The extinguishing powders used in powder extinguishing systems are highly efficient, quick-acting extinguishants. The sudden extinguishing effect of the powder cloud is caused by the suffocation effect and the anticatalytic effect, a chemical intervention into the combustion process. Extinguishing powders mainly consist of non-poisonous inorganic salts mixed with waterproofing and pouring agents. They are used for fires with solid, liquid or gaseous substances and for metal fires, thus, they are used for fire classification A, B, C and D.