Issue Date: August 23, 1999
Revision Date:  May 28, 2008

Mass Technology Corp.

Precision Mass Measurement Systems SIM-1000 and CBU-1000 (48 hour test)


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]. 
For a tank with PSA = 4,000 ft²; leak rate = [(4,000 ft² ÷ 6,082 ft²) x 0.294 gph] = 0.19 gph.
Leak rate may not be scaled below 0.2 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].
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. 
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.

Evaluator:  Ken Wilcox Associates

P. O. Box 1578

Tel:  (816) 443-2494

Kilgore, TX 75663

Date of Evaluation:  03/25/98

Tel:  (903) 986-3564



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