Issue Date: November 22, 1995
Revision Date: October 5, 2010

Containment Solutions, Inc.

(originally listed as Fluid Containment and O/C Tanks)

Hydrostatic Precision Tank Test for DWT-Type II Tanks

Interstitial Tank Tightness Test Method

Certification Leak rate of 0.1 gph with PD = 99.9% and PFA = 1.2% without dispensing.
Leak rate of 0.1 gph with PD = 95% and PFA = 5.0% with dispensing.
Leak Threshold 0.05 gph without dispensing and 0.07 gph with dispensing.
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, motor oil, biodiesel blends B6-B20 meeting ASTM D7467, biodiesel B100 meeting ASTM D6751*.
Other liquids with known coefficients of expansion and density may be tested after consultation with the manufacturer.
*NWGLDE Listings apply to leak detection functionality only and not material compatibility - see Disclaimer.
Tank Capacity Maximum of 30,000 gallons.
Tank must be between 0 and 100% full. Maximum tank diameter is 10 feet.
Waiting Time Minimum of 24 hours between delivery and testing.
Minimum of 3 hours between "topping off" the annular space with liquid and testing.
There must be no delivery during waiting time.
Test Period Minimum of 4 hours.
A leak is not declared unless the threshold is exceeded in two tests, separated by at least 8 hours which are performed without dispensing and with minimal changes in groundwater elevation above bottom of tank as described below.
Other Limitations Volume of trapped vapor must not exceed 20 gallons.
Change in barometric pressure must be less than 0.04 psia over the 4-hour test period.
Annular space must be at least 100% full with either water or antifreeze.
If groundwater is above bottom of tank, and no product is being dispensed during test, total change in groundwater elevation during test must be less than 1.5 inches per hour.
If groundwater is below bottom of tank or not changing during test, total change in product level during test must be less than 0.75 inch per hour.

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