What term describes a sudden ignition of flammable gases when oxygen is introduced to a ventilation-limited fire?

Backdraft is the term that describes a sudden ignition of flammable gases when oxygen is introduced to a ventilation-limited fire. In a situation where a fire has consumed the available oxygen and is smoldering, combustible gases can accumulate. If fresh air is introduced—such as through a door opening or window breaking—this influx of oxygen can ignite those flammable gases, resulting in a sudden and explosive combustion event.

The conditions leading to a backdraft are characterized by smoke and hot gases being trapped within an environment, creating a mix that is ripe for ignition when oxygen is added. Understanding backdraft is crucial for firefighters, as it poses a significant danger when entering a fire-affected structure.

In contrast, flashover refers to the rapid spread of fire that occurs when all combustible materials in a room ignite simultaneously after having reached their ignition temperatures. Smoke explosion refers to an explosive ignition of accumulated smoke in an area, which can also occur under certain conditions, but is not specifically related to sudden oxygen introduction. Ventilation itself is a process, not an event or condition that describes a specific ignition phenomenon.