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UST(Underground
Storage Tanks) Leak Detection System
The Need
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Low range differential pressure (LRDP) leak
detection system used to detect leaks in underground storage tanks (UST) was developed by
Vista Research, Inc. This leak detection and monitoring system is used for
early detection of small leaks in bulk fuel UST’s. The technology works independently
of the tank size and rate of leakage as low range differential pressure (LRDP) system is a
mass-based. If a tank is leaking, the LRDP
quantitatively measures the leak rate in gallons per hour underground storage tanks (UST).
It works by measuring the differential pressure changes in the tank over time. |
The Technology
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The LRDP system consists of an in-tank sensor
unit to make the measurements, a local controller to implement and analyze the data from a
test, and a host computer to initiate, report, and archive the results of a test. The LRDP
is also being integrated in the DoD Fuels Automated System (FAS) so that it is compatible
with DoD bulk storage facilities. The key
component of the LRDP system is a vertical reference tube that spans the full usable
height of the tank. The fuel in the tank is allowed to enter or leave the reference
tube through a valve located at the bottom of the tube. When the tank is to be tested, the
valve is closed, isolating the fuel in the tube from the fuel in the rest of the tank.
With the exception of a level change due to a leak, the level of the fuel in the reference
tube mimics the level of the fuel in the tank. The differential pressure sensor, which is
placed in a sealed container at the bottom of the tube (and tank), is used to detect very
small level (pressure) changes between the fuel in the tube and the fuel in the tank.
Thus, when the valve is closed, the differential pressure sensor directly senses and
quantifies the fuel level changes due to a leak, if a leak is present. This mass-based
system achieves a very high level of performance against small leaks because of (1) its
high precision and (2) its inherent method of compensating for the thermal expansion and
contraction of the fuel in the tank. The system has a
precision of 0.0002 in. for a single level measurement and a sensitivity to measure volume
changes as small as 0.03 gal/h in a 100-ft-diameter tank. This high degree of precision is
obtained because the differential pressure sensor does not have to operate over the entire
height of the tank (e.g., 20 ft). Thus, the LRDP not only delivers high performance, but
it is also rugged and field-worthy. 
Schematic and
installation photographs of the LRDP system. |
The Benefits
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- Fully automatic
- Used for on-line monitoring and tightness testing
- Can be permanently installed
- Much lower probability of false
- Better detection sensitivity than other methods
- Computer controlled system that is easily installed and
operated
- Can also be used as mobile systems, trucked in for periodic
tests
- Once integrated, can be used to test all of the tanks in a
fuel farm or bulk storage terminal
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Status
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The LRDP system was developed by the Naval
Facilities Engineering Service Center (NFESC) and its industrial partner, Vista Research,
Inc., and is being readied for commercial use under the DOD program called the
Environmental Security Technology Certification Program (ESTCP). The ESTCP program is
designed to demonstrate and validate new, innovative technologies that can be used to
address environmental and regulatory problems at all DOD military facilities. |
Points of Contact
- Mr. Brian Rustia, Environmental
Technology Evaluation Center (EvTEC), 1015 15th Street NW
Suite 600, Washington, DC 20005, Tel: (202)842-0555, Fax: (202)789-2943, E-Mail: brustia@cerf.org
- Mr. Mike Fierro, Product
Manager, Vista Research,
Inc., 755 North Mary Avenue, Sunnyvale, CA 94086, Tel: (408)830-3300, E-Mail: info@vrinc.com, MFierro@vrinc.com,
- Mr. Hayter, Gary, Vista Research, Inc.E-Mail: GHayter@vrinc.com
References
- Civil Engineering Research Foundation (CERF), Environmental
Technology Evaluation Center (EvTEC), Vista Research UST Leak Detection
Technology
- Vista Research, Inc. <http://www.vistaenvironmental.com/html/tank_sys_montor.html>
- J. W. Maresca, Jr. and J. W. Starr, "The LRDP System for
Detection of Leaks in Bulk Storage Tanks," Final Report, Naval Facilities Engineering
Service Center, Vista Research, Inc. March 1998.
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
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