§63.124. Process vents and storage vessels that are in ethylene oxide service—procedures to determine compliance. — Inbound Citations

(11) All affected sources that commenced construction or reconstruction on or before April 25, 2023, must be in compliance with the ethylene oxide requirements in §§ 63.104(k), 63.109, 63.113(j), 63.119(a)(5), 63.120(d)(9), 63.124, 63.163(a)(1)(iii), (b)(2)(iv), (c)(4), and (e)(7), 63.168(b)(2)(iv) and (d)(5), 63.171(f), and 63.174(a)(3), (b)(3)(vi), (b)(5), and (g)(3), upon initial startup or on July 15, 2026, whichever is later. All affected sources that commenced construction or reconstruction after April 25, 2023, must be in compliance with the ethylene oxide requirements listed in §§ 63.104(k), 63.109, 63.113(j), 63.119(a)(5), 63.120(d)(9), § 63.124, 63.163(a)(1)(iii), (b)(2)(iv), (c)(4), and (e)(7), 63.168(b)(2)(iv) and (d)(5), § 63.171(f), and 63.174(a)(3), (b)(3)(vi), (b)(5), and (g)(3), upon initial startup or on July 15, 2024, whichever is later.

(f) The owner or operator of an existing source may elect to control some of the emission points within the source to different levels than specified under §§ 63.113 through 63.148 of this subpart by using an emissions averaging compliance approach as long as the overall emissions for the source do not exceed the emission level specified in paragraph (a) of this section. The owner or operator using emissions averaging must meet the requirements in paragraphs (f)(1) and (f)(2) of this section.

(1) Calculate emission debits and credits for those emission points involved in the emissions average as specified in § 63.150 of this subpart; and

(2) Comply with the requirements of § 63.151 and § 63.152 of this subpart, as applicable.

(4) In addition to complying with the requirements in paragraphs (k)(1) through (3) of this section, for process vents in ethylene oxide service, subject to the requirements of § 63.124 that are designated as maintenance vents, owners and operators may not release more than 1.0 tons of ethylene oxide from all maintenance vents combined per any consecutive 12-month period. The owner or operator must keep monthly records of the quantity in tons of ethylene oxide released from each maintenance vent and include a description of the method used to estimate this quantity.

(f) To demonstrate compliance with the emission limits and work practice standards specified in § 63.113(j) for process vents in ethylene oxide service, owners and operators must meet the requirements specified in § 63.124.

(8) For process vents in ethylene oxide service subject to the requirements of § 63.124, the Periodic Report must include the records for periods specified in paragraph (l)(2) of this section. Indicate the start date and time and end date and time for each period.

(g) To demonstrate compliance with the emission limits and work practice standards specified in § 63.119(a)(5) for storage vessels in ethylene oxide service, owners and operators must meet the requirements specified in § 63.124.

(k) For storage vessels in ethylene oxide service, subject to the requirements of § 63.124, owners and operators must keep the records specified in paragraphs (k)(1) and (2) of this section in addition to those records specified elsewhere in this section.

(1) For storage vessels in ethylene oxide service, records of the concentration of ethylene oxide of the fluid stored in each storage vessel.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(1) Comply with § 63.124, except:

(i) Substitute “§ 63.100(k)(11)” with “§ 63.1422(h)”.

(ii) Substitute “§ 63.113(j)” with “§ 63.1425(g)”.

(iii) Substitute “§ 63.113(j)(1)” with “§ 63.1425(g)(1)”.

(iv) Substitute “§ 63.113(j)(2)” with “§ 63.1425(g)(2) or (3)”.

(v) Substitute “§ 63.108” with “§ 63.1436”.

(vi) When owners or operators conduct performance tests on batch process vents using the procedures in § 63.116(c):

(A) Substitute “the schedule in § 63.103(b)(1) of subpart F of this part” with “§ 63.1437(a)”.

(B) The inlet sampling site shall be located after the exit from the batch unit operation but before any recovery or control device.

(C) The minimum sampling time for each run shall be the complete duration of the batch venting episode or 1 hour, whichever is shorter, instead of that stated in § 63.116(c)(3)(i) or (c)(4)(i).

(D) For process vents from batch unit operations, performance tests shall be conducted either at absolute worst-case conditions or hypothetical worst-case conditions as specified in § 63.1437(a)(1).

