Foreword
1 Scope
2 Normative references
3 Definitions
4 Physical principles and general requirements
    4.1 Base conditions
    4.2 Flow measurement
    4.3 Calorific value measurement
    4.4 Energy measurement
    4.5 Security of supply
    4.6 Environmental conditions
    4.7 Safety
    4.8 Quality system
5 Design and construction
    5.1 Design
    5.2 Construction of measuring stations
6 Calorific value measurement
    6.1 General
    6.2 Measuring system
    6.3 Performance requirements
    6.4 Operation and maintenance
7 Stability and calibration of gas measuring systems
    7.1 Accuracy requirements
    7.2 Installation requirements
8 Commissioning
    8.1 General
    8.2 Test equipment
    8.3 Pre-commissioning
    8.4 Test and calibration procedures
9 Acceptance
    9.1 General
    9.2 Post-commissioning check
10 Operation and maintenance
    10.1 General
    10.2 Gas meters
    10.3 Conversion devices
    10.4 Post-maintenance check
    10.5 Compliance
    10.6 Documentation
Annex A (informative) Pulsation and vibration
Annex B (informative) Guidelines for instrumentation
Annex C (informative) Set of equations to calculate volume
or mass or energy
Annex D (informative) Secondary instrumentation -
test procedures
Annex E (informative) Performance characteristics
Annex F (informative) Documentation and records
Annex G (informative) Bibliography