40 CFR Table W-4 to Subpart W of Part 98: Table W-4 to Subpart W of Part 98—Default Total Hydrocarbon Leaker Emission Factors

Equipment components Emission factor (scf total hydrocarbon/hour/component)

If you survey using Method 21 as specified in § 98.234(a)(2)(i) If you survey using Method 21 as specified in § 98.234(a)(2)(ii) If you survey using any of the methods in § 98.234(a)(1), (3), or (5)

Leaker Emission Factors—Onshore Natural Gas Processing, Onshore Natural Gas Transmission Compression—Compressor Components, Gas Service

Valve 1 14.84 9.51 24.2

Connector 5.59 3.58 9.13

Open-Ended Line 17.27 11.07 28.2

Pressure Relief Valve 39.66 25.42 64.8

Meter 19.33 12.39 31.6

Other 2 4.1 2.63 6.70

Leaker Emission Factors—Onshore Natural Gas Processing, Onshore Natural Gas Transmission Compression—Non-Compressor Components, Gas Service

Valve 1 6.42 4.12 10.5

Connector 5.71 3.66 9.3

Open-Ended Line 11.27 7.22 18.4

Pressure Relief Valve 2.01 1.29 3.28

Meter 2.93 1.88 4.79

Other 2 4.1 2.63 6.70

Leaker Emission Factors—Underground Natural Gas Storage—Storage Station, Gas Service

Valve 1 14.84 9.51 24.2

Connector (other) 5.59 3.58 9.13

Open-Ended Line 17.27 11.07 28.2

Pressure Relief Valve 39.66 25.42 64.8

Meter and Instrument 19.33 12.39 31.6

Other 2 4.1 2.63 6.70

Leaker Emission Factors—Underground Natural Gas Storage—Storage Wellheads, Gas Service

Valve 1 4.5 3.2 7.35

Connector (other than flanges) 1.2 0.7 1.96

Flange 3.8 2.0 6.21

Open-Ended Line 2.5 1.7 4.08

Pressure Relief Valve 4.1 2.5 6.70

Other 2 4.1 2.5 6.70

1 Valves include control valves, block valves and regulator valves.

2 Other includes any potential equipment leak emission point in gas service that is not specifically listed in this table, as specified in § 98.232(d)(7) for onshore natural gas processing, § 98.232(e)(8) for onshore natural gas transmission compression, and as specified in § 98.232(f)(6) and (8) for underground natural gas storage.