(vii) If § 63.124(a)(4) refers to “5 pounds per year,” then substitute it for “100 pounds per year”; otherwise, § 63.124(a)(4) applies as written.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(ix) When § 63.124 refers to § 63.148:

(A) Substitute “§ 63.100(k)(10)” with “§ 63.1422(h)”.

(B) Substitute “For each source as defined in § 63.101,” with “For each affected source as described in § 63.1420(a),”.

(C) Substitute “Except for pressure relief devices subject to § 63.165(e)(4),” with “Except for pressure relief devices subject to § 63.1434(c),”.

(iii) If a combustion, recovery, or recapture device is used to reduce emission in conjunction with ECO, the owner or operator shall record the information specified in § 63.1430(d) and comply with the monitoring provisions in § 63.1429 or § 63.124 as specified in § 63.1426(g).

(3) To demonstrate compliance for storage vessels in ethylene oxide service, as defined in § 63.1423, and establish the parameter monitoring level(s), owners or operators shall meet the requirements in § 63.124 (in addition to the HON storage vessel requirements specified in this section), except as specified in paragraphs (s)(3)(i) and (ii) of this section.

(i) Substitute “§ 63.100(k)(11)” with “§ 63.1422(h)”.

(ii) Substitute “§ 63.108” with “§ 63.1436”.

(a) The owner or operator of a combustion, recovery, or recapture device that has one or more parameter monitoring level requirements specified under this subpart shall establish a maximum or minimum level for each measured parameter. Except for process vents and storage vessels in ethylene oxide service subject to §§ 63.1426(g) and 63.1432(s), if a performance test is required by this subpart for a combustion, recovery, or recapture device, the owner or operator shall use the procedures in either paragraph (b) or (c) of this section to establish the parameter monitoring level(s). For process vents and storage vessels in ethylene oxide service subject to §§ 63.1426(g) and 63.1432(s), the owner or operator shall use the procedures specified in § 63.124 to establish the parameter monitoring level(s). Except for flares subject to § 63.1436, if a performance test is not required by this subpart for a combustion, recovery, or recapture device, the owner or operator may use the procedures in paragraph (b), (c), or (d) of this section to establish the parameter monitoring levels. For flares subject to § 63.1436, the owner or operator shall use the procedures specified in § 63.1436 to establish the parameter monitoring levels. When using the procedures specified in paragraph (c) or (d) of this section, the owner or operator shall submit the information specified in § 63.1439(e)(4)(viii) for review and approval, as part of the Precompliance Report.

(1) The owner or operator shall operate combustion, recovery, and recapture devices such that the daily average value of monitored parameters remains at or above the minimum established level, or remains at or below the maximum established level, except as otherwise provided in this subpart.

(2) As specified in § 63.1439(e)(5)(ii), all established levels, along with their supporting documentation and the definition of an operating day, shall be submitted as part of the Notification of Compliance Status.

(3) Nothing in this section shall be construed to allow a monitoring parameter excursion caused by an activity that violates other applicable provisions of 40 CFR part 63, subparts A, F, G, H, or CC.

(A) All information specified in the HON periodic reporting requirements in § 63.122(a)(4) for storage vessels and in § 63.146(c) through (f) for process wastewater. In addition, if you comply with § 63.1433(a)(23)(iii)(D) and annual sampling shows that the combined ethylene oxide load of the excluded wastewater streams prior to treatment is 1.0 megagram per year or greater, you must document this in the Periodic Report and also include the actual combined ethylene oxide load prior to treatment, how the combined load was determined, and sampling dates and results for each wastewater stream contributing to the combined load. Beginning no later than the compliance dates specified in § 63.1422(h), include all information specified in § 63.130(d) for transfer racks. Beginning no later than the compliance dates specified in § 63.1422(h), for storage vessels in ethylene oxide service subject to the requirements of § 63.124, the Periodic Report must include the information specified in § 63.123(k)(2). Indicate the start date, start time, and duration in hours for each period.

(a) This section applies to owners or operators of existing sources who seek to comply with the emission standard in § 63.112(a) of this subpart by using emissions averaging according to § 63.112(f) of this subpart rather than following the provisions of §§ 63.113 through 63.148 of this subpart. Notwithstanding the definition of process vent in § 63.101 and the sampling site designation in § 63.115(a), for purposes of this section the location of a process vent shall be defined, and the characteristics of its gas stream shall be determined, consistent with paragraph (g)(2)(i) of this section.

