The Safe Handling of Pressurised Container Assemblies Used in Fire Extinguishing Systems

Transcription

1 Guidance Note The Safe Handling of Pressurised Container Assemblies Used in Fire Extinguishing Systems

2 The Safe Handling of Pressurised Container Assemblies Used in Fire Extinguishing Systems SCOPE... 3 BACKGROUND... 4 RISKS... 5 UNDERSTANDING THE HAZARDS... 6 MITIGATION BY SAFE WORKING PRACTICES... 7 TRAINING...11 REFERENCE DOCUMENTS of 12

3 SCOPE This FIA guidance sets out a generic industry best practice for practitioners that handle pressurised container assemblies as part of fixed fire fighting systems. Given the broad range of product types and of extinguishing agents that are available on the market the guidance can only provide an indicative overview of best safety practices. Practitioners will need to be familiar with the technical detail of each of the product and agent categories that they work on, and the pertinent product specific safety features of each. This guidance applies to the transportation, handling, installation, commissioning, maintenance and removal of pressurised container assemblies. 3 of 12

4 BACKGROUND The pressurised containers used as part of fixed fire fighting systems are designed and validated in accordance with the prevailing Codes, and do not present hazards of concern provided that they are managed and handled appropriately. Safety features are incorporated in such product designs to mitigate against risk of any loss of control when storing, transporting and handling such containers. These safety features typically include: Valve protection transport caps and/or shrouds: devices that are designed to protect the valve from damage during transportation and handling of the containers. Dependant on the design these may need to be removed to facilitate final connection to the agent delivery system. Anti-recoil device: outlet plug or cap that restricts the flow out of the valve outlet in the event of an unintended opening of the valve, such that the recoil thrust is not sufficient to disrupt a free standing container. Overpressure relief device: typically a burst disc and associated anti-recoil fitting that will actuate in the event of a container over-pressurisation to provide a controlled slow release of the contents. This would mitigate risk of container rupture in a fire or overheat condition. Purpose built restraining bracketry, or other means: racking that provides sufficient constraint of the containers to prevent mechanical disruption and container movement as a result of the reaction forces of any intended or unintended release of the contents 4 of 12

5 RISKS Risks associated with the storage, movement, transportation and handling of stored pressure containers are largely a consequence of inadvertent mishandling and could lead to the unintended toppling, rolling or dropping of the container and/or the uncontrolled release of the stored pressure, usually a consequence of valve activation or valve damage or detachment. It is essential that practitioners always comply with the guidance set out below to avoid risk of injury and damages. A hazard and operability approach to risk assessment will assist in identifying the risks and in evoking safety features to mitigate. The three principle concerns are: Loss of control or inappropriate handling of the heavy weight of these containers. This can lead to musculoskeletal injuries if appropriate handling and support measures are not taken. Sudden and unintended release of the stored gas. The recoil force, which will be a function of the stored pressure and orifice area, is liable to launch the unconstrained container in the workspace and accelerate it and any other debris or fragments. Unintended release of the stored gas in a confined space. This risks asphyxiation and, with some agents, frostbite chilling and pressure effects. Safety critical devices and safe working practices must be adopted to prevent or mitigate against such outcomes. 5 of 12

6 UNDERSTANDING THE HAZARDS The hazards are, of course, specific to the hardware type. Charged and pressurised fixed fire fighting containers vary in weight, height and diameter. They are liable to be heavy and cumbersome to handle. Any loss of control during handling can result in a container toppling or falling with risk of injury and of causing an unintended release of the pressure, which then acts to accelerate the container (if unconstrained) and/or the valve assembly if detached. In extreme circumstances it can represent a serious projectile hazard which could impact with other pressurised containers, personnel or structures. Containers that have a large height to diameter ratio have a higher centre of gravity and are more prone to topple, or to be inadvertently knocked over unless they are properly constrained. Containers that contain liquids can behave differently; the inertia of the liquid slopping around in the container adds to the handling challenge. The potential energy resulting from the compression of the stored gas represents the principle hazard. Fire fighting agents may be compressed ideal gases (such as nitrogen or argon), vaporising liquids stored under their own vapour pressure (such as carbon dioxide and HFC-23), vaporising agents that are super pressurised with nitrogen (such as HFC-227ea and FK ), and non-volatile agents (such as water, dry powders and foams) that are also pressurised with nitrogen. The consequent recoil thrust is a function of the stored pressure and the orifice area; thrusts of several tonnes force are possible. Whilst most fire fighting agents are not toxic, asphyxiation is also an attendant hazard arising from an unintended release of the agent into a confined space. With vaporising liquid agents, the consequent flash cooling represents an additional frostbite exposure. An unintended release of compressed gas into a confined space also risks pressure damages to the enclosure boundaries. 6 of 12

