What is the second phase of a fire?

The second phase of a fire is characterized as the Free-Burning Phase. During this phase, the fire has enough fuel and oxygen to sustain combustion at a higher intensity. The energy output increases significantly, leading to a well-defined and more stable fire protection footprint. This phase typically sees the flames spreading rapidly, and the temperature can escalate, which might lead to the eventual transition into further phases or dangerous situations if not controlled.

It is essential to understand that the other phases mentioned, such as the Incipient Phase, Smoldering Phase, and Flashover Phase, occur either before or after the Free-Burning Phase, indicating different characteristics of fire behavior. The Incipient Phase refers to the initial stage where the fire starts but is still contained and may be extinguished easily. The Smoldering Phase occurs when the fire burns without flames, often producing smoke and heat rather than prominent fire development. Meanwhile, the Flashover Phase represents a critical moment when the hot gases and materials in the room ignite almost simultaneously, leading to a sudden and intense fire condition. Understanding these phases helps in effectively assessing fire behavior and implementing safety measures during emergencies.