self locking when closed For more information on user related characteristics colour ease of manipulation etc and guard construction see Appendix A of this guide There are three types of guards 1 Fixed guards gt Surrounding fixed guards gt Barrier guards fixed distance gt Fixed in running nip guards 2 Interlocking guards 3 Interlocked guards with guard locking 16 2 2 1 Allowable Dimensions for Guard Openings A guard can have openings The specifications for allowable dimensions for guard openings in Table 2 1 are taken from CSA Standard Z432 1994 Guard opening dimensions can be verified with a tool called a Safety Ruler Table 2 1 This tool makes it possible to check if the hazard can be reached through the guard The safety ruler instruction manual is published by CSST DC 500 191 2 2 2 Fixed Guard A fixed guard is a guard that can be removed only by using a tool or that is permanently set in place for instance by welding Regulation Respecting Occupational Healt
33. educe the spill over hazards of carried loads Equipment installed high above the floor or ground must be equipped with protective devices for example roller restraining device protective plate gutter fillet mesh to prevent the fall of loads and debris This is particularly important where conveyors are above or near throughways see section 2 6 27 2 6 Conveyor Belt Safety Requirements for Operating Conditions The following pages outline the safety requirements for conveyor belt parts in operation in the following order 1 Power Transmission Moving Parts 2 Belt In good condition Deteriorated belt or belt splice 3 Upper and Lower Strands in a Straight Run In running nips between upper strand and rollers under the hopper upper strand under a skirtboard or skirt In running nips between upper strand and support rollers in a straight run In running nips between lower strand and return rollers in a straight run Return rollers Lower strand scrapers 4 Curved Zone 5 Transition Zone 6 Drums In running nips between belt and drum Take up system Junction between two conveyors 7 Moving Loads Skirtboard and individual moving loads Individual loads and fixed obstacles not part of the conveyor e g post wall tunnel entrance enclave associated fixed equipment detectors etc Loads and carrying rollers larger than the belt Loads falling from the belt 8 Moving Sub Assemblies 9 Moveable Conveyors
34. emain inaccessible at screen or cage ends and from under the belt 17 Table 2 1 Allowable Dimensions for Guard Openings Safe Distance c mm Maximum Aperture Width e mm 6 38 6 39 64 10 65 89 13 90 140 16 141 165 19 166 191 22 192 318 32 319 394 38 395 445 48 446 800 54 Greater than 800 152 How to Measure Openings Using the Safety Ruler The Safety Ruler 18 Grease point FIGURE 2 2 TYPICAL SURROUNDING FIXED GUARD Partiat CAGE To Prevent Access from Above Guards gt Cages should be closed on top gt Side screens may take on a variety of shapes as shown in figures 2 3 and 2 4 screens with a 90 or other angle bend to make in running nips inaccessible from above the guard The distance between the guard and the belt must be at least 100 mm to prevent a hand from getting jammed in between For troughed conveyors the distance which is calculated perpendicularly from the angled roller must be equal to one third the roller length from the roller top figures 2 3 and 2 4 gt Table 2 2 which applies to barrier guards can be used to determine the height of upright side screens To Prevent Access from Under the Conveyor gt Under conveyor access can be prevented by a screen such as the one illustrated in figure 2 3 gt Where there is no access restricting screen under a conveyor side screens must extend 1 000 mm below roller and belt in ru
35. for Shaft Ends Typical Protective Measures for Throughways Mechanical Splices Surrounding Fixed Guard in Loading Area In Running Nip Fixed Guard for Support Rollers Plates Surrounding Fixed Guard for Support Rollers Surrounding Fixed Guards for Return Rollers In Running Nip Fixed Guards for Return Rollers Typical Protective Devices for Throughways Deterrent Device Side Plate for Return Rollers Located less than 700 mm from the Floor Return Roller Retaining Device Surrounding Barrier Guard for Drum and Scraper Partial Cage Surrounding Fixed Guards for Curved Zone Curved Zone In Running Nip Guard Protectors for Head Drum and Transition Zone In Running Nip Guard for Drum Scraper Serving as an In Running Nip Guard Surrounding Fixed Guard for Tail Drum Barrier Guard for Gravity Type Tensioner Fixed Guard at Conveyor Belt Junction Pop Up Roller at Conveyor Belt Junction Typical Protective Measures against Hazards Associated with Individual Loads and Fixed Obstacles Typical Guard for Individual Loads and Rollers Exceeding Belt Width Typical Protective Devices for Throughways Typical Barriers for Ejectors Moveable Conveyor Standard Symbol Designating Forced to Break Contact Devices Typical Hinged Fixed Guard Typical Quarter Turn Keyed Spring Latch Captive Fasteners Separation Barrier Guard Example 1 Separation Barrier Guard Example 2 BIBLIOGRAPHY INTRODUCTION A number of accidents involving conveyor belt
36. for a person or any part of the body to be in the danger zone or between the danger zone and the guard when the guard is closed For more information on the design of interlocking guards and interlocked guards with guard locking refer to ISO Standard 14119 1998 24 FIGURE 2 10 OPERATING PRINCIPLE OF INTERLOCKING GUARDS NOTE CSA Standard Z432 section 8 1 1 5 defines this type of guard as an interlocking guard 2 2 4 Interlocked Guard with Guard Locking figure 2 11 An interlocked guard equipped with a locking device should have the following characteristics It should gt remain locked in place for as long as the machine or its hazardous components are moving gt make it impossible to start the machine or to operate its hazardous components for as long as it is not in place and reactivated gt not cause the machine or its hazardous components to be restarted once it is restored to its place and reactivated U TTT TT T ael 1 II A idad 788 IBPS LL FIGURE 2 11 OPERATING PRINCIPLE OF INTERLOCKED GUARD WITH GUARD LOCKING This type of guard may be used when it s possible to access the danger zone before the hazard has disappeared large inertia conveyors and long to stop conveyors NOTE CSA Standard Z432 section 8 1 1 6 defi nes this type of guard as a interlocking guard with guard locking 25 2 3 Deterrent Devices These are devices other than guards that reduce the risk of co
