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Issue Date: November 22, 1995
Revision Date: May 23, 2011
Hasstech
Leak Computer
Tank Test System
VOLUMETRIC TANK TIGHTNESS TEST
METHOD (OVERFILL)
Hasstech is no longer in business.
| Certification |
Leak rate of 0.1
gph with PD = 95% and PFA = 5%. |
| 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.
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| Tank
Capacity |
Maximum of 12,000
gallons.
Tank must be minimum 100% full. |
| Waiting
Time |
Test data are
acquired and recorded by system's computer that calculates a leak rate
every minute, and determines waiting time for satisfactory data (test is
finished when the standard deviation of 30 sequential leak rates is less
than half of the last leak rate determined).
There must be no dispensing or delivery during waiting time. |
| Test
Period |
Minimum of 1
hour, 10 minutes.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from data determined to be valid by statistical
analysis.
There must be no dispensing or delivery of product during test. |
| Temperature |
Average for
product is determined by a minimum of 7 thermistors. |
| Groundwater |
If depth to
groundwater in tank excavation backfill cannot be determined, tank must
pass a two level test with at least a 3 foot difference in product level.
If depth to groundwater in tank excavation backfill can be determined, a
single level test can be conducted provided a minimum net pressure of 1
psi exists at bottom of tank during test. |
| Calibration |
Level sensor must
be calibrated before each test.
Thermistors must be checked and, if necessary, calibrated in accordance
with manufacturer's instructions. |
| Comments |
Not evaluated
using manifolded tank systems.
Evaluated at EPA Edison Risk Reduction Engineering Laboratory prior to the
EPA standard protocols being written.
System no longer being manufactured and no support is available. |
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Hasstech
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Evaluator:
U.S. EPA Risk Reduction
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out of
business
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Engineering
Laboratory
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Tel:
(201) 321-6631
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Date of
Evaluation: 11/88
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