This article is about the phenomenon in fires. For the movie see Backdraft (movie).
A backdraft is a situation which can occur when a fire is starved of oxygen; consequently combustion ceases but the fuel gases and smoke remain at high temperature. If oxygen is re-introduced to the fire, eg by opening a door to a closed room, combustion can restart often resulting in a near-explosive effect as the gases heat and expand. This effect is the basis for the synonym smoke explosion. Characteristic signs include yellow or brown smoke, smoke which exits small holes in puffs (often found around the edges of doors and windows), and windows which appear brown or black when viewed from the exterior. These darker colors are caused by incomplete combustion.
This is a very dangerous situation, often surprising even professional firefighters. The most common tactic used by firefighters in defusing a potential backdraft is to ventilate from the highest point, allowing the heat and smoke to escape without igniting explosively.
Resources
- Hall, Richard & Adams, Barbara (1998). Essentials of firefighting (4th ed.). International Fire Service Training Association. ISBN: 0879391499.