37. g etc were less frequent 12 table 1 2 Table 1 2 Serious or Fatal Accidents by Worker Activity Work activity when accident occurred Cleaning a drum applying adhesive to the drum or cleaning another part 23 of the conveyor load carrying or return rollers etc Conveyor maintenance other than cleaning 20 Normal activities for example sorting packaging on or around a conveyor 12 Recovery of a jammed item from an unguarded in running nip 7 8 between a drum 9 and the belt 1 8 between a magnetic roller and the belt Cleaning around or under the conveyor Maintenance other than cleaning near a conveyor Unjamming a conveyor or removing accumulated debris Adjusting tension or centering the belt Other activities for example worker being transported by conveyor Freeing a frozen conveyor O BB Oo nN Not indicated These statistics illustrate the diversity and scope of hazards associated with conveyor belts regardless of the nature of worker activities Eleven investigations by the CSST from 1981 to 2000 42 by the INRS France from 1993 to 2000 and 32 by OSHA from 1984 to 1996 3 Hazards Hazards associated with conveyors are principally mechanical in nature They are discussed briefly below Other hazards are covered in Section 2 of this guide They are the hazards generated by neglecting ergonomic principles in machine design breakdown related or s
38. h and Safety section 174 Guards may be easily opened with tools or keys for instance when equipped with quarter turn latches When keyed latches are used responsibility for controlling and distributing socket keys or tools must be assigned For more information on types of tools and fixtures see Appendix A 2 2 2 1 Surrounding Fixed Guard This is a fixed guard that either completely or partially surrounds the danger zone Because of openings required for belt and load passage surrounding fixed guards only partially surround the danger zone In conveyor belts fixed guards that only partially surround the danger zone take on two principal shapes gt Partial cages as illustrated in figure 2 2 and used mainly for head and return drums gt Side screens as illustrated in figure 2 3 Guards must extend beyond the in running nips between belts and rollers so as to make them inaccessible from above below and from the ends To Prevent Access from Guard Ends gt For partial cages like the one illustrated in figure 2 2 the guard must extend 1 000 mm from a drum center gt Side screens must extend 1 000 mm from the center of the first roller load carrying or return or drum at the entrant side of the belt in the protected area On the exit side they must extend 620 mm from the center of a roller and 1 000 mm from the center of a drum figure 2 3 gt Whatever the length of side screens or cages in running nips must r
39. he control station is located below return rollers figures 2 22 and 2 23 Throughway Parallel to Conveyor In running nip is located at a height between 0 7 m and 2 5 m Surrounding in running nip guard or barrier guard or other deterrent devices guardrail figures 2 22 to 2 24 In running nip is located at a height less than 0 7 m Deterrent devices guardrail or side plate figures 2 24A and 2 25 Throughway Under a Conveyor Surrounding in running nip or barrier guards or deterrent devices guardrail and the addition of protection plates figures 2 22 to 2 24 ze Max 5 mm e t Opening specification according to safety ruler FIGURE 2 22 SURROUNDING FIXED GUARDS FOR RETURN ROLLERS FIGURE 2 23 IN RUNNING NIP FIXED GUARDS FOR RETURN ROLLERS SEE FIGURES 2 8 AND 2 9 AND TABLE 2 3 FOR DIMENSIONS Regulation Respecting Occupational Health and Safety specifications are 2 1 m but international standards specify 2 5 m 1f after risk analysis another solution is deemed appropriate it may be adopted 34 Upper and Lower Strands in a Straight Run Hazards In running nips between lower strand and return rollers in a straight run 2 of 3 ee as an f 1 1 in 2500 mm Protection Plate and Deterrent Device Guardrail B Protection Plate and Surrounding Fixed Guards FIGURE 2 24 TYPICAL PROTECTIVE DEVICES FOR THROUGHWAYS 35 Upper and Lower
40. horizontal distance c separating them is 550 mm 65 Where the horizontal distance c is not shown in table 2 2 use the last value given in the corresponding columns For example with a protector height b of 1 600 mm and a danger zone height a of less than 1 000 mm the minimum separation distance c is 300 mm For danger zone heights greater than 2 500 mm a guard is not required Excerpt from Table 2 2 Example 2 Protective Structure Height b mm 1400 1800 2000 Horizontal Distance from Danger Zone c 100 100 100 100 500 500 400 350 700 600 500 350 900 900 600 900 900 500 900 800 100 900 900 600 66 Appendix C Ontario Legislation Reference The following table is a list of applicable sections of the Ontario Occupational Health and Safety Act and its Regulations in regards to conveyor belts Please note that CSA standard CSA Z432 04 should be used in regards to conveyors Applicable Acts and Regulations Statutes Applicable Sections The Occupational Health and Safety 18 Functions and powers of Committee Act of Ontario R S O 1990 C 0 1 25 Duties of employers 27 Duties of supervisors 28 Duties of workers 31 Duties of suppliers R R O 1990 Regulation 851 for 21 Lighting Industrial Establishments amended 24 Guards machines prime movers transmission to O Reg 280 05 equipment 25 Guards in running nip hazards 27 Emergenc
