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UST Program - LG 113

UST Programs - LG 113

Mass Technology Corp.

Precision Mass Measurement Systems SIM-1000 and CBU-1000 (24 hour test)


Certification Leak rate is proportional to product surface area (PSA). 
For tanks with PSA of 1,257 ft² or less, leak rate is 0.1 gph with PD = 97.9% and PFA = 2.1%. 
For tanks with larger PSA, leak rate equals [(PSA in ft² ÷ 1,257 ft²) x 0.1 gph]. 
For a tank with PSA = 2,000 ft²; leak rate = [(2,000 ft² ÷ 1,257 ft²) x 0.1 gph] = 0.16 gph. 
Calculated minimum detectable leak rate is 0.078 gph with PD = 95% and PFA = 5%. 
Leak rate may not be scaled below 0.1 gph.
Leak Threshold Leak threshold is proportional to product surface area (PSA). 
For tanks with PSA of 1,257 ft² or less, leak threshold is 0.05 gph. 
For tanks with larger PSA, leak threshold equals [(PSA in ft² ÷ 1,257 ft²) x 0.05 gph]. 
For a tank with PSA = 2,000 ft²; leak threshold = [(2,000 ft² ÷ 1,257 ft²) x 0.05 gph] = 0.08 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.
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 3,143 ft² (approximately 63 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 24 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 120,000 gallon, vertical underground tank with product surface area (PSA) of 1,257 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:  03/25/98

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