(1) A list designating each emission point complying with §§ 63.113 through 63.149 and whether each emission point is Group 1 or Group 2, as defined in § 63.111. For each process vent within the source, provide the information listed in paragraphs (e)(1)(i) through (iv) of this section.

(i) The chemical manufacturing process unit(s) that is the origin of all or part of the vent stream that exits the process vent.

(ii) The type(s) of unit operations (i.e., an air oxidation reactor, distillation unit, or reactor) that creates the vent stream that exits the process vent.

(8) For process vents and storage vessels subject to the requirements of § 63.124, owners and operators must also submit the information in this paragraph in a supplement to the Notification of Compliance Status within 150 days after the first applicable compliance date. The supplement to the Notification of Compliance Status must identify all process vents and storage vessels that are in ethylene oxide service as defined in § 63.101, the method(s) used to control ethylene oxide emissions from each process vent and storage vessel (i.e., use of a flare, scrubber, or other control device) and the information specified in paragraphs (b)(8)(i) and (b)(8)(ii) of this section, as applicable.

(i) For process vents, all uncontrolled, undiluted ethylene oxide concentration measurements, and the calculations used to determine the total uncontrolled ethylene oxide mass emission rate for the sum of all vent gas streams; and

(ii) For storage vessels, include the concentration of ethylene oxide of the fluid stored in each storage vessel.

(c) References in § 63.150 to §§ 63.112 through 63.130 mean the corresponding requirements in §§ 63.2450 through 63.2490, including applicable monitoring, recordkeeping, and reporting.

(a) For initial compliance, owners and operators must comply with paragraphs (a)(1) through (4) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with § 63.148 and conduct the initial visible emissions demonstration required by § 63.670(h) as specified in § 63.108.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(3) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and either paragraph (a)(3)(i) or (ii) of this section.

(i) Install a continuous emissions monitoring system (CEMS) to continuously monitor the ethylene oxide concentration at the exit of the control device. The CEMS must meet the requirements of either paragraph (a)(3)(i)(A) or (B) of this section. Comply with the requirements specified in § 63.2450(j) for CEMS.

(A) An FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter.

(B) A gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(a) For initial compliance, owners and operators must comply with paragraphs (a)(1) through (4) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with § 63.148 and conduct the initial visible emissions demonstration required by § 63.670(h) as specified in § 63.108.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(3) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and either paragraph (a)(3)(i) or (ii) of this section.

(i) Install a continuous emissions monitoring system (CEMS) to continuously monitor the ethylene oxide concentration at the exit of the control device. The CEMS must meet the requirements of either paragraph (a)(3)(i)(A) or (B) of this section. Comply with the requirements specified in § 63.2450(j) for CEMS.

(A) An FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter.

(B) A gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(4) If an owner or operator is demonstrating compliance with the combined process vent mass emissions limit in § 63.1425(g)(2) or (3) and, within the process, some process vents are uncontrolled (i.e., neither control devices nor ECO are used to reduce ethylene oxide emissions) while others are controlled, then the owner or operator must comply with paragraph (g)(1), (2), or (3) of this section for the controlled process vents and must measure ethylene oxide from the uncontrolled process vents using the procedures specified in § 63.124(a)(2)(ii) and (iii), except:

(A) Substitute “ethylene oxide exiting the outlet of the process vent prior to any releases to the atmosphere” for “ethylene oxide entering the control device and exiting the control device”.

(B) When the inlet of a control device is referenced in any parameter in Equation 1 to § 63.124(a)(2)(iii), it refers to the outlet of the process vent prior to any releases to the atmosphere.

(C) Equation 2 to § 63.124(a)(2)(iii) does not apply.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(4) If an owner or operator is demonstrating compliance with the combined process vent mass emissions limit in § 63.1425(g)(2) or (3) and, within the process, some process vents are uncontrolled (i.e., neither control devices nor ECO are used to reduce ethylene oxide emissions) while others are controlled, then the owner or operator must comply with paragraph (g)(1), (2), or (3) of this section for the controlled process vents and must measure ethylene oxide from the uncontrolled process vents using the procedures specified in § 63.124(a)(2)(ii) and (iii), except:

(A) Substitute “ethylene oxide exiting the outlet of the process vent prior to any releases to the atmosphere” for “ethylene oxide entering the control device and exiting the control device”.

