Flashover is the stage of a fire at which all surfaces and objects within a space have been heated to their ignition temperature and flame breaks out almost at once.

• A. Stage of a fire at which all surfaces and objects within a space have been heated to their ignition temperature and flame breaks out almost at once
• B. A delayed ignition in a closed room
• C. The cooling of surfaces before exiting
• D. The venting of smoke from a room

Answer: (A)

Flashover is the rapid transition when heat inside a room raises all exposed fuels to their ignition temperature, causing nearly simultaneous ignition and widespread flames. This moment marks a shift from a growing fire to a fully involved space, making it extraordinarily dangerous because the entire environment can ignite at once. The description matches this sudden, all-at-once ignition of surfaces and objects. A delayed ignition in a closed room describes something different and does not capture the abrupt, comprehensive involvement of flashover. Cooling of surfaces before exiting is the opposite of ignition, and venting of smoke is about smoke movement, not ignition of fuels.