This European Standard specifies the requirements and test methods for the safety and efficiency of domestic gas-fired air heaters with (an) atmospheric burner(s) and without a fan to assist the transportation of combustion air and/or flue gases, hereafter referred to as "appliances". This European Standard applies to Type B11, B11AS, B11BS, B41, B41AS, B41BS C11, C21, C31 and C41 appliances with an input not exceeding 70 kW (net cv-basis), intended primarily for use in single unit residential dwellings. Provision of the heated air may be by means of ducting. This European Standard does not apply to: a) appliances of the condensing type; b) appliances for outdoor installation; c) dual purpose air conditioning appliances (heating and cooling); d) appliances where the air is heated by an intermediate fluid; e) appliances with forced draught burners; f) appliances fitted with a manual or automatic means of adjusting the combustion air supply or the combustion products evacuation (including flue dampers); g) portable or transportable forced convection appliances; h) appliances having multiple heating units with a single draught diverter; i) appliances fitted with more than one flue outlet; j) C21 and C41 appliances for 3rd family gases; NOTE For C41 appliances, see all requirements and test methods that are valid for C21 appliances, unless otherwise stated. k) appliances that are designed for continuous condensation within the flue system under normal operating conditions; l) appliances having Products Of Combustion Evacuation Ducts (POCED), that are non-metallic. This European Standard is applicable to appliances which are intended to be type tested. It also includes requirements concerning the evaluation of conformity, including factory production control, but these requirements only apply to POCEDs and their associated terminals.