41. in proximity to conveyors must be informed of the hazards they may encounter and receive training in established preventative measures and work procedures All safety related procedures and instructions must be documented Operator Training Only trained and authorized persons must be allowed to start up operate and interrupt the normal operation of a conveyor Among other things instruct operators in the following gt Conveyor start up gt Normal shut down and emergency stop devices gt Required checks before starting up a conveyor after an emergency shut down or accidental stoppage gt Proper loading procedures to avoid conveyor overload Maintenance Crew Training Assign only knowledgeable and trained workers possessing the necessary technical expertise to maintain conveyors Assigned workers must be informed of the conditions under which the various maintenance tasks are to be completed Among other training they must be trained in lockout procedures When the removal of a guard or deterrent device is scheduled the assigned maintenance crew must receive detailed instructions related to their tasks including procedures for installing or repositioning guards or deterrent devices Supervisors and workers must check that guards and deterrent devices are back in place when maintenance tasks are completed 59 Appendix A Guard Design This appendix deals only with the design and ergonomics of guards For information on types
42. ion required to activate the emergency shut down switch when applied perpendicularly to the cable The cable must move freely within its supports particularly at bends Cables must not be twisted nor suffer the risk of being twisted during use If the belt width is equal to or less than 800 mm a single central cable may be used above the belt Maximum cable length and other characteristics must conform to the supplier s recommendations for support rings and pulley protection freeze up prevention variations in length due to temperature changes etc Sensitive cable devices may be used where activation of the switch is done by pressure compression torsion or tension applied to the cable This method is best suited to complex cable runs and to dusty or heavy vibration environments 54 5 5 1 5 2 Safeguards against Maintenance Hazards S curit des convoyeurs courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety provides additional information on this subject It discusses the incidence of the design factor on conveyor safety explains conveyor failure and diagnostics and suggests solutions for use during the problem solving process A fault tree helps establish the relationship between failures and accidents General Principles Equipment must be designed in such a way that maintenance adjustments greasing cleaning unjamming unclogging etc can be accomplished away from danger zones
43. ixed guard can be placed at a height of an in running nip that will not allow access to this zone In running nip fixed guards may be form fitting figure 2 8 or made from angled deflectors with side plates figure 2 9 They are well suited to individual load conveyance as well as to rollers and drums with a smooth unbroken surface They may be used in troughed conveyor belts as long as they follow the belt profile However these guards are ill suited to cleated type ribbed or raised edge belts If it is impossible to maintain a maximum clearance of 5 mm between the guard and the roller or drum surface or between the guard and the belt then the use of the in running nip fixed guard is not recommended 22 The minimum length that an in running nip fixed guard must extend beyond the roller or drum center depends upon the diameter of the roller or drum To determine this length first determine the maximum distance C which is the distance from the center of the roller to where a finger may get pinched and drawn in table 2 3 Then to this distance C add either 150 mm for rollers or 600 mm for drums figures 2 8 and 2 9 Plates under a belt and between rollers may also serve as safeguards from in running nips figure 2 20 However a maximum gap of 5 mm must be maintained between a roller and adjacent plates Min C 150 mm ie Min C 150 mm gt fna Mae 5 mm FIGURE 2 8 IN RUNNING NIP FIXED GUAR
44. lt Troughing and Return Idlers Selection and Dimensions 2001 MINE SAFETY AND HEALTH ADMINISTRATION MSHA s Guide to Equipment Guarding OT 3 US Department of Labor 2000 NATIONAL SAFETY COUNCIL Conveyor Belt for Bulk Materials part 1 Equipment 1 569 1990 SUVA Liste de contr le Transporteurs bande pour marchandises en vrac SUVAPro r f 67043 f Suisse CONVEYORS GENERAL AMERICAN SOCIETY OF MECHANICAL ENGINEERS Safety Standard for Conveyors and Related Equipment ASME B20 1 2000 and addenda 2000 AMERICAN SOCIETY OF SAFETY ENGINEERS Safe use of conveyor Professional Safety vol 38 no 4 April 1993 COMIT EUROP EN DE NORMALISATION EN 618 quipements et syst mes de manutention continue Prescriptions de s curit et de CEM pour les quipements de manutention m canique des produits en vrac l exception des transporteurs fixes courroie avril 2002 COMIT EUROP EN DE NORMALISATION Projet d finitif prEN 619 quipements et syst mes de manutention continue Prescriptions de s curit et de CEM pour les quipements de manutention m canique des charges isol es octobre 2000 OONVEYCR EQUIPMENT MANUFACTURERS ASSOCIATION ANSICEMA 102 2000 Conveyor Terms and Definitions 2000 CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION ANS CEMA No 401 2002 Roller Conveyors Non Powered 2002 FYSON R Oliver Conveying safety to the user Professionnal Engineering June 1990 p 30
45. lt and Drum Cleaner Function To remove material accumulation from belts and drums These are often scrapers and brushes 10 Curved Zone This is the area of the conveyor where the belt is vertically curved 11 Transition Zone Conveyor area where the profile cross of the belt changes from troughed to flattened and vice versa 12 Shunting Mechanism Function To change load direction Various devices may be used bumpers pushers ejectors etc figure 1 7 2 Accident Information Based on information collected from 85 serious or fatal accidents involving conveyor belts the majority of accidents 55 involved head or tail drums or drive mechanisms table 1 1 Table 1 1 Serious or Fatal Accidents by Areas of Occurrence Conveyor belt area where accident occurred Between the live drum head drum or tail drum and the belt 48 inside one of these drums or between one drum and another Between a load carrying or return roller and the belt 13 Other areas for example between electromagnets and other parts 13 Motor to drum drive mechanism 7 Between a take up drum and the belt 5 Between a jammed tool and the belt or the conveyor chassis 2 Not indicated or explanations too vague 12 A large number of these accidents occurred during cleaning 30 or during the maintenance of or near a conveyor belt in motion 26 Accidents occurring during normal production activities sorting packagin
