What does the term 'pyrolysis' refer to in the context of fire science?

The term 'pyrolysis' in the context of fire science refers to the chemical change that occurs in solids during combustion. It specifically describes the thermal decomposition of materials at elevated temperatures in the absence of oxygen. During pyrolysis, organic materials break down into volatile gases and char, which can then contribute to fire behavior, such as producing flammable vapors that ignite and sustain combustion. This process is essential for understanding how materials burn and how combustion develops, as it is a critical step before ignition occurs.

The other options focus on different aspects of combustion and fire suppression but do not accurately define pyrolysis. The second option pertains to changes in gases, while the third relates to fire extinguishment processes, and the fourth addresses the production of new materials from combustion, which are not applicable to the specific definition of pyrolysis.