Underground Construction - October 2020 - 34

2020 CAPABILITIES GUIDE
SPECIAL ADVERTISING SECTION

Preventing Damage To Underground Infrastructure
Constructing and repairing underground outside
plant infrastructure are complex tasks that involve
multiple factors. One of the most critical factors is
how to safely avoid damaging existing buried pipes,
conduits, and cables.
While the Common Ground Alliance (CGA)
publishes a Best Practices Guide recognized as
the most comprehensive guideline for preventing
damage to underground facilities, and despite
technological advancements made in preventing
damage to buried infrastructure, accidental utility
hits continue to happen on daily basis.
These incidents can cause significant issues resulting in the disruption of essential services, property
damage, costly delays in construction, and serious
injuries-even death. Their aftermath often includes
litigation with costly legal fees and, sometimes, judgments that can force a contractor out of business.
Identifying the presence of utilities on job sites
during the planning stages is an important first step
in preventing utility hits. Utilizing the One-Call locating service is the first step in locating and marking
buried pipe and cable prior to excavation or boring.
However, the crew that arrives on a utility construction site has no role in the One-Call notification and
marking process. It is all arranged and executed by
others. Therefore, the foreman or supervisor of a
project must not blindly assume that paint and flags
marking buried infrastructure are, in fact, accurate.
Supervisors and crew members must have what
we call "underground awareness"-making themselves aware of what is underground and out of sight.

OCTOBER 2020 | UCONonline.com

Awareness of the underground means nothing
can be taken for granted.
Locations of nearby utilities may be marked,
but are the markings accurate? Are there utilities
present that were not marked? Failure to
consider these possibilities can have serious
consequences. Inaccurate locates and markings
continue to be a leading cause of accidental
damage to utilities. There are times that the
One-Call process fails, and marking is not done
before a construction crew arrives.
Never begin excavating, trenching, boring,
or drilling without knowing locations of
existing utilities.
A careful visual inspection of the job site may
reveal indications that other utilities are present.
Gas meters, electrical boxes, and communications
pedestals could mean there are buried lines.
Even when locations are confirmed, it often is
necessary to pothole-physically digging a small
hole to visibly confirm the exact location of a
pipe or cable-when adjacent utilities parallel or
cross the path of the new installation. Even if flag
or paint markings are accurate, personnel must
understand that all utility providers are not OneCall members and in many areas, water and sewer
lines may not be marked.
Also, on-site personnel should be aware of
tolerances required for depths of new installations
and distances they should be away from existing
facilities. Local codes and ordinances may be
applicable. Depending on local requirements, new
installations must be either 18 or 24 inches from
a utility already in place. Locations of most utilities
usually are measured from the outer edge, assuming the width is represented accurately by marks or
the size of utility is provided and that single painted
lines represent the center of the utility.
When a project is outside public right-of-way
or the work location is on private property such as
educational institutions, government complexes, or
business parks, One-Call will not make locates and
the responsibility falls on the property owner, primary contractor, and sometimes the utility contractor.
Regardless of who locates and marks buried
facilities, many contractors have found it's worth
the time and effort to confirm the locations with
their own personnel and locating equipment.
When locating responsibilities fall on them, they
must have the equipment to do the job or hire a
locating specialist.
Electromagnetic locators are the primary
locating tool used by utilities, contract locators,

and underground construction contractors.
Electromagnetic locators are relatively easy to
operate and when correctly used, are accurate.
An electromagnetic system consists of a handheld
receiver and small transmitter.
The operator walks above where utilities are
expected to be, and the receiver locates underground pipe and cable by detecting magnetic fields
created by electrical current passing through the
lines. Information is displayed on a window at the
top of the receiver.
For communications cable and metallic pipe,
the small transmitter is connected to cable or pipe
and sends current through the line to create a signal
which is detected by the receiver. For plastic pipe
with tracer wire, the wire is energized by the transmitter to provide a signal that the receiver can pick up.
Electromagnetic equipment has advanced
significantly in the past several years. For example,
the Subsite® UtiliGuard® 2 utilizes GPS positioning
and has an Ambient Interference Measurement
(AIM™) feature that scans the surrounding area for
noise that could interfere with the locating signal
and recommends the best frequencies to make
the fastest, most accurate locate. The system
provides both horizontal location and depth
of the line being located.
The first step in preventing accidental
underground strikes is education. Following the
guidelines put forth in the CGS's Best Practices
Guide (available online at commongroundalliance.
com) is key. This will not only reduce the risk of
damaging utility infrastructure, it will reduce the
risk of injury to construction personnel and the
general public. Avoiding shortcuts and reliance
on others is the next step in ensuring a safer job
site. There is no substitute for gaining accurate
underground awareness for yourself.

ABOUT SUBSITE® ELECTRONICS
Subsite® Electronics is committed to providing
underground construction professionals the most
comprehensive suite of electronic products in
the industry, including utility locators, Horizontal
Directional Drilling (HDD) guidance equipment,
utility inspection systems, and equipment machine controls. By utilizing innovative technologies, extensive market feedback and outstanding
customer support, Subsite has established itself
as the premier source of electronic technology
to support the installation, maintenance and
inspection of underground pipe and cable. For
more information, visit subsite.com. *
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Underground Construction - October 2020

Table of Contents for the Digital Edition of Underground Construction - October 2020