46. mblies Moveable Conveyors 3 Safeguards against Other Hazards 3 1 3 2 3 3 3 4 Hazards Generated by Poor Ergonomic Design Heat Related Hazards Electrical Hazards Fire and Explosion Hazards 4 Safeguards against Control System Failures or Malfunctions 4 1 4 2 4 3 4 4 Start Up Regular Stop Emergency Stop Emergency Stop Pull Cords 5 Safeguards against Maintenance Hazards 5 1 5 2 5 3 5 4 General Principles Lockout Procedures Safeguards for Maintenance within Operating Danger Zones Summary of Maintenance Safeguards 6 Operator and Maintenance Crew Training 6 1 6 2 APPENDICES Operator Training Maintenance Crew Training Appendix A Guard Design Appendix B How to Use Table 2 2 Appendix C Ontario Legislation Reference LIST OF TABLES Table 1 1 Table 1 2 Table 1 3 Table 2 1 Table 2 2 Table 2 3 Table 2 4 Serious or Fatal Accidents by Areas of Occurrence Serious or Fatal Accidents by Worker Activity Applicable Acts and Regulations Allowable Dimensions for Guard Openings Required Distances for Fixed Barrier Guards Minimum Lengths of In Running Nip Fixed Guards Safeguards for Maintenance Activities LIST OF FIGURES Figure 1 1 Figure 1 2 Figure 1 3 Figure 1 4 Figure 1 5 Figure 1 6 Figure 1 7 Conveyor Belt Diagrams Types of Belt Supports Typical Bulk Loading System Typical Power Transmission Moving Part Hazards Typical Mechanical Hazards Typical Hazards of Indivi
47. movement Min 1000 mm if access is possible from behind the hopper X c x AA KAL 7 SAINT FIGURE 2 19 SURROUNDING FIXED GUARD IN LOADING AREA Note Extend grease points beyond the guards 32 Upper and Lower Strands in a Straight Run Hazards In running nips between upper strand and support rollers in a straight run Possible Consequences Drawing in Protective Measures If hazard is less than 2 5 m from the floor or working platform Workstation Surrounding fixed guard plates between rollers figures 2 20 and 2 21 Throughway and Service Way Risk analysis except for mines section 373 4 of the Regulations Respecting Occupational Health and Safety in Mines Min 620 mm s pou FIGURE 2 20 IN RUNNING NIP FIXED a GUARD FOR SUPPORT ROLLERS PLATES FIGURE 2 21 SURROUNDING FIXED GUARD FOR SUPPORT ROLLERS Note Special Case When support rollers are themselves supported from above this configuration must be taken into account during risk analysis 33 Upper and Lower Strands in a Straight Run Hazards In running nips between lower strand and return rollers in a straight run 1 of 3 Possible Consequences Dragging Impact with rollers Protective Measures If hazard is less than 2 5 m from the floor or working platform Workstation beside or under conveyor Surrounding or in running nip guards and additional protection plates if t
48. nciples for design and selection AFNOR NF EN 292 1 S curit des machines Notions fondamentales principes g n raux de conception partie 1 Terminologie de base m thodologie December 1991 Available from the CSST Document Center English Web site under construction NO 001500 Machine Safety Fundamental Notions and General Design Principles Part 1 Basic Terminology and Methodology CENTRE TECHNIQUE DES INDUSTRIES M CANIQUES quipements de manutention continue pour charges isol es Mise en conformit CETIM 1996 Available from the CSST Document Center English Web site under construction MO 018973 Continuous Individual Load Handling Equipment Adherence Principles CETIM CANADIAN STANDARDS ASSOCIATION CAN CSA M421 F00 Use of Electricity in Mines 2000 CANADIAN STANDARDS ASSOCIATION CAN CSA M422 FM87 Fire Resistance and Anti Static Requirements for Conveyor Belts 2000 INTERNATIONAL STANDARDS ORGANISATION ISO 13850 Safety of machinery Emergency stop Principles for design 1996 Available from the CSST Document Center English Web site under construction NO 002190 UNION TECHNIQUE DE L LECTRICIT UTE NF EN 60947 5 5 Low voltage switchgear and controlgear Part 5 5 control circuit devices and switching elements Electrical emergency stop device with mechanical latching function April 1998 Available from the CSST Document Center English Web site under construction NO 002622 C
49. nning nips gt When in running nips are 1 000 mm or less from the floor the guard must extend to the floor For housekeeping purposes a 300 mm opening may be allowed under the guard provided it extends 550 mm or more under the pinch point for which it was designed to restrict access figures 2 2 2 5A and 2 33 If the distance of 550 mm cannot be maintained the opening under the guard must meet the specifications in table 2 1 gt When in running nips are more than 1 000 mm from the floor openings under the guard must not exceed 300 mm Bars like those illustrated in figure 2 5B may be used to block these openings 19 FIGURE 2 3 SURROUNDING BARRIER GUARD FOR LOAD CARRYING ROLLERS AND RETURN ROLLERS in 1000 mm Type B Min 620 mm 0 K length Min 1000 mm FIGURE 2 4 CURVED ZONE SURROUNDING FIXED GUARD 20 Min 1000 mm Min 620 mm Ke T en Min 1000 mm Min 620 mm 1000 mm 1600 mm 850 mm Min 300 mm A Hazard at 850 mm from floor B Hazard at 1 600 mm from floor WARNING Access to the return strand under the conveyor must be restricted FIGURE 2 5 TYPICAL SURROUNDING FIXED GUARDS Sie Screens with No PROTECTION UNDERNEATH 2 2 2 2 Barrier Guard NF EN Standard 953 section 3 2 2 Barrier guards do not completely surround danger zones but rather restrict or prevent access by their size and separation from the danger zone An example is a surroun
50. ntact with a danger zone These are often physical obstacles which without totally preventing access to a danger zone reduce the possibility of access NF EN Standard 292 1 section 3 24 Deterrent devices figure 2 12 include gt Roller side plates gt Guardrail with mid rails Note In order to be considered a deterrent device guardrails must be at least 1 000 mm high with a minimum of 1 400 mm separation from the danger zone Sections 12 and 13 of the Regulations Respecting Occupational Health and Safety describes other characteristics Deterrent devices must be designed with operating conditions in mind They must be capable of resisting the loads to which they will be subjected These devices must not create additional hazards or tempt workers to bypass their use For information on user related characteristics colour ease of manipulation etc and construction see Appendix A FIGURE 2 12 TYPICAL DETERRENT DEVICES SEE FIGURE 2 25 FOR PLATE DIMENSIONS 26 2 4 2 5 Service Ways and Throughways Where service ways and throughways run parallel to or underneath conveyors danger zones must be made inaccessible and the hazards of falling conveyor parts or falling loads must be prevented Safety requirements are outlined in section 2 6 These measures can only be applied correctly if throughways are well and clearly marked painted floor lines guardrails etc Where a throughway crosses under or is located below
