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Issue
Date: April 18, 1997
Revision Date: September 11, 1998
Tidel
Engineering, Inc.
Tidel
Environmental Monitoring System, 3500 Series
(Ultrasonic Probes #401-0009, #401-0010, #401-0023)
AUTOMATIC
TANK GAUGING METHOD
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Certification
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Leak
rate of 0.2 gph with PD = 95.3% and PFA = 4.7% for 2 hour
test.
Leak rate of 0.2 gph with PD = 99.5% and PFA = 0.5% for
4 hour test.
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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 15,000 gallons.
Tank must be between 50 and 95% full.
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Waiting
Time
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Minimum
of 2 hours, 29 minutes between delivery and testing.
Minimum of 15 minutes after dispensing.
There must be no delivery during waiting time.
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Test
Period
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Minimum
of 2 hours to achieve PD = 98.6% and PFA = 1.4%.
Minimum of 4 hours to achieve PD = 99.5% and PFA = 0.5%.
Test data are acquired and recorded by the microprocessor
contained within the EMS console.
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 1.48 inches.
Minimum detectable water level change is 0.035 inch.
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Calibration
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Temperature
sensors and ultrasonic 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.The water sensor, temperature sensor, and product
level monitor are contained in a single ultrasonic probe.
Not evaluated using manifolded tank systems.
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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Tidel
Engineering, Inc.
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Evaluator: Ken Wilcox Associates
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2310
McDaniel Dr.
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Tel: (816) 443-2494
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Carrollton
,
TX
75006
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Date
of Evaluation:
03/16/95
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Tel: (800) 678-7577
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