UST Programs - LG 113

Issue Date: November 22, 1995
Revision Date: January 12, 2015

Triangle Environmental, Inc.

TEI Ullage Test, Version 1.0 (Vacuum Test)

NON-VOLUMETRIC TANK TIGHTNESS TEST METHOD (ULLAGE)

Certification	Leak rate of 0.1 gph with PD = 100% and PFA = 0%.
Leak Threshold	A tank system should not be declared tight when an increase in the acoustic noise level (above background) of the tank under vacuum is detected due to air or water ingress.
Applicability	Gasoline, diesel, aviation fuel, fuel oil #4. Other liquids may be tested after consultation with the manufacturer.
Tank Capacity	Maximum ullage volume is 15,000 gallons. Microphone should be located within 24 feet of all points within the ullage.
Waiting Time	None if test is conducted after the underfilled tank test.
Test Period	Minimum of 1 minute. There must be no dispensing or delivery during test.
Test Pressure	Vacuum of 1 psi must be maintained in ullage. If vacuum cannot be maintained, see manufacturer's instructions.
Temperature	Acoustic signal is independent of product temperature.
Groundwater	Depth to the groundwater in tank excavation backfill must be determined. If groundwater is above product level, vacuum must be adequate to detect an ingress of groundwater.
Calibration	Sensors must be calibrated before each test in accordance with manufacturer's instructions.
Comments	Manifolded tank systems must be isolated prior to test. Evaluated using unleaded gasoline. Tests only ullage portion of tank. Product-filled portion of tank must be tested using an underfill test method. Microphone was 24 feet away from the leak source during evaluation. Headphones are used during test to listen for the signal of air ingress. Noise signals are tape recorded (not digitally recorded). Test method may not be effective in some tank excavation backfill (such as clay) because it may plug holes in tank. If soil is saturated with product, air or water ingress may not be declared by vacuum test. A well point in tank excavation backfill may help identify presence of this condition.

Triangle Environmental, Inc.
3726 Park Place. Burbank, CA 91020
Tel: (818) 301-7777

Evaluator: United States Testing Co. Inc.
Tel: (213) 723-7181
Date of Evaluation: 05/05/93

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