Issue: August 23, 1999
Revision Date:  December 29, 2011

Mass Technology Corp.

Precision Mass Measurement Systems SIM-1000 and CBU-1000 (72 hour test)


Certification Leak rate is proportional to product surface area (PSA). 
For tanks with PSA of 14,200 ft², leak rate is 0.638 gph with PD = 95% and PFA = 5%. 
For other tank sizes, leak rate equals [(PSA in ft² ÷ 14,200 ft²) x 0.638 gph]. 
For a tank with PSA = 20,000 ft²; leak rate = [(20,000 ft² ÷ 14,200 ft²) x 0.638 gph] = 0.898 gph.
Leak Threshold Leak threshold is proportional to product surface area (PSA). 
For tanks with PSA of 14,200 ft², leak threshold is 0.319 gph. 
For other tank sizes, leak threshold equals [(PSA in ft² ÷ 14,200 ft²) x 0.319 gph].
For a tank with PSA = 20,000 ft²; leak threshold = [(20,000 ft² ÷ 14,200 ft²) x 0.319 gph] = 0.449 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, ethanol blends up through E100, diesel, aviation fuel, fuel oil #4.
Tank Capacity Use limited to single field-constructed vertical tanks.
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 8 minutes to 42.5 hours.
Test Period Minimum of 72 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.

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 2,000,000 gallon, vertical underground tank with product surface area (PSA) of 14,200 ft².

Averaging of multiple test may be used to improve the performance of the system.


Mass Technology Corp.

Evaluator:  Ken Wilcox Associates

P. O. Box 1578

Tel:  (816) 443-2494

Kilgore, TX 75663

Dates of Evaluation:  03/25/98, 05/19/11

Tel:  (903) 986-3564



 | Home | Vendors: A - F | Vendors: G - M | Vendors: N - S | Vendors: T - Z | Method Index | Glossary |

Appearance on this list is not to be construed as an endorsement by any regulatory agency nor is it any guarantee of the performance of the method or equipment.
Equipment should be installed and operated in accordance with all applicable laws and regulations.  For full details, please refer to our expanded "DISCLAIMER" page.