What phase occurs just before flashover in a fire?

The growth phase is the correct answer because it is the stage in a fire's development where the intensity and volume of the heat and flames increase significantly. During this phase, the fire has moved beyond the initial ignition point and is actively consuming available fuels, which leads to an increase in temperature and pressure within the environment. As the conditions continue to evolve, the fire reaches a point where the combustible materials in the room can ignite almost simultaneously, resulting in flashover.

In contrast, the smoldering phase refers to a stage where combustion is slow, and flames are not yet present, while the incipient phase represents the very early stages of a fire where it is just beginning to ignite and is still small and contained. The fully developed phase occurs after flashover, where the fire has reached a maximum intensity and has likely consumed most of the available fuels in its vicinity. Understanding these phases is essential for effective fire prevention and safety education.