UST Programs - LG 113

Issue Date: November 22, 1995
Revision Date: December 6, 2002

Tanknology - NDE

UST Ullage Test, Version U2 (Pressure Test)

NON-VOLUMETRIC TANK TIGHTNESS TEST METHOD (ULLAGE)

Certification	Leak rate of 0.1 gph with PD = 95.24% and PFA = 0%.
Leak Threshold	A tank system should not be declared tight when the pressure decay trend equals or exceeds ± 0.016 psi/hr.
Applicability	Gasoline, diesel, aviation fuel, fuel oil #4. Other liquids may be tested after consultation with the manufacturer.
Tank Capacity	Maximum ullage volume is 10,260 gallons.
Waiting time	Minimum of 2 hours between delivery and testing.
Test Period	Minimum of 30 minutes (after data trend has been established). There must be no dispensing or delivery during test.
Test Pressure	Total pressure of 4.0 psi must be applied at bottom of tank.
Temperature	Ullage must be monitored during test, and a correction factor is applied to account for temperature changes. If ullage temperature changes exceed 5 degrees F, test must not be conducted.
Groundwater	Depth to groundwater in tank excavation backfill must be determined. If groundwater is above product level, net pressure must be maintained at a minimum of 1 psi in the ullage during test.
Comments	Not evaluated using manifolded tank systems. Evaluated using diesel. Tests only ullage portion of tank. Product-filled portion of tank must be tested using a volumetric underfill test method.

Tanknology - NDE	Evaluator: ADA Technologies, Inc.
8900 Shoal Creek Blvd. , Building 200	Tel: (303) 792-5615
Austin , TX 78757	Date of Evaluation: 04/10/92
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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