BCCSA & BCRMCA BEST PRACTICES GUIDELINES FOR CONTRACTORS USING CONCRETE PUMPS

Transcription

1 BCCSA & BCRMCA BEST PRACTICES GUIDELINES FOR CONTRACTORS USING CONCRETE PUMPS

2 TABLE OF CONTENTS Introduction... 3 Information for the Contractor... 4 Checklist for Concrete Pumping... 5 Concrete... 9 APPENDIX A Hand Signals for Concrete Pumping APPENDIX B Checklist for Concrete Pumping APPENDIX C Minimum Safe Limits of Approach from Power Lines for Persons and Equipment APPENDIX D WorkSafeBC 30M33 Form APPENDIX E WorkSafeBC Requirement for Scaffolding APPENDIX F Sample Concrete Pump Footprint APPENDIX G Setting Outriggers to Prevent Accidents Shortrigging ACPA Bulletin

3 INTRODUCTION Did you know that concrete pumping can be one of the most dangerous aspects on any construction site? Did you also know that one does not require any training or certification to operate a concrete pumper truck? Crazy, isn t it? How can a task fraught with danger, large equipment and the potential for catastrophic injuries not have any level of required certification? The BC Construction Safety Alliance and the BC Ready-Mixed Concrete Association have teamed up to create a voluntary competency certification program that we believe is needed and wanted by the majority of concrete pump operators in British Columbia, as well as these Best Practice Guidelines for the Contractors working with concrete pumps on jobsites. The purpose of these guidelines is to not only stress the importance of adequately training those in the concrete pumping business, but more importantly, lay out the parameters and responsibilities for both the contractors and the concrete pump operators for the safe operation of the concrete pumps on their respective sites. These Guidelines provides information, diagrams and suggested best practices to help ensure that not only the concrete pump operator works in a safe manner, and also outline the responsibilities of the Site Super to provide a safe jobsite for all involved. This project has been a collaborative effort with countless hours of research, speaking with provincial, national and international companies to determine what is working in these jurisdictions and what could be implemented here in British Columbia. It is a project whose time has come and we look forward to your feedback. Mike McKenna Executive Director, BC Construction Safety Alliance 3

4 INFORMATION FOR THE CONTRACTOR Pre-qualifications for Concrete Pumping Contractor (CPC): a) Proof that the operator of concrete pumping equipment is trained in accordance with the requirements of the Concrete Pump Operators Safety Training Program sponsored by the BC Ready-Mixed Concrete Association, or equivalent. b) Proof that concrete pumping equipment is inspected and certified in accordance with guidelines and requirements of CSA Z151 and/or the equipment manufacturer s certification program. o It is a WorkSafeBC regulation requirement that a concrete placing boom and mast must be inspected by a professional engineer, the manufacturer, or the manufacturer s authorized agent, at intervals not exceeding 12 months, and repaired as necessary. o Notation on inspection checklist documenting each piece of certified equipment and their corresponding certification dates. o Any documented deficiencies in the inspection checklist shall be accompanied by documentation verifying the efforts incorporated in bringing the equipment into compliance, and the corresponding dates. c) Examples of previous work experience on similar types of jobs To assist the Contractor to select the correct model of concrete pump, the CPC should be able to supply details of: a) maximum reach of each concrete placing boom, both horizontally and vertically b) the standard equipment carried on a truck-mounted concrete pump c) the weights of pipeline, placement hoses, delivery hoses and accessories d) the maximum likely loadings for each of the outrigger bases e) the footprint of the machine with all outriggers extended in accordance with the manufacturer s safe work procedures for the specific machine (see Appendix D) f) the boom configuration g) the maximum safe wind speed for the operation of the boom NOTE: The maximum pressure generated by the pump will depend on the delivery situation and other factors. This should be the subject of discussion between the Concrete Pump Owner and Contractor h) the concrete placing boom manufacturer s, or qualified person s documented recommended procedures for shortrigging, if it has been determined that shortrigging is unavoidable 4

