Code of Federal Regulations > Title 40 > Chapter I > Part 98 > Subpart W > Appendix - Table W-6 to Subpart W of Part 98

Regulations last checked for updates: Jan 31, 2025

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

Appendix - Table W-6 to Subpart W of Part 98—Default Methane Leaker Emission Factors

Equipment components	Emission factor (scf methane/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—LNG Storage and LNG Import and Export Equipment—Storage Components and Terminals Components, LNG Service
Valve	1.19	0.23	1.94
Pump Seal	4.00	0.73	6.54
Connector	0.34	0.11	0.56
Other ¹	1.77	0.99	2.9
Leaker Emission Factors—LNG Storage and LNG Import and Export Equipment—Storage Components and Terminals Components, Gas Service
Valve ²	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 and Instrument	19.33	12.39	31.6
Other ³	4.1	2.63	6.70
Leaker Emission Factors—Natural Gas Distribution—Transmission-Distribution Transfer Station ⁴ Components, Gas Service
Connector	1.69		2.76
Block Valve	0.557		0.91
Control Valve	9.34		15.3
Pressure Relief Valve	0.27		0.44
Orifice Meter	0.212		0.35
Regulator	0.772		1.26
Open-ended Line	26.131		42.7

¹ “Other” equipment type for components in LNG service should be applied for any equipment type other than connectors, pumps, or valves.

² Valves include control valves, block valves and regulator valves.

³ “Other” equipment type for components in gas service should be applied for any equipment type other than valves, connectors, flanges, open-ended lines, pressure relief valves, and meters and instruments, as specified in § 98.232(g)(6) and (7) and § 98.232(h)(7) and (8).

⁴ Excluding customer meters.

[89 FR 42327, May 14, 2024]

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

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