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Safe
Excavation
The Need
Excavating with a
backhoe or similar equipment has the potential risk of
hitting an underground utility which could cause serious
injuries and expensive damages. Contractors usually rely on
utility companies or other professional services to mark the
area where cables or pipes are buried. But without being
able to know the depth and exact position of the line.
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The Occupational
Safety and Health Administration - OSHA - estimated that the
fatality rate was at 50.8 deaths per 100,000 workers per
year from 1984 to 1988. The National Institute of
Occupational Safety and Health estimated that at least 127
persons were killed as a result of all excavation-related
accidents (Huang et al. 1996). |
The Technology
An electronic device
that provides a real-time warning of the utility lines
immediately ahead of the digging tool and provides an easily
interpreted, real-time computer readout of the depth,
location, and size buried metallic objects. Developed by Dr.
Leonhard E. Bernold, it consists of an active metal detector
search coil; a signal processing (control) unit; and a PC
computer equipped with an analog-to-digital converter
interface.
The active metal detector
generates a magnetic field. Its impact on any metal object
in its detection range is picked up by the control unit. The
data is converted from analog to digital at a high sampling
rate and transmitted to the computer. The computer receives
real-time data about magnetic changes in the detector
vicinity, graphs it on the screen, sounds a signal, and
stores it in a file for future analysis.
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The Benefits
The device helps in
the detection and location of hidden underground cables, gas
pipes, toxic waste drums and even bombs. It is a portable
system that can be attached to backhoes, trenchers and other
digging equipment. |
Status
The system is ready
for implementation but the designer is looking for investors
and a production contract. An actual job site application of
the system has not yet occurred. An enhanced device is being
developed that can detect plastic-coated utility cables and
fiber-optic telephone lines. |
Barriers
The cost of the
system is the current major barrier because of the lack of a
production contract. The device will not detect plastic
pipes or objects that do not have a metallic component. The
detection depth or range of the system is limited by the
capacity of the active metal detector. |
Points of Contact
Leonhard Bernold, Associate Professor of
Civil Engineering, North Carolina State University, Raleigh, NC. (919)
515-3677
References
- Huang, X., Bernd, D., and Bernold, L.E. "Equipment
Mounted Buried Utility Detection System"
- Huang, X., Bernd, D., and Bernold, L.E. "Innovative Technology Development for Safe
Excavation," Journal of
Construction Engineering and Management, Vol. 122, No. 1, March, 1996.
- "New N.C. State Device Uncovers: Hidden
Dangers Underground?" North Carolina State University News Release,
August 16, 1995.
Disclaimer Statement
Neither
the Construction Safety Alliance 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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