What phenomenon occurs when combustibles ignite due to heat transfer from convection, radiation, or both?

The phenomenon where combustibles ignite due to heat transfer from convection, radiation, or both is referred to as flashover. This critical stage in a fire occurs when the temperature of the environment reaches a point where virtually all combustible materials in the vicinity ignite almost simultaneously.

During flashover, intense heat can be transferred to adjacent combustibles through radiant heat from flames and hot gases – characteristics of radiation – as well as through convective currents of hot air. When these conditions are met, the fire can spread rapidly, resulting in a sudden and large-scale ignition that significantly increases the overall complexity and danger of firefighting operations.

Understanding flashover is crucial for firefighters, as it emphasizes the need for proper strategies and tactics to prevent conditions that may lead to this rapid escalation of fire. Recognizing the signs of an imminent flashover can be vital for survival and effective firefighting.