Explosions in industrial plants and equipments are the result of chemical reactions or physical processes which are connected with a pressure build-up. Chemical explosions are caused by exothermic reactions in the gas phase, the condensed phase or in hybrid phases. in the chemical industry such physical explosions are of importance, due to a spontaneous transition of matter from the liquid to the gas phase. There are some legislative regulations which concern the explosion prevention and protection. The most important are the Equipment Safety Act and the Explosivs Act with their ordinances; the Ordinance on Dangerous Substances and the Hazardous Incident Ordinances. Important for the protection against explosive atmospheres is the "Betriebssicherheitsverordnung".