When does rapid release of combustible compounds occur during pyrolysis?

The rapid release of combustible compounds during pyrolysis occurs primarily during Stage 3. This stage is characterized by the breakdown of solid materials into gases and liquids, which results in the liberation of significant amounts of flammable gases. This phase is crucial in the process of combustion, as it contributes to the fire's intensity by providing ample fuel in the form of volatile compounds that can ignite and sustain a fire.

Understanding the pyrolysis process is vital, particularly in the context of fire behavior and safety measures. Stages 1 and 2 generally involve initial thermal degradation and the formation of char and other by-products, without the significant release of flammable gases. Stage 4 is associated with the combustion of the materials following the pyrolysis process, rather than the breakdown itself. Recognizing the characteristics of each stage allows safety officers to anticipate when a rapid release of flammable substances may occur, helping to inform strategies for fire control and mitigation.