What does the term "flashover" refer to in fire dynamics?

The term "flashover" in fire dynamics refers to a rapid spread of flames due to extreme heat. It describes a phenomenon where the combustible materials in a room reach their ignition temperature almost simultaneously, resulting in a rapid increase in fire intensity and the transition from a controlled fire to a fully developed fire. This occurs when the temperatures rise enough to ignite all the available fuel in the vicinity, often driven by the buildup of heat and flammable gases.

Flashover represents a critical transition during a fire, as it signifies an increase in danger for firefighting operations and can completely change the dynamics of fire behavior. Understanding flashover is essential for firefighters in terms of tactics and safety, as they need to be aware of the signs that indicate an impending flashover condition, such as sudden increases in heat and a thickening smoke layer. This awareness helps fire crews to operate safely and effectively in a fire environment.