What is defined as the phase where all surfaces reach ignition temperature almost simultaneously?

Flashover is the term used to describe the phase in a fire event where all combustible surfaces within the environment reach their ignition temperature almost simultaneously. This phenomenon typically occurs when the heat produced by the fire becomes sufficient to ignite all the pre-heated combustibles in the room, resulting in a rapid spread of flames throughout the space.

During flashover, the fire transitions from a localized event to a fully involved fire, characterized by a dramatic increase in heat and fire intensity. This can make flashover one of the most dangerous moments in a fire scenario, as it can occur swiftly and without warning, creating a significant challenge for emergency responders.

Understanding flashover is crucial for fire investigators and firefighters as it provides insights into fire dynamics and the behavior of flames and heat in a given environment. Recognizing when a fire has reached this stage can also inform strategies for firefighting and rescue operations.