(B) When the inlet of a control device is referenced in any parameter in Equation 1 to § 63.124(a)(2)(iii), it refers to the outlet of the process vent prior to any releases to the atmosphere.

(C) Equation 2 to § 63.124(a)(2)(iii) does not apply.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(a) For initial compliance, owners and operators must comply with paragraphs (a)(1) through (4) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with § 63.148 and conduct the initial visible emissions demonstration required by § 63.670(h) as specified in § 63.108.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(3) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and either paragraph (a)(3)(i) or (ii) of this section.

(i) Install a continuous emissions monitoring system (CEMS) to continuously monitor the ethylene oxide concentration at the exit of the control device. The CEMS must meet the requirements of either paragraph (a)(3)(i)(A) or (B) of this section. Comply with the requirements specified in § 63.2450(j) for CEMS.

(A) An FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter.

(B) A gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(a) For initial compliance, owners and operators must comply with paragraphs (a)(1) through (4) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with § 63.148 and conduct the initial visible emissions demonstration required by § 63.670(h) as specified in § 63.108.

(2) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and paragraphs (a)(2)(i) through (viii) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the percent reduction requirement at the inlet and outlet of the control device. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation. This paragraph does not apply if the conditions specified in paragraphs (a)(2)(i)(A) through (D) of this section are met for a previously conducted measurement or performance test.

(A) No changes have been made to the process since the time of the measurement or performance test;

(B) The operating conditions and test methods used during measurement or performance test conform to the ethylene oxide related requirements of this subpart;

(C) The control device and process parameter values established during the previously conducted measurement or performance test are used to demonstrate continuous compliance with the ethylene oxide related requirements of this subpart; and

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling sites at each sampling location. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide entering the control device and exiting the control device using equations 1 and 2 to this paragraph.

(iv) An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii) if the overall reduction of ethylene oxide is greater than or equal to 99.9 percent by weight.

(v) If a new control device is installed, then conduct a performance test of the new device following the procedures in paragraphs (a)(2)(i) through (iv) of this section.

(vi) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this section during the performance test.

(A) Scrubber liquid-to-gas ratio (L/G), determined from the total scrubber liquid inlet flow rate and the inlet or exit gas flow rate. Determine the average L/G during the performance test as the average of the test run averages. Alternatively, separately monitor the total scrubber liquid flow rate and gas flow rate through the scrubber. Determine the average total scrubber liquid flow rate and gas flow through the scrubber as the average of the test run averages.

(B) The pH may be measured at any point between the discharge from the scrubber column and the inlet to the reactant tank. Determine the average pH during the performance test as the average of the test run averages.

(C) The temperature may be measured at any point after the heat exchanger and prior to entering the top of the scrubber column. Determine the average inlet scrubber liquid temperature as the average of the test run averages.

(vii) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must establish operating parameter limits by monitoring the operating parameters specified in paragraphs (a)(2)(vii)(A) and (B) of this section during the performance test.

(A) Determine the average combustion chamber temperature during the performance test as the average of the test run averages.

(B) Determine the average flue gas flow rate during the performance test as the average of the test run averages.

(viii) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must notify the Administrator of the operating parameters that are planned to be monitored during the performance test prior to establishing operating parameter limits for the control device.

(3) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), then the owner or operator must comply with § 63.148 and either paragraph (a)(3)(i) or (ii) of this section.

(i) Install a continuous emissions monitoring system (CEMS) to continuously monitor the ethylene oxide concentration at the exit of the control device. The CEMS must meet the requirements of either paragraph (a)(3)(i)(A) or (B) of this section. Comply with the requirements specified in § 63.2450(j) for CEMS.

(A) An FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter.

(B) A gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter.

(ii) If the owner or operator does not install a CEMS under paragraph (a)(3)(i) of this section, then the owner or operator must comply with paragraphs (a)(3)(ii)(A) through (C) of this section.

(A) Conduct an initial performance test at the outlet of the control device that is used to comply with the concentration requirement.