51. of guards and deterrent devices application dimensions and selection see sections 1 and 2 of Section 2 of this guide For detailed information on the construction of guards and selection of material consult EN Standard 953 Guard construction and design must take into account all aspects of foreseeable use Guards must not be the source of new hazards It is important to consider ergonomic issues when designing guards Correct application of ergonomic principles can enhance safety and reduce physical effort Moveable guards should be designed so that the dimensions and weight of their parts allow for easy handling To this end articulated or hinged guards are preferred figure A 1 Opening a guard must be possible only with a tool or similar device FIGURE A 1 TYPICAL HINGED FIXED GUARD Guard removal and reinstallation must be quick and easy for example quarter turn keyed latches figure A 2 Ideally guards should be self locking when closed 60 In order to reduce as much as possible the number of times guards need to be opened guard construction should be such that the protected components can be easily seen Therefore it is suggested that the screen of the guard be painted in a dark colour flat black charcoal grey with the frame in a light colour By painting hazardous machine components in bright contrasting colours attention is drawn to the danger zone when a guard is opened or removed Fixed barrier
52. onnect device is less than10 m from any conveyor access point An emergency stop device must allow equipment to shut down in the best possible manner that is by slowing down moving parts at an optimal rate by gt An immediate interruption of power to the motors gt A controlled stop motors remain energized to bring the equipment to a progressive stop and power is interrupted once the equipment has come to a halt The resetting of the emergency stop device must not by itself cause the start up of the machine unless the conveyor is a slow moving type and workers can access it safely section 270 of the Regulation Respecting Occupational Health and Safety Moreover start up must be confirmed by a distinct and deliberate manual action manual resetting The emergency stop command must have priority over all other commands and cannot be allowed to create dangerous situations such as load spillage The conveyor emergency stop device must also stop any downstream or upstream conveyors if their continued operation constitutes a safety hazard for workers section 193 of the Regulation Respecting Occupational Health and Safety An emergency stop device must not be used to bring the conveyor to an all stop state The emergency stop must not be used as a regular stop Remember that the installation of an emergency stop device does not replace appropriate protective devices As well emergency stop devices must not replace equipment lockout
53. ons for consideration in the problem solving process In another chapter a fault tree illustrates links between conveyor defects and accidents S curit des convoyeurs a courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety targets engineers designers conveyor belt manufacturers and maintenance managers APPLICATION This guide applies to conveyor belts designed to transport continuous bulk or individual loads along a predetermined path between loading and unloading points Movable conveyors are also discussed for example conveyors that swing around a hopper on wheels or used on semi trailers or float SECTION 1 GENERAL INFORMATION 1 Context Analysis and Definitions 1 1 Context Analysis From a safety standpoint the following characteristics of conveyor belts are gt A belt which may vary greatly in length conveyors may be from a few meters to several kilometers long and split into smaller lengths or sections gt The fact that the majority of accidents occur in the areas of head drums tail drums and drive mechanisms gt The fact that the majority of accidents occur during cleaning or other maintenance activities gt The existence of hazards related to Power transmission moving parts motor parts transmission parts gears etc Moving loads Moving sub assemblies switch mechanisms pushers etc Proximity to unrestricted access throughways and throughways passing over or under equipmen
54. r cold surfaces by the use of screens fixed surrounding or barrier guards gt Reduce the temperature of hot surfaces Electrical Hazards Conveyor electrical equipment must conform to the Qu bec Electrical Code Such equipment includes materials accessories devices appliances fasteners and other equipment used in the electrical power supply of a conveyor or in connection with a conveyor these include power disconnect devices In mines electrical equipment must also conform to the CAN CSA Standard M421 93 particularly those sections dealing with conveyors Fire and Explosion Hazards The use of conveyors can in itself be a fire and explosion hazard These hazards can be caused by the use of the conveyor itself or by the load the conveyor is carrying for example combustible particles These hazards may be amplified by tunnels or the stack effect Preventative measures to implement are described in division VIII of the Regulation Respecting Occupational Health and Safety and in section 374 of the Regulation Respecting Occupational Health and Safety in Mines In underground mines fire and explosion hazards related to belts can have particularly serious consequences Belts must conform to CAN CSA Standard M422 M87 51 4 1 4 2 4 3 Safeguards against Control System Failures or Malfunctions Start Up The start up of equipment must require a voluntary action Equipment start up must be prevented in the following sit
