(b) For the purpose of this Part, the following definitions also apply:

1. (1) Centrifugal compressor means equipment that increases the pressure of natural gas by centrifugal action through an impeller.
2. (2) Centrifugal compressor seal means a wet or dry seal around the compressor shaft where the shaft exits the compressor case.
3. (3) City gate means a point or measuring where custody transfer occurs between a natural gas transmission system pipeline company/operator and a distribution system company/operator.
4. (4) Component is meant to include but is not limited to; a valve, fitting, flange, threaded-connection, process drain, stuffing box, pressure-vacuum valve, pressure-relief device, pipes, seal fluid system, diaphragm, hatch, sight-glass, meter, open-ended line, well casing, natural gas actuated pneumatic device, natural gas actuated pneumatic pump, or reciprocating compressor rod packing or compressor seals.
5. (5) Condensate means liquid hydrocarbons that were originally in the gaseous phase in the reservoir and liquids recovered by surface separation from natural gas.
6. (6) Continuous bleed means the continuous venting of natural gas from a gas actuated pneumatic device to the atmosphere by design.
7. (7) Critical component means any component that would require the shutdown of a critical process unit if that component was shutdown or disabled.
8. (8) Critical process unit means a process unit or group of components at such unit that must remain in service because of their importance to the overall process. A critical process unit is required to continue to operate, has no equivalent equipment to replace it, cannot be bypassed, and for which it is technically infeasible to repair leaks from that process unit without shutting it down and opening the process unit to the atmosphere.
9. (9) Emulsion means any mixture of crude oil, condensate, or produced water with varying quantities of natural gas entrained in the liquids.
10. (10) Equipment means any stationary or portable machinery, object, or contrivance covered by this Part.
11. (11) Fuel gas means gas generated at a petroleum refinery or petrochemical plant and that is combusted separately or in any combination with any type of gas.
12. (12) Fuel gas system means any system that supplies natural gas as a fuel source to on-site natural gas actuated equipment other than a vapor control device.
13. (13) Hoop stress means the stress in a pipe wall, acting circumferentially in a plane perpendicular to the longitudinal axis of the pipe and produced by the pressure of the fluid in the pipe.
14. (14) Intermittent bleed means the intermittent venting of natural gas from a gas actuated pneumatic device to the atmosphere by design.
15. (15) Leak or fugitive leak means the unintentional release of emissions at a rate greater than or equal to the leak thresholds specified in this Part.
16. (16) Leak detection and repair or LDAR means the inspection of components to detect leaks of VOC and CH₄ and the repair of those components with leak rates above the standards and within the timeframes specified in this Part.
17. (17) Metering station means a station designed for the continuous measurement of the quantity of natural gas being transported in a pipeline and may include simultaneous analysis of natural gas quality.
18. (18) Natural gas means a naturally occurring mixture or process derivative of hydrocarbon and non-hydrocarbon gases. Its constituents include the greenhouse gases CH₄ and carbon dioxide, and may include natural gas liquids
19. (19) Natural gas gathering and boosting station means all equipment and components associated with moving natural gas to a natural gas processing plant, or transmission pipeline, or distribution pipeline.
20. (20) Natural gas transmission compressor station means all equipment and components located within a facility fence line associated with moving natural gas from production fields or natural gas processing plants through natural gas transmission pipelines, or within natural gas underground storage fields.

21. (21) Natural gas transmission pipeline means a pipeline, other than a gathering line, that:

