Which phase of fire development signifies the highest intensity of the fire?

The fully developed stage of fire development is characterized by the fire reaching its peak intensity, where it consumes available fuel and oxygen at the maximum rate. During this phase, the combustion process is at its most vigorous, producing the highest temperatures and generating significant amounts of heat and smoke. The fire has moved beyond the growth phase, where it is still escalating, and has reached a state of stability that produces a sustained and intense release of energy.

In contrast, the ignition phase is the initial stage where the fire starts, while the growth phase is where the fire begins to spread and gain strength but has not yet reached its maximum potential. Lastly, the extinguishing phase involves the efforts to control and put out the fire, marking a significant decrease in intensity rather than a peak. Thus, the fully developed stage distinctly represents the point of highest fire intensity.