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Issue Date: November 22, 1995
Revision Date: September 22, 2009
Tanknology
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. |
| 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. |
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Tanknology
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Evaluator:
ADA Technologies, Inc.
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11000 North MoPac Expressway, Suite 500
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Tel:
(303) 792-5615
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Austin, TX 78759
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Date of Evaluation:
04/10/92
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Tel: (800) 800-4633
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