ONORM EN 12261 : 2007

1 Scope
2 Normative references
3 Terms, definitions and symbols
  3.1 Terms and definitions
  3.2 Symbols
4 Meter classification
  4.1 Flange pressure ratings
  4.2 Gas meter sizes, rangeability and connection diameter sizes
  4.3 Connections and dimensions
  4.4 Temperature ranges
5 Metrological performance requirements
  5.1 General
  5.2 Type testing
6 Design and material requirements
  6.1 General
  6.2 Robustness
  6.3 Resistance to environmental conditions
  6.4 Removable meter mechanisms
  6.5 Indicating devices and accessories
  6.6 Pressure and temperature tappings
  6.7 Lubrication
7 Meter output
  7.1 General
  7.2 Indicating device
  7.3 Pulse generator
  7.4 Output shaft
  7.5 Test element
8 Marking
  8.1 General
  8.2 Data plate
  8.3 Direction of flow
  8.4 Working position
  8.5 Other connections
Annex A (normative) Test facility specifications
Annex B (normative) Perturbation testing
Annex C (informative) Recommendations for use
Annex D (normative) Individual factory testing
Annex E (normative) Metrological requirements and tests for
        each meter prior to dispatch (Individual meter testing)

Describes the measuring conditions, requirements and tests for the construction, performance and safety of class 1,0 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.