(B) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. If the non-flare control device is a combustion device, correct the ethylene oxide concentration to 3 percent oxygen according to § 63.116(c)(iii)(B), except “TOC or organic HAP” and “TOC (minus methane and ethane) or organic HAP” in the Variables Cc and Cm must be replaced with “ethylene oxide”. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) or § 63.119(a)(5)(ii), if the ethylene oxide concentration is less than 1 ppmv.

(C) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(vii) If § 63.124(a)(4) refers to “5 pounds per year,” then substitute it for “100 pounds per year”; otherwise, § 63.124(a)(4) applies as written.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(4) If owners and operators choose to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a non-flare control device that reduces ethylene oxide to less than 5 pounds per year for all combined process vents within the process as specified in § 63.113(j)(2), then the owner or operator must comply with § 63.148 and paragraphs (a)(4)(i) through (iv) of this section.

(i) Conduct an initial performance test of the control device that is used to comply with the mass emission limit requirement at the outlet of the control device.

(ii) Conduct the performance test according to the procedures in § 63.116(c). Except as specified in § 63.109(a)(6), use Method 18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix A to this part to determine the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the sampling site. Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix A-3 to part 60 of this chapter to convert the volumetric flowrate to a dry basis.

(iii) Calculate the mass emission rate of ethylene oxide exiting the control device using Equation 2 to paragraph (a)(2)(iii) of this section. An owner or operator has demonstrated initial compliance with § 63.113(j)(2) if the ethylene oxide from all process vents (controlled and uncontrolled) within the process is less than 5 pounds per year when combined.

(iv) Comply with the requirements specified in paragraphs (a)(2)(v) through (viii) of this section, as applicable.

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.(m) For each maintenance vent opening subject to the requirements of § 63.113(k), owners and operators must keep the applicable records specified in paragraphs (m)(1) through (5) of this section.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(ii) If emissions are vented through a closed vent system to a non-flare control device, then the owner or operator shall keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record shall specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.(m) For each maintenance vent opening subject to the requirements of § 63.113(k), owners and operators must keep the applicable records specified in paragraphs (m)(1) through (5) of this section.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(ii) If emissions are vented through a closed vent system to a non-flare control device, then the owner or operator shall keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record shall specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.(m) For each maintenance vent opening subject to the requirements of § 63.113(k), owners and operators must keep the applicable records specified in paragraphs (m)(1) through (5) of this section.

(2) If emissions are vented through a closed-vent system to a non-flare control device, then the owner or operator must keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record must specify the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.

(b) For continuous compliance, owners and operators must comply with paragraphs (b)(1) through (6) of this section, as applicable.

(1) If an owner or operator chooses to reduce emissions of ethylene oxide by venting emissions through a closed vent system to a flare as specified in § 63.113(j)(1) or § 63.119(a)(5)(i), then the owner or operator must comply with §§ 63.148 and 63.108.

(2) If you choose to reduce emissions of ethylene oxide by venting emissions through a closed-vent system to a non-flare control device that reduces ethylene oxide to less than 1 ppmv as specified in § 63.113(j)(2) or § 63.119(a)(5)(ii), and you choose to comply with paragraph (a)(3)(i) of this section, then continuously monitor the ethylene oxide concentration at the exit of the control device using an FTIR CEMS meeting the requirements of Performance Specification 15 of appendix B to part 60 of this chapter and § 63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner or operator does not need to conduct the performance testing required in paragraph (b)(3) of this section or the operating parameter monitoring required in paragraphs (b)(4) through (6) of this section.

(3) Conduct a performance test no later than 60 months after the previous performance test and reestablish operating parameter limits following the procedures in paragraph (a)(2) through (4) of this section. The Administrator may request a repeat performance test at any time. For purposes of compliance with this paragraph, owners and operators may not use a design evaluation.

(4) If an owner or operator vents emissions through a closed vent system to a scrubber with a reactant tank, then the owner or operator must comply with § 63.148 and meet the operating parameter limits specified in paragraphs (b)(4)(i) through (v) of this section.

