This European Standard specifies the measuring conditions, requirements and tests for the construction, performance and safety of axial and radial turbine gas meters with mechanical indicating devices, herein after referred to as a meter(s), having in-line pipe connections for gas flow measurement. This European Standard applies to turbine gas meters used to measure the volume of fuel gases of the 1st and 2nd gas families, the composition of which is specified in EN 437, at maximum working pressures up to 420 bar, actual flow rates up to 25 000 m3/h over a gas temperature range of at least 10 °C to +40 °C. Unless otherwise specified in this standard, all pressures used are gauge. Clauses 1 to 7 and annex B are for design and type testing only, with the exception of 6.2.2.3, 6.2.3.3, 6.6.1.1.2 and 6.6.2.2.2. Annex C may be used to provide guidance on periodic tests during use. Clause 8 and annexes D and E are for each meter prior to dispatch. Annex A shall be used for both type and individual testing.