ATCP 93.515(1)(a)(a) Leak detection methods for tank systems shall meet the requirements of this section.
ATCP 93.515(1)(b)
(b) The leak detection test information reports submitted to the department, or maintained on site as required in s.
ATCP 93.500 (9), shall include at least all of the following:
ATCP 93.515(1)(b)1.
1. Site information including the name of the business, the street address, and the municipality in which the site is located.
ATCP 93.515(1)(b)2.
2. Tank system information including the department-assigned tank identification number, the site identification number designated by the owner or operator, the tank capacity, the product in the tank, the type of pipe system, and whether there are pipe manifolds in the tank system.
ATCP 93.515(1)(b)3.
3. Test method information including the name of the method or equipment used, the material approval number as issued under s.
ATCP 93.130, the date the test was performed, the threshold value used to declare a leak, the rate of volumetric change, whether the final result was a pass or fail, and the name and certification of the technician performing the test.
ATCP 93.515(2)(a)(a)
General methodology. Inventory control that is used as the leak detection method shall be conducted in accordance with API 1621 and with this subsection.
ATCP 93.515(2)(b)
(b)
Prescriptive requirements. Product inventory control shall be conducted monthly and reconciled to detect a leak rate of at least 0.5 percent of throughput on a monthly basis, in the following manner:
ATCP 93.515 Note
Note: A leak rate of 0.5 percent is equal to 5 gallons out of every 1,000 gallons of throughput.
ATCP 93.515(2)(b)1.
1. Inventory volume measurements for inputs, withdrawals, and the amount still remaining in the tank shall be recorded each operating day.
ATCP 93.515(2)(b)2.
2. The equipment used shall be capable of measuring the level of product over the full range of the tank's height to the nearest one-eighth of an inch.
ATCP 93.515(2)(b)3.a.a. The inputs shall be reconciled with delivery receipts by measurement of the tank inventory volume before and after delivery.
ATCP 93.515(2)(b)3.b.
b. Where tanks are interconnected by a manifold, reconciliation may address all of the interconnected tanks as a group rather than as individual tanks.
ATCP 93.515(2)(b)4.
4. The measurement of any water level in the bottom of the tank shall be electronically or manually gauged to the nearest one-eighth of an inch at least once a month and recorded.
ATCP 93.515(2)(c)
(c)
Product losses. Tank systems that exceed the losses allowed under par.
(b) for 2 consecutive months shall follow the requirements in ss.
ATCP 93.575 to
93.585 for assessing and responding to a release.
ATCP 93.515(2)(d)
(d)
Precision tightness test. A precision tightness test shall be performed in accordance with sub.
(4) within 10 business days of notification from the authorized agent or the department for any of the following reasons:
ATCP 93.515(2)(d)1.
1. Failure to provide monthly inventory control data for the past 12 months.
ATCP 93.515(2)(d)2.
2. Incomplete or inconsistent data entry reflected during any 2 months of data entry out of the most recent 3 months of inventory control record keeping.
ATCP 93.515(3)(a)1.1. Manual tank gauging may be used as the sole method of leak detection for tanks that have a capacity of 1,000 gallons or less for the life of the tank.
ATCP 93.515(3)(a)2.
2. For tanks that have a capacity of more than 1,000 gallons to 2,000 gallons, manual tank gauging may be used if all of the following conditions are met:
ATCP 93.515(3)(a)2.a.
a. The tank system has a precision tightness test performed in accordance with sub.
(4) at least once every 5 years from the date of installation until the tank is ten years old.
ATCP 93.515(3)(a)2.c.
c. The piping either receives an annual precision tightness test or has electronic line leak detection testing, and this tightness test or leak detection testing is performed in accordance with the capabilities specified in s.
ATCP 93.130 (3) (b).
ATCP 93.515(3)(a)3.
3. Tanks which have a capacity of more than 1,000 gallons to 2,000 gallons and which are more than 10 years old shall be provided with monthly monitoring in accordance with sub.
