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


Computerized VPLT Testing System


Certification Leak rate of 0.1 gph with PD = 99.9% and PFA = 0.1%.
Leak Threshold 0.05 gph. 
A tank system should not be declared tight if the test result indicates a loss or gain that equals or exceeds this threshold.
Applicability Gasoline, diesel, aviation fuel, fuel oil #4, waste oil.
Tank Capacity Maximum of 18,000 gallons. Tank must contain minimum 24 inches of product.
Waiting Time Must be long enough between delivery and testing to ensure a temperature change of less than 0.09 degrees F per hour, typically a minimum of 2 hours. 
None between dispensing and testing. There must be no delivery during waiting time.
Test Period Minimum of 2 hours. 
Test data are acquired and recorded by system's computer. 
Leak rate is calculated from average over data window. 
There must be no dispensing or delivery during test.
Temperature Average for product is typically determined by 5 thermistors. 
A minimum of 1 thermistor is required.
Groundwater Depth to groundwater in tank excavation backfill must be determined. 
If groundwater is above bottom of tank, product level must be adjusted to provide a minimum net pressure of 1 psi at bottom of tank during test.
Calibration Thermistors must be checked annually and, if necessary, calibrated in accordance with manufacturer's instructions.
Comments Not evaluated using manifolded tank systems. 
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. 
EPA leak detection regulations require testing of the portion of the tank system which routinely contains product.



Evaluator:  Ken Wilcox Associates

11000 North MoPac Expressway, Suite 500

Tel:  (816) 443-2494

Austin, TX 78759

Date of Evaluation:  02/15/93

Tel: (800) 800-4633



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