Mass
Technology Corp.
Precision
Mass Measurement Systems SIM-1000 and CBU-1000 (48 hour test)
BULK
UNDERGROUND STORAGE TANK LEAK DETECTION METHOD (50,000 gallons
or greater)
Certification |
Leak
rate is proportional to product surface area (PSA).
For tanks with PSA of 6,082 ft², leak rate is 0.294 gph
with PD = 95% and PFA = 5%.
For other tank sizes, leak rate equals [(PSA in ft² ÷
6,082 ft²) x 0.294 gph].
Example:
For a tank with PSA = 4,000 ft²; leak rate = [(4,000 ft²
÷ 6,082 ft²) x 0.294 gph] = 0.19 gph. |
Leak
Threshold |
Leak
threshold is proportional to product surface area (PSA).
For tanks with PSA of 6,082 ft², leak threshold is 0.147
gph.
For other tank sizes, leak threshold equals [(PSA in ft²
÷ 6,082 ft²) x 0.147 gph].
Example:
For a tank with PSA = 4,000 ft²; leak threshold = [(4,000
ft² ÷ 6,082 ft²) x 0.147 gph] = 0.1gph.
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. |
Applicability |
Gasoline,
diesel, aviation fuel, fuel oil #4.
Other liquids may be tested after consultation with the
manufacturer. |
Tank
Capacity |
Use
limited to single field-constructed vertical tanks.
Maximum product surface area (PSA) is 6,082 ft² (approximately
88 ft diameter).
Performance not sensitive to product level. |
Waiting
Time |
Minimum
of 1 hour, 6 minutes after delivery or dispensing.
Valve leaks and pump drain-back may mask a leak.
Allow sufficient waiting time to minimize these effects.
Waiting times during evaluation ranged from 62 minutes
to 31 hours. |
Test
Period |
Minimum
of 48 hours.
There must be no dispensing or delivery during test. |
Temperature |
Measurement
not required by this system. |
Water
Sensor |
None.
Water leaks are measured as increase in mass inside tank. |
Calibration |
Differential
pressure sensor must be checked regularly in accordance
with manufacturer's instructions. |
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 a nominal 600,000 gallon, vertical underground
tank with product surface area (PSA) of 6,082 ft². |
Mass
Technology Corp.
P.
O. Box 1578
Kilgore,
TX 75663
Tel:
(903) 986-3564
E-mail: info@mtctesting.com
URL: www.mtctesting.com |
Evaluator:
Ken Wilcox Associates
Tel:
(816) 443-2494
Date
of Evaluation: 07/31/06 |
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