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Issue
Date: April 18, 1997
Revision Date: May 23, 2011
Tidel
Engineering, Inc.
Tidel
Environmental Monitoring System, EMS 4000
(Ultrasonic Probe #312-9000)
AUTOMATIC
TANK GAUGING METHOD
Tidel Engineering, Inc. no longer manufactures or supports the use of this method.
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Certification
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Leak
rate of 0.2 gph with PD = 97.4% and PFA = 2.6% for 2 hour
test.
Leak rate of 0.2 gph with PD = 99.9% and PFA = 0.1% for
4 hour test.
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Leak
Threshold
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0.1
gph for leak rate of 0.2 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 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 between dispensing and testing.
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 = 97.4% and PFA = 1.8% for leak
rate of 0.2 gph.
Minimum of 4 hours to achieve PD = 99.9% and PFA = 0.1%
for leak rate of 0.2 gph.
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 1.045 inches.
Minimum detectable water level change is 0.053 inch.
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Calibration
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Gain
adjustment on probe must be checked annually 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.
This is a longer version of model #312-9001.
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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Tidel
Engineering, Inc.
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Evaluator: Ken Wilcox Associates
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2025 West Beltline Road, #114
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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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