What occurs when the introduction of oxygen into an oxygen-starved mixture of superheated gases results in explosive ignition?

The scenario described involves the sudden introduction of oxygen into an environment where superheated gases are present but already lacking sufficient oxygen. This condition sets the stage for a backdraft, which is characterized by a rapid and explosive ignition due to the sudden combustion of the accumulated flammable gases when oxygen is reintroduced.

In a backdraft situation, the temperature of the gases can be extremely high, and when additional oxygen enters the space—such as when a door or window is opened—the mixture can ignite explosively. This event is particularly dangerous and is accompanied by a loud noise, often resembling an explosion, and can lead to intense fire conditions.

The other terms refer to different fire phenomena. For example, flashover occurs when all combustible materials in a space ignite almost simultaneously due to significant heat build-up, but is not primarily a result of introducing oxygen into an already superheated environment. Rollover refers to flaming combustion of gases in the upper layer of a compartment, and mushrooming pertains to the shape of a smoke cloud before flashover occurs. Understanding these distinctions helps in recognizing the critical factors involved in fire behavior and the risks associated with fire dynamics.