Surveillance from first commissioning on measuring devices used in natural gas supply to the installations of the activities under the Directive 2003/87/EC establishing a scheme of CO2 emissions trading|Performance testing, Stability, Equations, Errors, Data stations, Accuracy, Volume, Calorific value, Records (documents), Testing conditions, Pipework systems, Industrial, Gas supply, Calibration, Conversion (units of measurement), Maintenance, Pulsating flow, Gas-supply meters, Technical documents, Performance, Design, Service pressure, Measurement, Measuring instruments, Bibliography, Density measurement, Natural gas, Safety measures, Electronic equipment and components, Flow measurement, Ratings, Vibration, Commissioning, Acceptance (approval)