What does calcination of gypsum create when exposed to heat?

Calcination of gypsum is a process that occurs when gypsum (calcium sulfate dihydrate) is exposed to heat, typically at temperatures above 150 degrees Celsius (302 degrees Fahrenheit). This process leads to the dehydration of gypsum, resulting in the loss of water content as steam. As the gypsum loses moisture, it undergoes a transformation into calcium sulfate hemihydrate, commonly known as plaster of Paris.

The creation of a fire effect due to moisture loss is significant because the removal of moisture can affect the thermal properties of the material. In conditions of fire, this moisture can impact how the material behaves, including its ability to resist fire and how it contributes to the fire environment. The loss of water not only changes the chemical composition of the gypsum but also plays a crucial role in contributing to the dynamics of heat release and smoke production during a fire, highlighting the importance of understanding how materials react when exposed to heat.

In contrast, the other options do not accurately represent the effects of calcination on gypsum. For example, calcination does not increase the structural integrity of the material, nor does it generate energy through a chemical reaction. Lastly, calcination does not enhance flame spread capability; rather, it alters the behavior of the material under thermal stress.