7 MITIGATION BY SAFE WORKING PRACTICES WARNING: Before handling or transporting any pressurised container the valve assembly MUST be protected by the fitting of the safety cap and/or safety shroud and anti-recoil device, which is always supplied (fitted) by the manufacturer for all pressurised fixed fire fighting containers. Safety Cap Container with Safety Shroud NEVER remove these safety devices until the container is adequately constrained in its intended location and the connections can be made immediately. NEVER attempt to move or transport the container for any purpose unless this safety cap/shroud and, where applicable, the anti-recoil plug are correctly and securely fitted. When handling/moving pressurised containers on site Undertake a site specific risk assessment and make mitigation provisions: Exclude personnel from installation and stowage work areas, communicate that hazardous works are planned and deploy appropriate warning signage Never work in an area where other works are ongoing in the vicinity and/or above the impacted workspace(s) Do not permit use of any scissor lift, mobile trucks and/or carts of other trades within the area Check the planned movement path for the pressurised containers to ensure that the eventual container standing is flat, clean, dry and fit for purpose and the route has no obstructions or trip hazards. Note: If manual handling for short distances, be aware of uneven, slippery or painted floor surfaces. If necessary, lay non-slip material on floor before moving containers Doors to container storage area to be secured in the open position. Always wear pertinent PPE (footwear/gloves/eye protection, etc.) Always secure each container after each container movement. Never turn your back on a freestanding/unsecured vertical container. Never remove the safety transport cap unless making an immediate connection to the agent delivery system. 7 of 12

8 Take care when moving containers. Only use approved transport trolleys or cradles that are intended and fit for the purpose. Never move a container unless it has been fixed to the trolley/ cradle by strap or chain. Always check that containers placed on pallets, or in storage, or transport cages are ALL secured. Straighten any leaning container before releasing its restraining strap or chain. Where transported horizontally on pallets, valves should not protrude beyond the edge of the pallet. Avoid repetitive and heavy lifting, bending and twisting and never work in an unsecure or uncomfortable position. Use only purpose built cradles or twin rope slings for hoisting. DO NOT ATTEMPT TO CATCH A FALLING CONTAINER GET OUT OF THE WAY! Never exert excessive force when handling pressurised containers DO NOT move the container using the valve Only work with pressurised containers if fit and well When receiving or transporting/pressurised containers at site Transporting includes movements of the containers to and from the site, and movements to intended locations within the site using motorised vehicles. Pressurised containers must be retained on pallets, or in transport cages, or cradles, secured and, if necessary, cover the containers to protect from direct sunlight, whilst being transported on the road and around the site. When transporting by motor vehicle, use vehicles equipped with racks or other means of securing the containers if palletised or within skids. Never transport pressurised containers in vehicles that do not have a bulkhead that seals and protects the load area from the driver s cab. This requirement may help to mitigate the risk of asphyxiation should a container develop a leak. It is a requirement to display the pertinent regulatory warnings on the vehicle. When receiving pressurised containers at site do not accept any container that has unidentified content or is damaged, in poor condition, or leaking. In such cases quarantine the container. Do not attempt to repair a damaged or leaking container. Contact the manufacturer/supplier for advice immediately. When unloading containers for movement to the eventual storage or install location, use only appropriate container handling equipment such as a pallet truck or trolley. Excessive manual handling of individual containers is not recommended since it increases risk of a toppling or dropping incident. Do not roll containers. If unloading containers using a crane, use appropriately rated and certified lifting straps/cradles/ platforms. Do not attempt to lift containers by the transport shroud or transport cap unless specifically intended for that purpose. In many cases the shroud and/or cap will have been specifically designed to pass a drop test and not rated for a lifting purpose. Do not use lifting lugs to lift containers unless the manufacturer approves their use and confirms that the lugs have been tested for dynamic loading. Avoid shock loading containers when manoeuvring because this may cause an accidental discharge. 8 of 12

