What is the term for the chemical decomposition of a substance through the action of heat?

The term for the chemical decomposition of a substance through the action of heat is pyrolysis. This process involves breaking down complex organic materials into simpler compounds when exposed to high temperatures, typically in the absence of oxygen. Pyrolysis plays a significant role in fire dynamics, as it occurs before ignition and contributes to the production of flammable gases that can sustain combustion.

In contrast to pyrolysis, vaporization refers to the transition of a substance from a liquid phase to a gas phase, often through the addition of heat. Combustion is the rapid chemical reaction that occurs when a fuel reacts with oxygen, producing heat, light, and often gaseous products. Oxidation is a chemical reaction involving the loss of electrons or an increase in oxidation state, typically accompanied by the reaction of a substance with oxygen, but it does not specifically denote decomposition through heat.

Understanding these processes is essential for grasping fire behavior and the stages of combustion.