(5),
(6), or
(7).
ATCP 93.515(3)(a)4.
4. Tanks that have a capacity of more than 2,000 gallons may not use manual tank gauging as the method of required leak detection.
ATCP 93.515(3)(b)
(b)
Manual tank gauging procedures. Manual tank gauging shall meet all of the following requirements:
ATCP 93.515(3)(b)1.
1. Liquid level measurements shall be taken with a gauge stick that is marked to measure the liquid to the nearest one-eighth of an inch over the full range of the tank's height.
ATCP 93.515(3)(b)2.
2. Tank liquid level measurements shall be taken at the beginning and ending of the test duration periods given in Table 93.515, during which no liquid may be added to or removed from the tank and shall be based on the average of 2 stick readings taken at both the beginning and ending of the period.
ATCP 93.515(3)(b)3.
3. A leak is suspected and subject to the requirements of ss.
ATCP 93.575 to
93.585 if the variation between beginning and ending measurements exceeds the weekly or monthly standards in Table 93.515.
Table 93.515
1 Requires precision tightness testing every 5 years. This method is only allowed until the tank is 10 years old.
ATCP 93.515(4)(a)
(a) Precision tightness testing shall be conducted in one of the following ways:
ATCP 93.515(4)(a)1.
1. By a certified tank system tightness tester, using methods approved under s.
ATCP 93.130 to perform precision tightness testing for tanks or piping.
ATCP 93.515 Note
Note: The approval criteria in s.
ATCP 93.130 include capability of detecting a leak rate of 0.1 gallons per hour.
ATCP 93.515(4)(a)2.
2. With permanently installed leak detection equipment as approved under s.
ATCP 93.130 to perform precision tightness testing for tanks or piping.
ATCP 93.515(4)(b)
(b) Where a certified tank system tightness tester is used, the tester shall include the date and the beginning and end times in the test results report.
ATCP 93.515(4)(c)
(c) Precision tightness testing of double-wall underground product piping shall include testing of both the inner and outer wall.
ATCP 93.515(4)(d)
(d) Precision tightness testing shall be recorded on the department's tank precision tightness testing form, TR-WM-152, or line tightness testing form, TR-WM-125, as applicable and shall be maintained onsite in accordance with s.
ATCP 93.500 (9) (a). Alternative forms may be used with the permission of the department.
ATCP 93.515(5)
(5)
Automatic tank gauging. Automatic tank gauging shall meet all of the following requirements:
ATCP 93.515(5)(a)1.1. No more than 30 days may elapse between monthly monitoring tests using an automatic tank gauge.
ATCP 93.515(5)(a)3.
3. An automatic tank gauge shall be placed in the center of the tank and no closer than 12 inches from the fill pipe and the submersible pump.
ATCP 93.515(5)(b)
(b) Automatic tank gauges shall be provided with a printer that provides at least all of the following information:
ATCP 93.515(5)(b)3.
3. The measured leak rate in gallons per hour and whether this leak rate indicates a pass or a fail.
ATCP 93.515(5)(b)4.
4. The specific identification of the tank, associated piping, or sumps used for interstitial monitoring that are being tested.
ATCP 93.515(5)(c)
(c) Automatic tank gauges shall be programmed to provide an audible and visual alarm in the event of a tank or line test failure, a periodic monthly tank or line test not performed within a 30-day interval, or a tank or line interstitial sensor actuation. Manual operator action shall be needed to silence the alarm.
ATCP 93.515(6)(a)2.
2. Be capable of detecting a leak rate of 0.2 gallon per hour or a release of 150 gallons within 30 days; and
ATCP 93.515(6)(a)3.
3. Use a threshold that does not exceed one-half the minimum detectable leak rate.
ATCP 93.515(6)(b)
(b) Tank systems or portions of tank systems using statistical inventory reconciliation as the primary method of leak detection shall be monitored and evaluated for leaks at least every 30 days with a conclusive result of pass or fail within the 30-day monitoring period.
