What is NOT an indicator of the potential for a backdraft?

An open free-burning fire is not an indicator of the potential for a backdraft. In fact, a freely burning fire indicates that sufficient oxygen is available for combustion, which mitigates the risks associated with backdraft. Backdraft conditions typically arise in situations where a fire is smoldering and has consumed most of the available oxygen in a confined space. This leads to a buildup of heat and flammable gases within the environment.

In contrast, thick and dark smoke, the presence of a hot smoke layer, and a rapid temperature increase are all strong signs of backdraft potential. Thick, dark smoke suggests incomplete combustion and that there are likely flammable gases, while a hot smoke layer indicates significant heat within the compartment. A rapid increase in temperature is also a critical factor, as it suggests that conditions are changing quickly and may lead to explosive combustion if oxygen is suddenly reintroduced to the environment.