Section 22a-449(d)-104 - Release detection(a)General requirements for all UST systems.(1) Owners and operators of new and existing UST systems shall provide a method, or combination of methods, of release detection that: (A) Can detect a release from any portion of the tank and the connected underground piping except vent and vapor recovery piping unless such vent and vapor recovery piping routinely contains product;(B) Is installed, calibrated, operated, and maintained in accordance with the manufacturer's instructions, including routine maintenance and service checks for operability or running condition; and(C) Meets the performance requirements in subsections 22a-449(d) -104 (e) or (f) of these regulations, with any performance claims and their manner of determination described in writing by the equipment manufacturer or installer. In addition, methods used after the date shown in the following table corresponding with the specified method except for methods permanently installed prior to that date, shall be capable of detecting the leak rate or quantity specified for that method in the corresponding section of the rule (also shown in the table) with a probability of detection (Pd) of 0.95 and a probability of false alarm (Pfa) of 0.05. Method | Subdivision of this section 22a-449(d) -104 | Date after which Pd/Pfa must be demonstrated |
Manual Tank Gauging. . . . . . . . . . . | (e) (2) | December 22, 1990. |
Tank Tightness Testing. . . . . . . . . . . | (e) (2) | December 22, 1990. |
Automatic Tank Gauging. . . . . . . . . | (e) (4) | December 22, 1990. |
Automatic Line Leak Detectors. . . . | (f) (1) | September 22, 1991. |
Line Tightness Testing. . . . . . . . . . . | (f) (2) | December 22, 1990. |
(2) When a release detection method operated in accordance with the performance standards in subsections 22a-449(d) -104 (e) and (f) of these regulations indicates a release may have occurred, owners and operators shall notify the implementing agency in accordance with section 22a-449(d) -105 of these regulations.(3) Owners and operators of all UST systems shall comply with the release detection requirements of section 22a-449(d) -104 of these regulations by December 22 of the year listed in the following table: Schedule for Phase-in of Release Detection
Year system was installed | Year when release detection is required (by December 22nd of the year indicated) |
| 1989 | 1990 | 1991 | 1992 | 1993 |
Before 1965 or date unknown | RD | P | | | |
1965-69 . . . . . . . . . . . . | | P/RD | | | |
1970-74 . . . . . . . . . . . . | | P | RD | | |
1975-79 . . . . . . . . . . . . | | P | | RD | |
1980-88 . . . . . . . . . . . . | | P | | | RD |
New tanks (after December 22) immediately upon installation. |
P = Shall begin release detection for all pressurized piping as defined in subdivision 22a-449(d) -104 (c) (2) (A) of these regulations.
RD = Shall begin release detection for tanks and suction piping in accordance with subdivisions 22a-449(d) -104 (c) (1), (c) (2) (B) and subsection 22a-449(d) -104 (d) of these regulations.
(4) Any existing UST system that cannot apply a method of release detection that complies with the requirements of section 22a-449(d) -104 of these regulations shall complete the closure procedures in section 22a-449(d) -107 of these regulations by the date on which release detection is required for that UST system under subdivision 22a-449(d) -104 (a) (3) of these regulations. (b)Additional Requirements(1) Failure determination. On and after the effective date of RCSA section 22a-449(d) -104 the owner and operator of an UST system which was regulated under RCSA section 22a-449(d) -1 prior to the effective date of these regulations, shall perform and report failure determinations in accordance with RCSA section 22a-449(d) -1 until the date that release detection is provided and performed in accordance with all the requirements in subsection 22a-449(d) -104 (c) of these regulations including any tightness testing that is required thereunder.(2) Tank tightness test. In addition to the tank testing requirements in these regulations, the owner or operator of a fiberglass-reinforced plastic UST system shall conduct a tank tightness test in accordance with subdivision 22a-449(d) -104 (e) (3) of these regulations within three to six months after the installation of such system.(3) Inventory. (A) On and after the effective date of RCSA section 22a-449(d) -104 the owner and operator of an UST system which was regulated under RCSA section 22a-449(d) -1 prior to the effective date of these regulations, shall perform and maintain daily inventory records in accordance with RCSA section 22a-449(d) -1 including, but not limited to, the confirmation and reporting of an abnormal loss or gain until the date that release detection is provided and performed in accordance with all the requirements in subsection 22a-449(d) -104 (c) of these regulations including any monthly inventory control that is required thereunder.(B) The commissioner may require an owner or operator to perform a failure determination, in accordance with RCSA section 22a-449(d) -1, of any UST system for which daily inventory records are not maintained in accordance with this subdivision.(c)Requirements for petroleum UST systems.Owners and operators of petroleum UST systems shall provide release detection for tanks and piping as follows:
