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2.
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For all components of distribution and transmission networks, LDAR surveys shall be carried out at the following minimum frequency:
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Type of LDAR survey
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Type of component
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Frequency
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Type 1 LDAR survey
(design pressure > 16 bar)
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Compressor station
Regulating and metering station
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4 months
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Valve station
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9 months
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Type 2 LDAR survey
(design pressure > 16 bar)
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Compressor station
Regulating and metering station
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8 months
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Valve station
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18 months
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Type 2 LDAR survey
(design pressure ≤ 16 bar)
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Regulating and metering station
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9 months
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Valve station
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21 months
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Type of LDAR survey
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Type of material
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Frequency of survey
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Type 1 LDAR survey
(design pressure > 16 bar)
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Grey cast iron
Bitumen sheet
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3 months
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Asbestos
Ductile cast iron
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6 months
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Non-protected steel
Copper
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12 months
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Polyethylene
PVC
Protected steel
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24 months
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Type 2 LDAR survey
(design pressure > 16 bar)
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Grey cast iron
Bitumen sheet
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6 months
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Asbestos
Ductile cast iron
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12 months
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Non-protected steel
Copper
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24 months
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Polyethylene
PVC
Protected steel
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36 months
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Type 2 LDAR survey
(design pressure ≤ 16 bar)
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Grey cast iron
Bitumen sheet
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6 months
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Asbestos
Ductile cast iron
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12 months
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Non-protected steel
Copper
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24 months
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Polyethylene
PVC
Protected steel
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36 months
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Where the type of material cannot be determined, the highest frequency for the respective type of LDAR survey shall be used.
LDAR surveys may be carried out using a two-step approach: first from a distance and, only where a leak is detected, via a second detection as close as possible to the source.
For underground and below-the-sea-level protected steel pipelines with design pressure above 16 bar, operators shall also perform risk-based preventive pipeline integrity management to prevent any leakage in accordance with relevant European standards or national pipeline integrity management legislation. Preventive pipeline integrity management shall include constant monitoring of flow, fluid composition, pressure and temperature of the gas transported in the system to ensure that those parameters correspond to the applicable pipeline integrity specifications, as well as to locate the source of potential methane emissions and to estimate them. Taking into account the results of that preventive pipeline integrity management, the competent authority may approve a different frequency of up to 36 months for a type 1 LDAR survey and up to 48 months for a type 2 LDAR survey.
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