What is the third and final phase of a confined fire?

In the context of fire dynamics, the third and final phase of a confined fire is the smoldering phase. This phase occurs after the free-burning phase, where the fire has consumed most of the available fuel and oxygen, leading to a reduction in combustion activity. During the smoldering phase, the fire does not produce visible flames but can still generate significant heat and smoke. It is characterized by a slow, low-temperature oxidation process, which continues as long as there is sufficient heat and fuel present. Understanding this phase is crucial for fire management and safety measures, as it can sometimes reignite if not properly extinguished, leading to unexpected flare-ups. Recognizing the smoldering phase highlights the importance of thorough firefighting efforts to ensure that all residual heat sources are adequately addressed to prevent re-ignition.