(1) Tanks. Daily measurements for any water level in the bottom of the tank shall be made to the nearest one-eighth of an inch and recorded, except such measurements for water are not required for double wall tanks with interstitial monitoring performed in accordance with section 22a-449(d) -104 these regulations. Tanks shall be monitored at least every thirty (30) days for releases using one of the methods listed in subdivisions 22a-449(d) -104 (e) (4), (5), (6), (7) and (8) of these regulations except that: (A) UST systems that meet the performance standards in subsection 22a-449(d) -102 (a) of these regulations and the monthly inventory control requirements in subdivisions 22a-449(d) -104 (e) (1) or (2) of these regulations may use tank tightness testing, conducted in accordance with subdivision 22a-449(d) -104 (e) (3) at least every five years and at thirty-six to thirty-three months prior to the end of their life expectancy and annually thereafter until December 22, 1998, or until ten years after the tank is installed, whichever is later;(B) UST systems that do not meet the performance standards in subsection 22a-449(d) -102 (a) of these regulations may use monthly inventory controls, conducted in accordance with subdivisions 22a-449(d) -104 (e) (1) or (2) of these regulations, and annual tank tightness testing, conducted in accordance with subdivision 22a-449(d) -104 (e) (3) of these regulations, until the closure date specified in subsections 22a-449(d) -110 (a) and (b) of these regulations for that UST system or December 22, 1998, whichever date is earlier.(C) Tanks with capacity of 550 gallons or less may use weekly tank gauging, conducted in accordance with subdivision 22a-449(d) -104 (e) (2) of these regulations.(2) Piping. Underground piping that routinely contains regulated substances shall be monitored for releases in a manner that meets one of the following requirements:(A) Pressurized piping. Underground piping that conveys regulated substances under pressure shall:(i) Be equipped with an automatic line leak detector conducted in accordance with subdivision 22a-449(d) -104 (f) (1) of these regulations; and(ii) Have an annual line tightness test conducted in accordance with subdivision 22a-449(d) -104 (f) (2) of these regulations or have monthly monitoring conducted in accordance with subdivision 22a-449(d) -104 (f) (3) of these regulations.(B) Suction piping. Underground piping that conveys regulated substances under suction shall either have a line tightness test conducted at least every three years until thirty-six to thirty-three months prior to the end of their life expectancy, on which date and annually thereafter line tightness tests shall be conducted, and all such line tightness tests shall be conducted and in accordance with subdivision 22a-449(d) -104 (f) (2) of these regulations, or use a monthly monitoring method conduct in accordance with subdivision 22a-449(d) -104 (f) (3) of these regulations. For suction piping that is designed and constructed to meet the following standards, a line tightness test shall be conducted thirty-six to thirty-three months prior to the end of their life expectancy and annually thereafter and such line tightness shall be conducted in accordance with subdivision 22a-449(d) -104 (f) (2) of these regulations:(i) The below-grade piping operates at less than atmospheric pressure;(ii) The below-grade piping is sloped so that the contents of the pipe shall drain back into the storage tank if the suction is released;(iii) Only one check valve is included in each suction line;(iv) The check valve is located directly below and as close as practical to the suction pump; and(v) A method is provided that allows compliance with subparagraphs 22a-449 (d)-104 (c) (2) (B) (ii), (iii) and (iv) of these regulations of this section to be readily determined.(d)Requirements for hazardous substance UST systems.Owners and operators of hazardous substance UST systems shall provide release detection that meets the following requirements:
(1) Release detection at existing UST systems shall meet the requirements for petroleum UST systems in subsection 22a-449(d) -104 (c) of these regulations. By December 22, 1998, all existing hazardous substance UST systems shall meet the release detection requirements for new systems in subdivision 22a-449(d) -104 (d) (2) of these regulations.(2) Release detection at new hazardous substance UST systems shall meet the following requirements: (A) Secondary containment systems shall be designed, constructed and installed to:(i) Contain regulated substances released from the tank system until they are detected and removed;(ii) Prevent the release of regulated substances to the environment at any time during the operational life of the UST system; and(iii) Be checked for evidence of a release at least every thirty days.(B) Double-walled tanks shall be designed, constructed, and installed to:(i) Contain a release from any portion of the inner tank within the outer wall; and(ii) Detect the failure of the inner wall.(C) External liners (including vaults) shall be designed, constructed, and installed to: (i) Contain 100 percent of the capacity of the largest tank within its boundary;(ii) Prevent the interference of precipitation or ground-water intrusion with the ability to contain or detect a release of regulated substances; and(iii) Surround the tank completely so that it is capable of preventing lateral as well as vertical migration of regulated substances.