Regulations last checked for updates: Nov 25, 2024

Title 40 - Protection of Environment last revised: Nov 21, 2024
Appendix - Table W-1A to Subpart W of Part 98—Default Whole Gas Emission Factors for Onshore Petroleum and Natural Gas Production Facilities and Onshore Petroleum and Natural Gas Gathering and Boosting Facilities
Link to an amendment published at 89 FR 42323, May 14, 2024.

Table W-1A to Subpart W of Part 98—Default Whole Gas Emission Factors for Onshore Petroleum and Natural Gas Production Facilities and Onshore Petroleum and Natural Gas Gathering and Boosting Facilities

Onshore petroleum and natural gas production and Onshore petroleum and natural gas gathering and boosting Emission factor
(scf/hour/component)
Eastern U.S.
Population Emission Factors—All Components, Gas Service 1
Valve0.027
Connector0.003
Open-ended Line0.061
Pressure Relief Valve0.040
Low Continuous Bleed Pneumatic Device Vents 21.39
High Continuous Bleed Pneumatic Device Vents 237.3
Intermittent Bleed Pneumatic Device Vents 213.5
Pneumatic Pumps 313.3
Population Emission Factors—All Components, Light Crude Service 4
Valve0.05
Flange0.003
Connector0.007
Open-ended Line0.05
Pump0.01
Other 50.30
Population Emission Factors—All Components, Heavy Crude Service 6
Valve0.0005
Flange0.0009
Connector (other)0.0003
Open-ended Line0.006
Other 50.003
Population Emission Factors—Gathering Pipelines, by Material Type 7
Protected Steel0.47
Unprotected Steel16.59
Plastic/Composite2.50
Cast Iron27.60
Western U.S.
Population Emission Factors—All Components, Gas Service 1
Valve0.121
Connector0.017
Open-ended Line0.031
Pressure Relief Valve0.193
Low Continuous Bleed Pneumatic Device Vents 21.39
High Continuous Bleed Pneumatic Device Vents 237.3
Intermittent Bleed Pneumatic Device Vents 213.5
Pneumatic Pumps 313.3
Population Emission Factors—All Components, Light Crude Service 4
Valve0.05
Flange0.003
Connector (other)0.007
Open-ended Line0.05
Pump0.01
Other 50.30
Population Emission Factors—All Components, Heavy Crude Service 6
Valve0.0005
Flange0.0009
Connector (other)0.0003
Open-ended Line0.006
Other 50.003
Population Emission Factors—Gathering Pipelines by Material Type 7
Protected Steel0.47
Unprotected Steel16.59
Plastic/Composite2.50
Cast Iron27.60

1 For multi-phase flow that includes gas, use the gas service emissions factors.

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

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

4 Hydrocarbon liquids greater than or equal to 20°API are considered “light crude.”

5 “Others” category includes instruments, loading arms, pressure relief valves, stuffing boxes, compressor seals, dump lever arms, and vents.

6 Hydrocarbon liquids less than 20°API are considered “heavy crude.”

7 Emission factors are in units of “scf/hour/mile of pipeline.”

[80 FR 64297, Oct. 22, 2015]
source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.