Issue Date: August 23, 1999
Revision Date: December 21, 2005
Varec, Inc.
(originally listed as Coggins Systems, Inc. and later as Endress + Hauser Systems and Gauging)
Fuels Manager with Barton Series 3500 ATG (48 hour test) (72 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 2.0 gph with PD = 97.8% and PFA = 2.2% for 48 hour test and PD = 98.5% and PFA = 1.5% for 72 hour test. For other tank sizes, leak rate equals [(PSA in ft² ÷ 6,082 ft²) x 2.0 gph]. Example: For a tank with PSA = 10,000 ft²; leak rate = [(10,000 ft² ÷ 6,082 ft²) x 2.0 gph] = 3.29 gph. Calculated minimum detectable leak rate is 1.59 gph with PD = 95% and PFA = 5% for 48 hour test and 1.44 gph with PD = 95% and PFA = 5% for 72 hour test. 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 1.0 gph. For other tank sizes, leak threshold equals [(PSA in ft² ÷ 6,082 ft²) x 1.0 gph]. Example: For a tank with PSA = 10,000 ft²; leak threshold = [(10,000 ft² ÷ 6,082 ft²) x 1.0 gph] = 1.64 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. Other liquids may be tested after consultation with the manufacturer. |
| Tank Capacity | Use limited to single field-constructed vertical tanks 50,000 gallons or greater. Maximum product surface area (PSA) is 15,205 ft². Performance not sensitive to product level. |
| Waiting Time | Minimum of 12 hours, 20 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 7.3 to 17.2 hours. |
| Test Period | Minimum of 48 hours (48 hour test). Minimum of 72 hours (72 hour test). 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 | The differential pressure sensor must be checked regularly and, if necessary, calibrated 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. |
- Varec, Inc.
5834 Peachtree Corners East
Norcross, GA 30092
Tel: (770) 447-9202 - Evaluator: Ken Wilcox Associates
Tel: (816) 443-2494
Date of Evaluation: 05/20/98
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