What does flashover signify in a compartment fire?

Flashover signifies a critical transition in a compartment fire, marking the shift between the growth stage and the fully developed stage of the fire. During flashover, the temperature in the environment becomes sufficiently high that all combustible materials within the room ignite almost simultaneously. This dramatic increase in heat and flame spread indicates that the fire has reached its maximum potential for growth and is about to escalate into a fully developed stage, where the fire consumes all available fuel.

Understanding this transition is essential for firefighters, as it represents a dangerous moment when the conditions can change rapidly. Recognizing the signs of an impending flashover can help firefighters make timely decisions regarding their tactics, such as evacuation or the need for additional resources.

The other options address different characteristics and stages of fire behavior but do not accurately describe the transition that flashover represents. For example, the decay stage involves a reduction in fire intensity as the fuel is consumed, which occurs after the fully developed stage, rather than transitioning toward it. Oxygen levels being insufficient is associated with smoldering or deprivation of combustion, and the complete consumption of fuel indicates the end of the fire rather than the moment of flashover itself.