Code of Federal Regulations > Title 40 > Chapter I > Part 63 > Subpart PPPPP > Appendix - Table 2 to Subpart PPPPP of Part 63

Regulations last checked for updates: Feb 22, 2025

Title 40 - Protection of Environment last revised: Nov 22, 2025

Appendix - Table 2 to Subpart PPPPP of Part 63—Operating Limits

If you are required to comply with operating limits in § 63.9302, you must comply with the applicable operating limits in the following table:

For the following device . . .	You must meet the following operating limit . . .	and you must demonstrate continuous compliance with the operating limit by . . .
1. Thermal oxidizer	a. The average combustion temperature in any 3-hour period must not fall below the combustion temperature limit established according to § 63.9324(a)	i. Collecting the combustion temperature data according to § 63.9306(c); ii. Reducing the data to 3-hour block averages; and iii. Maintaining the 3-hour average combustion temperature at or above the temperature limit.
2. Catalytic oxidizer	a. The average temperature measured just before the catalyst bed in any 3-hour period must not fall below the limit established according to § 63.9324(b)	i. Collecting the temperature data according to § 63.9306(c); ii. Reducing the data to 3-hour block averages; and iii. Maintaining the 3-hour average temperature before the catalyst bed at or above the temperature limit.
	b. Either ensure that the average temperature difference across the catalyst bed in any 3-hour period does not fall below the temperature difference limit established according to § 63.9324(b)(2) or develop and implement an inspection and maintenance plan according to § 63.9324(b)(3) and (4)	i. Either collecting the temperature data according to § 63.9306(c), reducing the data to 3-hour block averages, and maintaining the 3-hour average temperature difference at or above the temperature difference limit; or ii. Complying with the inspection and maintenance plan developed according to § 63.9324(b)(3) and (4).
3. Emission capture system that is a PTE according to § 63.9322(a)	a. The direction of the air flow at all times must be into the enclosure; and either	i. Collecting the direction of air flow; and either the facial velocity of air through all natural draft openings according to § 63.9306(d)(1) or the pressure drop across the enclosure according to § 63.9306(d)(2); and ii. Maintaining the facial velocity of air flow through all natural draft openings or the pressure drop at or above the facial velocity limit or pressure drop limit, and maintaining the direction of air flow into the enclosure at all times.
	b. The average facial velocity of air through all natural draft openings in the enclosure must be at least 200 feet per minute; or	Follow the requirements in 3ai and ii of this table.
	c. The pressure drop across the enclosure must be at least 0.007 inch H2O, as established in Method 204 of appendix M to 40 CFR part 51	Follow the requirements in 3ai and ii of this table.
4. Emission capture system that is not a PTE according to § 63.9322(a)	a. The average gas volumetric flow rate or duct static pressure in each duct between a capture device and add-on control device inlet in any 3-hour period must not fall below the average volumetric flow rate or duct static pressure limit established for that capture device according § 63.9306(d)	i. Collecting the gas volumetric flow rate or duct static pressure for each capture device according to § 63.9306(d); ii. Reducing the data to 3-hour block averages; and iii. Maintaining the 3-hour average gas volumetric flow rate or duct static pressure for each capture device at or above the gas volumetric flow rate or duct static pressure limit.

authority: 42 U.S.C. 7401

source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.