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Issue
Date: August 23, 1999
Revision Date: December 4, 2002
Vista
Research, Inc.
Model
HT-100-n Monitoring Method and Line Tightness Test Method
Version 1.0, Version 1.1
LARGE
DIAMETER LINE LEAK DETECTION METHOD (6 inches diameter or
above)
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Certification
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Leak
rate of 0.004%÷ v¯(n) of line capacity in
gph with PD = 95% and PFA = 1.25% for Version 1.0, where
n is the number of tests averaged together (smallest leak
rate for Version 1.0 evaluation, which was conducted on
a 306,477 gallon line at 160 psi where n = 3, was 7.08
gph).
Leak rate of 0.00209%÷ v¯(n) of line capacity
in gph with PD = 95% and PFA = 5% for Version 1.1, where
n is the number of tests averaged together (smallest leak
rate for Version 1.1 evaluation, which was conducted on
a 306,477 gallon line at 160 psi where n = 3, was 3.71
gph).
The USEPA has not set a minimum detectable leak
rate for large diameter pipeline systems (airport hydrant
systems) at the time of this evaluation.
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Leak
Threshold
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0.00282%
÷ v¯(n) of line volume in gph for Version
1.0. 0.000916% ÷ v¯(n) of line volume in gph
for Version 1.1.
A pipeline system should not be declared tight if the
test result indicates a loss that equals or exceeds these
thresholds.
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Applicability
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Gasoline,
diesel, aviation fuel, fuel oil #4.
Other liquids may be tested after consultation with the
manufacturer.
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Specification
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System
tests fiberglass or steel piping.
Tests are conducted at operating pressure to a maximum
of 200 psi.
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Pipeline
Capacity
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Maximum
of 612,954 gallons.
Minimum of 3,000 gallons.
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Waiting
Time
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None
between delivery and testing.
None between dispensing and testing.
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Test
Period
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Minimum
of 3 hours, 10 minutes after setup and after pipeline
is fully isolated.
Test data are acquired and recorded by a microprocessor.
Calculations are automatically performed by the microprocessor.
Averaging of individual tests, where tests may be selected
over any time frame yet not necessarily consecutive.
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System
Features
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System
may be permanently installed on pipeline to perform monitoring,
or may be transported and set up to perform line tightness
testing.
A single 3-hour 10-minute test is required consisting
of a 1-hour 10-minute monitoring period at operating pressure,
and a 2-hour monitoring period at atmospheric pressure.
System measures change in volume and reports output quantity
in gph, while compensating for thermal effects. Printed
message and alarm activation if leak is declared.
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Calibration
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System
must be calibrated in accordance with manufacturer's instructions.
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Comments
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System
is to be used only on large bulk pipelines and airport
hydrant fueling systems.
This evaluation utilized a total of 87 tests, one with
an induced leak rate of 13.1 gph.
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Vista
Research, Inc.
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Evaluator:
Ken Wilcox Associates
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755
North Mary Ave.
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Tel:
(816) 443-2494
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Sunnyvale,
CA 94085
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Date
of Evaluation: 11/24/98
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Tel:
(408) 830-3300
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