What indicates that a fire may be reaching its flashover point?

A rapid increase in heat and smoke production serves as a clear indicator that a fire may be approaching its flashover point. Flashover is a critical phase in a fire's development where the entire room or area can ignite almost simultaneously due to extreme heat. During this phase, the temperature can rise dramatically, causing materials in the vicinity to emit flammable gases. As these gases accumulate, the heat and smoke intensity also increase significantly.

Monitoring the conditions in a fire scene is essential for safety and effective firefighting strategies. The rapid change in heat and smoke signals that the environment is becoming increasingly volatile and dangerous. In contrast, a steady decrease in smoke production or a decrease in oxygen levels would suggest a different behavior of the fire, likely indicating that it is beginning to die down rather than reaching the flashover stage. Changes in the fire's color can reflect different burning materials or phases but are not as reliable a predictor of flashover conditions as the rate of heat and smoke production.