Vapor lock defined

Vaporizing liquid halogen agents are electrically non-conductive and are effective on a wide range of combustibles, particularly flammable liquids and electrical fires. A lock-off system is required on fixed installations to protect personnel, the normal extinguishing concentration being 5% by volume. The use of such liquids is being phased out except for defined essential uses they will be banned from 31 December 2003. 

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