The paper deals with the issue and classification of burning processes. Basic crisis situations and situations that occur during the existence of mankind are also fires. Examination of burning processes is closely related to fires, as they pose uncontrollable and unlimited burning in space and time. Fire occurring not only in the natural environment (eg forest fires) but also in various industrial, transport, manufacturing, processing and storage technologies, in accommodation facilities and elsewhere. Controllable and controlled burning processes can be useful for humans, for example: domestic heating, cooking and others. Uncontrollable combustion processes (fires) can cause serious losses and threats to health, life, property, tangible and intangible property and the environment. Burning is a set of complex physicochemical processes in which flammable substances and materials react with oxidizing agents and change to combustion products (combustion products). Burning is accompanied by intense radiation of heat, light energy, and smoke. The combustion processes can be classified according to different criteria.