SECTION 115.764. Monitoring and Testing Requirements

(a) The owner or operator of a cooling tower heat exchange system with a design capacity to circulate 8,000 gallons per minute (gpm) or greater of cooling water shall:

(1) install, calibrate, operate, and maintain a continuous flow monitor on each inlet of each cooling tower. Each monitor shall be calibrated on an annual basis to within ±5.0% accuracy. When the cooling tower flow monitor is down, flow measurements shall be used for the most recent 24-hour period in which the flow measurements are representative of cooling tower operations during monitor downtime;

(2) install, calibrate, operate, and maintain a system to continuously determine the total strippable volatile organic compound (VOC) concentration at each inlet of each cooling tower. The continuous monitoring system must have a minimum detection limit capability of no more than 25 parts per billion by weight (ppbw) of strippable VOC in the cooling water. The continuous monitor must be calibrated with methane or a VOC that best represents potential leakage into the cooling tower system and the emissions from the system. Calibration must be checked weekly or more frequently, as necessary, to maintain a monitor drift of less than 5.0%. During out-of-order periods of the VOC monitor(s) of 24 hours or greater, a sample must be collected for total VOC analysis according to the air-stripping method in Appendix P of the Texas Commission on Environmental Quality Sampling Procedures Manual (January 2003). This sample must be collected at least three times per calendar week, with an interval of no less than 36 hours between samples;

(3) continuously operate each monitoring system as required by this section at least 95% of the time when the cooling tower is operational, averaged over a calendar year. The percent measurement data availability must be calculated as the total operating hours of the cooling tower heat exchange system for which valid quality-assured data was recorded divided by the total operating hours of the cooling tower heat exchange system. Time required for normal calibration checks required under this subsection is not considered downtime for purposes of this calculation;

(4) determine the speciated strippable highly-reactive volatile organic compound (HRVOC) concentration by collecting samples from each inlet of each cooling tower at least once per month in accordance with the air-stripping method in Appendix P;

(5) if the concentration of total strippable VOC is equal to or greater than 50 ppbw in the cooling tower water for more than a one-hour block of time, collect an additional sample to determine speciated and total HRVOC in accordance with the air-stripping method in Appendix P from each inlet of the affected cooling tower at least once daily, beginning on the next calendar day. The additional sampling to determine speciated and total HRVOC shall continue on a daily basis until the concentration of total strippable VOC drops below 50 ppbw; and

(6) in lieu of the monitoring in paragraph (2) of this subsection and the sampling for speciation of strippable HRVOC in paragraphs (4) and (5) of this subsection, a continuous on-line monitor capable of providing total HRVOC and speciated HRVOCs in ppbw may be installed. The sampling system for the continuous on-line monitoring system must be demonstrated equivalent to the air-stripping apparatus used in Appendix P for determining strippable HRVOC concentrations in the water as specified in subsection (f) of this section. The continuous on-line monitor system must satisfy the requirements of Sections 8.3, 10, 13.1, and 13.2 of 40 Code of Federal Regulations (CFR) Part 60, Appendix B, Performance Specification 9, as amended through October 17, 2000 (65 FR 61744). The multi-point calibration procedure in Section 10.1 of Performance Specification 9 must be performed at least once every calendar quarter instead of once every month. During out-of-order periods of the on-line HRVOC monitor(s) of 24 hours or greater, sampling must be performed for total and speciated HRVOC analysis according to the air-stripping method in Appendix P. Sampling must be performed at least three times per calendar week, with an interval of no less than 36 hours between sampling times, until the continuous on-line monitor is properly operating and within the required performance specifications.

(A) During out-of-order periods of the monitoring system, data should be handled as follows for purposes of recordkeeping and demonstrating compliance:

(i) For each out-of-order period less than 24 hours, the maximum one-hour average HRVOC concentrations from the 24-hour period immediately prior to the out-of-order period must be used; and

(ii) For each out-of-order period of 24 hours or greater, the maximum one-hour average HRVOC concentrations from the 24-hour period immediately prior to the out-of-order period must be used for the time period from the initial outage of the monitoring system to time of collection of the first manual sample required by this paragraph. The results of each manual sample must be used for the time period from collection of that sample to the collection of the subsequent sample, or to the time that the continuous monitoring system is on-line and within the required performance specifications.

(B) For periods that only the analyzer system is out of order and the sampling system (i.e., HRVOC sparging or stripping system) is still functioning within normal specifications, the owner or operator may elect to collect the manual samples required by this paragraph using the sampling system of the continuous HRVOC monitoring system.