ATCP 93.515(6)(c)
(c) The daily tank system product inventory records shall be kept current and shall be maintained on site.
ATCP 93.515(6)(d)
(d) Tank product level measurements shall be recorded using an electronic inventory probe or an automatic tank gauge.
ATCP 93.515(6)(e)
(e) The operator shall have an effective process to submit their data to the vendor according to the vendor requirements for producing an evaluation report within the 30-day monitoring period.
ATCP 93.515(6)(f)
(f) The statistical inventory reconciliation vendor shall analyze the data and supply an evaluation report to the operator within the 30-day monitoring period.
ATCP 93.515(6)(g)
(g) If the result of the 30-day monitoring period is inconclusive or missing, another method of leak detection shall be used to determine a conclusive pass or fail for that monitoring period.
ATCP 93.515(6)(h)
(h) If during the initial 30-day monitoring period, a conclusive result has not been obtained, another method of leak detection shall be used to determine a conclusive pass or fail for that monitoring period.
ATCP 93.515(6)(i)
(i) Operators using statistical inventory reconciliation shall review the vendor summary report within 24 hours of receipt. If the summary report indicates a failure, the operator shall take immediate action in accordance with the requirements in ss.
ATCP 93.575 to
93.585 for assessing and responding to a leak or release.
ATCP 93.515(6)(j)
(j) Statistical inventory reconciliation may not be used as a method of precision tightness testing.
ATCP 93.515(6)(L)
(L) Before changing from another method of leak detection to statistical inventory reconciliation, the operator shall provide the department with proof that precision testing was performed in accordance with sub.
(4) within the previous 12 months, showing the tank system to be liquid-tight.
ATCP 93.515(7)
(7)
Interstitial monitoring. Interstitial monitoring between an underground tank system and a secondary barrier immediately around it may be used only if the system is installed and maintained to detect a leak from any portion of the tank that could contain product, and the system meets one of the following requirements:
ATCP 93.515(7)(a)
(a)
System testing. Post-installation testing shall be performed on the interstitial monitoring system to verify that the system operates in accordance with the manufacturer's specifications.
ATCP 93.515(7)(b)
(b)
Double-walled systems. For double-walled systems, the sampling or testing method shall be capable of detecting a leak through the inner or outer wall in any portion of the tank or piping that routinely contains product.
ATCP 93.515(7)(c)1.1. For tank systems with an internally fitted liner, a monitoring system shall be installed that is capable of detecting a leak between the inner wall of the tank and the liner.
ATCP 93.515(7)(d)
(d)
Systems with a barrier in the excavation zone. Systems with a secondary barrier within the excavation zone shall meet all of the following requirements:
ATCP 93.515(7)(d)1.
1. The testing method shall be capable of detecting a leak between the system and the secondary barrier.
ATCP 93.515(7)(d)2.
2. The secondary barrier around the system shall consist of manufactured material which is impermeable to at least 10
-6 cm/sec for the regulated substance stored, and which will direct a leak to the monitoring point, to be detected.
ATCP 93.515(7)(d)4.
4. 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.
ATCP 93.515(7)(d)5.
5. The test method shall be designed, installed, and maintained so groundwater, soil moisture, and rainfall do not render the method inoperative, so that a leak could go undetected.
ATCP 93.515(7)(d)6.
6. The site shall be investigated to ensure that the secondary barrier is always above groundwater and not in a 25-year flood plain, unless the barrier and monitoring designs are for use under such conditions.
ATCP 93.515(7)(d)7.
7. Monitoring wells shall be clearly marked and secured to avoid unauthorized access and tampering.
ATCP 93.515(7)(e)
(e)
Interstitial monitoring sensors. Interstitial monitoring sensors shall be capable of providing an audible or visual alarm in the event of a tank or line interstitial sensor actuation. Manual operator action shall be needed to silence the alarm.
