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Certification
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Leak
rate of 0.2 gph with PD = 99.9% and PFA = 0.1%. Leak rate
of 0.1 gph with PD = 96.7% and PFA = 3.3%.
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Leak
Threshold
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0.1
gph for leak rate of 0.2 gph. 0.05 gph for leak rate of
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, waste oil. 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.
Minimum product level required to conduct a test is 18
inches.
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Waiting
Time
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Minimum
of 12 hours, 25 minutes between delivery and testing.
Minimum of 15 minutes between dispensing and testing.
There must be no delivery during waiting time.
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Test
Period
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Minimum
of 3 hours, 15 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 during test.
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Temperature
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Average
for product is determined from the measurement of the
change in the speed of sound.
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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 0.921 inch. Minimum detectable change
in water level is 0.0315 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.
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. Water sensor, temperature sensor and product
level monitor are contained in a single ultrasonic probe.
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. If the
0.1 gph test is used as a tank tightness test there
must be no water present in the backfill (groundwater
must be below the bottom of the tank), the tank must
be equipped with an overfill protection device, and
the product level in the tank must be at the overfill
protection device set point. Local agency pre-approval
is required. To use the 0.1 gph test as a monthly option
see title 23 CCR Section 2643 (b)(2).
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