Code of Federal Regulations > Title 40 > Chapter I > Part 98 > Subpart W > Appendix - Table W-2 to Subpart W of Part 98—Default Whole Gas Leaker Emission Factors

Regulations last checked for updates: Jan 31, 2025

Title 40 - Protection of Environment last revised: Nov 08, 2025

Appendix - Table W-2 to Subpart W of Part 98—Default Whole Gas Leaker Emission Factors

Equipment components	Emission factor (scf whole gas/hour/component)
Equipment components	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 Petroleum and Natural Gas Production and Onshore Petroleum and Natural Gas Gathering and Boosting—All Components, Gas Service
Valve	9.6	5.5	16
Flange	6.9	4.0	11
Connector (other)	4.9	2.8	7.9
Open-Ended Line ¹	6.3	3.6	10
Pressure Relief Valve	7.8	4.5	13
Pump Seal	14	8.3	23
Other ²	9.1	5.3	15
Leaker Emission Factors—Onshore Petroleum and Natural Gas Production—All Components, Oil Service
Valve	5.6	3.3	9.2
Flange	2.7	1.6	4.4
Connector (other)	5.6	3.2	9.1
Open-Ended Line	1.6	0.93	2.6
Pump ³	3.7	2.2	6.0
Other ²	2.2	1.0	2.9

¹ The open-ended lines component type includes blowdown valve and isolation valve leaks emitted through the blowdown vent stack for centrifugal and reciprocating compressors when using the population emission factor approach as specified in § 98.233(o)(10)(iv) or (p)(10)(iv).

² “Others” category includes any equipment leak emission point not specifically listed in this table, as specified in § 98.232(c)(21) and (j)(10).

³ The pumps component type in oil service includes agitator seals.

[89 FR 42324, May 14, 2024]

authority: 42 U.S.C. 7401-7671q.

source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.