Issue Date: September 19,
June 27, 2011
and MCX Pipe Monitoring System
Liquid Filled Interstitial Space
CONTINUOUS INTERSTITIAL MONITORING METHOD (LIQUID
Certified as a continuous, liquid-filled interstitial space leak detection
system for use only with Ameron Dualoy 3000/LCX and MCX fiberglass double-wall
pipe. Applicable liquids include water and aqueous solutions of brine
(i.e., CaCl and NaCl) or glycols (e.g., propylene) in concentration sufficient
to reduce evaporation and prevent liquid from freezing in any portion of the
monitoring system under extremes of local temperature conditions.
Maximum length is 344 feet.
No restrictions on pipeline diameter.
Similar to the methodology that has been applied to liquid-filled interstitial
An applicable liquid solution is used to fill the pipeline interstice.
A vacuum may be placed on the interstice to assist as applicable liquid is filled from the
low point in the pipeline to minimize trapped air.
The reservoir is the high point of the system and is open or vented at the top
and contains a dual-point level sensor.
The dual-point level sensor system monitors the liquid level in the interstitial
reservoir and provides an alarm if the liquid level is either too high (ingress
of liquid) or too low (egress of liquid).
The method must be used with a dual-point sensor system that will properly fit
into the reservoir, is compatible with the interstitial liquid, and is on the
NWGLDE list. The spacing between the high and low sensors must be at least 10
Sensors can be used to shut down the turbine system and/or alert the operator
that a potential problem exists.
For a leak rate of 0.10 gph in to or out of the interstice, the maximum time to
alarm for a 10-inch sensor spacing with a reservoir diameter of 3.33 inches is
This method declares a pipeline to be leaking when the loss or gain of
applicable liquid in
the 3.33 inch reservoir is 0.311 gallons.
The change in level in the reservoir is proportional to the volume of fluid
flowing into or out of the interstice. It is cumulative and therefore not
dependent on the rate of fluid gain or loss.
Time to alarm is based on evaluations conducted using a 30% CaCl2 (brine)
solution and a leak (liquid egress) 341 feet from the reservoir.
Equivalent results are expected for other applicable liquids.
Time to alarm for a catastrophic primary pipe failure with a pressure of 38 psi
is 8 seconds at a distance of 2.14 feet from the reservoir and 10.48 minutes at
a distance of 341 feet. This is based on a liquid level change of 10” or 0.311
gallons in a reservoir that measures 12 inches in height and 3.33 inches in
underground double-walled piping as specified above containing gasoline,
gasohol, diesel, heating oil #2, kerosene, aviation fuel, or motor oil.
Other liquids may be stored after consultation with the manufacturer.
Equipment requires no calibration other than an annual inspection.
The electronics must be calibrated and maintained in accordance with the
sensor/monitoring equipment instructions.
System must be designed and installation done in accordance with the
instructions provided by the manufacturer.
Direct burial of pipeline fittings and reservoir is permitted provided the
reservoir has an observation manway at grade level.
The liquid level in the reservoir must be at least 12 inches above the water
The interstice must be filled from the low point in the pipeline to minimize
The evaluation was conducted in an Ameron, double-wall, fiberglass pipeline with
an interstitial capacity of 12.97 gallons, an inside diameter of 2.22 inches,
and a length of 344 feet.
The alarm conditions are based on a rise or fall of 10 inches of applicable
liquid in a
reservoir that is 3.33 inches in diameter and 12 inches in length.
Installers must be certified by both the piping and sensor manufacturer.
Texoma Engineering Services, LLC
1004 Ameron Rd.
Evaluator: Ken Wilcox Associates
Tel: (816) 443-2494
Date of Evaluation: 11/08/09