Validation of the Low-Range Differential Pressure (LRDP) Leak Detection System for Small Leaks in Bulk Fuel Tanks

The Naval Facilities Engineering Service Center (NFESC), Port Hueneme, California, and its industrial partners, Vista Research, Inc. and Vista Engineering Technologies, L.L.C., have demonstrated and validated (DEM/VAL) an innovative mass-based leak detection system for bulk fuel underground storage tanks (USTs). The Low-Range Differential Pressure (LRDP) system is a computer-controlled system that can reliably detect small leaks in bulk USTs ranging in size from 50,000 gal to 12,500,000 gal. As part of this project, it has been evaluated for performance by an independent third party in a 122.5-ft diameter, 2,100,000-gal tank following EPA s standard test procedures. The LRDP meets monthly monitoring and annual precision (tightness) test regulatory compliance requirements using either a 10-h (overnight) or 24-h test. All of the objectives of the project have been met, and the LRDP is ready for commercial use. Both (1) on-line, permanently installed monitoring systems and (2) tightness testing services using the LRDP can be obtained commercially through Vista Research, Inc. The LRDP system achieves a very high level of performance against small leaks because of its high precision (0.0002 in.) and its accurate methods of compensating for the thermal expansion and contraction of the fuel, the instrumentation, and the tank. Because of its innovative design, the LRDP achieves this high level of precision and accuracy with an off-the-shelf, industrial-grade differential pressure sensor. Thus, the LRDP not only delivers high performance, but it is also rugged and field-worthy. The LRDP system is fully automatic and comprises (1) an innovative in-tank level sensing unit, (2) an embedded remote test controller to collect and analyze the data from a test, and (3) a host computer to initiate, report, and archive the results of a test. A test can be initiated by an operator or can be automatically scheduled for a future date and time.
Prepared in collaboration with the Army Corps of Engineers Construction Engineering Research Laboratory (CERL), Champaign, IL, and Vista Research, Inc., Sunnyvale, CA and Edison, NJ.