What is calcination in the context of fire investigations?

Calcination refers specifically to a chemical process that occurs when a material, typically a mineral or an inorganic substance, is subjected to extreme heat, resulting in the thermal decomposition of that material. This process can significantly affect the physical properties of that material, often resulting in a change in its structure.

In the context of fire investigations, calcination is particularly relevant when examining gypsum products, such as drywall or plaster. When exposed to high temperatures during a fire, gypsum undergoes calcination, which causes it to lose water and change its appearance. This can lead investigators to identify areas of severe heat exposure, which can aid in determining the fire's behavior and origin.

Understanding calcination helps investigators assess the extent of damage and gauge the fire's intensity in different materials. While other processes such as metal melting, organic burning, and various chemical changes occur in fires, calcination is uniquely associated with the influence of heat on gypsum and similar materials, making it an important concept in fire investigations.