Which stage of fire development indicates that the fire has reached its peak intensity?

The fully developed stage of fire development indicates that the fire has reached its peak intensity. During this stage, the fire is consuming all available fuel and oxygen, leading to a state where the fire is fully established and sustaining itself. The heat output is at its maximum, and the flames are often large and difficult to control.

At this point, the conditions within the structure or environment where the fire is occurring are extremely hazardous. This stage follows the growth stage, where the fire begins to spread and intensify, and precedes the decay stage, where the fire starts to diminish as fuel is consumed and the thermal energy decreases. The flashover stage, while significant, refers to a rapid transition where combustible materials in the surrounding area reach ignition temperature, usually leading to a fully developed stage shortly thereafter. Understanding this progression of fire stages is essential for firefighters when strategizing effective response and suppression tactics.