- 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) | 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 | 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 | 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 | 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 |
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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.