Hot water boilers and boilers for the production of water vapour under high pressures are considered to be steam boilers. As a generic term, boiler is used to denote steam generators and hot water installations. In the industry there are two types of boilers; the steam engine boilers and fire tube boilers.

Steam engine boilers are used to generate steam to operate steam turbines.In current utility steam boilers, up to 3,600 t steam is generated per hour under pressures of 300 bar and steam temperatures of 620 °C.

Fire tube boilers are often used in small and medium-sized industrial plants, for example in the paper or food industry, where small and medium-sized mixtures of hot water or water vapour are required at low pressures. These boilers are used in the technical building appliances of large complexes, such as hotels, hospitals etc.