(D) Underground piping shall be equipped with secondary containment that satisfies the requirements of subdivision 22a-449(d) -104 (d) (2) (A) of these regulations, including, but not limited to, trench liners and jacketing of double-walled pipe. In addition, underground piping that conveys regulated substances under pressure shall be equipped with an automatic line leak detector in accordance with subdivision 22a-449(d) -104 (f) (1) of these regulations.(E) Other methods of release detection may be used if owners and operators: (i) Demonstrate to the implementing agency that an alternate method can detect a release of the stored substance as effectively as any of the methods allowed in subdivisions 22a-449(d) -104 (e) (2) to (8), inclusive, of these regulations can detect a release of petroleum;(ii) Provide information to the implementing agency on effective corrective action technologies, health risks, and chemical and physical properties of the stored substance, and the characteristics of the UST site; and,(iii) Obtain prior written approval from the implementing agency to use the alternate release detection method before the installation and operation of the new UST system.(F) The provisions of 40 CFR 265.193, Containment and Detection of Releases, may be used to comply with these requirements of subdivision 22a-449(d) -104 (d) (2) of these regulations.(e)Methods of release detection for tanks.Each method of release detection for tanks used to meet the requirements of subsection 22a-449(d) -104 (c) of these regulations shall be conducted in accordance with the following:
(1) Inventory control. The owner or operator of an UST system shall assure that the following information is recorded: on a daily basis, the amount of regulated substances sold, used and received, and the level of water and product in the tank or container; and on a weekly basis, a reconciliation comparing these figures to determine whether an abnormal loss or gain has occurred. Separate records shall be maintained for each system of interconnected tanks or containers and serving pumps or dispensers. The owner or operator shall review such records and attest to their accuracy by signing them no later than seven days following their recording. Inventory control shall also be conducted in the following manner: (A) The equipment used is capable of measuring the level of product over the full range of the tank's height to the nearest one-eighth of an inch;(B) The regulated substance inputs are reconciled with delivery receipts by measurement of the tank inventory volume before and after delivery;(C) Deliveries are made through a drop tube that extends to within one foot of the tank bottom;(D) Product dispensing is metered and recorded within the local standards for meter calibration or an accuracy of 6 cubic inches for every 5 gallons of product withdrawn, except that if the local standards for meter calibration is more stringent than an accuracy of 6 cubic inches for every 5 gallons of product withdrawn, the product dispensing shall be calibrated to the local standards; and(E) The measurement of any water level in the bottom of the tank is made to the nearest one-eighth of an inch at least once a day.(F) The commissioner may require an owner or operator to perform a tank and line tightness test in accordance with subdivisions 22a-449(d) -104 (e) (3) and (f) (2) of these regulations of any UST system for which daily inventory records are not maintained in accordance with the requirements in these regulations;(G) When inventory reconciliation indicates an abnormal loss or gain which is not explainable by spillage, temperature variations or other known causes, the owner or operator shall assure the immediate investigation and correction of the source of the abnormal loss or gain. At a minimum, the owner or operator shall take as many of the steps listed below in subparagraph (i), (ii), and (iii) as necessary to confirm an abnormal loss or gain. In addition, if an abnormal loss or gain is measured during a weekly reconciliation and there were four (4) consecutive days of loss or four (4) consecutive days of gain during the ten (10) day period prior to reconciliation, or abnormal losses or abnormal gains are measured during two consecutive weekly reconciliations, the owner or operator shall take as many of the steps listed below in subparagraph (iv), (v), and (vi) as necessary to confirm an abnormal loss or gain. (i) When an inventory record error is not apparent, a recalculation to determine abnormal loss or gain shall be made starting from a point where records indicate no abnormal loss or gain;(ii) A detailed visual inspection of these components of the facility which are readily accessible for evidence of failure shall be performed;(iii) The dispensers of the particular regulated substances in question shall be checked for proper calibration;(iv) A line tightness test shall be performed on the piping system between the storage tank or container and dispenser(s) in accordance with subdivision 22a-449(d) -104 (f) (2) of these regulations;(v) A tank tightness test shall be performed on all other piping attached to the tank in accordance with subdivision 22a-449(d) -104 (e) (3) of these regulations; and (vi) A line tightness test shall be performed on all other piping attached to the tank in accordance with subdivision 22a-449(d) -104 (f) (2) of these regulations.