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Table 2 to Subpart DDDD of Part 63—Operating Requirements

Operating Requirements

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  3. Title 40
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  5. Chapter I
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  7. Part 63
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  9. Subpart DDDD
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  11. Subject Group Other Requirements and Information
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  13. Appendix Table 2 to Subpart DDDD of Part 63
CorpusDaily eCFR
Displayed edition2026-07-09
Last updated2026-07-09

Table 2 to Subpart DDDD of Part 63—Operating Requirements

Table 2 to Subpart DDDD of Part 63—Operating Requirements

If you operate a(n) . . .You must . . .Or you must . . .
(1) Thermal oxidizerMaintain the 3-hour block average firebox temperature above the minimum temperature established during the performance testMaintain the 3-hour block average THC concentration 1 in the thermal oxidizer exhaust below the maximum concentration established during the performance test.
(2) Catalytic oxidizerMaintain the 3-hour block average catalytic oxidizer temperature above the minimum temperature established during the performance test; and check the activity level of a representative sample of the catalyst annually except as specified in footnote “2” to this tableMaintain the 3-hour block average THC concentration 1 in the catalytic oxidizer exhaust below the maximum concentration established during the performance test.
(3) BiofilterMaintain the 24-hour block biofilter bed temperature within the range established according to § 63.2262(m)Maintain the 24-hour block average THC concentration 1 in the biofilter exhaust below the maximum concentration established during the performance test.
(4) Control device other than a thermal oxidizer, catalytic oxidizer, or biofilter used to meet the compliance options in table 1B or 1C to this subpartPetition the EPA Administrator for site-specific operating parameter(s) to be established during the performance test and maintain the average operating parameter(s) within the range(s) established during the performance testMaintain the 3-hour block average THC concentration 1 in the control device exhaust below the maximum concentration established during the performance test.
(5) Process unit that meets a compliance option in table 1A, 1C, 1D, or 1E to this subpart without the use of a control deviceMaintain on a daily basis the process unit controlling operating parameter(s) within the ranges established during the performance test according to § 63.2262(n)Maintain the 3-hour block average THC concentration 1 in the process unit exhaust below the maximum concentration established during the performance test.
(6) Wet electrostatic precipitator used to meet the compliance options in § 63.2240(d)(2) and (3) and table 1D or 1E to this subpartMaintain the 3-hour block average total secondary electric power input and liquid flow rate above the minimum limits established during the performance test.For a WESP followed by a control device with a dry exhaust, maintain the 24-hour block average opacity of no more than 10 percent (or the highest hourly average measured during the performance test).
(7) Dry electrostatic precipitator used to meet the compliance options in § 63.2240(d)(2) and (3) and table 1D or 1E to this subpartMaintain the 3-hour block average total secondary electric power input above the minimum limit established during the performance testMaintain the 24-hour block average opacity of no more than 10 percent (or the highest hourly average measured during the performance test).
(8) Wet PM scrubber used to meet the compliance options in § 63.2240(d)(2) and (3) and table 1D or 1E to this subpartMaintain the 3-hour block average liquid flow rate and pressure drop above the minimum limits established during the performance test
(9) Wet acid gas scrubber used to meet the compliance options in table 1D or 1E to this subpartMaintain the 3-hour block average liquid flow rate and effluent pH above the minimum limits established during the performance test
(10) Electrified filter bed used to meet the compliance options in § 63.2240(d)(2) and (3) and table 1D or 1E to this subpartMaintain the 3-hour block average ionizer voltage and the bed voltage above the minimum limits established during the performance test; AND maintain the pressure drop within the range established during the performance test
(11) Mechanical collector or other dry control device (not listed elsewhere in this table) used to meet the compliance options in § 63.2240(d)(2) and (3) and table 1D or 1E to this subpartMaintain the 24-hour block average opacity of no more than 10 percent (or the highest hourly average measured during the performance test)Maintain the 3-hour block average pressure drop across the control device above the minimum limit established during the performance test AND maintain average weekly 6-minute opacity readings below the maximum limit established according to § 63.2262(u).
(12) Process unit bypass stack (defined in § 63.2292) on and after July 6, 2029, except as noted in footnote “3” to this tableContinuously monitor usage of the process unit bypass stack at all times while the process units are operating
1 You may choose to subtract methane from THC measurements.
2 You may forego the annual catalyst activity check during the calendar year when a performance test is conducted according to table 4 to this subpart.
3 New or reconstructed affected sources that commenced construction or reconstruction after May 18, 2023, must comply with this requirement beginning on July 6, 2026, or upon initial startup, whichever is later.

[91 FR 41452, July 6, 2026]