What is a key indicator of a potential flashover?

The presence of thick, black smoke is a key indicator of a potential flashover. This thick smoke often suggests that combustible materials are burning and releasing a significant amount of soot and toxins. As the volume of smoke increases and becomes denser, it is a sign that the fire is consuming oxygen and that the environment is reaching critical temperatures. Thick smoke indicates that heat has built up in the room, and once the temperature reaches certain levels, it can ignite accumulated flammable gases and vapors, leading to a sudden and intense fire event known as flashover. This phenomenon requires firefighters to be especially cautious, as it can drastically change the dynamics of a fire scene in a matter of seconds.

In contrast, minimal smoke in the area does not indicate an ongoing significant fire and suggests a lack of combustible materials actively burning that would lead to flashover conditions. Low temperatures at the ceiling level would indicate that a flashover is unlikely, as flashover is typically preceded by high heat concentration. A gradual increase in flames may suggest a developing fire, but without the immediate indicators of rapid growth and dense smoke, it might not signal an imminent flashover.