What is the term for the event when all surfaces ignite simultaneously?

The event when all surfaces ignite simultaneously is called flashover. During flashover, the temperature within a room or confined space reaches a point where the combustible materials are unable to withstand the heat, leading to a rapid transition from smoldering combustion to full-scale flames. This phenomenon often occurs during a fire when the accumulated heat causes the gases and materials in the space to reach their ignition temperatures almost instantaneously.

Flashover is a critical concept in fire inspections and firefighting, as it represents a significant change in fire behavior. Once flashover occurs, the fire spreads rapidly and becomes far more dangerous, making timely detection and suppression essential for safety.

In contrast, backdraft refers to an explosive event that occurs when oxygen is suddenly introduced to a smoldering fire, leading to a rapid combustion of gases. Intermittent flame refers to flames that appear and disappear during the combustion process, and flame spread describes the movement of flames across a surface or through a medium. While these terms relate to fire behavior, none captures the essence of all surfaces igniting at once like flashover does.