Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 115 - CONTROL OF AIR POLLUTION FROM VOLATILE ORGANIC › Subchapter H - HIGHLY-REACTIVE VOLATILE ORGANIC COMPOUNDS › Division 3 - FUGITIVE EMISSIONS › Section 115.788 - Audit Provisions

Current through Reg. 49, No. 28; July 12, 2024
(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.