Xerxes Truchek Interstitial Monitoring for Double Wall FRP Tank
The petroleum equipment industry, tank owners and UST regulators have come to define continuous monitoring as a leakdetection method which uses a constant vacuum, air pressure or hydrostatic pressure on the interstice of a double-wall tank, pipe or sump. When Xerxes customers choose TRUCHEK, the interstice is factory filled with an environmentally safe brine solution, creating a small hydrostatic pressure on both tank walls. The brine solution level is then monitored within a tank top reservior for any change in level, either up or down.
TRUCHEK® Continuous Monitoring – When you order a Xerxes double-wall tank with the TRUCHEK option, the interstice between the two tank walls is factory-filled with calcium-chloride fluid that also partially fills a tank-top reservoir. This innovative design creates a hydrostatic pressure throughout the interstice, thereby monitoring both tank walls on a continuous basis. An electronic probe placed in the tank’s reservoir alarms when the fluid level falls below or rises above the acceptable level. The alarm system is compatible with SCADA communications systems for 24/7 monitor reporting. TRUCHEK also provides a precise and reliable method to perform a tank-tightness test that meets the strict NFPA 329 criteria.
10-Hour Test Procedure – Using a 10-hour tightness-test procedure while the tank is not in use, TRUCHEK is capable of detecting a loss of liquid in the tank at a rate of 0.05 gallons per hour with a 99% probability of detection (PD) and a 1% probability of false alarm (PFA). This meets the strict NFPA 329 criteria.
4-Hour Test Procedure – A shorter 4-hour test, which allows product dispensing, is capable of detecting a loss of liquid in the tank at a rate of 0.05 gallons per hour with a 95% probability of detection (PD) and a 5% probability of false alarm (PFA). This shorter test exceeds EPA’s criteria for a tank-tightness test stating that a test must be able to detect a leak rate of 0.1 gallon per hour with a 95% PD and 5% PFA.