This British Standard specifies the installation requirements for gas-fired overhead radiant heaters and systems for the environmental heating of premises other than domestic dwellings. This standard only applies to appliances falling within the scope of the Gas Appliances (Safety) Regulations 1995 [1]. It is applicable to the installation of heaters that are designed to use gases of group H of the 2nd family (e.g. natural gas), gases of group P of the 3rd family (e.g. propane) as well as gases of group B of the 3rd family (e.g. butane) (see BSEN437+A1). NOTE1 This standard does not specifically cover LPG/air for which additional requirements might be necessary. It is applicable to the installation of gas-fired overhead luminous radiant heaters conforming to BSEN419‑1, single burner gas-fired overhead radiant heaters conforming to BSEN416‑1 and multi-burner gas-fired overhead radiant tube heater systems conforming to BSEN777‑1, BSEN777‑2, BSEN777‑3 and BSEN777‑4. NOTE2 For the purposes of this standard, installation includes design, inspection and commissioning. It is recognized that each of these tasks may, at times, be performed by the same persons. NOTE3 The heat inputs and ventilation rates in cm2/kW of heat input given in this standard are based on the net calorific value. It is not applicable to the installation of gas-fired overhead radiant heaters and systems: to which the Gas Appliances (Safety) Regulations 1995 [1] do not apply; that are designed for use in domestic premises; that are supplied with a heated fluid from a separate source; or that are portable or transportable.