This standard applies to the application design and installation of electrical equipment, control circuits and protective systems for furnaces which are operated with solid, liquid or gaseous fuels and their ancillary equipment. It specifies requirements to meet the operating conditions of furnaces, to reduce the hazards of combustion and to protect the heated systems from damage e.g. by overheating. Such furnaces and the electrical equipment may be part of the following plants for example: a) Water heating systems b) Steam boiler installations (steam and hot-water boilers) and heat recovery steam boilers NOTE 1 The requirements of this standard apply according to the electrical equipment of electrically heated steam boilers. NOTE 2 Seagoing vessels and offshore facilities are governed by International Maritime Law and as such are not within the scope of this standard. These requirements may be used for such facilities. c) Warm air heaters d) Hot-gas heaters e) Heat exchanger systems f) Combustion chambers of stationary turbines g) As long as no other standard is applicable for combined heat and power stations it is recommended to use the requirements of this standard h) This standard may also be used as reference for electrical equipment requirements for thermo-processing equipment. NOTE 3 The requirements of this standard are applicable in all cases where an equipment specific standard does not specify a requirement. The requirements in this standard are not applicable to electrical equipment for: i) Non electrically heated appliances and burner control systems for household and similar purpose; j) Furnaces using technologies for the direct conversion of heat into electrical energy; k) Combustion chambers of non-stationary prime movers and turbines; l) Central oil supply systems for individual heating appliances; m) Furnaces using solid fuels for heating purposes for household use with a nominal thermal output up to 1 MW; n) Furnaces which are used to heat process fluids and gasses in chemical plant. This standard may be used as a basis for the requirements placed on electrical equipment for furnaces which are excluded from its field of application.