scope:

This European Standard specifies ranges, construction, performances, output characteristics and testing of rotary displacement gas meters (hereinafter referred to as RD meters or simply meters) for gas volume measurement. This European Standard applies to rotary displacement gas meters used to measure the volume of at least fuel gases of the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437, at a maximum working pressure up to and including 20 bar over an ambient and gas temperature range of at least- 10 °C to + 40 °C. This standard applies to meters that are installed in locations with vibration and shocks of low significance (class M1 according to MID) and in - closed locations (indoor or outdoor with protection as specified by the manufacturer) with condensing or with non-condensing humidity or, if specified by the manufacturer, - open locations (outdoor without any covering) with condensing humidity or with non-condensing humidity. For use in open location, the meters shall fulfil the specification in annex G and in locations with electromagnetic disturbances. Unless otherwise specified in this standard: all pressures used are gauge; - all influence quantities, except the one under test, are kept relatively constant at their reference value. This standard also applies to meters with a maximum allowable pressure PS and the volume V of less than 6 000 bar - litres or with a product of PS and DN of less than 3 000 bar, as defined by EU directive 97/23/EC. The risk philosophy adopted in this standard is based on the analysis of hazards on account of pressure. The standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated appropriate protection measures are specified. Any residual hazard identified has to be communicated to the user where appropriate. Depending on the installation situation additional requirements may apply to cover the risks arising from traffic, wind, earthquake loading and external fire. This European Standard is primarily written to address metrological aspects and conformity assessment of RD meters. This standard clearly identifies in annex ZA and ZB which clauses are specific to the metrological or pressure containing requirements, or those that are applicable to both. As well as providing conformity assessment requirements, this standard provides requirements that shall be fulfilled prior to delivery of the product, i.e. Individual meter testing.