Issue
Date: August 23, 1999
Revision Date: December 4, 2002
Vista
Research, Inc.
Model
LT-100a Monthly Monitoring Method and Line Tightness Test
Method Version 1.0
(Segmented Method)
LARGE
DIAMETER LINE LEAK DETECTION METHOD (6 inches diameter or
above)
Certification
|
Leak
rate of 0.2 gph at 50 psi with PD > 97% and PFA <
3% for Monthly Monitoring Method.
Leak rate of 0.1 gph at 50 psi with PD = 97% and PFA =
3% for Line Tightness Test Method.
The USEPA has not set a minimum detectable leak
rate for large diameter pipeline systems (airport hydrant
systems) at the time of this evaluation.
|
Leak
Threshold
|
0.174
gph for leak rate of 0.2 gph.
0.074 gph for leak rate of 0.1 gph.
A pipeline system should not be declared tight if the
test result indicates a loss that equals or exceeds this
threshold.
|
Applicability
|
Gasoline,
diesel, aviation fuel, fuel oil #4.
Other liquids may be tested after consultation with the
manufacturer.
|
Specification
|
System
tests fiberglass or steel piping.
Tests are conducted at operating pressure to a maximum
of 200 psi.
|
Pipeline
Capacity
|
Maximum
of 3,400 gallons.
|
Waiting
Time
|
None
between delivery and testing.
None between dispensing and testing.
|
Test
Period
|
Minimum
of 2 hours after setup and after pipeline is fully isolated.
Test data are acquired and recorded by a microprocessor.
Calculations are automatically performed by the microprocessor.
|
System
Features
|
System
may be permanently installed on pipeline to perform monthly
monitoring or line tightness testing, or may be transported
and set up to perform line tightness testing.
A single 2-hour test is required consisting of two 5-minute
monitoring segments at atmospheric pressure spaced 25
minutes apart, and two 5-minute monitoring segments at
operating pressure spaced 25 minutes apart.
Discrete test method (Monthly Monitoring Method only).
Preset threshold.
Printed message and alarm activation if leak is declared.
|
Calibration
|
System
must be calibrated in accordance with manufacturer's instructions
during system setup.
|