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Certification
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Leak
rate of 0.1 gph with PD = 99.95% and PFA = 0.05%.
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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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Minimum
of 6 hours between delivery and testing. Minimum of 3
hours between "topping off" and testing.
Total minimum waiting time is 6 hours.
There must be no delivery or dispensing during waiting
time.
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Test
Period
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Minimum
of 1 hour, 40 minutes (33 minutes monitor mode and 1 hour,
7 minutes test mode).
At the conclusion of test mode, data are checked for the
manufacturer's stop test criteria.
If data do not meet the criteria, testing must continue.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from last 1 hour, 7 minutes of
test period data.
There must be no dispensing or delivery during test.
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Temperature
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Average
for product is determined by a resistance temperature
detector (RTD).
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Groundwater
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Depth
to groundwater in tank excavation backfill must be determined.
If groundwater is above bottom of tank, product level
must be adjusted to provide net pressure of 2-4 psi at
bottom of tank.
Groundwater level must be stable prior to and during test.
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Calibration
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Load
cell must be calibrated in accordance with manufaturer's
instructions before each use.
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Comments
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Not
evaluated using manifolded tank systems.
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