Issue Date: November 22, 1995
Revision Date: March 20, 2003

USTest, Inc.

UST 2000/LL


USTest, Inc., no longer supports the use of this method *

Certification Leak rate of 0.1 gph with PD = 98.12% and PFA = 1.88%.
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, water, kerosene.
Tank Capacity Maximum of 15,000 gallons.
Tank must be minimum 15% full.
There must be at least 20 inches and not more than 67 inches of product in the tank.
Waiting Time Ranges from 3 to 12 hours between delivery and testing.
Testing may begin when the rate of product temperature change does not exceed 0.1 degree F per hour.
There must be no dispensing or delivery during waiting time.
Test Period Minimum of 2 hours.
Test data are acquired and recorded by system’s computer, which does a regression analysis to determine the leak rate.
An ultrasonic device is used to measure changes in product level.
There must be no dispensing or delivery during test.
Temperature Average for product is determined from the measurement of the change in the speed of sound.
Groundwater Depth to groundwater in tank excavation backfill must be determined.
If groundwater is above bottom of tank, product level must be adjusted to provide a minimum net pressure of 1 psi at bottom of tank during test.
Calibration Temperature sensors and probes must be checked annually and, if necessary, calibrated 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.

* USTest Inc. has requested removal of the 2000/LL equipment from the NWGLDE List and discourages the use of this method due to software security and data integrity problems.


USTest, Inc.
c/o Dubois, Bryant, Campbell & Schwartz

Evaluator:  Ken Wilcox Associates
Tel:  (816) 443-2494

P.O Box 909

Date of Evaluation:  06/09/94

Austin, TX 78767


Tel: 512-457-8000



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