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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)
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 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. |
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Southwest Environmental
Services, Inc.
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Evaluator:
Ken Wilcox Associates
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102 Abigayle Row
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Tel: (816) 443-2494 |
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Scott, LA 70508
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Date
of Evaluation: 03/24/92
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Tel: (337) 235-1184
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