Issue Date: November 22, 1995
Revision Date: February 6, 2015

Purpora Engineering, Inc.

(originally listed by Alert Technologies, Inc.)

Alert Model 1000

Volumetric Tank Tightness Test Method (Underfill)

Certification Leak rate of 0.1 gph with PD = 98.2% and PFA = 1.8% for 2 hour test.
Leak rate of 0.1 gph with PD = 99.8% and PFA = 0.2% for 4 hour test.
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.
Other liquids may be tested after consultation with the manufacturer.
Tank Capacity Maximum of 30,000 gallons.
Tank must be between 20 and 95% full.
Waiting Time Minimum of 1 hour between delivery and testing.
Minimum of 1 minute between dispensing and testing.
There must be no delivery during waiting time.
Test Period Minimum of 2 hours to achieve PD = 98.2% and PFA = 1.8%.
Minimum of 4 hours to achieve PD = 99.8% and PFA = 0.2%.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from the data determined to be valid by statistical analysis.
There must be no dispensing or delivery during test.
Temperature System measures product mass (which is not affected by temperature) instead of product volume.
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 2 psi at bottom of tank during test.
Calibration Load cell must be calibrated before each test.
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.
The manufacturer does not support test results if the technician does not hold a current Alert Technologies certification when the test is performed. Recertification is required by the manufacturer every two years.

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