5 CHECKLIST FOR CONCRETE PUMPING The Contractor should make reference to a Checklist for Concrete Pumping, (see Appendix B), to assist the CPC to provide the correct machine for the job. Contractor s Responsibilities Responsibilities of the Contractor in requesting a suitable concrete pump should include: a) access to and egress from the site suitable for the size of the machine b) sufficient area for all the machine s outriggers to be fully deployed c) the ability of the ground to support the loads likely to be imposed by the machine s outriggers d) underground restrictions, e.g. cellars under pavements, cables close to the surface e) overhead obstructions, e.g. cables and structures; it is the Contractor s responsibility to devise a safe method of working in the vicinity of overhead cables f) the reach of the boom to the most remote point of the concrete pour NOTE: In the case of truck-mounted pumps, consideration ought to be given to the optimum concrete placing boom size for site conditions. Correct selection of the concrete placing boom will reduce any safety risks. g) where practical, suitable ladders, work platforms and scaffolds must be provided for activities requiring positioning at elevations above a floor or grade (WorkSafeBC OHS Regulation 20.4) See Appendix E h) suitable access for the ready-mixed concrete truck to the receiving hopper of the concrete pump i) the need for a signaller in circumstances where the operator will not be able to see the delivery end of the pipeline or hopper j) adequate protection of the permanent works from potential damage by the concrete placing boom NOTE: It is the Contractor s responsibility to ensure that adequate insurance is in place in the event of damage k) any special operational requirements or limitations imposed l) the need for additional delivery pipeline to supplement the boom pipeline m) the need for properly designed support for the additional pipeline 5

6 The Contractor, in consultation with other involved contractors and the CPC, should: ensure that enough trained and competent workers are available to safely use the pumping equipment ensure that pumping equipment is well maintained and in a sound mechanical condition select the most suitable location for the pump set-up, including: o an accessible, reasonably level area with a firm base, able to support the fully loaded working pump and concrete delivery trucks o clearance from obstructions and excavations o observing the restrictions of operating near overhead power lines o the pump s operational safety zone If the pump unit or delivery area is set up in the street: o observe all local by-laws o observe any requirements for traffic management o ensure that the general public is provided with safe and segregated access away from the pumping operation Have an appropriate method for the collection of residue or waste concrete, before it enters storm water drains, which may result from: o concrete truck deliveries o spillage o the wash-out and cleaning of the pump or lines o if the job site is within 30 metres (98.4 ft) of a watercourse or surface water drainage, the contractor should have the appropriate environmental safety equipment on site to use in the event of a spill and the personnel trained in its use Set a realistic time schedule for pumping concrete, allowing for: o weather conditions o capacity of the pump o volume of concrete o slab and site limitations o traffic requirements o local by-laws o the concrete contractor s work capacity 6

7 Protect Personnel Working Near the Concrete Pump Concrete truck drivers and the pump operators may be required to be close to the back end of a concrete pump to do their jobs. This area is potentially dangerous as the greatest concrete pressures occur at the elbow at the base of the pump. Provisions should be taken by the CPC to increase safety in the event of a blow-out, such as installing a barrier of rubber matting between personnel and the pump or laying the placing line so that it is positioned away from personnel. Shutting Down Due to Malfunction If the pump or machine develops an unanticipated problem that creates an unsafe condition, the CPC should shut down the system. The concrete delivery driver and other workers should be instructed on how to signal the pump operator if there is a problem at the pump or hopper. Every pumping machine must be equipped with a signaling device. 7

8 Shortrigging Shortrigging is a condition in which one or more outriggers are not fully deployed on the side away from the boom operational area. Shortrigging may be used only if: it has been determined that shortrigging is unavoidable the boom is not operated beyond the area of fully extended outriggers unless the boom/outrigger control system is range limiting any outriggers still retracted are jacked and the unit is leveled in accordance with the manufacturer's recommended procedures the manufacturer's or qualified person's documented procedures are followed Shortrigging only be used if it is impracticable to fully deploy all outriggers. For example, The outriggers would put the machine within an unsafe distance to hazards such as excavations and power lines The outriggers would extend into traffic and the circumstances of the job render it impracticable to get permission to close traffic lanes (closing traffic lanes is generally subject to municipal approval) An adjacent structure or an excavated or natural bank restricts deployment It is not considered impracticable to fully deploy all outriggers if the purpose is just to Increase convenience or save money Avoid repositioning the pump Avoid moving stored materials that might reasonably be moved The pump operator should be trained to recognize the circumstances that justify not fully deploying the outriggers. Written instructions that address the following factors must be available to the operator: Safe operating range Outrigger deployment on the pumping side Outrigger deployment on the side opposite to the pumping side Outrigger bearing load Procedure for unfolding the boom Precautions for over-centre booms (i.e., moving the centre of gravity toward the side that does not have fully extended outriggers) The American Concrete Pumping Association Safety Bulletin "Setting outriggers to prevent accidents - Shortrigging" provides useful guidance in preparing instructions that are specific to the site and equipment conditions, and can be found in Appendix E. 8

