Issue Date: March 27, 2018
Leighton O’Brien
Dry Test (Pressure Decay Test)
NON-VOLUMETRIC TANK TIGNTNESS TEST METHOD (ULLAGE)
Certification |
Leak rate of 0.1 gph with PD = 100% and PFA = 0%. |
Leak Threshold |
A tank system should not be declared tight when the pressure decay trend results in an indication of failure or inconclusive on the test apparatus screen.
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Applicability |
Gasoline, diesel, aviation fuel, fuel oil #4, biodiesel blends B6-B20 meeting ASTM D7467, biodiesel B100 meeting ASTM D6751. |
Tank Capacity |
Maximum tank volume evaluated is 20,000 gallons. Larger tanks may be tested provided that the Test Period is correspondingly increased by extrapolation. |
Waiting Time |
Not evaluated. |
Test Period |
Average is 15 minutes with tank filled to 5%
Average is 6 minutes with tank filled to 50%
Average is 3 minutes with tank filled to 95%
There must be no dispensing or delivery during test. |
Test Pressure |
Proprietary. |
Temperature |
Not evaluated. |
Groundwater |
Depth to groundwater in tank excavation backfill must be determined.
If groundwater is above product level, net test pressure must be increased by 2.2 psi (15 kPa) in the ullage during the test. |
Comments |
Not evaluated using manifolded tank systems.
Evaluated using unleaded fuel calibrated orifice.
Tests only ullage portion of tank.
Product-filled portion of tank must be tested using a volumetric underfill test method. |
Leighton O’Brien |
Evaluator: Ken Wilcox Associates |
3rd Floor, 20 Council Street |
Tel: (816) 443-2494 |
Hawthorn East, Victoria, Australia 3123 |
Dates of Evaluation: 12/01/2016 |
Tel: +61 3 9804 220 |
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E-mail: info@leightonobrien.com |
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URL: www.leightonobrien.com |
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