X-ray vision isn’t just for superheroes.
Underground utility contractors have it too…or maybe the next best thing:
Advanced Utility Detection Technology.
Our sub-surface infrastructure is
truly a world of its own. A snapshot of a typical urban underground system reveals
a complex network of communications, gas, electric, and water/sewer services
that originated in the early 20th century. It’s quite a challenge to the crews
responsible with its daily maintenance, repair, and upgrades. A construction project, especially in an urban
area, is a potential minefield of utilities and objects that can be ruptured,
dislodged, or broken by excavator activity.
Contractors must know the
locations of these utilities before any
construction project begins as contractors
can’t risk damaging expensive utilities or endangering their work force. Damaging utilities can be costly, leading to cost
overruns and project delays. Records
of a site’s underground utilities may be available but unfortunately, utilities and contractors know that
there is no reliable paper record. In some parts of the country, utilities are
more than 100 years old, and many utilities have been added or abandoned
without being recorded. Even abandoned and
decommissioned utilities can prove dangerous. For example, an old abandoned
natural gas pipeline could have retained significant quantities of flammable
methane that could explode upon contact with an excavator bucket.
construction industry, therefore, heavily relies on various types of
underground detection technologies. The technology helps reduce the guesswork
and can answer questions like what exactly lies in the subsurface of a job
site? Where is it and how deep is it?
Different technologies are required
for detecting metal, plastic, concrete pipes, and fiber cables. Products used
to locate metal or metallic lines are based on electromagnetic (EM) detection,
a technology that has been around for a long time. It is one of the most common
and cost-effective techniques. The locating equipment generates an electromagnetic
radio signal that is directed onto the utility line. It is used to locate lines
that are made of metal or have conductive tracer wire.
The GPR can locate non-metallic material, it often
gets used in applications where the previous electromagnetic methods aren’t
well suited. These units send out an electromagnetic
wave down into the ground; if it hits anything, it sends a signal back in the
form of a reflected wave. One of the benefits of this technology is that
it makes no distinctions in materials. It finds anything that is down there.
This is because GPR reflects off changes in dielectric property between
two materials, like between soil and a PVC pipe. It’s extremely valuable
when you can’t see what you are looking for.
Potholing, digging holes to locate
utilities, is another way to identify buried utilities. It is the most accurate
but by far the costliest method. In addition to the high cost of potholing, the
poorly or undocumented buried utilities can result in many months of project
Buried infrastructure suffers from “out
of sight, out of mind”. A line strike can add thousands of dollars in project
costs and can sometimes be dangerous or even deadly. With the aid of advanced utility technology, like the GPR, utility
contractors to can “see” what is buried underneath.
Here is an example of a
jobsite where GPRS was contacted by an electrical contractor
in Dallas, Texas to locate underground utilities prior to directional boring
for a new underground electric line. GPRS was able to identify and locate
numerous underground utilities including fire waterlines, communication lines,
electric lines, sanitary sewer lines, gas lines, and storm drains in the ground
and mark them on the surface in order for the client to proceed with their work