La. Admin. Code tit. 33 § XI-701

Current through Register Vol. 50, No. 11, November 20, 2024

Section XI-701 - Methods of Release Detection

A. Tanks. Each method of release detection for tanks used to meet the requirements of LAC 33:XI.703.B shall be conducted in accordance with the following.

1. Inventory Control. Product inventory control (or another test of equivalent performance) shall be conducted monthly in a manner to ensure the detection of any release as small as 1.0 percent of flow-through plus 130 gallons on a monthly basis in the following manner.

a. Inventory volume measurements for regulated substance inputs, withdrawals, and the amount still remaining in the tank shall be recorded each operating day.

b. The equipment used shall be capable of measuring the level of product over the full range of the tank's height to the nearest 1/8 of an inch.

c. Inputs of regulated substances shall be reconciled with delivery receipts measuring the tank inventory volume before and after delivery.

d. Deliveries shall be made through a drop tube that extends to within 1 foot of the tank bottom.

e. Product dispensing shall be metered and recorded within the local standards for meter calibration or an accuracy of 6 cubic inches for every 5 gallons of product withdrawn.

f. Measurements of any water level in the bottom of the tank shall be made to the nearest 1/8 of an inch at least once a month.

g. Practices described in the American Petroleum Institute Publication 1621, "Recommended Practice for Bulk Liquid Stock Control at Retail Outlets," may be used, where applicable, as guidance in meeting the requirements of Paragraph A.1 of this Section.

2. Manual Tank Gauging. Tanks having a nominal capacity of 550 gallons or less and tanks having a nominal capacity of 551 to 1,000 gallons that meet the tank diameter criteria in the table in Subparagraph 2.d of this Subsection may use manual tank gauging as the sole method of release detection. All other tanks with a nominal capacity of 551-2,000 gallons may use this method in place of the manual inventory control described in Paragraph 1 of this Subsection. Tanks having a nominal capacity of greater than 2,000 gallons may not use this method to meet the requirements of this Subsection. Manual tank gauging shall meet the following requirements.

a. Tank liquid levels shall be measured at the beginning and ending of a period using the appropriate minimum duration of the test provided in the table in Paragraph 2.d of this Section, during which no liquid is added to or removed from the tank. For the purposes of Subparagraph d of this Paragraph, this constitutes one test.

b. Liquid level measurements shall be based on an average of two consecutive stick readings at both the beginning and ending of the period.

c. The equipment used shall be capable of measuring the level of product over the full range of the tank's height to the nearest 1/8 of an inch.

d. A leak shall be suspected and subject to the requirements of LAC 33:XI.707-713 if the variation between beginning and ending measurements exceeds the weekly or monthly standards in the following table.

Nominal Tank Capacity	MinimumDuration ofTest	Weekly Standard (One Test)	Monthly Standard (Average of 4 Tests)
550 gallons or less	36 hours	10 gallons	5 gallons
551-1000 gallons (when tank diameter is 64 inches)	44 hours	9 gallons	4 gallons
551-1000 gallons (when tank diameter is 48 inches)	58 hours	12 gallons	6 gallons
551-1000 gallons (also requires periodic tank tightness testing)	36 hours	13 gallons	7 gallons
1001-2000 gallons (also requires periodic tank tightness testing)	36 hours	26 gallons	13 gallons

3. Tank Tightness Testing. Tank tightness testing (or another test of equivalent performance) shall be capable of detecting a 0.1-gallon-per-hour leak rate from any portion of the tank that routinely contains product while accounting for the effects of thermal expansion or contraction of the product, vapor pockets, tank deformation, evaporation or condensation, and the location of the water table.

4. Automatic Tank Gauging (ATG)

a. Equipment for automatic tank gauging that tests for the loss of product and conducts inventory control shall meet the following requirements:

i. the automatic product level monitor test shall be capable of detecting a 0.2-gallon-per-hour leak rate from any portion of the tank that routinely contains product;

ii. the automatic tank gauging equipment shall meet the inventory control requirements of Subparagraphs 1.b and 1.f of this Subsection (or another test of equivalent performance); and

iii. the test shall be performed with the system operating in one of the following modes:

(a). in-tank static testing conducted at least once every 30 days; or

(b). continuous in-tank leak detection operating on an uninterrupted basis or operating within a process that allows the system to gather incremental measurements to determine the leak status at least once every 30 days.

