This European Standard defines the specifications and test methods for the construction, safety, rational use of energy and fitness for purpose, environment and classification and marking of gas-fired storage water heaters for domestic hot water uses. This standard applies to appliances :a) of types B11, B11BS, C11, C12, C13, C21, C31, , C32, C33, C42, C43, C51,C52, C53, C62, C63, C72, C73, C81 connected to an individual flue duct, C82 and C83; b) fitted with atmospheric burners; c) using one or more combustible gases corresponding to the three gas families and the pressures indicated in EN 437; d) of nominal heat input not exceeding 150 kW (net calorific value); e) using or not the water condensation heat in the combustion products; f) fitted with electrically operated mechanical flue dampers that are positioned downstream of the heat exchanger and tested as an integral part of the water heater; g) appliances whether subject to the water mains pressure or open-circuit.