    1. (i) transports gas from a gathering line or storage facility to a distribution center or storage facility, or directly to a large volume user that is not downstream from a distribution center; or
    2. (ii) operates at a hoop stress of 20 percent or more of specific minimum yield strength; or
    3. (iii) transports gas within a storage field.
22. (22) Natural gas underground storage or reservoir means all equipment and components, including the surface components of underground storage wells, associated with the temporary subsurface storage of natural gas in any underground reservoir, natural or artificial cavern or geologic dome, sand or stratigraphic trap, whether or not previously occupied by or containing oil or natural gas.
23. (23) Non-associated gas means natural gas that is not produced as a byproduct of crude oil production and may or may not be produced with condensate.
24. (24) Oil means crude petroleum oil and all other hydrocarbons, regardless of API gravity, that are produced at the wellhead in liquid form by ordinary production methods and that are not the result of condensation of gas.
25. (25) Optical gas imaging or OGI means using an instrument, such as a thermal infrared camera, that makes emissions visible that may otherwise be invisible to the naked eye.
26. (26) Pigging means using devices or instruments known as 'pigs' to perform various cleaning, clearing, maintenance, inspection, dimensioning, process and pipeline testing operations on new and existing pipelines.
27. (27) Pneumatic device means an automation device that uses natural gas or compressed air to control a process.
28. (28) Pneumatic pump means a device that uses natural gas or compressed air to power a piston or diaphragm in order to circulate or pump liquids.
29. (29) Portable pressurized separator means a pressure vessel, that can be moved from one location to another without having to be dismantled, and is capable of separating and storing crude oil, condensate, or produced water at the temperature and pressure of the separator required for sampling.
30. (30) Portable tank means a tank that can be moved from one location to another without having to be dismantled.
31. (31) Pressure vessel means any hollow container used to hold gas or liquid and rated, as indicated by an ASME pressure rating stamp, and operated to contain normal working pressures of at least 15 pounds per square inch, gauge (psig) without continuous vapor loss to the atmosphere.
32. (32) Production means all activities associated with the production or recovery of emulsion, crude oil, condensate, produced water, or natural gas at facilities to which this Part applies.
33. (33) Produced water means water recovered from an underground reservoir as a result of crude oil, condensate, or natural gas production that may be recycled, disposed, or re-injected into an underground reservoir.
34. (34) Reciprocating natural gas compressor means equipment that increases the pressure of natural gas by positive displacement of a piston in a compression cylinder that is powered by an internal combustion engine or electric motor.
35. (35) Reciprocating natural gas compressor rod packing means a seal comprised of a series of flexible rings in machined metal cups that fit around the reciprocating compressor piston rod to limit the amount of compressed natural gas that vents into the atmosphere.
36. (36) Reciprocating natural gas compressor seal means any device or mechanism used to limit the amount of natural gas that vents from a compression cylinder into the atmosphere.
37. (37) Regulating station means a station that is placed along a pipeline to reduce the pressure of the gas to the appropriate operating pressure for each system.
38. (38) Sales gas means the raw natural gas, after processing to remove liquid petroleum gas, condensate and carbon dioxide. Sales gas usually consists mainly of CH₄ and ethane.
39. (39) Separator means a tank used to physically separate the oil, gas, and water produced simultaneously from a well.
40. (40) Separator and tank system means the first separator in a crude oil or natural gas production system and any tank or sump connected directly to the first separator.
41. (41) Storage vessel means any container constructed primarily of non-earthen materials used for the purpose of storing, holding, or separating emulsion, crude oil, condensate, or produced water and that is designed to operate below a normal operating pressure of 15 psig.
42. (42) Successful repair means tightening, adjusting, or replacing equipment or a component for the purpose of stopping or reducing fugitive leaks below the minimum leak detection threshold or emission flow rate standard specified in this Part.
43. (43) Total hydrocarbon means organic compounds of hydrogen and carbon whose densities, boiling points, and freezing points increase as their molecular weights increase. Although composed of only two elements, hydrocarbons exist in a variety of compounds, because of the strong affinity of the carbon atom for other atoms and for itself.
44. (44) Vapor collection system means equipment and components installed on compressors, pressure vessels, separators, tanks, or sumps including piping, connections, and flow-inducing devices used to collect and route emission vapors to a processing, sales gas, or fuel gas system, or to a vapor control device.
45. (45) Vapor control device means equipment used to reduce hydrocarbon emissions.
46. (46) Vapor control efficiency means the ability of a vapor control device to reduce emissions, expressed as a percentage, that can be estimated by calculation or by measuring the total hydrocarbon concentration or mass flow rate at the inlet and outlet of the vapor control device.
47. (47) Vent or venting means the intentional or automatic release of natural gas into the atmosphere from components, equipment, or activities described in this Part.

48. (48) Well means a boring in the earth for the purpose of the following:

    1. (i) exploring for or producing oil or gas;
    2. (ii) injecting fluids or gas for stimulating oil or gas recovery;
    3. (iii) re-pressuring or pressure maintenance of oil or gas reservoirs;
    4. (iv) disposing of oil field waste gas or liquids; or
    5. (v) injection or withdrawal of gas from an underground storage facility.
49. (49) Well site means the well pad and access roads, equipment storage and staging areas, vehicle turnarounds, and any other areas directly or indirectly impacted by activities involving a well.