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Certification
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Leak
rate of 0.2 gph with PD = 95.1% and PFA = 2.7%.
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Leak
Threshold
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0.13
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 75,000 gallons.
Tank must be between 50 and 95% full.
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Waiting
Time
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Minimum
of 7.3 hours between delivery and testing.
Minimum of 2 hours between dispensing and testing.
There must be no delivery during waiting time.
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Test
Period
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Minimum
of 24 hours.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from the average of subsets
of all data collected.
There must be no dispensing or delivery during test.
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Temperature
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Average
for product is determined by 5 temperature resistance
detectors (RTDs).
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Water
Sensor
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Must
be used to detect water ingress.
Minimum detectable water level in the tank is 0.238
inch.
Minimum detectable change in water level is 0.017
inch.
Water level in tank should not exceed 2 inches.
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Calibration
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Probe
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. Therefore,
this certification is only applicable when there
is a probe used in each tank and the siphon is broken
during testing.
Tests only portion of tank containing product.
As product level is lowered, leak rate in a leaking
tank decreases (due to lower head pressure). Consistent
testing at low levels could allow a leak to remain
undetected.
EPA leak detection regulations require testing of
the portion of the tank system which routinely contains
product.
California regulations
require at least one test per month after routine
product delivery or when the tank is filled to within
10% of the highest operating level of previous month.
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