UST Programs - LG 113

Issue Date: October 19, 2007

Western Fiberglass, Inc.

Liquid-Filled Reservoir for Double-Wall Sumps
with Liquid Sensor Models WF-3 and WF-750

CONTINUOUS INTERSTITIAL MONITORING METHOD (LIQUID FILLED)

Certification:
Certified as a continuous, liquid-filled interstitial space leak detection system for use only with Western Fiberglass, Inc., double-walled sumps or under dispenser containment sumps.
Method can be used on 1 ½ inch diameter Western Fiberglass piping manufactured November 2006 or later.

Operating Principle:
Hydrostatic monitoring using single-level float switch. Methodology is similar to that which has been applied to liquid-filled interstitial double-walled tanks.
Propylene glycol is used to fill the interstice of Western Fiberglass' double-walled sumps or under dispenser containment sumps.
An interstitial liquid reservoir is connected to a port at the highest point of the double-walled space.
Single-level liquid sensor model WF-3 or WF-750 monitor the liquid in the interstitial reservoir and provide an alarm if the liquid drops too low (egress of liquid).

Alarm Conditions:

* Volume of liquid lost to alarm depends on the amount of liquid in the reservoir. This amount is determined by the operator when filling the reservoir. This amount needs to be sufficient to prevent false alarms from occurring due to the normal fluctuations in the reservoir which result from temperature and pressure variations in the sump. Minimum alarm volumes were obtained by filling the reservoir to the lowest possible level to reset the alarm. While this condition provides the shortest response time, it is also subject to the highest false alarm rate.

Calibration:
Reservoir requires no calibration other than to insure the upper reservoir is half full.
Sensors must be calibrated and maintained in accordance with manufacturer's instructions.