This European Standard specifies the requirements and tests for the construction, performance, safety and production of class 1,5 diaphragm gas meters (referred to as meters). This applies to meters with co-axial single pipe, or two pipe connections, that are used to measure volumes of fuel gases, which are within the limits of test gases of the 1st, 2nd and 3rd families described in EN 437. The meters have maximum working pressures not exceeding 0,5 bar and maximum actual flow rates not exceeding 160 m3.h−1 over a minimum ambient temperature range of −10 °C to 40 °C and a gas temperature range as specified by the manufacturer with a minimum range of 40 K. This standard applies to meters with and without built-in temperature conversion that are installed in locations with vibration and shocks of low significance (see MID Annex 1 Chapter 1.3.2 (a), class M1). It also applies to meters in: - closed locations (indoor or outdoor with protection as specified by the manufacturer) both with condensing humidity or with non-condensing humidity; or, if specified by the manufacturer: - open locations (outdoor without any covering) both with condensing humidity and with non-condensing humidity; - in locations with electromagnetic disturbances corresponding to those likely to be found in residential, commercial and light industrial buildings (see MID Annex 1 Chapter 1.3.3 (a), class E1). Unless otherwise stated, all pressures given in this document are gauge pressure. Requirements for electronic indexes, batteries, valves incorporated in the meter and other additional functionalities are given in EN 16314. Unless otherwise stated in a particular test, the tests are carried out on meters that include additional functionality devices intended by the manufacturer. Clauses 1 to 9 and Annexes B and C are for design and type testing only. NOTE The content of OIML Publication 'International Recommendation R 137' has been taken into account in the drafting of this standard. If no specific requirements are given for test equipment, the instruments used should be traceable to a national or international reference standard and the uncertainty (2σ) should be better than 1/5 of the maximum value of the parameter to be tested. For differential results the repeatability (2σ)/resolution should be better than 1/5 of the maximum value of the parameter to be tested.