55. r the weight FIGURE 2 34 BARRIER GUARD FOR GRAVITY TYPE TENSIONER Note For gravity type tensioning devices the height of the barrier preventing access under the counterweight must be 2 500 mm Tensioner drums head or tail must also be protected 43 Drums Hazard Junction between two conveyors Possible Consequences Drawing in and trapping if the gap is greater than 5 mm Protective Measures If hazard is less than 2 5 m from the floor or working platform Fixed guard plate or free wheeling pop up roller figures 2 35 and 2 36 xN Max 5 mm De jip x 5 FIGURE 2 35 FIXED GUARD AT CONVEYOR BELT JUNCTION Max 5 mm Min 120 mm FIGURE 2 36 POP UP ROLLER AT CONVEYOR BELT JUNCTION 44 2 6 7 Moving Loads Hazard Skirtboards Individual moving loads Possible Consequences Trapped between belt and skirtboard or between the load and the skirtboard Protective Measures If hazard is less than 2 5 m from the floor or working platform Workstation Limit the gap between the skirtboard and belt to a maximum of 5 mm Remove the skirtboard Design a surrounding fixed guard if need determined in risk analysis Other Areas Risk analysis Note When doing the risk analysis take into account the possibility of falling loads with the removal of the skirtboard 45 Moving Loads Hazard Individual loads and fixed obstacles not pa
56. ropriate controls First assess the risks Then systematically eliminate or reduce the risks by implementing the following control measures 1 Eliminate or reduce the hazard through design methods 2 Install safeguards or protective devices for each hazard that cannot be eliminated or reduced through design methods Evaluate the need for additional controls warnings signs work procedures personal protective equipment etc 3 Inform workers of all hazards Safeguards implemented at the design stage are preferred over safeguards implemented by the user The principles of safe conveyor belt design are addressed in S curit des convoyeurs courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety The planning of control measures and recommendations should be part of the prevention program or of the action plan of the company 14 SES Risk k i Identify hazards Risk v Analysis Assessment Estimate the risks ee Sc New Risks Risk reduction by design Hazard reduction YES Guards an with N i YES safety devices i Safety devices l Risk Me R duction Warnings i ME signs i m j YES 2 Work methods N NO i AN iN N m N Information training l Aa m om m 0 e 0 e aa ae e a a a n m aD SD SD SSS Se oo aS So an anam a n am am an am o an os ot P FIGURE 2 1 RISK ASSESSMENT AND REDUCTION FLOWCHART 15 2 2 1 2 2 Safeguards against Mechanical Hazards
57. rotector height b must be at least 1 800 mm Finally the selected protector must ensure the highest level of safety In this example both possibilities yield the same minimum height b of 1 800 mm Conclusion The minimum height of the barrier guard must be 1 800 mm when the danger zone height is 1 500 mm and the horizontal distance is 700 mm figure B 1 Excerpt from Table 2 2 Example 1 Protective Structure Height b mm 1400 1600 1800 2000 Horizontal Distance from Danger Zone c 100 100 100 100 500 500 4 00 350 700 600 5 00 350 900 900 6 00 900 900 5 00 900 800 100 900 500 62 Danger zone Separation barrier guard b 1800 mm min FIGURE B 1 SEPARATION BARRIER GUARD EXAMPLE 1 If the horizontal distance c between the danger zone and the planned guard is increased to more than 900 mm then the height can be reduced to 1 400 mm Excerpt from Table 2 2 Example 1 Contd Protective Structure Height b mm 1400 1600 1800 2000 Horizontal Distance from Danger Zone c 100 100 100 100 500 500 400 350 700 600 500 350 900 900 600 900 900 500 900 800 100 900 500 63 Example 2 Calculating Horizontal Distance c between Protector and Danger Zone Initial Data Protector height b is 1 500 mm and the danger zone height a is 2 100 mm Rationale In table 2 2 consider the allowable distance
58. rt of the conveyor e g post wall tunnel entrance enclave associated fixed equipment detectors etc large bulk sized loads e g boulders Possible Consequences Crushed between loads and fixed objects Shearing Impact with loads or other objects Protective Measures If hazard is less than 2 5 m from the floor or working platform Fixed guard or deterrent device figure 2 37 in accordance with risk analysis results in respecting the safe distances between loads and obstacles following are minimum distances for different situations If the entire body can be drawn in 500 mm minimum If arms can be drawn in 120 mm minimum If legs can be drawn in 180 mm minimum FIGURE 2 37 TYPICAL PROTECTIVE MEASURES AGAINST HAZARDS ASSOCIATED WITH INDIVIDUAL LOADS AND FIXED OBSTACLES Note The objective is to keep the body arms and legs away from the crushing area The type of guard and its dimensions will depend upon body part at risk of being trapped and the weight of the load as determined in the risk analysis The guard must not in itself create a drawing in or trapping area 46 Moving Loads Hazard Load and load carrying rollers exceeding belt width Possible Consequences Trapping Crushing Protective Measures If hazard is less than 2 5 m from the floor or working platform Workstation Fixed barrier guard separation type or plates between rollers figure 2 38 Other
59. s Hazards In running nips between belt and drums 1 of 2 Possible Consequences Drawing in Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding in running nip or barrier guards figures 2 30 to 2 33 Max 5 mm FIGURE 2 31 IN RUNNING NIP GUARD FOR DRUM SEE TABLE 2 3 FOR C DIMENSIONS The distance between the scraper the drum and the belt must remain constant regardless of the bearing movement for adjustment etc FIGURE 2 32 SCRAPER SERVING AS AN IN RUNNING NIP GUARD 41 Drums Hazard In running nips between belt and drums 2 of 2 Skirt Min 620 mm in the Hopper board direction of belt ki movement Max 300 mm a Max 550 mm FIGURE 2 33 SURROUNDING FIXED GUARD FOR TAIL DRUM Note If it s not possible to comply with the 550 mm minimum distance between the in running nip and the bottom edge of the surrounding fixed guard the opening for housekeeping should be in accordance with table 2 1 42 Drums Hazard Take up system Possible Consequences Crushed by falling weights Drawn in at pinch points Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding or barrier guards figures 2 33 and 2 34 If the weight is always more than 2 5 m from the floor or working platform Deterrent device guardrail to prevent access unde
