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May 5,
2004
Subject:
The Relationship of a 3 Gallon Per Hour @ 10 Pounds Per Square Inch
Orifice for Catastrophic LLD Testing and the Pressures LLD Equipment
Perform Their Test At.
To
Whom It May Concern:
The
question has been raised as to; Why is the fluid flow (leak) higher
during an annual test of line leak detection equipment than the fluid
flow during the calibration process to establish a 3 GPH @ 10 PSI leak.
This question is a good one as it appears the test equipment is somehow
passing a higher flow than the regulation allows. To answer the
question we need to look at the regulations and how they have been
understood.
EPA
regulations state that Catastrophic Line Leak Detection Equipment must
be capable of detecting a line leak defined as 3 GPH @ 10 PSI.
Additionally, testing of the line leak detection device is required
annually (section 280.44 Methods of Release Detection for Piping).
The
regulations do not state the leak detection device must search
for a leak at 10 PSI, nor do they state that the leak detection
device must detect a 3 GPH leak at the pressure
the
device is testing the line at. What is defined is the size of
leak (or hole) the device must detect when a leak search is attempted.
No two
line leak detection devices search for a leak at the same pressure, some
search @ 24-30 PSI, some at 18-22 PSI, some @ 12-15 PSI and some search
@ 8-12 PSI. This is of course assuming you have a standard 30 PSI
submersible pump. If there is a high pressure pump installed, these
pressures slide up in relationship to the submersible pressure.
Conversely, when a lower pressure submersible is used, the scale slides
down.
This
was understood from the beginning of the certification process for all
line leak devices. When a third party evaluator performs the evaluation
work on line leak detection equipment the hole size is made to pass the
fluid through at a rate of 3 GPH at a standard pressure of 10 PSI. Once
the hole size has been calibrated, the portion of the test device that
limited the flow to 10 PSI is removed, and the device tests at what ever
pressure it tests at. It must then detect the hole (or orifice) that
was previously calibrated. A review of a KWA certification outlines
this and a call to a third party certifier (such as KWA) will confirm
this.
I hope
this brings some clarity to the apparent higher flow when line leak
detection devices search for leaks above 10 PSI.
Sincerely,
Steve
Wilson
Vaporless Manufacturing Inc.
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