What is pyrolysis?

Pyrolysis is accurately defined as the decomposition of organic material through the application of heat in the absence of oxygen. This thermal degradation process results in the breakdown of complex molecules into simpler ones, producing gases, liquids, and solid residues like charcoal or coke. Pyrolysis is a critical concept in fire science and material science, particularly in understanding how materials behave under heat and the products formed when materials are exposed to elevated temperatures without sufficient oxygen to support combustion.

This definition underscores the importance of pyrolysis in various applications, including waste management, energy production, and fire investigation, as it helps to elucidate the conditions under which certain materials can decompose and form the by-products that may contribute to fire spread and intensity. Understanding pyrolysis also aids investigators in assessing fire scenes, particularly in identifying materials that were involved in fire development.

The other options, while related to combustion and material behavior, do not accurately describe pyrolysis. For example, burning in the presence of oxygen refers to combustion, while a phase transition from solid to gas typically describes sublimation, and the ignition process relates more to the initial stage of combustion rather than the thermal decomposition that occurs in pyrolysis.