During which fire development stage are all combustible materials in the compartment fully burning?

In the Fully Developed Stage of fire development, all combustible materials within the compartment are actively engaged in combustion. At this stage, the fire has reached its maximum intensity and is producing a significant amount of heat and flames. The availability of fuel and oxygen has allowed the fire to consume all available combustible materials, resulting in a state where the entire area is fully involved in the fire.

Understanding this stage is crucial for firefighters, as it signifies that the fire is at its peak, making it extremely hazardous. Firefighting tactics during this phase often necessitate a focus on controlling the fire spread and protecting exposures rather than trying to extinguish it immediately, as that might not be feasible. Firefighters have to be particularly aware of the rapid changes that can occur in the environment, including potential flashover, which can happen in this stage, further emphasizing the need for proper training and situational awareness when dealing with fully developed fires.