(H) When an abnormal loss or gain is confirmed, the owner or operator shall immediately report the abnormal loss or gain to the commissioner in accordance with Section 22a-450 of the General Statutes as amended.(I) 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 subdivision 22a-449(d) -104 (e) (1) of these regulations.(2) Manual tank gauging. Manual tank gauging shall meet the following requirements: (A) Tank liquid level measurements are taken and recorded, including date and time of measurements, at the beginning and ending of a period of at least 36 hours during which no liquid is added to or removed from the tank;(B) Level measurements are based on an average of two consecutive stick readings at both the beginning and ending of the period;(C) The equipment used is capable of measuring the level of product over the full range of the tank's height to the nearest one-eighth of an inch;(D) A leak is suspected and subject to the requirements of section 22a-449(d) -105 of these regulations if the variation between beginning and ending measurements exceeds the weekly or monthly standards in the following table: Nominal tank capacity | Weekly standard (one test) | Monthly standard (average of four tests) |
550 gallons or less | 10 gallons . . . . . . . . . | 5 gallons. |
551-1,000 gallons | 13 gallons . . . . . . . . . | 7 gallons. |
1,001-2,000 gallons | 26 gallons . . . . . . . . . | 13 gallons. |
(E) Only tanks of 550 gallons or less nominal capacity may use this as the sole method of release detection. Tanks of 551 to 2,000 gallons may use the method in place of manual inventory control in subdivision 22a-449(d) -104 (e) (1) of these regulations except that this method shall not be used for compliance with the requirements in subdivision 22a-449(d) -104 (e) (4) (B) of these regulations. Tanks of greater than 2,000 gallons nominal capacity shall not use this method to meet the requirements of section 22a-449(d) -104 of these regulations;(F) Daily measurements are taken for any water level in the bottom of the tank to the nearest one eighth of an inch except such measurement for water shall not be required for double wall tanks with interstitial monitoring performed in accordance with subsection 22a-449(d) -104 (e) of these regulations.(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 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. Equipment for automatic tank gauging that tests for the loss of product and conducts inventory control shall meet the following requirements: (A) The automatic product level monitor test can detect a 0.2 gallon per hour leak rate from any portion of the tank that routinely contains product; and(B) Inventory control or another test of equivalent performance is conducted in accordance with the requirements of subdivision 22a-449(d) -104 (e) (1) of these regulations.(5) Vapor monitoring. Testing or monitoring for vapors within the soil gas of the excavation zone shall meet the following requirements: (A) The materials used as backfill are sufficiently porous, including, but not limited to, gravel, sand and crushed rock to readily allow diffusion of vapors from releases into the excavation area;(B) The stored regulated substance, or a tracer compound placed in the tank system, is sufficiently volatile, including, but not limited to, gasoline, to result in a vapor level that is detectable by the monitoring devices located in the excavation zone in the event of a release from the tank;(C) The measurement of vapors by the monitoring device is not rendered inoperative by the ground water, rainfall, or soil moisture or other known interferences so that a release could go undetected for more than 30 days;(D) The level of background contamination in the excavation zone shall not interfere with the method used to detect releases from the tank;(E) The vapor monitors are 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;(F) In the UST excavation zone, the site is assessed to ensure compliance with the requirements in subparagraphs 22a-449(d) -104 (e) (5) (A), (B), (C), and (D) of these regulations and to establish the number and positioning of monitoring wells that shall detect releases within the excavation zone from any portion of the tank that routinely contains product; and(G) Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering.(6) Groundwater monitoring. Testing or monitoring for liquids on the ground water shall meet the following requirements:(A) The regulated substance stored is immiscible in water and has a specific gravity of less than one;(B) Groundwater is never more than 20 feet from the ground surface and the hydraulic conductivity of the soil(s) between the UST system and the monitoring wells or devices is not less than 0.01 cm/sec. The soil shall be a permeable material, including, but not limited to, gravels, coarse to medium sands, coarse silts or other permeable materials;(C) The slotted portion of the monitoring well casing shall be designed to prevent migration of natural soils or filter pack into the well and to allow entry of regulated substance on the water table into the well under both high and low ground-water conditions;(D) Monitoring wells shall be sealed from the ground surface to the top of the filter pack;(E) Monitoring wells or devices intercept the excavation zone or are as close to it as is technically feasible;(F) The continuous monitoring devices or manual methods used can detect the presence of at least one-eighth of an inch of free product on top of the ground water in the monitoring wells;(G) Within and immediately below the UST system excavation zone, the site is assessed to ensure compliance with the requirements in subparagraphs 22a-449(d) -104 (e) (6) (A), (B), (C), (D), and (E) of these regulations and to establish the number and positioning of monitoring wells or devices that shall detect releases from any portion of the tank that routinely contains product; and(H) Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering; and(I) Groundwater samples shall be obtained monthly from each monitoring well and checked by visual and vapor testing methods to determine the presence of a release.