40 CFR § 63.11623 - What are the testing requirements?

---
identifier: "/us/cfr/t40/s63.11623"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 63.11623 - What are the testing requirements?"
title_number: 40
title_name: "Protection of Environment"
section_number: "63.11623"
section_name: "What are the testing requirements?"
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"
---


# 63.11623 What are the testing requirements?

(a) If you are demonstrating that the cyclone required by § 63.11621(e) is designed to reduce emissions of particulate matter by 95 percent or greater by the performance test option in § 63.11621(e)(1)(iii), you must conduct a test in accordance with paragraph (b) of this section and calculate the percent reduction in accordance with paragraph (c) of this section.

(b) You must use Method 5 in Appendix A to part 60 to determine the particulate matter mass rate at the inlet and outlet of the cyclone. You must conduct at least three runs at the cyclone inlet and three runs at the cyclone outlet. Each run must have a sampling time of at least 60 minutes and a sample volume of at least 0.85 dscm (30 dscf).

(c) You must calculate the percent particulate matter reduction using Equation 1.

Where:

PM RED = particulate matter reduction, percent;

M<sub>INLET</sub> = Mass of particulate matter at the inlet of the cyclone, dry basis, corrected to standard conditions, g/min;

M<sub>OUTLET</sub> = Mass of particulate matter at the outlet of the cyclone, dry basis, corrected to standard conditions, g/min;