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The consequences of incorrect storage, handling, transportation and use of highly flammable liquids can be catastrophic it is therefore vital that this guidance and the guidance covering fire safety is followed.
Any liquid, liquid solution, emulsion or suspension which gives off, under defined laboratory conditions a flammable vapour at a temperature less than 320 C and supports combustion can be defined as a highly flammable liquid. The term "highly flammable liquids"(HFL) includes liquefied flammable gases and liquefied petroleum gases. It does not include aqueous ammonia.
The term liquefied flammable gas is any substance which would be a flammable gas at a temperature of 200 C and atmospheric pressure, but which is in a liquid form as a result of the application of pressure or refrigeration or both.
Liquefied petroleum gas (LPG) covers commercial propane, butane and any mixture of both.
Highly flammable liquids present a significant fire risk. Vapours are usually heavier than air and travel long distances, it is therefore highly likely that vapours will meet a source of ignition on their journey. Faulty storage containers, poor plant design, installation, use or maintenance can cause liquid leaks and vapour evolution. Many vapour releases however are caused by simply failing to put tops back on containers after use.
Areas where HFL's are stored or used should be designated as "no smoking areas" and suitable "no smoking" signs displayed. The no smoking policy should be strictly enforced.
HFL's should, whenever possible, be eliminated from use or replaced with less flammable materials. Quantities should be reduced to the smallest amount possible and no more than half a day's use kept in the workplace. It is preferable to store HFL's outside in the open or in a suitable building outside. Quantities up to 50 litres may be stored in the workroom providing they are kept in a container or room that provides a half-hour fire-resisting exterior. Where the fabric used in its construction meet, the junction should be bonded or fire stopped. Any hinges should be made from a material with a high melting point. A means of containing leaks should be included in the design e.g. a sill.
Quantities greater than 50 litres should be stored in the open air on impervious ground away from sources of ignition or in a properly designed store. Such stores should have a low retaining wall (sill) with a ramp to facilitate access and secured with a boundary fence. Where open-air stores are not used enclosed stores outside the work area can be used. These stores should be a fire resisting structure with adequate high and low level ventilation and have a sill across the doorway/declivity in the floor to contain spillage. The electrical equipment installed should be classified as suitable for use in potentially explosive atmospheres.
Fixed tanks located in a safe position can also be used. They should not be sited inside or on the roofs of buildings. They may be sited underground but not below the floors of process areas. The tank should be bunded and the bund capable of containing 110% of the tanks volume.
Where HFL's are stored in drums a sill capable of containing the maximum quantity of the largest drum should surround the area.
LPG may be stored in underground reservoirs, fixed tanks or movable tanks or vessels. The tanks should be sited in a safe position.
Pipelines including their pumps may be used if they form part of an enclosed system.
Cylinders must be kept in safe positions in the open air, however where this is not reasonably practicable they may be stored in a safely positioned storeroom that is well ventilated. It should be a fire resisting structure and be used to store only LPG and or acetylene cylinders. Only the minimum number of cylinders required for use should be in the work area and they should be returned to store as soon as possible after they become empty. Cylinders should be secured to prevent toppling.
Every storeroom, cupboard, bin etc used to store HFL's should be signed "HIGHLY FLAMMABLE" or "FLASHPOINT BELOW 32o C" or "FLASHPOINT IN THE RANGE OF 22o C to 32oC". Where LPG is stored the store should be signed "HIGHLY FLAMMABLE - LPG".
All proprietary safety cans or sealed containers should be marked to clearly identify their contents.
Ideally conveyance of HFL's within a workplace should be by a totally enclosed pipe system. Where this is impractical, closed non-spill containers should be used. Portable vessels should be removed to a safe place once empty. Procedures should be in place and employees instructed on the action to be taken if a spill or leak occurs. Information regarding emergency action and suitable materials to be used to mop up or contain spills are contained in the manufacturers safety data sheet for the substance involved and they should be used when establishing emergency procedures.
Steps should be taken to minimise the risk of vapour release into the workplace. Containers should be resealed immediately after use. Where escape can not be avoided then a means of safe dispersal such as extraction equipment should be provided. No sources of ignition should be present in areas where a concentration of HFL vapours may be present. Electrical apparatus in areas where highly flammable liquids are stored or used should be classified as suitable for use in potentially explosive atmospheres.
Where two metal surfaces come into contact with each other there is a possibility of static electricity discharging from one surface to the other. This can cause a fire. A typical example of this is where an HFL is being poured from one container to another. The problem can be overcome by earth bonding the plant and equipment. Containers can be bonded by the use of a clip that is connected by an earth wire to earth. Other precautions include insulation mats, insulated footwear and cotton clothing. Where forklift trucks and pallet transporters are used wood or other insulating material can be used to cover racking shelves to avoid metal to metal contact.
It is important that a safe means of escape is provided and maintained from areas where HFL's are manufactured or used. A fire certificate will usually be in force for premises that manufacture or store HFL's or LPG / liquefied flammable gases. The means of escape and other conditions and precautions will be detailed in the certificate. Suitable fire fighting equipment should be readily available. Manufacturers safety data sheets will provide information on the type of extinguishing media appropriate for the HFL concerned. Where a fire certificate is in force it will show the type and position of all the necessary fire equipment.
Deposits of HFL's or their residues create a significant fire hazard. A routine cleaning schedule should be established to prevent the build up of residues around the premises.
Employees should be given suitable information, training and instruction regarding the safe handling, storage transportation and use of HFL's. The training should include action in the event of fire or other emergency and the precautions to be taken following leaks or spills. Emergency procedures should be regularly practised and recorded.
Adequate supervision commensurate with the degree of risk should be provided to ensure that precautions are being taken and procedures are being followed.
Highly Flammable Liquids and Liquified - Petroleum Gases Policy.
Highly Flammable Liquids and Liquified Petroleum Gases (LPGs and HFLs) Procedure.
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