40 CFR § 63.9320 - What procedures must I use?

---
identifier: "/us/cfr/t40/s63.9320"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 63.9320 - What procedures must I use?"
title_number: 40
title_name: "Protection of Environment"
section_number: "63.9320"
section_name: "What procedures must I use?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "63"
part_name: "NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401"
regulatory_source: "57 FR 61992, Dec. 29, 1992, unless otherwise noted."
cfr_part: "63"
---


# 63.9320 What procedures must I use?

(a) You must conduct each initial compliance demonstration that applies to you in Table 3 to this subpart.

(b) You must conduct an initial performance evaluation of each capture and control system according to §§ 63.9321, 63.9322, 63.9323 and 63.9324, and each CEMS according to the requirements in 40 CFR 63.8 and according to the applicable Performance Specification of 40 CFR part 60, appendix B (PS-3, PS-4A, or PS-8).

(c) The initial demonstration of compliance with the carbon monoxide (CO) or THC concentration limitation consists of either the first 4-hour rolling average CO or THC concentration recorded after completion of the CEMS performance evaluation if CEMS are installed or the average of the test run averages during the initial performance test. You must correct the CO or THC concentration at the outlet of the engine test cell/stand or the emission control device to a dry basis and to 15 percent O<sub>2</sub> content according to Equation 1 of this section:

Where:

C<sub>c</sub> = concentration of CO or THC, corrected to 15 percent oxygen, ppmvd

C<sub>unc</sub> = total uncorrected concentration of CO or THC, ppmvd

%O<sub>2d</sub> = concentration of oxygen measured in gas stream, dry basis, percent by volume

(d) The initial demonstration of compliance with the CO or THC percent reduction emission limitation consists of the first 4-hour rolling average percent reduction in CO or THC recorded after completion of the performance evaluation of the capture/control system and/or CEMS. You must complete the actions described in paragraphs (d)(1) through (2) of this section.

(1) Correct the CO or THC concentrations at the inlet and outlet of the emission control device to a dry basis and to 15 percent O<sub>2</sub> content using Equation 1 of this section.

(2) Calculate the percent reduction in CO or THC using Equation 2 of this section:

Where:

R = percent reduction in CO or THC

C<sub>i</sub> = corrected CO or THC concentration at inlet of the emission control device

C<sub>o</sub> = corrected CO or THC concentration at the outlet of the emission control device.

[68 FR 28785, May 27, 2003, as amended at 85 FR 34346, June 3, 2020]