A room and its contents simultaneously reach their ignition temperature and the area rapidly becomes fully involved. This best describes:

• A. Flashover
• B. Backdraft
• C. Boilover
• D. Ignition

Answer: (A)

Flashover is the rapid transition in a room fire where the heat causes all exposed fuels in the space to reach their ignition temperatures nearly at once, so the room and its contents become fully involved. This describes the situation where the entire area lights up simultaneously and the fire spreads quickly to everything in contact with the heated surfaces, creating a fully engulfed space.

This differs from a backdraft, which is a violent ignition of accumulated flammable gases when fresh air suddenly mixes with them after having been limited, often producing an explosion rather than a uniform, simultaneous ignition of all contents. Boilover involves liquids boiling and ejecting flammable layers due to intense heat, not the entire room igniting at once. Ignition alone is simply the start of combustion at one point, not the sudden involvement of the whole room.