9 CONCRETE It is important to have all concrete mixes specified as "pumpable" prior to any concrete pours. There are mixes that do not pump at all or cause the pump lines to clog- big problems if you have 8 trucks arriving on the job ready to discharge concrete. The aggregate diameter must not exceed 1/3 of the inside diameter of the pipeline. For small line pumps, it is recommended that inside diameter of the pipeline be 4 times the largest aggregate size. Concrete Delivery Area The concrete truck delivery area, including the area around the pump hopper, should be set up to ensure that: workers are safe from other vehicles adequate lighting is provided if pumping in non-daylight hours appropriate signage is posted there is clear access for delivery trucks If multiple concrete deliveries are expected and on-site traffic management is not provided, only one delivery truck should approach and discharge into the hopper at a time. If a designated on-site traffic controller is provided, the following safety rules should be followed: all personnel connected with discharging from concrete trucks are to wear appropriate high-visibility safety vests The appointed signaller and operator should be instructed on: the use of the code of signals in Appendix A the use of any communications device supplied any special risks on the site, e.g. overhead obstructions the traffic controller and truck driver should be in positions which prevent them from being caught between the hopper and a reversing truck the traffic controller should warn the driver at the pump of the presence of another truck being reversed into position the traffic controller should be in a position visible to the reversing driver and where the hopper area can be observed delivery drivers should ensure that their vehicles remain clear of the discharge area until signaled to reverse into position by the traffic controller if the driver loses sight of the traffic controller when reversing into position, the driver should stop immediately. 9

10 Pedestrian Controls If the general public can come close to any part of the concrete pumping operation, the following options are recommended: directing the public to an alternative footpath, or providing an alternative pathway installing protective screens to prevent concrete splashing on members of the public erecting barricades and warning signs that are compliant with WSBC requirements For longer concrete pumping operations, pedestrian controls should be of a more permanent nature. Traffic Controls The principal, in consultation with the pumping contractor, should provide adequate traffic control measures to comply with WSBC requirements. 10

11 APPENDIX A HAND SIGNALS FOR CONCRETE PUMPING 11

12 APPENDIX B CHECKLIST FOR CONCRETE PUMPING This short Checklist for Concrete Pumping was developed by National Ready Mixed Concrete Association (NRMCA), American Society of Concrete Contractors (ASCC) and the American Concrete Pumping Association (ACPA). With permission of the original author, the BC Ready-Mixed Concrete Association (BCRMCA) have reviewed and revised this document for use on Canadian construction projects following the requirements of the most recent CSA A23.1/.2. The intent of this document is to identify details of the process of pumping concrete prior to the start of the placement so that all impacted parties are aware of the issues related to the construction specification, equipment and schedules, responsible persons and jobsite safety. The presumption is that on larger projects the concrete construction team has been through a pre-construction conference and has addressed the pertinent items and those items are excluded from this document. This document can be included in a broader pre-construction meeting agenda. This checklist is not intended to be all inclusive of the items that need to be considered and depending on a specific project many items regarding specification requirements, testing details, construction logistics and jobsite safety may need to be addressed in greater detail than outlined in this document. Many of these items will be critical to the success of the project and should be discussed and agreed upon prior to the placement of concrete with appropriate notification to the owner and his representative. 12

13 CHECKLIST FOR CONCRETE PUMPING Project: Location: Directions: 1. Contacts Contractor Ready-Mix Supplier Who Name Phone Fax Concrete Pump Contractor 2. General Conditions Start Time Pump: am/pm Concrete: am/pm Placement Location Slabs Walls Footings Other Placement Rate (m3/hr.) Volume (m3) Type of Pump Regular Z-Boom Telescoping Trailer Size of Pump (m) Pipeline dia, mm Pumping Distance (m) Vertical Horizontal Slump/Air Spec Point of Discharge Point of Placement Testing Priming Agent Point of Discharge Grout Point of Placement Slick Pack 3. Concrete Mixture Strength (MPa) 28 days: Other: Max Size of Aggregate (mm) (no larger than 1/3 pipeline diameter) Density (kg/m3) Lightweight Yes No Slump (mm) Lightweight Yes No Density (kg/m3) Air (%) Water Reducer Regular MRWR HRWR Fibres Yes No Special Requirements Set Time Requirements (hr.) Initial: Final: Water Addition Permitted Yes No 4. Jobsite Safety Wash Out Area Yes No Location: Power Lines Yes No Safe Set Up Area Yes No Restrictions: Clean Water Available for Washout Yes No 13

