Tuesday 30 October 2012

Gas cylinder fire prevention - Special Precautions for hot works at height in Petroleum Refinery

Gas cylinder fire prevention

General Considerations

1.            Either the work-piece shall be moved to a safe location for carrying gas-cutting work or Combustible materials and flammable materials shall be removed from the work place. 
2.            Spaces where gas could accumulate shall be ventilated.
3.            If combustible materials that cannot be moved shall be protected from close contact with flame, heat, sparks or hot slag. Suitable guards or covers such as metal sheeting, mineral fibre boards or fire retardant blankets shall be used; in such case hot work permit shall be obtained.
4.            Guards or covers shall be used to prevent cylinders from hot particles passing through openings in floors and walls;
5.            Fire extinguishers shall be kept nearby.

Prevention of Gas Leaks from Gas Cutting Sets

1.            Hoses shall be kept clear of sharp edges and abrasive surfaces or where vehicles can run over them;
2.            Hot metal or spatter shall not be allowed to fall on hoses;
3.            Gas cylinders kept in upright position shall be chained to prevent them from falling down or being knocked over. For example, cylinders can be chained in a wheeled hand trolley or against a wall or a suitable support;
4.            Gas Supply shall be turned off at the cylinder when the job is finished;
5.            All the equipment shall be kept in good condition:
6.            All the connections and equipment shall be regularly checked for faults and leaks;
7.            Taking gas cylinders into a poorly ventilated rooms or confined spaces shall be avoided.

Special Precautions for hot works at height in Petroleum Refinery

When the nature of work to be performed falls under the conditions given under the third point of subheading 3.1 the following additional precautions shall be taken:

1.            After the combustible floors have been swept clean, they shall be pro­tected by thoroughly wetting with water, covering with damp sand, sheet metal etc. or such other equivalent material. Provisions shall be made to protect welders from the hazard of shock when floors are wet;
2.            Suitable, incombustible tables, jigs or work places shall be provided for support of small or moderate size work during welding and cutting operations. Such operations should not be undertaken on work resting directly on concrete floors;
3.            Guards or covers shall be used to prevent cylinders from hot particles passing through openings in floors and walls;
4.            Suitable fire-extinguishing equipment, such as pails of water, buckets of sand, hose lines or portable extinguishers shall be kept in readiness for instantaneous use.
5.            Firewatchers shall be stationed at the required locations to extinguish the same if any fire breaks out.

Welding or Cutting of empty diesel or petrol Drums/Tanks

1.            Welding / Cutting of oil drums, motor car petrol tanks or any other contain­ers, which might at any time have contained a liquid giving off and in­flammable gas shall not normally be permitted. However, in case welding of such container’s is absolutely necessary, the following precautions shall be taken before welding them:

a.       They shall be thoroughly degreased using an alkaline or any other type of degreasing solution;
b.      They shall then be thoroughly rinsed with hot water and allowed to dry for a few days;
c.       After drying and before welding, they shall be purged thoroughly for a period of at least five minutes with an inert gas;
d.      The inert gas shall be allowed to flow through the container under a positive pressure while welding is taking place.

Sprinkler Protection

Where sprinkler protection exists, it shall be maintained without interruption while welding or cutting work is being performed. If welding or cutting is to be done quite close to automatic sprinkler heads, sheet asbestos or damp cloth guards shall be used to shield the individual leads temporarily.

When Acetylene Cylinder gets heated

If an acetylene cylinder is heated or becomes hot accidentally due to excessive or severe back fire from use of faulty equipment, it shall be dealt with promptly as follows:

1.            The valve shall be shut.
2.            Regulator or other fittings shall be detached.
3.            The cylinder shall be taken outdoors.
4.            It shall be immersed in water or water shall be applied copiously.
5.            The valve shall be opened and the cylinder,’ kept cool in water until it becomes empty.

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