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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)
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Certification
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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.
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Leak
Threshold
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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.
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Applicability
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Gasoline,
diesel, aviation fuel, fuel oil #4, waste oil.
Other liquids may be tested after consultation with the
manufacturer.
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Tank
Capacity
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Maximum
of 30,000 gallons.
Tank must be between 20 and 95% full.
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Waiting
time
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Minimum
of 1 hour between delivery and testing.
Minimum of 1 minute between dispensing and testing.
There must be no delivery during waiting time.
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Test
Period
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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.
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Temperature
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System
measures product mass (which is not affected by temperature)
instead of product volume.
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Groundwater
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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.
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Calibration
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Load
cell must be calibrated before each test.
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Comments
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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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Purpora Engineering, LLC
P.O. Box 80265
Saukville, WI 53080
Tel: (800) 352-2011
E-mail: info@purporaengineering.com
URL: www.purporaengineering.com |
Evaluator: Midwest Research Institute
Tel: (816) 753-7600
Date of Evaluation: 03/11/91
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