In the project "Numerical simulation of the thermal and mechanical behavior of components during firing in a test furnace", so-called "simple" components were defined with the most homogeneous and non-layered structure possible. This is for example on gypsum or wood components too.
In the course of the above-mentioned research project, however, it was found that chemical reactions in the materials mentioned release gaseous components into the gas phase of the furnace. These may include combustible components such as CO (gasification product of
Wood components) or non-flammable such as water vapor or carbon dioxide (gypsum). The release of these components raises or lowers the temperature in the furnace, which affects the flow in the furnace and the heat transfer to the part being tested. Furthermore, the loss of mass (2.8 in gypsum) during the fire test causes noticeable cracks, especially on the side facing the fire, so that it is no longer possible to speak of a completely homogeneous material. For this reason, in the course of the follow-up project these materials are referred to as "complicated" components.