14 APPENDIX C MINIMUM SAFE LIMITS OF APPROACH FROM POWER LINES FOR PERSONS AND EQUIPMENT The key to safety is to keep a safe distance from overhead and underground power lines. Part 19 of the Occupational Health and Safety Regulation (OHSR) lists the distances that workers must keep away from exposed energized conductors. Table 19-1A in the Regulation gives the general limits of approach. This is the minimum distance from overhead energized high-voltage lines that non-qualified workers and their materials, equipment, and machinery must maintain. The limits of approach vary with the voltage. The tools and equipment that you hold or operate are an extension of your reach. You must ensure that you have enough room for movement with your tools without violating these limits. Table 19-1A: Minimum approach distance for working close to exposed electrical equipment and conductors Minimum Distance Voltage, Phase to Phase Metres Feet Over 750 V to 75 kv 3 10 Over 75 kv to 250 kv Over 250 kv to 550 kv

15 APPENDIX D The WorkSafeBC 30M33 form contains special instructions and conditions from the power company for working in the vicinity of electrical lines at a specific location. This form must be completed by the contractor and the owner of the power system prior to commencement of work near energized high-voltage electrical equipment or conductors per Part 19.

16 APPENDIX E: WORKSAFEBC REQUIREMENT FOR SCAFFOLDING Concrete Pouring and Pumping: Best Practices Advisory for Pump Rental Job Sites WorkSafeBC Occupational Health & Safety Regulation require that, where practicable, suitable ladders, work platforms and scaffolds must be provided for and used by a worker for activities requiring positioning at elevations above a floor or grade, such as when working on a concrete wall that requires the concrete placers to be working off of the ground and where they could be exposed to a fall. See WorkSafeBC OHS Regulation The pump operator shall check for a suitable work platform or scaffolding upon arrival at a job site. If the concrete forming does not have either a suitable work platform or scaffolding then the pump operator shall advise the site supervisor of the WorkSafeBC requirements and hand out a copy of this advisory. If the supervisor or site personnel choose not to provide a suitable work platform or scaffolding on the forming for the concrete placers, the pump operator shall advise them of their responsibility and obligation to provide a suitable work platform or scaffolding and of their potential liability in the event of an injury due to the lack of providing such equipment. Workers must not walk on top of the formwork. General Requirements Safe Access Unless working on the ground, pouring and pumping concrete into wall forms must be done from suitable work platforms In selecting suitable work platforms or scaffolding, employers have a number of options. Specifically, scaffoldings using manufactured scaffolding brackets, when installed and used in accordance with the manufacturer's instructions, are considered suitable. Single-pole wood scaffolds may also be suitable when properly installed and used. For more information on suitable work platforms and scaffolding, see the following WorkSafeBC publications: Safe Work Practices for House Construction or Construction Safety Series The platforms must be a minimum of 510 mm (20 in.) wide. As well, guardrails maybe required. As per WorkSafeBC Occupational Health & Safety Regulation 11.2 (1) an employer must ensure that a fall protection system is used when work is being done at a place (a) from which a fall of 3 m (10 ft.) or more may occur or (b) where a fall from a height of less than 3 m involves a risk of injury greater than the risk of injury from the impact on a flat surface. Single-pole wooden scaffolding for pouring or pumping concrete. Note: Guardrails may not be required if scaffolding is less than 3 m (10 ft.) above grade. NOTE: Exposed skin that contacts wet concrete can become extremely irritated. In some cases, the irritation is serious enough to result in injuries. To prevent exposure, personal protective equipment is required: Hard hat, gloves and safety glasses. Wear a long-sleeved shirt to protect against both site hazards and sun exposure. 16

17 APPENDIX F SAMPLE CONCRETE PUMP FOOTPRINT 17

18 APPENDIX G

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20 Safety Bulletin This document is intended to supplement but not supersede the manufacturer s applicable insrtuctions. Copyright 2010 ACPA All rights reserved 1/22/10

21 January 22, 2010 Safety Bulletin Safety Bulletin Setting outriggers to prevent accidents II Shortrigging Shortrigging The green area represents the area in which the boom can be safely moved. Use of the boom in any other area could cause the machine to tip. Job to be pumped eps Figure 1 Shortrigging Shortrigging describes the act of not extending the outriggers on the side away from the pour (Figure 1). Shortrigging is not recommended, but under certain conditions it may be required, and can be done safely if proper procedures are followed. If it is not possible to extend the outriggers on the side away from the pour, the unit can be set-up with the outriggers jacked down but not extended. To avoid a tipping accident while shortrigged, you must follow a few rules: Have a qualified person document that shortrigging is required. Whenever possible, completely extend the outriggers. Never shortrig the machine on the side of the pour. Do not position the boom outside the center lines of the extended outriggers. The unit can tip when the center of gravity is beyond the extended outriggers. The manufacturer s or a qualified person s documented procedures are to be followed. Remember that not all of the outriggers are extended. Forgetting this fact is the most frequent cause of accidental tipping.