5. External Release Detection Devices

a. General. External release detection devices (RDDs) consist of slotted (screened) piping installed within the excavation zone to permit either the testing or monitoring of vapors or the testing or monitoring for liquids on the water table. All RDDs shall meet the following requirements.

i. All RDDs shall have a 4-inch inside diameter and be constructed of either polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or stainless steel, and shall be chemically compatible with the stored product. The screened interval shall be commercially fabricated, slotted, or continuously wound. Screen size shall be 0.01 inches. No solvents, glues, epoxies, thermal processes, or rivets shall be used.

ii. The screened interval shall extend from 1 foot beneath the ground surface through the entire excavation zone.

iii. Each RDD shall be sealed from the ground surface to a depth of 1 foot and provided with a locking cap. Each RDD shall be installed in such a fashion as to preclude the introduction of surface contaminants into the RDD.

iv. No RDD shall be installed within or penetrate native soils unless the hydraulic conductivity of the native soil is no less than 0.01 centimeters per second.

v. If only one UST system is located within the excavation zone, at least two RDDs shall be installed. For excavation zones containing between two and four UST systems, at least four RDDs shall be installed. If more than four UST systems are situated within a common excavation zone, additional RDDs shall be installed as appropriate to ensure adequate coverage for release detection. If, prior to the implementation of these regulations, fewer RDDs than required in this Clause were installed at a specific location, the owner or operator may request a variance by demonstrating to the satisfaction of the administrative authority that the excavation zone in question can be adequately monitored.

vi. A UST owner or operator may request a variance to the RDD construction requirements outlined above by demonstrating to the department that the proposed deviations will allow the excavation zone to be adequately monitored.

b. Vapor Monitoring. Testing or monitoring for vapors within the soil gas of the excavation zone shall meet the following requirements.

i. The materials used as backfill shall be sufficiently porous (e.g., gravel, sand, crushed rock) to readily allow diffusion of vapors from releases into the excavation area.

ii. The stored regulated substance, or a tracer compound placed in the tank system, shall be sufficiently volatile (e.g., gasoline) to result in a vapor level detectable by the monitoring devices located in the excavation zone in the event of a release from the tank.

iii. The measurement of vapors by the monitoring devices shall not be rendered inoperative by the groundwater, rainfall, or soil moisture, or other known interferences, so that a release could go undetected for more than 30 days.

iv. The level of background contamination in the excavation zone shall not interfere with the method used to detect releases from the tank.

v. The vapor monitors shall be designed and operated to detect any significant increase in concentration above background of the regulated substance stored in the tank system, a component or components of that substance, or a tracer compound placed in the tank system.

vi. In the UST excavation zone, the site shall be assessed to ensure compliance with the requirements in Clauses A.5.b.i-iv of this Section and to establish the number and positioning of monitoring wells that will detect releases within the excavation zone from any portion of the tank that routinely contains product.

vii. Monitoring wells shall be clearly marked and secured to avoid unauthorized access and tampering.

c. Liquid Monitoring. Testing or monitoring for liquids on the water table shall meet the following requirements.

i. The regulated substance stored shall be immiscible in water and have a specific gravity of less than one.

ii. When an RDD is installed in the tank hold backfill, there shall be water present in the RDD during measurement at least once every 30 days in order to use liquid monitoring. When an RDD is installed in native soil, the distance to the water table shall never be more than 20 feet from the ground surface and shall be present in the RDD during measurement at least once every 30 days, and the hydraulic conductivity of the soil(s) between the UST system and the RDD shall not be less than 0.01 centimeters per second (e.g., the soil should consist of gravels, coarse-to-medium sands, coarse silts, or other permeable materials) in order to use liquid monitoring.

iii. The slotted portion of the RDD shall be designed to prevent migration of soils or the filter pack into the RDD and to allow entry of the regulated substance on the water table into the RDD under both high and low groundwater conditions.

iv. The continuous monitoring devices or manual methods used shall be capable of detecting the presence of at least 1/8 of an inch of free product on top of the water within the RDD.

v. Within and immediately below the excavation zone of the UST system, the site shall be assessed to ensure compliance with the requirements in Clauses A.5.c.i-iii of this Section and to establish the number and positioning of devices that will detect releases from any portion of the tank that routinely contains product.

vi. RDD shall be clearly marked and secured to avoid unauthorized access and tampering.

6. Interstitial Monitoring. Interstitial monitoring between the UST system and a secondary barrier immediately around or beneath it may be used, but only if the system is designed, constructed, and installed to detect a leak from any portion of the tank that routinely contains product and also meets one of the following requirements.

a. For double-walled UST systems, the sampling or testing method used shall be capable of detecting a leak through the inner wall in any portion of the tank that routinely contains product. Interstitial monitoring of double-walled or jacketed tanks shall be conducted either continuously by means of an automatic leak sensing device that signals to the operator the presence of any liquid in the interstitial space, or manually every 30 days by means of a procedure capable of detecting the presence of any liquid in the interstitial space.

b. For UST systems with a secondary barrier within the excavation zone, the sampling or testing method used shall be capable of detecting a release between the UST system and the secondary barrier, and the following criteria shall be met.

i. The secondary barrier around or beneath the UST system consists of artificially constructed material that is sufficiently thick and impermeable (at least 10^-6 centimeters per second for the regulated substance stored) to direct a leak to the monitoring point and permit its detection.

ii. The barrier is compatible with the regulated substance stored so that a leak from the UST system will not cause deterioration of the barrier that would allow a release to pass through undetected.

iii. For cathodically protected tanks, the secondary barrier is installed so that it does not interfere with the proper operation of the cathodic protection system.

iv. The groundwater, soil moisture, or rainfall will not render the testing or sampling method used inoperative so that a release could go undetected for more than 30 days.

v. The site is assessed to ensure that the secondary barrier is always above the water table and not in a 25-year floodplain, unless the barrier and monitoring designs are for use under such conditions.

vi. Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering.

c. Tanks with internally fitted liners shall be equipped with an automated device that can detect a leak between the inner wall of the tank and the liner, and the liner shall be compatible with the substance stored.