(b) The owner or operator of a cooling tower heat exchange system with a design capacity to circulate less than 8,000 gpm of cooling water or a cooling tower heat exchange system in dedicated service to a jacketed reactor, as defined in §115.760(b) of this title (relating to Applicability and Cooling Tower Heat Exchange System Definitions), shall:

(1) install, calibrate, operate, and maintain a continuous flow monitor on each inlet of each cooling tower. Each monitor must be calibrated on an annual basis to within ±5.0% accuracy. When the cooling tower flow monitor is down, flow measurements must be used for the most recent 24-hour period in which the flow measurements are representative of cooling tower operations during monitor downtime;

(2) determine the total strippable VOC concentration by collecting samples from each inlet of each cooling tower at least twice per week in accordance with the air-stripping method in Appendix P with an interval of not less than 48 hours between samples;

(3) operate each monitoring system as required by this section at least 95% of the time when the cooling tower is operational, averaged over a calendar year. The percent measurement data availability must be calculated as the total operating hours of the cooling tower heat exchange system for which valid quality-assured data was recorded divided by the total operating hours of the cooling tower heat exchange system. Time required for normal calibration checks required under this subsection is not considered downtime for purposes of this calculation;

(4) determine the speciated strippable HRVOC concentration by collecting samples from each inlet of each cooling tower at least once per month in accordance with the air-stripping method in Appendix P;

(5) if the concentration of total strippable VOC is equal to or greater than 50 ppbw in the cooling tower water, collect an additional sample to determine total strippable VOC, speciated HRVOC, and total HRVOC from each inlet of the affected cooling tower at least once daily, beginning on the next calendar day, in accordance with the air-stripping method in Appendix P. The additional sampling to determine total strippable VOC, speciated HRVOC, and total HRVOC must continue on a daily basis until the concentration of total strippable VOC drops below 50 ppbw; and

(6) in lieu of the monitoring in paragraph (2) of this subsection and the sampling for speciation of strippable HRVOC in paragraphs (4) and (5) of this subsection, a continuous on-line monitor capable of providing total HRVOC and speciated HRVOCs in ppbw may be installed. The sampling system for the continuous on-line monitoring system must be demonstrated equivalent to the air-stripping apparatus used in Appendix P for determining strippable HRVOC concentrations in the water as specified in subsection (f) of this section. The continuous on-line monitor system must satisfy the requirements of Sections 8.3, 10, 13.1, and 13.2 of 40 CFR Part 60, Appendix B, Performance Specification 9. The multi-point calibration procedure in Section 10.1 of Performance Specification 9 must be performed at least once every calendar quarter instead of once every month. During out-of-order periods of the on-line HRVOC monitor(s) of 24 hours or greater, sampling must be performed for total and speciated HRVOC analysis according to the air-stripping method in Appendix P. Sampling must be performed at least twice per calendar week, with an interval of no less than 72 hours between sampling times, until the continuous on-line monitor is properly operating and within the required performance specifications.

(A) During out-of-order periods of the monitoring system, data should be handled as follows for purposes of recordkeeping and demonstrating compliance.

(i) For each out-of-order period less than 24 hours, the maximum one-hour average HRVOC concentrations from the 24-hour period immediately prior to the out-of-order period must be used.

(ii) For each out-of-order period of 24 hours or greater, the maximum one-hour average HRVOC concentrations from the 24-hour period immediately prior to the out-of-order period must be used for the time period from the initial outage of the monitoring system to time of collection of the first manual sample required by this paragraph. The results of each manual sample must be used for the time period from collection of that sample to the collection of the subsequent sample, or to the time that the continuous monitoring system is on-line and within the required performance specifications.

(B) For periods that only the analyzer system is out of order and the sampling system (i.e., HRVOC sparging or stripping system) is still functioning within normal specifications, the owner or operator may elect to collect the manual samples required by this paragraph using the sampling system of the continuous HRVOC monitoring system.

(c) When periodic sampling is required, the owner or operator of the cooling tower heat exchange system shall determine the speciated HRVOC concentration as soon as this information is available, but no later than seven days after the sample(s) have been collected. Samples collected in a Tedlar^TM bag must be analyzed no later than 72 hours after the samples have been collected. The samples must be analyzed according to the procedures in Test Method 18, 40 CFR Part 60, Appendix A, and/or Method TO-14A, published in "U.S. EPA Compendium for Determination of Toxic Organic Compounds in Ambient Air (1996)," United States Environmental Protection Agency Document Number 625/R96/010B.

(d) In lieu of subsections (a)(2) - (5) and (b)(2) - (5) of this section, the owner or operator of cooling tower heat exchange systems in which no individual heat exchanger has 5.0% or greater HRVOC in the process-side fluid, shall determine total strippable VOC and the HRVOC concentration in the cooling tower water at least once per month, with an interval of not less than 20 days between samples, according to the air-stripping method in Appendix P. If the total strippable VOC concentration in the cooling tower water is 50 ppbw or greater, the owner or operator shall determine the total strippable VOC weekly and the HRVOC concentration weekly. The additional sampling for the total strippable VOC concentration and HRVOC concentration continue until the total strippable VOC concentration drops below 50 ppbw.

