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Issue
Date: February 17, 1998
Revision Date: May 5, 2003
Warren
Rogers Associates, Inc.
WRA
Statistical Inventory Analysis, Version 5.2
STATISTICAL
INVENTORY RECONCILIATION TEST METHOD (QUANTITATIVE)
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Certification
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Leak
rate of 0.1 gph with PD = 99.9% and PFA = 0.1%
"If a method meets the requirement for detecting
a leak rate of 0.1 gph, it will meet the requirement for
0.2 gph.", according to "Standard Test Procedures
for Evaluating Leak Detection Methods: Statistical Inventory
Reconciliation Methods", EPA/530/UST-90/007, June
1990, Section 7.2.3, page 30.
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Leak
Threshold
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If
the absolute value of the calculated leak rate (gain or
loss) is less than the leak threshold and the minimum
detectable leak rate is less than or equal to 0.1 gph
(0.2 gph for the 0.2 gph test), the test result is "pass."
If the absolute value of the calculated leak rate is greater
than or equal to the leak threshold, the result is "fail."
If the minimum detectable leak rate exceeds 0.1 gph (0.2
gph for the 0.2 gph test) and the absolute value of the
calculated leak rate is less than the leak threshold,
the test result is "inconclusive."
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Applicability
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Gasoline,
diesel.
Other more viscous liquids may be tested after consultation
with the vendor.
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Tank
Capacity
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Maximum
of 36,000 gallons for single tank.
Maximum of 36,000 gallons cumulative capacity for manifolded
tank systems with no more than 3 tanks in system.
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Data
Requirement
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Minimum
of 30 days of product level and flow through data.
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Comments
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50%
of data sets evaluated were from manifolded tanks systems.
82 data sets were submitted for evaluation.
All were analyzed with conclusive results.
Median monthly throughput of tanks evaluated was 52,207
gallons.
Median monthly throughput of separate manifolded tank
system evaluation was 14,944 gallons. Leak rates of 0.05,
0.10, and 0.20 gph were used in evaluation.
All manifolded tank system data sets evaluated were supplied
by evaluator.
A portion of the data sets drawn from the WRA Statistical
Inventory Analysis Version 5.1 evaluation for tanks that
were not manifolded, were provided by the vendor.
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Warren
Rogers Associates, Inc.
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Evaluator: Ken Wilcox Associates
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747
Aquidneck Ave.
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Tel
: (816) 443-2494
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Middletown, RI 02840
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Date
of Evaluation: 12/08/97
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Tel:
(401) 846-4747
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| E-mail:
info@wraenviro.com |
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| URL:
www.wraenviro.com |
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