What is the effect of heating on gypsum products?

Heating gypsum products primarily drives off water, leading to calcination. Gypsum, chemically known as calcium sulfate dihydrate, contains water in its crystalline structure. When subjected to heat, this water is released, resulting in the transformation of gypsum into calcium sulfate hemihydrate, commonly known as plaster of Paris. This process alters the physical properties of the material, decreasing its structural integrity and making it more brittle.

The effect of this transformation is significant in fire investigations, as the presence of calcined gypsum can indicate areas that have been subjected to high temperatures during a fire. Understanding this process allows investigators to draw conclusions about the fire's intensity and duration based on the amount of gypsum that has undergone calcination. Thus, recognizing the implications of heating on gypsum products is crucial for accurate analysis during fire investigations.