(e) In lieu of using a continuous flow monitor as described in subsections (a)(1) and (b)(1) of this section, the owner or operator of a cooling tower heat exchange system may:

(1) use the maximum potential flow rate based on manufacturer's pump performance data, assuming no back pressure; or

(2) install, calibrate, operate, and maintain, in accordance with the manufacturer's recommendations, a monitor to continuously measure and record each cooling water pump discharge pressure to establish the total dynamic head of the cooling water system. The owner or operator of the cooling water system must establish, use, and demonstrate in the QAP required in §115.766(i) of this title (relating to Recordkeeping and Reporting Requirements, a calculation methodology that will provide, on a continuous basis, the cooling water circulation flow rate (in gpm) based on the following: cooling water discharge pressure for each pump; the manufacturer's certified pump performance data; and the number of pumps in operation. This calculated flow rate will then be used to determine the hourly emission rate in pounds per hour, as required by §115.766(a)(3) of this title.

(f) Minor modifications to the monitoring and testing methods in this section may be approved by the executive director. Monitoring and testing methods other than those specified in this section may be used if approved by the executive director and validated by 40 CFR Part 63, Appendix A, Test Method 301 (December 29, 1992). For the purposes of this subsection, substitute "executive director" in each place that Test Method 301 references "administrator."

(g) In lieu of using the monitor location described in subsections (a), (b), and (h) of this section:

(1) the owner or operator of cooling tower heat exchange systems in which a single cooling tower services both HRVOC and non-HRVOC process units, or a single cooling tower that services multiple types of heat exchange systems (i.e., jacketed reactor or finite volume system), may:

(A) install a flow monitor or monitors, meeting the requirements of subsections (a)(1) and (b)(1) of this section at a point that represents the flow of cooling water from only the HRVOC-containing process units; and

(B) monitor the total strippable VOC or HRVOC concentration, in accordance with subsection (a), (b), (d), or (h) of this section at a point leaving the HRVOC-containing process unit and prior to mixing with cooling tower water from other units; or

(2) the owner or operator of cooling tower heat exchange systems may elect to monitor cooling water flow rate at a location that is representative of the total flow rate to the cooling tower.

(h) In lieu of the requirements of subsection (a) of this section, the owner or operator of a cooling tower heat exchange system in dedicated service to a finite volume system, as defined in §115.760(b) of this title, with HRVOC and with a design capacity to circulate 8,000 gallons gpm or greater of cooling water may elect to comply with the following requirements:

(1) install, calibrate, operate, and maintain a continuous flow monitor on each inlet of each cooling tower. Each monitor must be calibrated on an annual basis to within ±5.0% accuracy. When the cooling tower flow monitor is down, flow measurements must be used for the most recent 24-hour period in which the flow measurements are representative of cooling tower operations during monitor downtime;

(2) determine the speciated strippable HRVOC concentration by collecting samples from each inlet of each cooling tower at least once per month in accordance with the air-stripping method in Appendix P;

(3) determine the total strippable VOC concentration by collecting samples from each inlet of each cooling tower at least twice per week in accordance with the air-stripping method in Appendix P with an interval of not less than 48 hours between samples;

(4) if the concentration of total strippable VOC is equal to or greater than 50 ppbw in the cooling tower water, collect an additional sample to determine total strippable VOC, speciated HRVOC, and total HRVOC from each inlet of the affected cooling tower at least once daily in accordance with the air-stripping method in Appendix P. The additional sampling to determine total strippable VOC, speciated HRVOC, and total HRVOC must continue on a daily basis until the concentration of total strippable VOC drops below 50 ppbw;

(5) install, calibrate, operate, and maintain a continuous monitoring system to monitor the inventory level of the HRVOC in the finite volume system;

(6) develop, implement, and follow a written monitoring plan to satisfy the requirements of paragraph (5) of this subsection. The monitoring plan must include:

(A) specifications for all monitors used to satisfy the requirements of paragraph (5) of this subsection;

(B) the normal hourly variation in the inventory level for the continuous monitoring system;

(C) all process information, design specifications, and engineering calculations, used to establish the normal hourly variation in the inventory level; and

(D) at a minimum, quarterly inspections of the continuous monitoring system to ensure proper operation;

(7) if the hourly inventory level monitored in accordance with paragraphs (5) and (6) of this subsection is not within the normal hourly variation in the inventory level established as required in paragraph (5) of this subsection, except during maintenance activities, then the owner or operator must perform sampling for total strippable VOC as specified in paragraph (3) of this subsection within 24 hours. If the concentration of total strippable VOC is equal to or greater than 50 ppbw in the cooling tower water, then the owner or operator shall perform daily sampling to determine total strippable VOC, speciated HRVOC, and total HRVOC in accordance with paragraph (4) of this subsection until the concentration of total strippable VOC drops below 50 ppbw; and

(8) upon written request by the executive director, the monitoring plan required in accordance with paragraph (6) of this subsection must be submitted within 30 days for review. The executive director may require additional or alternative monitoring requirements.

Source Note: The provisions of this §115.764 adopted to be effective January 17, 2003, 28 TexReg 113; amended to be effective November 13, 2003, 28 TexReg 9835; amended to be effective December 23, 2004, 29 TexReg 11623