SECTION 115.788. Audit Provisions

(a) At least once every calendar year, the owner or operator of a site as defined in §122.10 of this title (relating to General Definitions) that is subject to the highly-reactive volatile organic compound (HRVOC) fugitive monitoring requirements of this division (relating to Fugitive Emissions) shall retain the services of an independent third-party organization to conduct an audit of the process units subject to HRVOC monitoring in this division. The field survey conducted as part of the audit must be based on a random sampling of the affected valves at the site. The random sample must be such that each valve has an equal chance of being selected from the total number of valves being sampled. The valves to be considered in this random sampling are all of the valves at the site in HRVOC service that are not exempted from quarterly monitoring by §115.787 of this title (relating to Exemptions) and are not listed on either the difficult-to-monitor or the unsafe-to-monitor lists.

(1) The independent third-party organization shall verify that all affected valves are properly tagged in accordance with §115.782(a) of this title (relating to Procedures and Schedule for Leak Repair and Follow-up).

(2) The independent third-party organization shall perform a field survey to determine the representative percentage of leaking valves determined from the random sampling of the affected units at the site as follows.

(A) The field survey must begin after the owner or operator's contracted or usual monitoring service has completed monitoring the valves for that monitoring period. The field survey must be completed by the end of the next monitoring period.

(B) The following table must be used to determine the number of valves required to be monitored in the field survey. The total valve population count is all of the valves in HRVOC service that are not exempted from quarterly monitoring by §115.787 of this title and are not listed on either the difficult-to-monitor or the unsafe-to-monitor lists based on the average of the previous four quarters of monitoring. The company claimed leaker rate is the number of leaking valves found in the total valve population count based on the previous four quarters of monitoring divided by the total valve population count.

Attached Graphic

(C) The following alternatives may be used in lieu of subparagraph (B) of this paragraph to determine the number of valves required to be monitored in the field survey. The required sample size must be calculated using a hypergeometric distribution that characterizes sampling from a given finite population of valves without replacement and reported leaker rate. Commercially available statistical software programs may be used. The sample size must be determined according to the following requirements.

(i) The total valve population count is all of the valves in HRVOC service that are not exempted from quarterly monitoring by §115.787 of this title and are not listed on either the difficult-to-monitor or the unsafe-to-monitor lists based on the average of the previous four quarters of monitoring. The company claimed leaker rate is the number of leaking valves found in the total valve population count based on the previous four quarters of monitoring divided by the total valve population count.

(ii) Type I error rate must be less than or equal to 0.05. A Type I error occurs when the company claimed leaker rate accurately reflects the true proportion of leakers, yet the test falsely indicates that the true percentage of leakers is greater than reported (false positive).

(iii) Type II error rate must be less than or equal to 0.20, when the minimum difference between the company's claimed leaker rate and the true population leaker rate is at least 2%. A Type II error occurs when the true leaker rate is in fact greater than the reported rate, but the test fails to so indicate (false negative).

(D) The independent third-party organization shall perform the field survey in accordance with Method 21 in 40 Code of Federal Regulations Part 60, Appendix A-7 (October 17, 2000) if the majority of valves in HRVOC service are monitored according to Method 21. The independent third-party organization shall follow subsection (h) of this section if the majority of valves in HRVOC service are monitored according to the alternative work practice in §115.358 of this title.

(3) The independent third-party organization shall conduct a review of all data generated by monitoring technicians in the previous quarter. This review must include:

(A) identification of data patterns indicative of failure to properly implement Method 21 including, but not limited to, a review of the number of valves monitored per technician and the time between monitoring events to validate that the sampling procedures accurately reflect the requirements of Method 21 including identification of specific instances in which a monitoring technician recorded data faster than was physically possible due to the hydrocarbon gas analyzer response time and/or the time required for the technician to move to the next component; and

(B) a review of records to verify that the calibration requirements of Method 21 have been properly implemented.

(b) For purposes of this section, an independent third-party organization is an organization in which the owner or operator (including any subsidiary, parent company, sister company, or joint venture) of the petroleum refinery; synthetic organic chemical, polymer, resin, or methyl tert-butyl ether manufacturing process; or natural gas/gasoline processing operation has no ownership or other financial interest. If the owner or operator's routine monitoring is done by a contractor rather than by in-house monitoring, then the independent third-party organization must be a different contractor from that ordinarily used for those services.

(c) The owner or operator shall submit a verbal notification to the Houston regional office and any local air pollution control agency having jurisdiction that provides the date that the independent third-party organization is scheduled to begin the audit. The notification must be submitted at least 30 days prior to the start date of the audit. The notification must also identify whether the audit will be conducted using Method 21 or the alternative work practice in §115.358 of this title.

