What is the decay stage of a fire characterized by?

The decay stage of a fire is characterized by a decrease in the intensity of the fire due to a reduction in the fuel supply or a limited oxygen supply. During this stage, the combustion process is unable to sustain itself at its previous levels of intensity because the available material that can burn is either being consumed or is in short supply. As the fire burns down, it experiences a decline in temperature and flame size, leading to a gradual extinguishment.

In this phase, it's vital to understand that the conditions surrounding the fire heavily influence its behavior. If there is insufficient oxygen to support combustion or if the fuel source is nearly exhausted, the fire will begin to fade, marking the transition from a fully developed stage to the decay stage. This shift is an important aspect for firefighters to recognize, as it can indicate that the fire is nearing the end of its life cycle and can influence tactical decisions regarding extinguishment and safety measures.