60. s c when the protector height b is between 1 400 mm and 1 600 mm and the danger zone height a is between 2 000 mm and 2 200 mm Always select the distance that will yield the greatest level of safety Conclusion Minimum horizontal distance c between the danger zone and the protector must be 700 mm when the protector height b is 1 500 mm and the danger zone height a is 2 100 mm figure B 2 Excerpt from Table 2 2 Example 2 Protective Structure Height b mm 1800 2000 Horizontal Distance from Danger Zone c 100 100 100 100 400 350 500 350 600 500 100 64 Danger zone Separation barrier guard lb 1500 mm FIGURE B 2 SEPARATION BARRIER GUARD EXAMPLE 2 Example 3 Calculating Danger Zone Height a Initial Data Protector height b is 1 700 mm and horizontal distance c from the danger zone is 550 mm Rationale First find the horizontal distances c for protector heights of 1 600 mm and 1 800 mm The required distance c being greater for 1 600 mm high protectors this value must be used since the safest distance is to be considered Then find the c values that are 550 mm or smaller The danger zone can now be located to the corresponding a values Conclusion The danger zone height must be less than 1 200 mm or more than 2 200 mm when the protector height b is 1 700 mm and the
61. s can be attributed to accessibility to danger zones The majority of these occur during maintenance activities with conveyors still in operation and danger zones unprotected Preventative measures must be implemented in order that work on or near conveyors can be performed safely Right from the design stage worker exposure to hazards must be controlled by reducing the frequency of under conveyor clean ups conveyor maintenance removing jams etc This guide suggests possible preventative measures but they are by no means exhaustive In many situations the risk must be analyzed before any preventative measures are implemented This guide is composed of two sections Section 1 provides definitions information on conveyor belt accidents an overview of mechanical hazards and applicable legal requirements Section 2 discusses risk assessment and hazard control procedures specific safeguards against mechanical and other hazards safeguards against hazards encountered during maintenance and training for operators and maintenance personnel This guide is directed mainly to workers technicians supervisors joint health and safety committee members and other interested parties Conveyor design and modification for enhanced safety are discussed in S curit des convoyeurs a courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety An entire chapter is devoted to operational problems and diagnostics and includes suggested soluti
62. t Conflicts between repeated stoppages to clear jams and production requirements Stoppages from causes unknown to operators and other workers not located near the conveyor resulting in situations that may lead to dangerous actions Falling loads gt The existence of varying degrees of risk depending upon the conveyor belt s dimensions and the load size e g large conveyors in mines gt Hazards posed by a particular mechanism or by an entire conveyor zone 1 2 Definitions Equipment safety must be designed from the standpoint of workers who are carrying out their tasks in the workplace 1 2 1 Tasks These are associated with two distinct activities gt PRODUCTION OPERATIONS Start up shut down and other operations such as loading and unloading assembly fastening labelling coding monitoring etc gt MAINTENANCE Inspection cleaning unclogging load unjamming greasing adjustments repairs or other maintenance 1 2 2 Workers gt OPERATORS Persons operating the machinery or equipment used in the production process and generally posted at the control station gt MAINTENANCE CREW Persons trained and authorized to maintain equipment NOTE Properly trained operators can perform maintenance tasks such as unclogging unjamming and cleaning 1 2 3 Areas INTERVENTION AREA The area in and around equipment and the moving load including access points and integrated access ways This includes gt DANGER ZONE any
63. t to determine which hazards to address first and the most effective methods to control them so that the risk at each work station is systematically controlled A method for doing this is outlined in Section 2 of this guide and explained in detail in the document S curit des machines ph nom nes dangereux situations dangereuses v nements dangereux dommages Machine Safety Hazards Hazardous Situations Dangerous Events Damages For more on preventative measures refer to the document Guide de pr vention en milieu de travail l intention de la petite et de la moyenne entreprise Publication Number DC 200 16082 2 2000 A Guide to Prevention in the Workplace for Small and Medium Sized Businesses Maintenance Information Maintenance must be carried out according to the conditions set forth in sections 185 and 186 of the Regulation Respecting Occupational Health and Safety These sections stipulate that safety measures must be in effect before attempting any maintenance in a machine s danger zone These measures are addressed in point 5 in the second section of this guide Maintenance can be performed only by workers assigned to that type of task and designated to carry out the task 13 SECTION 2 SAFEGUARDS AGAINST HAZARDS 1 Risk Assessment and Reduction The diagram in figure 2 1 describes an ongoing process for risk assessment and reduction The guidelines will be helpful in selecting the app
