Carbon dioxide fire extinguishers equipped with metal nozzle nozzles must not be used in Class E fire (live electrical fire) areas.
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Areas with Class E fires (fires involving electricity): foam fire extinguishers, ammonium bicarbonate dry powder fire extinguishers, ammonium phosphate dry powder fire extinguishers, carbon dioxide fire extinguishers, and halon fire extinguishers; however, carbon dioxide fire extinguishers equipped with metal nozzles should not be used. Carbon dioxide fire extinguishers equipped with metal nozzle nozzles must not be used. Reason?
The nozzle is made of metal and conducts electricity; isn’t the handle behind it also metal, which would also conduct electricity? It’s likely that when carbon dioxide is ejected, the temperature of the nozzle drops sharply, which may cause frostbite to the hands.
First, when a metal horn releases carbon dioxide, it absorbs heat from its surroundings, causing water vapor in the air to condense; this increases the humidity in the air (and lowers the temperature), which may facilitate electrical conduction； Second, a hand-held horn may be needed during use, and metal horns can cause frostbite.