What stage of fire development involves an unlimited supply of fuel but limited oxygen, resulting in smoldering and smoke production?

The smoldering stage of fire development is characterized by a situation where there is an abundant supply of fuel but a limitation on oxygen availability. This results in combustion that produces smoke and potentially hazardous gases without the presence of flames. In this stage, materials can burn very slowly, often indicating that the fire has not transitioned into a more active burning state. The low level of oxygen restricts the rate of combustion, which is why the fire smolders rather than bursts into flames.

In contrast, the ignition stage marks the beginning of a fire when enough heat and fuel come together to initiate combustion, typically in the presence of oxygen. The fully developed stage occurs when the fire has reached its peak intensity with sustained combustion and sufficient fuel and oxygen. The extinguishing stage is the phase where measures are taken to eliminate the fire and cool down the materials, effectively stopping the combustion process. Understanding these stages highlights the characteristics of each, particularly the unique behavior of fires during the smoldering stage.