7. Statistical Inventory Reconciliation (SIR)

a. Release detection methods based on the application of statistical principles to inventory data similar to those described in LAC 33:XI.701.A.1 shall meet the following requirements:

i. report a quantitative result with a calculated leak rate;

ii. be capable of detecting a leak rate of 0.2 gallons per hour or a release of 150 gallons within 30 days; and

iii. use a threshold that does not exceed one-half the minimum detectable leak rate.

b. The UST system owner or operator shall receive a report from the SIR provider/vendor/software that performs the SIR analysis within the 30day monitoring period for which the analysis was performed.

8. Other Methods. Any other type of release detection method, or combination of methods, can be used if it meets the following requirements.

a. The release detection method can detect a 0.2-gallon-per-hour leak rate or a release of 150 gallons within 30 days with a probability of detection of at least 0.95 and a probability of false alarm of no greater than 0.05.

b. The release detection method has been approved by the Office of Environmental Assessment on the basis of a demonstration by the owner and operator that the method can detect a release as effectively as any of the methods allowed in Paragraphs 3-8 of this Subsection. In comparing methods, the Office of Environmental Assessment shall consider the size of release that the method can detect and the frequency and reliability with which it can be detected. If the method is approved, the owner and operator shall comply with any conditions imposed on its use by the Office of Environmental Assessment.

B. Piping. Each method of release detection for piping used to meet the requirements of LAC 33:XI.703.B shall be used in accordance with the following.

1. Automatic Line Leak Detectors. Methods that alert the operator to the presence of a leak by restricting or shutting off the flow of regulated substances through piping or by triggering an audible or visual alarm may be used only if they detect leaks of 3 gallons per hour at 10 pounds per square inch line pressure within 1 hour. A test of the operation of the leak detector shall be conducted at least once every 12 months in accordance with the following:

a. in accordance with the manufacturers requirements;

b. by simulating a release in order to determine if the system can detect leaks of 3 gallons per hour at 10 pounds per square inch line pressure within 1 hour and is fully operational; and

c. tested to ensure that the submersible pump does not run continuously during normal facility operation.

2. Line Tightness Testing. Periodic testing of piping is acceptable only if such testing can detect a 0.1 gallons per hour leak rate at 1.5 times normal operating pressure.

3. Applicable Tank Methods. Any of the methods in Paragraphs A.4-8 of this Section may be used if they are designed to detect a release from any portion of the underground piping that routinely contains regulated substances. Line tightness testing conducted at normal operating pressure with an ATG and pressurized line leak detectors, or with statistical inventory reconciliation must meet a 0.08 gallon-per-hour leak rate in order to qualify as an annual line tightness test.

4. Interstitial Monitoring. Interstitial monitoring of double-walled or jacketed piping shall be conducted either continuously by means of an automatic leak sensing device that signals to the operator the presence of any liquid in the interstitial space or sump, or manually every 30 days by means of a procedure capable of detecting the presence of any liquid in the interstitial space or sump.

a. The interstitial space or sump shall be maintained free of water, debris, or anything that could interfere with leak detection capabilities.

b. Subparagraph a of this Paragraph applies only to containment sumps that are used for interstitial monitoring of piping.

c. Sump sensors that are used for interstitial monitoring of piping shall be installed at the lowest part of the containment sump and in a vertical position, unless otherwise specified by the sensor manufacturer.

La. Admin. Code tit. 33, § XI-701

Promulgated by the Department of Environmental Quality, Office of Solid and Hazardous Waste, Underground Storage Tank Division, LR 16:614 (July 1990), amended by the Office of Environmental Assessment, LR 31:1072 (May 2005), amended by the Office of the Secretary, Legal Affairs Division, LR 33:2172 (October 2007), LR 34:2120 (October 2008), amended by the Office of the Secretary, Legal Division, LR 38:2762 (November 2012), Promulgated by the Department of Environmental Quality, Office of Solid and Hazardous Waste, Underground Storage Tank Division, LR 16:614 (July 1990), amended by the Office of Environmental Assessment, LR 31:1072 (May 2005), amended by the Office of the Secretary, Legal Affairs Division, LR 33:2172 (October 2007), LR 34:2120 (October 2008), amended by the Office of the Secretary, Legal Division, LR 38:2762 (November 2012), amended by the Office of the Secretary, Legal Affairs and Criminal Investigations Division, LR 432144 (11/1/2017), Amended LR 441607 (9/1/2018).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq.