Which term refers to the final phase of a fire where activity diminishes and the environment cools?

• A. Growth stage
• B. Incipient stage
• C. Fully developed stage
• D. Decay stage

Answer: (D)

Fire development stages explain how a fire evolves in a space. The final phase is the decay stage. In this phase, burning activity diminishes as fuel is exhausted or burned, so flames lessen or disappear. Heat release drops and the environment cools toward ambient temperatures, though smoke and hot gases can still linger. This contrasts with earlier phases: the incipient stage is the ignition moment; the growth stage sees flames spreading and heat increasing; the fully developed stage is when the fire reaches peak intensity and consumes much of the available fuel. So the decay stage best fits the description of the fire ending activities and the space cooling down.