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Issue Date: November 22, 1995
Revision Date: November 6, 1997
Western Environmental
Resources
AES System II
(Large Tanks)
VOLUMETRIC TANK TIGHTNESS TEST
METHOD (OVERFILL)
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Certification |
Leak rate of 0.1
gph with PD = 98.9% and PFA = 1.1%. |
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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. |
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Applicability |
Gasoline, diesel,
aviation fuel, fuel oil #4. |
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Tank Capacity |
Maximum of 75,000
gallons.
Tank must be minimum 100% full. |
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Waiting Time |
Minimum of 24
hours after delivery. Between "topping off" and beginning test, waiting time
is computer-dictated by real-time analysis of level and temperature data and
must be minimum of 1 hour.
There must be no dispensing or delivery during waiting time.
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Test Period |
Minimum of 4
hours.
Test data are acquired and recorded by system’s computer.
Leak rate is calculated from the last 3 hours of test period data.
There must be no dispensing or delivery during test. |
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Temperature |
Average for
product is determined by a minimum of 12 thermistors. |
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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 2 psi at bottom of the tank during test.
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Calibration |
Level sensors
must be calibrated before each test in accordance with manufacturer's
instructions.
Thermistors must be checked annually and, if necessary, calibrated in
accordance with manufacturer's instructions. |
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Comments |
Not evaluated
using manifolded tank systems. |
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Western Environmental
Resources |
Evaluator: Ken Wilcox
Associates |
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PO Box 37 |
Tel: (816) 443-2494 |
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Bakersfield, CA 93302 |
Date of Evaluation: 02/28/92 |
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Tel: (805) 326-0173 |
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