An explosive ignition of gases that results when air enters a compartment and mixes with hot, unburned gases is known as what?

The phenomenon described occurs when a fire has depleted available oxygen, leading to the buildup of hot gases at the top of a confined space. When air is introduced—whether by an opening, a door being opened, or some other means—this fresh oxygen mixes with the hot, unburned gases. This mixture can ignite explosively, resulting in a rapid release of energy and fire. This event is termed a backdraft.

Understanding backdraft is critical for firefighting, as it poses significant risks to fire personnel. A backdraft can happen suddenly and unexpectedly, often after a sufficient amount of heat and smoke has built up in a compartment. Firefighters are trained to recognize signs of a potential backdraft, such as smoke that is heavy and stagnant, as well as signs of heat buildup, to safeguard themselves and effectively manage the fire situation.