22 The following steps will help you to shortrig in the safest possible manner: 1. Before extending any outrigger, check which way the hydraulic hoses are wrapped in the turret. You must be able to unfold to the side with fully extended outriggers without moving the boom to the side with retracted outriggers (Figure 2). 2. If the boom is folded up on the wrong side you will need to fully extend the outriggers while you raise the boom and swing it around 360 to put it back in the cradle, then retract the outriggers which require shortrigging. Move the pump to a safe area to do this, if necessary. 3. Fully extend and jack the outriggers on the side of the pour (Figure 1). Use proper cribbing for the soil conditions. 4. Do not partially extend the outriggers on the side of the unit opposite the pour for the reasons shown on the following page. They should, however, be jacked to provide stability. 5. After raising the boom from the cradle, do not unfold the boom until you have rotated to the area between the fully extended and jacked outriggers. The boom may then be unfolded and the tip hose released or attached. 6. At no point during the pour should the boom be moved outside the area between the center lines of the fully extended outriggers (Figure 1). 7. Upon completion of the pour, the cleanout ball should be inserted and sucked back, and the boom should be folded up completely, all the while staying on the same side as the fully extended outriggers, before slewing back toward the cradle. 8. Do not retract the extended outriggers until the boom is in the travel position eps The hydraulic hoses must be wrapped so the boom can be unfolded over the extended outriggers. If the hoses are wrapped the other way, completely extend and jack all outriggers, swing the boom around and place it in the cradle, before retracting the outriggers which require shortrigging. Move the pump to a safe area to do this, if necessary. Figure 2 Check hydraulic hoses before unfolding Page 2 of 5

23 Do not partially extend outriggers Structural damage could result (Figure 3 and Figure 4) NO! Outrigger Inner Box Reinforcements Outrigger Outer Box Reinforcements nopartialextension.eps Figure 3 Transparent outrigger shows reinforcement areas (curved outriggers have the same limitations) Force Fulcrum Fulcrum OK 1. Outrigger fully retracted. No lever action. Force absorbed by reinforcements. Force must be low, or unit will tip. CAUTION Force Force Fulcrum OK Structural damage to outriggers is possible. Do not jack outriggers unless they are either fully extended or fully retracted eps 2. Outrigger fully extended. Lever action present, but force absorbed by reinforcements. force&leveroutrig.eps Partial extension of telescoping outriggers is not acceptable at any time. Jacking the outriggers while they are in any position other than fully extended or fully retracted could cause structural damage to the outrigger outer box and/or the inner box (Figure 3). The three illustrations shown in Figure 4 explain the configurations of the outrigger in all positions. Remember that in configuration number 1, the boom must never be extended over a retracted outrigger. Fulcrum Force Force NO! Fulcrum 3. Outrigger partially extended. Lever action present, but force transmitted to areas with no reinforcements. Could cause damage. Figure 4 Examples of outrigger reinforcements in three different configurations Page 3 of 5

24 Tipping and Blocking Traffic NO! orftip2.eps Figure 5 Danger of tipping if over center boom is retracted too far. With any boom that can go over center, you must be careful to not retract #1 so far that the center of gravity will shift to the shortrigged side. In addition to the tipping hazard, the boom should never be placed in an area that will obstruct traffic (Figure 5). Responsibilities Contractors One of the things a contractor can do to help is to order the right size boom: If the boom is too small, for example, he may have to set up too close to an excavation to reach the pour. If the boom is too large, it will require much more cribbing than a smaller unit, and will require a larger set-up area. Have a place prepared for the pump before it arrives on the job. Inform the operator of backfilled areas, soft or muddy areas, or underground obstructions. Have cribbing nearby the set-up area prior to the pump s arrival (including steel sheets if the soil is known to be bad). Monitor the set-up. Don t let the operator cut corners or take chances. Dispatcher The dispatcher can help by communicating with the contractor when he calls to order the pump, and: Send the size pump that is needed, if available. If availability causes you to send a unit that is too big or too small, warn of possible complications. Ask about soil conditions, underground obstructions, and traffic considerations. Operator The operator is ultimately in charge and must make good decisions regarding set-up including: Know restrictions of boom movement caused by shortrigging and never exceed them. Partial extension is not allowed on extendable outriggers. Keep people out from under the boom whenever practical. This document is intended to supplement, but not supersede the manufacturer s applicable instructions. - By Danny Mace and Robert Edwards, Edited by the ACPA. Page 4 of 5