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Certification
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Leak
rate of 0.2 gph with PD = 97.2% and PFA = 2.8%
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Leak
Threshold
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0.1
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 may be tested after consultation with the
manufacturer.
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Tank
Capacity
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Maximum
of 20,000 gallons.
Tanks greater than 90% full may not be tested.
Product level must be at least 2 inches above the lowest
temperature sensor.
Minimum product level required is based on tank diameter
as follows:
48" dia/min 10.4";
64" dia/min 13";
96" dia/min 18.4";
120" dia/min 22.4";
144" dia/min 26.4".
For other tank diameters, consult manufacturer.
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Waiting
Time
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Minimum
of 8 hours between delivery and testing.
There must be no delivery during waiting time.
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Test
Period
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Minimum
of 8 hours.
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 magnetostrictive probe
containing 5 temperature sensors.
Sensors located above the product surface are not used
in data analysis.
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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 0.81 inch.
Minimum detectable change in water level is 0.011 inch.
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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.
System consists of a magnetostrictive probe, a micro
processing unit, and a modem that provides a data link
to the home office.
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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