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Issue Date: December 5, 2002
Engineering Design
Group, Inc.
EDG XLD 2000
Plus (Revision 1.02) Leak Detection System
(MTS DDA Magnetostrictive Probe)
BULK UNDERGROUND STORAGE TANK
LEAK DETECTION METHOD (50,000 gallons or greater)
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Certification |
Leak rate is proportional to product
surface area (PSA).
For tanks with PSA of 12,074 ft², leak rate is 1.92 gph with PD = 95% and
PFA = 5%.
For other tank sizes, leak rate equals [(PSA in ft² ÷ 12,074 ft²) x 1.92
gph].
Example: For a tank with PSA = 1,260 ft²; leak rate = [(1,260 ft² ÷ 12,074
ft²) x 1.92 gph] = 0.2 gph.
Leak rate may not be scaled below 0.2 gph. |
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Leak Threshold |
Leak threshold is proportional to product
surface area (PSA).
For tanks with PSA of 12,074 ft², leak threshold is 0.96 gph
For other tank sizes, leak threshold equals [(PSA in ft² ÷ 12,074 ft²) x
0.96 gph].
Example: For a tank with PSA = 1,260 ft²; leak threshold = [(1,260 ft² ÷
12,074 ft²) x 0.96 gph] = 0.1 gph.
A tank system should not be declared tight if the test result indicates a
loss or gain that equals or exceeds the calculated leak threshold.
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Applicability |
Gasoline, diesel, aviation fuel, fuel oil
#4.
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Tank Capacity |
Use limited to single, field-constructed,
vertical-walled tanks having a capacity of 50,000 to 2,100,000 gallons.
Minimum product surface area (PSA) is 1260 ft².
Maximum product surface area (PSA) is 12,076 ft².
Performance not sensitive to product level. |
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Waiting Time |
Minimum of 30 hours, 18 minutes after
delivery or transfer. |
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Test Period |
Minimum of 40 hours, 12 minutes.
There must be no delivery, transfer, or dispensing during test. |
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Temperature |
Average for product is determined by five
resistance temperature detectors (RTDs) |
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Water Sensor |
Must be used to detect water ingress.
Minimum detectable water level in the tank is 2.655 inches.
For tanks with a PSA of 12,076 ft² and containing 2.665 inches of water,
system takes 52.7 hours to detect a 0.20 gph water ingress rate.
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Calibration |
System must be checked and, if necessary,
calibrated in accordance with manufacturer's instructions. |
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Comments |
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.
Evaluated in nominal 2,100,000 gallon tank with PSA of 12,076 ft² (124 feet
in diameter).
If product temperature change exceeds 1.8 degrees F during test, test will
abort. |
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Engineering Design Group,
Inc. |
Evaluator: Ken Wilcox
Associates |
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Manufacturer’s Previously Listed Contact Information is No
Longer Valid. |
Tel: (816) 443-2494 |
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Date of Evaluation: 11/16/01 |
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