This European Standard specifies the requirements and tests for the construction, performance, safety and production of class 1,5 mechanical diaphragm gas meters (hereinafter referred to as meters) having co-axial single pipe, or two pipe connections, used to measure volumes of fuel gases of the 1st, 2nd and 3rd families according to EN 437, at maximum wokring pressures not exceeding 0,5 bar and maximum actual flow rates not exceeding 160 m3/h over a minimum ambient temperature range of -10 C degrees to + 40 C degrees and a gas temperature range as specified by the manufacturer with a minimum span of 40 K.