40 CFR Appendix Table W-7 to Subpart W of Part 98 - Default Methane Emission Factors for Natural Gas Distribution

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Table W-7 to Subpart W of Part 98 - Default Methane Emission Factors for Natural Gas Distribution
Natural gas distribution Emission factor (scf/hour/
component)
Leaker Emission Factors - Transmission-Distribution Transfer Station 1 Components, Gas Service
Connector 1.69
Block Valve 0.557
Control Valve 9.34
Pressure Relief Valve 0.27
Orifice Meter 0.212
Regulator 0.772
Open-ended Line 26.131
Population Emission Factors - Below Grade Metering-Regulating station 1 Components, Gas Service 2
Below Grade M&R Station, Inlet Pressure >300 psig 1.30
Below Grade M&R Station, Inlet Pressure 100 to 300 psig 0.20
Below Grade M&R Station, Inlet Pressure <100 psig 0.10
Population Emission Factors - Distribution Mains, Gas Service 3
Unprotected Steel 12.58
Protected Steel 0.35
Plastic 1.13
Cast Iron 27.25
Population Emission Factors - Distribution Services, Gas Service 4
Unprotected Steel 0.19
Protected Steel 0.02
Plastic 0.001
Copper 0.03

1 Excluding customer meters.

2 Emission Factor is in units of “scf/hour/station.”

3 Emission Factor is in units of “scf/hour/mile.”

4 Emission Factor is in units of “scf/hour/number of services.”

[76 FR 80594, Dec. 23, 2011]

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