UST Programs - LG 113

Issue Date: November 22, 1995
Revision Date: November 21, 2002

Tanknology - NDE

Sure Test - Assured Tight System, Series IV

VOLUMETRIC TANK TIGHTNESS TEST METHOD (UNDERFILL)

Certification	Leak rate of 0.1 gph with PD = 99.99% and PFA = 0.005%.
Leak Threshold	0.05 gph. A tank system should not be declared tight if the test result indicates a loss or gain that equals or exceeds this threshold.
Applicability	Gasoline, diesel, aviation fuel, fuel oil #4. Other liquids with known coefficients of expansion and density may be tested after consultation with the manufacturer.
Tank Capacity	Maximum of 18,000 gallons. Tank must be between 11 and 95% full.
Waiting Time	Minimum of 6 hours between delivery and testing. None between dispensing and testing. There must be no delivery during waiting time.
Test Period	Minimum of 3 hours. Test data are acquired and recorded by system's computer. Leak rate is calculated from average of subsets of all collected data. There must be no dispensing or delivery during test.
Temperature	Average for product is determined by temperature sensor probes. A minimum 12 inches of product must be present for the temperature probes to operate properly.
Groundwater	Depth to groundwater in tank excavation backfill must be determined. If groundwater is above bottom of tank, product level must be adjusted during test to provide a minimum net pressure of 1 psi at bottom of tank during test.
Calibration	Temperature probes and floats must be checked for proper operation prior to each test in accordance with manufacturer's instructions.
Comments	Not evaluated using manifolded tank systems. Tests only portion of tank containing product. As product level is lowered, leak rate in a leaking tank decreases (due to lower head pressure). Consistent testing at low levels could allow a leak to remain undetected. EPA leak detection regulations require testing of the portion of the tank system which routinely contains product.

Tanknology - NDE	Evaluator: ADA Technologies
8900 Shoal Creek Blvd. , Building 200	Tel: (303) 792-5615
Austin , TX 78757	Date of Evaluation: 09/09/92
Tel: (800) 800-4633

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Equipment should be installed and operated in accordance with all applicable laws and regulations.
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