9 Pressurised containers storage at site Store pressurised containers in a cool, dry, well-ventilated area away from all sources of heat or flames and within the temperature range stated by the manufacturer. Do not leave containers free standing. Always provide adequate constraint for pressurised containers and only stow with the transport cap and other safety devices fitted. Do not store pressurised containers in damp areas or near salt, corrosive chemicals, fumes, heat or in direct sunlight. Do not store pressurised containers under stairways or in hallways designated for emergency exit. Do not store any pressurised containers in locations where other objects may strike or fall on them. Do not store pressurised containers near elevators, gangways, stairwells or other places where they could be affected by other works. Do not store any pressurised containers in public areas or in unprotected (insecure) areas. Store pressurised containers by gas type in accordance with local fire code requirements, manufacturers recommendations or national legislative requirements. Pressurised containers shall be stored under the following conditions:- The temperature range shall not exceed the manufacturer s stated storage temperature range. If not known, the storage temperate range shall be in the range of 0 degrees C to 50 degrees C Containers shall not be placed in direct sunlight. If an outdoor sun shade is used, it shall be verified that it provides shade to the entire surface of the container at all times of the day and year. Containers shall not be placed in areas subject to excessive radiant heat. Containers shall not be stored in close proximity to flammable materials or areas where a fire risk exists. The storage area shall be well ventilated. If an indoor location is used, it should have suitable natural ventilation (ie grilles or air bricks) placed at both high level and low level, preferably on two opposite sides or ends of the enclosure. If natural ventilation is not possible, the area should be fitted with a forced draught ventilation system. If the container storage area is not ventilated, it shall be fitted with an oxygen monitoring system and a safe practice of work adopted to restrict/control access to the container store. Containers shall not be stored in areas subject to adverse environmental contamination, eg damp, running water, excess dust, chemical attack, etc. If stored outdoors, containers should not be placed in direct contact with the ground where this is likely to become damp. Pressurised container installation/connection/removal The designated container location for the fire protection system should be away from general free access such as a plant room or dedicated container store. Where this is not possible, the pressurised containers should be installed in a cage which has restricted access. If an outdoor cage is used, this should be locked. The pressurised containers should not be placed in a location associated with movement of vehicles, equipment, plant or machinery. If this is not possible, suitable physical barriers should be installed which will prevent any contact with the containers, even in an accident condition. Pressurised containers must not be located in any areas that are subject to potential falling objects. No access should be permitted to the headspace above the containers, except where it is necessary to work on system equipment above the containers, such as manifolds or hoses. 9 of 12

10 Move the required pressurised containers into their intended final location and retain with the constraining brackets/straps before initiating any connection works to the agent delivery system. To connect the pressurised containers to the pipework it may now be necessary to carefully remove the safety (transport) cap and any anti recoil plug fitted on the outlet. These must be retained for reuse for eventual container removal. Except where it is necessary to work on system equipment above the containers, such as manifolds or hoses, never work above a mechanically unprotected pressurised container and avoid using scissor lifts, ladders or platforms because these could fall and strike the containers, which risks an unintended pressure release. Install and connect one pressurised container at a time, making good all connections and tightening the container into its final position with the constraining brackets/straps. When all pressurised containers are installed and connected, complete all commissioning checks before handover of the fixed fire fighting system. Removal of a pressurised container is strictly the reverse of the install. Always ensure that you have to hand the necessary safety caps and anti-recoil devices before disconnecting any container (pressurised or discharged) from the installation. Always handle a container as if it is pressurised. You should never rely on the pressure gauge reading or on any site worker s report. It is safer to assume that they are pressurised and handle them accordingly. 10 of 12

11 TRAINING Personnel involved in the handling of pressurised containers shall be trained in the correct procedures to be followed for manual handling and those specific to the equipment. This will include manufacturers recommendations and any applicable legislation. If the containers contain agents covered under the F-Gas Regulations (HFCs, PFCs), all personnel must be trained and certificated and their employers must have company certification under the legislation. 11 of 12

12 REFERENCE DOCUMENTS For further guidance please refer to the publications listed below: BCGA GUIDANCE NOTE GN 2 Guidance for the Storage of Gas Containers in the Workplace BCGA GUIDANCE NOTE GN 3 Safe Container Handling and the Application of the Manual Handling Operations Regulations to Gas Containers BCGA GUIDANCE NOTE GN 11 Reduced Oxygen Atmospheres Guidance on the Periodic Testing of Transportable Gas Containers used in Fire Extinguishing Systems DISCLAIMER The information set out in this document is believed to be correct in the light of information currently available but it is not guaranteed and neither the Fire Industry Association nor its officers can accept any responsibility in respect of the contents or any events arising from use of the information contained within this document. Tudor House, Kingsway Business Park, Oldfield Road, Hampton, Middlesex TW12 2HD Tel: +44 (0) of 12