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Alert 8200 Series Sonde
NON-VOLUMETRIC TANK TIGNTNESS TEST METHOD (VACUUM)
Certification
Leak rate of 0.1 gph with PD = 100% and PFA = 0%.
Leak Threshold
A tank system should not be declared tight if the ratio of the ultrasonic signal (when the tank is under vacuum) to the background signal (prior to evacuation) equals or exceeds 1.5 for either 12 kHz or 25 kHz frequency band.
Applicability
Gasoline, diesel, aviation fuel, fuel oil #4, waste oil.
Tank Capacity
Maximum of 30,000 gallons.
Waiting Time
None between delivery and testing.
Test Period
– 2 minutes reference plus 2 minutes test.
– Test data are acquired and recorded by system’s computer.
– There must be no dispensing or delivery during test.
Test Pressure
Minimum of -0.5 psi to a maximum of -2 psi.
Temperature
Acoustic/ultrasonic and background signals are independent of product temperature.
Groundwater
Groundwater level in tank excavation backfill must be determined by observation well or soil probe in tank excavation backfill.
If groundwater level in tank excavation backfill is above bottom of tank or the groundwater level in the tank excavation backfill has not been determined, this method cannot be used.
Comments
Method can also be used on double wall tanks to test the primary tank where a dry interstice is present.
Microphone was 25 ft away from leak source during evaluation.
Although not tested on completely empty tanks, a third party acoustics specialist has certified the device is equally effective when tanks are empty as when tanks contain product.
Test may be inconclusive if there is high background noise.
Vacuum test method may not be effective in some tank excavation backfill (such as clay) because it may plug holes in tank.
More than 4 psi pressure differential across the tank wall at any location in the tank could damage tank.
Alert 8200 Series Sonde
NON-VOLUMETRIC TANK TIGNTNESS TEST METHOD (VACUUM)
Certification
Leak rate of 0.1 gph with PD = 100% and PFA = 0%.
Leak Threshold
A tank system should not be declared tight if the ratio of the ultrasonic signal (when the tank is under vacuum) to the background signal (prior to evacuation) equals or exceeds 1.5 for either 12 kHz or 25 kHz frequency band.
Applicability
Gasoline, diesel, aviation fuel, fuel oil #4, waste oil.
Tank Capacity
Maximum of 30,000 gallons.
Waiting Time
None between delivery and testing.
Test Period
– 2 minutes reference plus 2 minutes test.
– Test data are acquired and recorded by system’s computer.
– There must be no dispensing or delivery during test.
Test Pressure
Minimum of -0.5 psi to a maximum of -2 psi.
Temperature
Acoustic/ultrasonic and background signals are independent of product temperature.
Groundwater
Groundwater level in tank excavation backfill must be determined by observation well or soil probe in tank excavation backfill.
If groundwater level in tank excavation backfill is above bottom of tank or the groundwater level in the tank excavation backfill has not been determined, this method cannot be used.
Comments
Method can also be used on double wall tanks to test the primary tank where a dry interstice is present.
Microphone was 25 ft away from leak source during evaluation.
Although not tested on completely empty tanks, a third party acoustics specialist has certified the device is equally effective when tanks are empty as when tanks contain product.
Test may be inconclusive if there is high background noise.
Vacuum test method may not be effective in some tank excavation backfill (such as clay) because it may plug holes in tank.
More than 4 psi pressure differential across the tank wall at any location in the tank could damage tank.
Volumetric Tank Tightness Test Method (Underfill)
Certification
Leak rate of 0.1 gph with PD = 99.58% and PFA = 0.42% for 1 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, biodiesel blends B6-B20 meeting ASTM D7467, biodiesel B100 meeting ASTM D6751 and water. The principle of mass displacement testing allows the operator to adjust the weight of the test probe in proportion to the specific gravity of the test liquid.
Tank Capacity
Maximum of 30,000 gallons.
Tank must be between 16% (with a fuel height of 14” or more) and 95% full.
Waiting Time
Minimum of 3 hours 41 minutes between delivery and testing.
There must be no delivery during waiting time.
Test Period
– Minimum of 1 hour 28 minutes to achieve PD = 99.58% and PFA = 0.42%.
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 0.2 psi pressure differential between the water table and fuel level at the bottom of tank during test.
If no water table info available, two tests are required at different product heights of different tank pressures.
Calibration
Load cell must be calibrated at least once per year following manufacturers recommended practices, but not necessarily by manufacturer.
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 Pupora Enginerring certification when the test is performed. Recertification is required by the manufactuer every two years.