The EU Methane Regulation (Regulation (EU) 2024/1787) requires operators in the energy sector to systematically record, reduce and regularly report methane emissions. A key component of this are leak detection and repair (LDAR) programmes.

The DVGW regulations provide recognised technical rules that transform European obligations into practical procedures. In this context, DVGW G 465-5 describes the procedure for determining methane emissions from gas pipelines in the gas distribution network up to 16 bar. This includes the detection, quantification and identification of emitting components as a basis for repair.

The methodology for the metrological quantification of emission rates is described in the DVGW information sheets of the G 425 series. While G 425-1 defines general principles, the subsequent parts describe specific procedures. For example, G 425-2 applies to underground installations, while DVGW G 425-3 details the extraction method (bagging) for above-ground installations at source level.

Pipeline network inspection & leak detection

Above-ground inspection

Reference to DVGW information sheets:

  • G 465-1: Inspection of gas pipe networks up to 16 bar.
  • G 465-4-1 ff.: Equipment technology for inspection (vehicles, hand-held devices, remote detection)

Use of hand-held gas concentration measuring devices for precise localisation and classification of the hazard

Reference to DVGW information sheets:

  • G 465-3: Localisation, classification and handling of gas leaks
  • G 465-4-2: Hand-held gas concentration measuring devices

Measurement of emission rates

Reference to DVGW information sheets:

  • G 425-2: Extraction method for underground installations
  • G 425-3: Extraction method for above-ground installations / bagging

Planning and carrying out maintenance measures

Reference to DVGW information sheets:

  • G 465-2: Maintenance, commissioning and decommissioning

Entry into the network and damage statistics and transfer of values for the annual methane emissions report

Reference to DVGW information sheets:

  • G 426: Preparation of methane emissions reports
  • G 465-5: Overall accounting and reporting at distribution network level

Methane emission measurement using the bagging method (DVGW G 425-3)

Preparation and safety assessment

Before a measurement is carried out, any hazards must be ruled out as part of a risk assessment. This includes, for example, maintaining a sufficient distance from hazardous areas, carrying out a clearance measurement and securing the work area.

Measurement procedure

Once the leak has been detected, the component or part is enclosed in an airtight foil. This creates a defined extraction chamber, which ensures that the entire amount of methane escaping can be captured. A vacuum pump is used to extract the methane-air mixture from the sealed chamber. The extraction process continues until a steady state (constant methane concentration) is reached. The emission rate is determined from the volume flow under standard conditions and the methane concentration in the steady state. Only then is the measurement terminated.

Laser HUNTER Gas detection & Gas measurement device
Laser HUNTER Gas detection & Gas measurement device
Highly sensitive and selective gas detection & gas measurement device with laser technology for the inspection of underground gas pipes using suitable probes (e. g. carpet probe). The device can also be used for the vehicle-based pipeline inspection. With built-in diaphragm pump, wireless data transfer and rechargeable Li-Ion battery. One out of two different laser modules can be assembled: - single laser module for methane or - dual laser module for methane & ethane Moreover, the device can be equipped with additional sensors to enable further applications. The following applications are possible: - Inspection of underground pipes - Inspection of accessible pipes in buildings - Inspection of accessible pipes on plants, etc. - Inspection of ground soil for pinpointing (optional) - Purging of gas pipelines (optional, only in combination with pinpointing) - Gas analysis (with dual laser module) Operating time up to 10 hours Measurement range depending on built-invsensors Dimensions (LxWxH): 143 x 240 x 85 mm Weight: 2.1 kg Temperature ranges: 0 °C to 40 °C (dual laser module) -10 °C to 50 °C (single laser module)
Bagging probe 50 x 50 cm with Geka coupling
Bagging probe 50 x 50 cm with Geka coupling
With the "Quantification" menu item and the bagging probe, the Laser HUNTER enables the standard-compliant determination of methane emissions at above-ground installations in accordance with DVGW G 425 3 (suction method). The antistatic bagging probe (dimensions 100 × 100 cm) is equipped with a GEKA coupling and is connected directly to the Laser HUNTER via the PVC hose (2 m, S20C-GEKA – item 412008). The result is a closed, safe measuring system for the precise, reproducible and fully documented quantification of methane emissions.
Bagging probe 50 x 50 cm with Geka coupling
Bagging probe 50 x 50 cm with Geka coupling
With the "Quantification" menu item and the bagging probe, the Laser HUNTER enables the standard-compliant determination of methane emissions at above-ground installations in accordance with DVGW G 425 3 (suction method). The antistatic bagging probe (dimensions 50 × 50 cm) is equipped with a GEKA coupling and is connected directly to the Laser HUNTER via the PVC hose (2 m, S20C-GEKA – Art. 412008). The result is a closed, safe measuring system for the precise, reproducible and fully documented quantification of methane emissions.

Technical requirements

The guideline defines clear limits and recording intervals for reliable and standard-compliant quantification.

  • Temperature limits and environmental conditions:
    Measurements may only be carried out at ambient temperatures between 5 °C and 35 °C.

  • Data acquisition and measurement intervals:
    The measurement data is recorded every 5 seconds during the measurement.

  • Required measurement parameters:
    The volume flow, methane concentration, temperature and pressure are recorded.

  • Device requirements:
    The methane detector must have a detection limit of at least 10 ppm and cover a working range of 0 to 100 vol.%.

How to calculate emission rates?

The emission rate of the leak is calculated from the constant methane concentration and the standardised extraction volume flow. The calculation is performed using the formula:

Formula for calculating emission rates

Documentation requirements in accordance with G 425-3

To ensure that the quantification is reportable and auditable, G 425-3 requires a short report to be prepared. This must contain the following elements:

  • The measurement results, including measurement uncertainties
  • The measuring instruments used
  • The extraction volume flow and the recording of the concentration measurement
  • A technical assessment of the plausibility of the measurement results

Conclusion: Why accurate methane quantification matters

DVGW G 425-3 enables comparable, measurement-based emission rates at above-ground sources. In conjunction with the procedural framework of DVGW G 465-5, it forms the technical basis for accurately quantifying methane emissions. This is essential for prioritising repair measures and consistent, standard-compliant reporting within the framework of the EU Methane Regulation.