Flashover Training

When the room bursts into flame, flashover has occurred. The scientific definition of flashover states it is caused by the radiation feedback of heat. Heat from the growing fire is absorbed into the upper walls and contents of the room, heating up the combustible gases and furnishings to their auto-ignition temperature. This build up of heat in the room triggers flashover. Flashover signals several major changes in a fire and is the end of an effective search and rescue in a room; It means the death of any person trapped in the blazing room - either civilians or firefighters. It signals the end of using a portable extinguisher to extinguish the fire; an attack hose-line is required after flashover occurs. It signals the end of the growth stage and that the fire is in the second stage of combustion - the fully developed stage. Finally, flashover signals the change from a contents to a structure fire. This is the beginning of the collapse danger. When operating at a fire, Chiefs and firefighters want to delay flashover inside a burning room. By delaying flashover you can "buy" several minutes which may be critical. For example, you may want to delay flashover to make a search and rescue of the burning room or allow a firefighter to go above a fire to make a rescue of a trapped victim. By Ret. Chief Vincent Dunn (found at http://www.workingfire.net/misc3.htm)

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