What occurs during flashover?

During flashover, the critical phenomenon that occurs is the rapid ignition of all combustible materials in a room. This event is a result of the pyrolysis and accumulation of heat and gases, leading to a dramatic increase in temperature that causes the materials to reach their ignition temperature almost simultaneously. The process is characterized by the transformation of localized burning into an inferno, as the heat radiated from the flames ignites other combustible surfaces.

Understanding flashover is vital for fire investigators and responders, as it significantly changes the dynamics of a fire situation. At this stage, the environment becomes exceedingly hazardous, presenting serious risks to both life and property due to the overwhelming heat and intensity of the combustion.

The other scenarios depicted do not accurately represent the critical nature of flashover. For example, strong winds extinguishing flames would typically hinder fire growth, not contribute to flashover. Similarly, contained and controlled fires imply management rather than the chaotic conditions existing during flashover. Lastly, cutting off the air supply would generally aim to suppress a fire rather than the rapid ignition event associated with flashover. Understanding the nature of flashover is essential for comprehending how fires can evolve quickly and unpredictably.