What is the difference between "flashover" and "backdraft"?

The distinction between flashover and backdraft is crucial for understanding fire behavior and the strategies needed for effective firefighting.

Flashover refers to the rapid spread of fire through the combustible materials in a room or enclosed space. It occurs when the temperatures in the room rise significantly, causing the materials to ignite almost simultaneously. This phenomenon is characterized by a uniform increase in temperature and involves the transition to a fully involved fire state, where almost everything in that space catches fire at once.

On the other hand, backdraft is an explosive re-ignition of gases that have accumulated in a space devoid of adequate oxygen. This often occurs when firefighters introduce fresh air into a hot, smoke-filled environment, which can suddenly ignite the concentrated flammable gases that have built up from incomplete combustion. This can result in a sudden and violent ignition, creating a significant hazard for both the fire and any personnel in the vicinity.

Understanding this difference is vital for firefighters, as it influences their tactics and safety measures during an incident.