This European Standard specifies the requirements and test methods for the construction, safety, classification, marking and efficiency of non-domestic gas-fired overhead radiant tube heaters incorporating a single burner and multiple burner systems (referred to in the body of the text as the system ) with each burner unit under the control of an automatic burner control system. For radiant tube heaters incorporating a single burner, this standard is applicable to Type A2, A3, B12, B13, B22, B23, B42, B43, B52, B53, C12, C13, C32, C33, C52 and C53 appliances intended for use in other than domestic dwellings, in which the supply of combustion air and/or the evacuation of the products of combustion is achieved by mechanical means located upstream of the draught diverter, if provided. For radiant tube heater systems incorporating multiple tube heater segments, this standard is applicable to Type B52, B52x, B53 and B53x systems intended for use in other than domestic dwellings, in which the supply of combustion air and/or the evacuation of the products of combustion is achieved by mechanical means. This standard also includes appliances incorporating a secondary heat exchanger in the flue system. This standard is not applicable to: a) appliances designed for use in domestic dwelling; b) outdoor appliances; c) appliances where the heat input of any individual burner unit is in excess of 120 kW (based on the net calorific value of the appropriate reference test gas); d) appliances having combustion products evacuation ducts that are non-metallic in the flue system except ducts downstream of a possible additional condensing exhaust gas heat exchanger. In addition, for heater systems incorporating multiple tube heaters this standard is not applicable to: e) appliances and systems that are designed for continuous condensation within the flue system under normal operating conditions except downstream a possible additional exhaust gas heat exchanger. This standard is applicable to systems which are intended to be type tested.