Issue Date: November 22, 1995
Revision Date: September 22, 2009


UTS-4T Ullage Test (Pressure Test)


Certification Leak rate of 0.1 gph with PD = 95.24% and PFA = 0%.
Leak Threshold A tank system should not be declared tight when the make-up gas flow rate into ullage equals or exceeds 0.275 cubic feet/hour.
Applicability Gasoline, diesel, aviation fuel, fuel oil #4.
Tank Capacity Maximum ullage volume is 7,500 gallons.
Waiting time Minimum of 2 hours between delivery and testing.
Test Period Minimum of 20 minutes, consisting of 2 consecutive 10-minute test periods. 
Test data are acquired and recorded manually.
There must be no dispensing or delivery during test.
Test Pressure Pressure must be increased in ullage such that total pressure at bottom of tank does not exceed 5.0 psi.
Pressure must be maintained for a minimum of 5 minutes per 1,000 gallons of ullage. 
At conclusion of this stabilization period, ullage pressure must be reduced by 0.5 psi for remainder of test.
Temperature Ullage must be monitored for rate of temperature change, which must not exceed manufacturer's tabulated values.
Groundwater Depth to groundwater in tank excavation backfill must be determined. 
If groundwater is above product level, net pressure must exceed 1 psi in the ullage during test. 
If this requires more than 5 psi total pressure at tank bottom, the ullage test must not be used.
Comments Not evaluated using manifolded tank systems. Evaluated using diesel. Tests only ullage portion of tank. Product-filled portion of tank must be tested using a volumetric underfill test method.



Evaluator:  Midwest Research Institute

11000 North MoPac Expressway, Suite 500

Tel:  (816) 753-7600

Austin, TX 78759

Date of Evaluation:  12/04/92

Tel: (800) 800-4633



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