(7) 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 can detect a release through the inner wall in any portion of the tank that routinely contains product; (i) The provisions outlined in the Steel Tank Institute's "Standard for Dual Wall Underground Storage Tanks" may be used as guidance for aspects of the design and construction of underground steel double-walled tanks.(B) For UST systems with a secondary barrier within the excavation zone, the sampling or testing method used can detect a release between the UST system and the secondary barrier; (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 m/sec for the regulated substance stored) to direct a release to the monitoring point and permit its detection;(ii) The barrier is compatible with the regulated substance stored so that a release from the UST system shall not cause a deterioration of the barrier allowing a release to pass through undetected;(iii) For cathodically protected tanks, the secondary barrier shall be installed so that it does not interfere with the proper operation of the cathodic protection system;(iv) The ground water, soil moisture, or rainfall shall 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 ground water and not in a 25-year flood plain, unless the barrier and monitoring designs are for use under such conditions; and,(vi) Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering.(C) For tanks with an internally fitted liner, an automated device can detect a release between the inner wall of the tank and the liner, and the liner is compatible with the substance stored.(8) Other methods. Any other type of release detection method, or combination of methods, can be used if the implementing agency gives prior, written approval including any conditions as deemed necessary and if: (A) It can detect a 0.2 gallon per hour leak rate or a release of 150 gallons within a month with a probability of detection of 0.95 and a probability of false alarm of 0.05; or(B) The implementing agency may approve another method if the owner and operator can demonstrate that the method can detect a release as effectively as any of the methods allowed in subdivisions 22a-449(d) -104 (e) (3), (4), (5), (6), (7) and (8) of these regulations. In comparing methods, the implementing agency 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 by the implementing agency on its use to ensure the protection of human health and the environment.(f)Methods of release detection for piping.Each method of release detection for piping used to meet the requirements of subsection 22a-449(d) -104 (c) of these regulations shall be conducted in accordance with the following:
(1) Automatic line leak detectors. Methods which alert the operator to the presence of a leak by restricting or shutting off the flow of regulated substances through piping or 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. An annual test of the operation of the leak detector shall be conducted in accordance with the manufacturer's requirements.(2) Line tightness testing. A periodic test of piping may be conducted only if it can detect a 0.1 gallon per hour leak rate at one and one-half times the operating pressure.(3) Applicable tank methods. Any of the methods in subdivisions 22a-449 (d)-104 (e) (5), (6), (7) and (8) of these regulations may be used if they are designed to detect a release from any portion of the underground piping that routinely contains regulated substances.(g)Release detection recordkeeping.All UST system owners and operators shall maintain records in accordance with subsection 22a-449 (d)-103 (e) of these regulations demonstrating compliance with all applicable requirements of section 22a-449(d) -104 of these regulations. These records shall include the following:
(1) All written performance claims pertaining to any release detection system used, and the manner in which these claims have been justified or tested by the equipment manufacturer or installer, shall be maintained for 5 years beyond the operational life of the UST system;(2) The results of any sampling, testing, or monitoring shall be maintained for at least 5 years beyond the operational life of the UST system; and(3) Written documentation of all calibration, maintenance, and repair of release detection equipment permanently located on-site shall be maintained for at least 5 years beyond the operational life of the UST system. Any schedules of required calibration and maintenance provided by the release detection equipment manufacturer shall be retained for 5 years beyond the operational life of the UST system.Conn. Agencies Regs. § 22a-449(d)-104