Issue Date: November 22, 1995
Revision Date: April 4, 2007

USTest, Inc.
(previously listed as Sound Products Manufacturing, Inc.)

UST 2000/U 
(Pressure and Vacuum Test)


Certification Leak rate of 0.1 gph with PD = 100% and PFA = 0%.
Leak Threshold A tank system should not be declared tight when there is a substantial increase in the acoustic noise signal (when the tank is under pressure or vacuum) above the background signal (prior to pressurization or evacuation) in the frequency interval of 10 kHz to 20 kHz. 
The acoustic signal to noise ratio is preprogrammed into the system's computer and is not revealed to or adjustable by the operator.
Applicability Gasoline, diesel, aviation fuel, fuel oil #4, waste oil. 
Equipment is not in contact with the product.
Tank Capacity Maximum ullage volume is 7,550 gallons for pressure test and 5,250 gallons for vacuum test.
Waiting Time None if test is conducted after an underfilled tank tightness test.
Test Period Minimum of 15 minutes (includes collection of background information).
There must be no dispensing or delivery during test.
Test Pressure Net pressure of 2.0 psi or vacuum of 1.0 psi must be maintained in ullage.
Temperature Acoustic signal is independent of product temperature.
Groundwater Depth to groundwater in tank excavation backfill must be determined. 
If groundwater is above product level, vacuum test must not be used. 
Pressure test must be conducted using net pressure exceeding 2.0 psi in the ullage.
Calibration Test equipment must be checked and, if necessary, calibrated by tester before each test.
Comments Not evaluated using manifolded tank systems. 
Evaluated using unleaded gasoline as test product. 
Tests only ullage portion of tank. 
Product-filled portion of the tank must be tested using an underfill test method. 
Microphone was less than 8 feet, 6 inches from the leak source during evaluation. 
If the background noise is too high, test is inconclusive. 
Maximum background noise is preprogrammed into system's computer and not revealed to or adjustable by the technician. 
Vibration due to nearby equipment or dripping condensation may interfere with test. 
Vacuum 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.


Southwest Environmental Services, Inc.

Evaluator:  Ken Wilcox Associates

102 Abigayle Row Tel:  (816) 443-2494

Scott, LA  70508

Date of Evaluation:  03/24/92

Tel:  (337) 235-1184



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