Why do firefighters recommend the use of a deluging volume of water when extingu

Question

Why do firefighters recommend the use of a deluging volume of water when extinguishing an oxidizer-supported fire? What may happen to a large (i.e., 30-50lb) container of trichloro-s-triazinetrione, or calcium hypochlorite, if it is left to sit in the water and muck remaining in a building after fire fighting efforts have ended, but clean-up will not begin for several days? The assumption here is that the plastic container has been compromised in some way by the heat of the fire and possibly creating cracks in the base or sides.

Explanation / Answer

The recommended method of extinguishing fires supported by most liquid or solid oxidizers is to deluge them with water. Metallic oxidizers are generally soluble in water. On dilution, there chemical reactivity is sharply reduced (Meyer, E. 2010 515).

Meyer, E. (2010). Chemistry of hazardous materials (5th ed.). Upper Saddle River, NJ: Pearson Education Inc.

Water and electricity generally do not mix very well. Impurities in ordinary tap water help make it a good conductor of electricity. Using a water fire extinguisher on an electrical fire will almost always present a major shock hazard and should never be considered. That being said there is a "special" type of water fire extinguisher that can be used on electrical fires, but it uses purified distilled water and a special nozzle that disperses the water in tiny beads. To be safe, unless you know what type of extinguisher you have and what it is used for, it is best to evacuate the area and call the fire department.
it makes big sparks

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