What are the four phases of fire behavior in building fires?

• A. Growth, fully developed, decay, and post-fire/overhaul.
• B. Ignition, expansion, flashover, burnout.
• C. Start, growth, extinguish, finish.
• D. Pulse, rise, peak, decline.

Answer: (A)

In building fires, fire behavior progresses through four stages: growth, fully developed, decay, and post-fire/overhaul.

Growth is the period where the fire is expanding; flames spread through available fuels and the heat release increases. How quickly it grows depends on how much fuel is present and how much ventilation the space has.

Fully developed is when the fire has access to most or all of the combustible materials in the space and is burning at its maximum intensity. The environment can become extremely hot and filled with smoke and gases, and the risk of rapid changes like flashover is high during this stage.

Decay follows as the fuels are consumed and the heat release begins to decline. Oxygen becomes depleted and the fire may continue burning in pockets, gradually easing as conditions improve or as firefighting efforts cut off the remaining fuels.

Post-fire/overhaul is the phase after the main fire is controlled, focusing on extinguishing any remaining hotspots, checking for hidden fires, and making the structure safe for investigators and cleanup.

The other options mix in terms that describe events or actions rather than the recognized sequence of building-fire behavior.