What is flashover?

Flashover is a critical phenomenon in fire dynamics that occurs when the temperatures in a room rise to a level where all combustible materials ignite almost simultaneously. This stage results from the accumulation of heat and smoke, leading to a rapid transition from a localized fire to an intense and widespread fire throughout the space.

Understanding flashover is crucial for firefighting operations as it presents significant hazards to life safety and complicates fire control efforts. Firefighters must be trained to recognize the indicators of flashover, such as high heat, dense smoke, and rapid flame spread, to adjust their tactics accordingly and protect themselves and others from the dangers posed during this phase of a fire.

The other options do not accurately depict the nature of flashover. The first option suggests a scenario where only walls ignite, which does not capture the full scope of flashover. The second option implies a state where flames are extinguished, which is the opposite of what occurs during flashover. Lastly, the fourth option describes a phase just before a fire goes out, which again misrepresents the violent transformation that takes place during a flashover event.