Q481. Which calculation from 40 CFR 98.233(o) should be used for compressor venting at onshore petroleum and natural gas production facilities?

A481. Onshore petroleum and natural gas production facilities should refer to 40 CFR 98.233(o)(10) to determine which centrifugal compressor calculation method is most appropriate for your facility.

• If the facility is subject to the centrifugal compressor standards in § 60.5380b of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter for dry seals and self-contained wet seals, you must conduct the volumetric emission measurements as required by § 60.5380b(a)(5) of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter, conduct all additional volumetric emission measurements specified in 40 CFR 98.233(o)(1) using methods specified in 40 CFR 98.233(o)(2) through (5) (based on the compressor mode (as defined in 40 CFR 98.238) in which the compressor was found at the time of measurement), and calculate emissions as specified in paragraphs 40 CFR 98.233(o)(6) through (9).
• If the facility is not subject to the centrifugal compressor standards in § 60.5380b of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter for dry seals and self-contained wet seals, you may elect to conduct the volumetric emission measurements specified in 40 CFR 98.233(o)(1) using methods specified in 40 CFR 98.233(o)(2) through (5) (based on the compressor mode (as defined in 40 CFR 98.238) in which the compressor was found at the time of measurement), and calculate emissions as specified in 40 CFR 98.233(o)(6) through (9).
• If 40 CFR 98.233(o)(10)(i) does not apply and you do not elect to conduct the volumetric measurements specified in 40 CFR 98.233(o)(1), you must calculate total atmospheric wet seal oil degassing vent emissions from all centrifugal compressors using equation W-25A, and you must calculate wet seal oil degassing vent emissions from each centrifugal compressor using equation W-25B.

Onshore petroleum and natural gas production facilities should refer to 40 CFR 98.233(p)(10) to determine which reciprocating compressor calculation method is most appropriate for your facility.

• If the facility is subject to the reciprocating compressor standards in § 60.5385b of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter, you must conduct the volumetric emission measurements as required by § 60.5385b(b) and (c) of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter, conduct any additional volumetric emission measurements specified in 40 CFR 98.233(p)(1) using methods specified in 40 CFR 98.233(p)(2) through (5) (based on the compressor mode (as defined in 40 CFR 98.238) in which the compressor was found at the time of measurement), and calculate emissions as specified in 40 CFR 98.233(p)(6) through (9).
• If the facility is not subject to the reciprocating compressor standards in § 60.5385b of this chapter or an applicable approved state plan or applicable Federal plan in part 62 of this chapter, you may elect to conduct volumetric emission measurements specified in 40 CFR 98.233(p)(1) using methods specified in 40 CFR 98.233(p)(2) through (5) (based on the compressor mode (as defined in § 98.238) in which the compressor was found at the time of measurement), and calculate emissions as specified in 40 CFR 98.233(p)(6) through (9).
• If 40 CFR 98.233(p)(10)(i) does not apply, and you do not elect to conduct volumetric emission measurements specified in 40 CFR 98.233(p)(1), you must calculate total atmospheric rod packing emissions from all reciprocating compressors using equation W-29D, and you must calculate rod packing vent emissions from each reciprocating compressor using equation W-29E.