(d) The owner or operator shall furnish the Houston regional office and any local air pollution control agency having jurisdiction a copy of the results of the audit authored by the independent third-party organization within 30 days after completion of the audit requirements listed in subsection (a) of this section. The report must include:

(1) the number of valves that were not tagged, but should have been tagged in accordance with §115.782(a) of this title;

(2) the number of valves monitored during the field survey, the number of leaking valves found during the field survey, the percentage of leaking valves identified by the independent third-party organization during the field survey, and a detailed description of the sampling scheme used to ensure that a random sample of valves was selected so that each valve had an equal chance of being selected from the total number of valves being sampled;

(3) the total number of valves in HRVOC service that are not exempted from quarterly monitoring by §115.787 of this title and are not listed on either the difficult-to-monitor or the unsafe-to-monitor lists monitored based on the average of the previous four quarters of monitoring, the total number of leaking valves found at the site by the owner or operator's contracted or usual monitoring service based on the average of the previous four quarters of monitoring, and the percentage of leaking valves based on the average of the previous four quarters of monitoring;

(4) the methodology used to select the field survey sample size, and if the alternative provided in subsection (a)(2)(C) of this section was used to determine the number of valves to be sampled in the field survey, documentation must include:

(A) the actual Type I and Type II error rates associated with the sample size used; and

(B) a detailed description of the methodology used to calculate the sample size; and

(5) a summary of the independent third-party organization's review of all data generated by monitoring technicians in the previous quarter by the owner or operator's contracted or usual monitoring service for each of the categories specified in subsection (a)(3)(A) and (B) of this section.

(e) If the results of the independent third-party audit indicate deficiencies in the implementation of Method 21 or in the implementation of the alternative work practice in §115.358 of this title, the owner or operator shall submit a corrective action plan with the audit report to the Houston regional office and any local air pollution control agency having jurisdiction.

(f) Authorized representatives of the executive director, United States Environmental Protection Agency, or any local air pollution control agency with jurisdiction may conduct an audit of the owner or operator's leak detection and repair program.

(g) In lieu of complying with subsections (a) - (d) of this section, an owner or operator may request approval from the executive director of an alternative method that demonstrates equivalency with the independent third-party audit, provided that the request:

(1) includes a detailed explanation of how the equivalency will be demonstrated, including the appropriate recordkeeping and reporting requirements that will be implemented that are sufficient to demonstrate compliance with the alternative method; and

(2) demonstrates that it is a replicable procedure and details how the equivalency will be demonstrated.

(h) If the owner or operator of a site subject to the third-party audit requirements of this section elects to use the alternative work practice in §115.358 of this title to monitor valves in HRVOC service, the following additional provisions will apply.

(1) The field survey must be conducted as specified in subsection (a)(2) of this section, except that the independent third-party organization shall perform the field survey according to the alternative work practice in §115.358 of this title.

(2) In lieu of the data review specified under subsection (a)(3) of this section, the independent third-party organization shall conduct a review of all data and video generated by the monitoring personnel in the previous monitoring interval as specified in §115.358 of this title. For example, if the frequency for performing the alternative work practice is monthly, the review includes data from the monitoring event in the prior calendar month.

(A) The review must include a review of records to verify:

(i) the optical gas imaging instrument meets the requirements referenced in §115.358(c)(1) of this title;

(ii) the daily instrument check was performed as required by §115.358(c)(2) of this title; and

(iii) monitoring personnel performing the alternative work practice have satisfied the training requirements specified in §115.358(h) of this title.

(B) The review must also include identification of any:

(i) instances that components were imaged at a distance greater than demonstrated during the daily instrument check;

(ii) instances that the optical gas imaging instrument was not operated in accordance with the instrument manufacturer's operating parameters; and

(iii) leaking components in the video records that were not identified as leaking by the routine monitoring personnel.

(C) In lieu of the categories specified in subsection (a)(3)(A) and (B) of this section, the report contents specified in subsection (d)(5) of this section must include a summary of the independent third-party organization's review based on the categories specified in subparagraphs (A) and (B) of this paragraph.

(3) If the owner or operator is performing a combination of Method 21 hydrocarbon gas analyzer monitoring according to §115.781 of this title (relating to General Monitoring and Inspection Requirements) and the alternative work practice according to §115.358 of this title on different valves in HRVOC service, the field survey and data review must be performed based on how the majority of valves in HRVOC service were monitored in the evaluation period of the third party audit (e.g., if greater than 50% of valves in HRVOC service were monitored according to the alternative work practice, then the field survey and data review must be conducted according to this subsection). The population of valves used for the field survey in subsection (a)(2) of this section must only include those valves monitored according to the method (i.e., Method 21 or alternative work practice) that will be used in the field survey.

(i) Upon review of the audit results, the executive director may specify additional corrective actions beyond any potential corrective actions submitted in the documentation required under subsection (e) of this section.

Source Note: The provisions of this §115.788 adopted to be effective January 17, 2003, 28 TexReg 113; amended to be effective December 23, 2004, 29 TexReg 11623; amended to be effective June 24, 2010, 35 TexReg 5293