64. uations gt The closing of a guard gt The actuation of an operation mode selector gt The resetting of an emergency stop device gt The resetting of a thermal protection device In conveyors designed to supply loads to other conveyors start up of the supply conveyor must be linked with the receiving conveyors using appropriate interlocking devices These devices must control and ensure proper sequential start up and prevent conveyor loading when not in use or when fully loaded For automatic or remote control start up conveyors as well as conveyors for which the operator or the user cannot see the entire conveyor a visual or audible warning device shall announce the starting of the conveyor sections 191 of the Regulation Respecting Occupational Health and Safety and 373 6 of the Regulation Respecting Occupational Health and Safety in Mines To prevent unexpected start ups replace two stable position toggle switches start stop with self powered contacts maintained by power or single stable position stable at the unenergized condition control devices These switches will bring the controls to an off circuit mode open contacts should there be a power outage or conveyor failure Regular Stop There must be a device or a method accessible to the operator and other users whereby equipment operations can be interrupted safely while guaranteeing that the equipment cannot be unexpectedly restarted An all stop switch is not
65. ulated energy purging reservoirs removing counterweights unloading springs etc and checking for absence of energy gt Padlocking of energy disconnect devices by each worker accessing the work area gt Double checking to ensure that the equipment is in fact disconnected e g running a Start up test Consult document DD 754 20 ANSI Standard Z244 1 or the CSA Standard Z460 55 5 3 Safeguards for Maintenance within Operating Danger Zones Section 186 of the Regulation Respecting Occupational Health and Safety stipulates When a worker must access a machine s danger zone for adjustment unjamming maintenance apprenticeship or repair purposes including for detecting abnormal operations and to do so he must move or remove a protector or neutralize a protective device the machine shall only be restarted by means of a manual control or in compliance with a safety procedure specifically provided for allowing such access This manual control or this procedure shall have the following characteristics 1 it causes any other control mode or any other procedure as the case may be to become inoperative 2 it only allows the operating of the dangerous parts of the machine by a control device requiring continuous action or a two hand control device 3 it only allows the operation of these dangerous parts under enhanced security conditions for instance at low speed under reduced tension step by step or by separate steps
66. xed object figure 1 5 gt Moving load hazards figure 1 6 Injuries result from shearing and crushing between the load and a fixed object Injuries can also be caused by falling loads or impact with loads gt Moving sub assembly hazards figure 1 7 Injuries result from shearing and crushing between the load and a fixed object occurring mainly with equipment that re orients the load FIGURE 1 5 TYPICAL MECHANICAL HAZARDS 10 Note Safety devices are not shown for the sake of clarity of the illustration ill P the FIGURE 1 7 TYPICAL HAZARDS OF MOVING SUB ASSEMBLIES 11 Applicable Acts and Regulations The table below lists the principal sections applying to conveyor belts by statute Table 1 3 Applicable Acts and Regulations Statutes Sections Applicable to Conveyor Belts with Title An Act Respecting Occupational 2 Law Object Participation of Workers and Employers Health and Safety R S Q C S 2 1 51 Employers Obligations 63 Dangerous Substance Supplier Regulation Respecting Occupational 20 Machine Guidance Tracks Health and Safety D 885 2001 172 Danger Zone 173 Applicable Provisions 174 Permanent Protector 175 Interlocking Protector 176 Interlocked Protector 177 Automatic Closing Protector 178 Adjustable Protector 179 Sensor Device 180 Two Hand Controls 181 Multiple Two Hand Controls 182 Controlling the Danger Zone 183 Equivalent Safety Precautions 184 Inst
67. y stop 28 Operating controls acting as guards 33 Automatic start up warning devices 34 Guards beneath conveyors 40 Suitability and certifi cation of electrical equipment 75 Maintenance stopping and blocking moving parts precautions against accidental start up 76 Locking and tagging R R O 1990 Regulation 854 for Part VII Electrical contains the following provisions Mines and Mining Plants amended 159 Operation of electrical equipment to O Reg 31 04 160 Locking and tagging Part VIII Mechanical contains the following provisions Guards machines prime movers transmission equipment Stopping moving parts and dissipating energy sources before carrying out work on moving parts This section relates specifi cally to conveyors and covers the following gt Riding on conveyors prohibited gt Pull cords gt Safe means of applying belt dressing gt Start up warning devices gt Guarding of tension pulleys gt gt 185 196 Guards beneath conveyors Conveyors in underground mines gt Maintenance 262 Lighting underground mines 263 Lighting on the surface 67 References 10 11 12 13 14 15 16 17 18 19 20 21 COMMISSION DE LA SANT ET DE LA S CURIT DU TRAVAIL CSST S curit des machines ph nom nes dangereux situations dangereuses v nements dangereux dommages Publication Number DC 900 337 2002 Machine Security Hazards Hazardous Situ
68. yor figure 2 17 Protection plate able to withstand belt impact in case of breakage Service way passing under conveyor Install protection plate as determined by risk analysis Protection plate 2500 mm banat VIN NMin 1400 mm FIGURE 2 17 TYPICAL PROTECTIVE MEASURES FOR THROUGHWAYS Note Cleated ribbed or raised edge belts present additional hazards impact drawing in which must be considered during the risk analysis 30 Belt Hazards Deteriorated belt or belt splice figure 2 18 Possible Consequences Drawing in burns pokes cuts Protection Measures If hazard is less than 2 5 m from the floor or working platform Change the belt splice design or manufacture Maintenance of belt and or splice A Splice in proper condition FIGURE 2 18 MECHANICAL SPLICES Note Refer to Types of Splices in S curit des convoyeurs courroie guide du concepteur A Designer s Guide to Conveyor Belt Safety B Damaged splice 31 2 6 3 Upper and Lower Strands in a Straight Run Hazards In running nips between the upper strand and the rollers under the hopper Upper strand under the skirtboard or skirt Possible Consequences Drawing in Shearing Burns from the belt Protective Measures If hazard is less than 2 5 m from the floor or working platform Surrounding or barrier guard figure 2 19 Min 620 mm in the direction of belt
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