(i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the average L/G measured during the most recent performance test. Determine total scrubber liquid inlet flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 1.9 liters per minute (0.5 gallons per minute), whichever is greater. Determine gas flow rate at either the inlet or the exit of the scrubber with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. If gas flow rate is determined at the inlet of the scrubber, ensure that all gas flow through the scrubber is accounted for at the measurement location. Compliance with the minimum L/G operating limit must be determined continuously on a 1-hour block basis. Alternatively, minimum total scrubber liquid flow rate, equal to the average total scrubber liquid inlet flow rate measured during the most recent performance test, and maximum gas flow rate through the scrubber, equal to the average gas flow rate through the scrubber during the most recent performance test. Compliance with the total scrubber liquid flow rate and gas flow rate through the scrubber must be determined continuously on a 1-hour block basis.

(ii) Maximum scrubber liquid pH of the liquid in the reactant tank, equal to the average pH measured during the most recent performance test. Compliance with the pH operating limit must be determined continuously on a 1-hour block basis. Use a pH sensor with a minimum accuracy of ±0.2 pH units.

(iii) Pressure drop across the scrubber column, within the pressure drop range specified by the manufacturer or established based on engineering analysis. Compliance with the pressure drop operating limit must be determined continuously on a 1-hour block basis. Use pressure sensors with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(iv) Maximum temperature of the scrubber liquid entering the scrubber column, equal to the average temperature measured during the most recent performance test. Compliance with the inlet scrubber liquid temperature operating limit must be determined continuously on a 1-hour block basis. Use a temperature sensor with a minimum accuracy of ±1 percent over the normal range of the temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater.

(v) Liquid feed pressure to the scrubber column within the feed pressure range specified by the manufacturer or established based on engineering analysis. Compliance with the liquid feed pressure operating limit must be determined continuously on a 1-hour block basis. Use a pressure sensor with a minimum accuracy of ±5 percent over the normal operating range or 0.12 kilopascals, whichever is greater.

(5) If an owner or operator vents emissions through a closed vent system to a thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must meet the operating parameter limits specified in paragraphs (b)(5)(i) and (ii) of this section and the requirements in paragraph (b)(5)(iii) of this section.

(i) Minimum combustion chamber temperature, equal to the average combustion chamber temperature measured during the most recent performance test. Determine combustion chamber temperature with a temperature sensor with a minimum accuracy of at least ±1 percent over the normal range of temperature measured, expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is greater. Compliance with the minimum combustion chamber temperature operating limit must be determined continuously on a 1-hour block basis.

(ii) Maximum flue gas flow rate, equal to the average flue gas flow rate measured during the most recent performance test. Determine flue gas flow rate with a flow sensor with a minimum accuracy of at least ±5 percent over the normal range of flow measured, or 280 liters per minute (10 cubic feet per minute), whichever is greater. Compliance with the maximum flue gas flow rate operating limit must be determined continuously on a 1-hour block basis.

(iii) The owner or operator must maintain the thermal oxidizer in accordance with good combustion practices that ensure proper combustion. Good combustion practices include, but are not limited to, proper burner maintenance, proper burner alignment, proper fuel to air distribution and mixing, routine inspection, and preventative maintenance.

(6) If an owner or operator vents emissions through a closed vent system to a control device other than a flare, scrubber with a reactant tank, or thermal oxidizer, then the owner or operator must comply with § 63.148, and the owner or operator must monitor the operating parameters identified in paragraph (a)(2)(viii) of this section and meet the established operating parameter limits to ensure continuous compliance. The frequency of monitoring and averaging time will be determined based upon the information provided to the Administrator.

(viii) To demonstrate compliance with § 63.124(b)(2), in lieu of an FTIR CEMS, you may choose to use a gas chromatographic CEMS meeting the requirements of Performance Specification 9 of appendix B to part 60 of this chapter. If an owner or operator uses a gas chromatographic CEMS, then the owner or operator does not need to conduct the performance testing required in § 63.124(b)(3) or the operating parameter monitoring required in paragraphs § 63.124(b)(4) through (6).

(ii) If emissions are vented through a closed vent system to a non-flare control device, then the owner or operator shall keep records of all periods during which operating values are outside of the applicable operating limits specified in § 63.124(b)(4) through (6) when regulated material is being routed to the non-flare control device. The record shall specify the identification of the control device, the operating parameter, the applicable limit, and the highest (for maximum operating limits) or lowest (for minimum operating limits) value recorded during the period.