This standard specifies the definition, classification, basic parameters, structural requirements, main performance, test methods and signs, packaging, storage and transportation of gas-fired volumetric water heaters (hereinafter referred to as water heaters) with a rated heat load less than or equal to 180Mj/h (50kW). . Gas volumetric water heaters greater than 180Mj/h (50kW) but less than 360Mj/h (100kW). Not suitable for other types of gas water heaters. The gas referred to in this standard is the gas specified in GB/T 13611-1992 "Classification of Urban Gas" and GB 13612-1992 "Artificial Gas".