Certification
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Leak
rate of 0.1 gph with PD = 95% and PFA = 5%.
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Leak
Threshold
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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
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Gasoline,
diesel, aviation fuel, fuel oil #4.
Other liquids with known coefficients of expansion and
density may be tested after consultation with the manufacturer.
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Tank
Capacity
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Maximum
of 12,000 gallons.
Tank must be minimum 100% full.
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Waiting
Time
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Test
data are acquired and recorded by system's computer that
calculates a leak rate every minute, and determines waiting
time for satisfactory data (test is finished when the
standard deviation of 30 sequential leak rates is less
than half of the last leak rate determined).
There must be no dispensing or delivery during waiting
time.
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Test
Period
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Minimum
of 1 hour, 10 minutes.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from data determined to be valid
by statistical analysis.
There must be no dispensing or delivery of product during
test.
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Temperature
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Average
for product is determined by a minimum of 7 thermistors.
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Groundwater
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If
depth to groundwater in tank excavation backfill cannot
be determined, tank must pass a two level test with at
least a 3 foot difference in product level.
If depth to groundwater in tank excavation backfill can
be determined, a single level test can be conducted provided
a minimum net pressure of 1 psi exists at bottom of tank
during test.
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Calibration
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Level
sensor must be calibrated before each test.
Thermistors must be checked and, if necessary, calibrated
in accordance with manufacturer's instructions.
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Comments
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Not
evaluated using manifolded tank systems.
Evaluated at EPA Edison Risk Reduction Engineering Laboratory
prior to the EPA standard protocols being written.
System no longer being manufactured and no support is
available.
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