by Jim
Schill
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According
to Gas Operations Manager Mitch Bogrand the piercing
tool is an important part of daily operations. He
said, "We use pneumatic piercing tools for a
wide range of applications including gas, electric
and phone. For our gas service line installations
we rarely use anything else."
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Look
in the toolbox of any successful contractor and you
will see some of the reasons why they are successful.
Aside from the other essentials for success, skill,
dedication and commitment to quality, a contractor’s
toolbox can give a keen insight into why they are successful.
Since
its beginnings in the 1960s, utility contractor Potelco,
Sumner WA, has seen many changes. The assortment of
tools in its toolbox has changed with the times, as
well as Potelco’s expanding
service offerings. One tool in particular has evolved from
a novelty into an essential piece of equipment—the
piercing tool.
According
to Gas Operations Manager Mitch Bogrand the tool is
an important part of daily operations. He said, "We use pneumatic
piercing tools for a wide range of applications including
gas, electric and phone. For our gas service line installations
we rarely use anything else. It’s just so much nicer
then tearing up someone’s yard, their sprinkler system
and grandma’s rose bush."
According
to Scott Langfeldt, piercing tool specialist from trenchless
equipment manufacturer TT Technologies, Aurora, IL, Potelco
really gets the most out of their piercing tools. He
said, "The folks at Potelco are utilizing piercing
tools to the utmost. Those tools are in the field day
in and day out performing bore after bore. The piercing
tool has unquestionably helped make Potelco one of the
leading utility contractors in the United States."
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The
three-man Potelco crew used a 2-inch diameter Grundomat-P
55 from TT Technologies for the job.
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37 Years
of Service
Potelco, Inc, a subsidiary of Quanta Services, Inc., is
a full service utility contracting firm, serving customers
throughout the Northwest in Washington, Oregon, Idaho, and
Montana. For more than 37 years, Potelco has been providing
construction services to the power transmission and distribution,
natural gas distribution, fiber optics, aerial and underground
telecommunications industries.
With a staff
of project engineers, Potelco is a design/build contractor.
Potelco offers its clients comprehensive project planning
including construction design, projected costs of materials
and labor, and the construction of the project itself.
Bogrand
said, "We
specialize in designers who are field oriented and who
understand how design affects construction and future
maintenance of the overall project. Often those designs
include the use of trenchless technology, specifically
piercing tools. We own and operate over 200 of them from
one and three quarters to five inches in diameter."
Accuracy
is Key
While the principal function
of the piercing tool hasn’t
changed much over the last 50 years, its design has. Bogrand
said, "We’ve been using piercing tools for more
than a decade. The tools have really come a long way. They
have become more accurate."
According
to Langfeldt, that improvement accuracy comes from
improved design. He said, "While the Grundomat [piercing tool]
basically works on the same principles found in the first
piercing tools, the major improvement comes in the reciprocating
head. A piston inside of a casing generates power. The piston
drives the tool, and air drives the piston. Today’s
conventional piercing tools, as well as the Grundomat,
operate in this fashion.
The
Grundomat’s
reciprocating chisel head assembly, however, moves independently
of the main casing, creating a pilot bore for the rest
of the tool body to follow. This ultimately leads to
greater bore accuracy over conventional tools. The chisel
like action helps the tool to power through difficult
soils and obstructions without being pushed off course."
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The
first shot went from the main under the sidewalks
and the street, approximately 50 feet. After that
we divided the subsequent shots into 40-foot lengths.
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On
the Job Training
Potelco currently performs all the electrical power related
installations for Puget Sound Energy, Bellevue, WA, as well
as the new business portion of its gas division. According
to Bogrand, typical crew sizes vary between two and four
people. Each crew is equipped with at least two piercing
tools some have three. New crewmembers receive training
in the field.
Bogrand
said, "We
put new crewmembers with an experienced person. They
seem to grab onto very quickly. It is a basic process,
but there is a feel for the ground conditions and how
the tool is going to run that you can only develop through
experience."
Potelco’s
crews see a wide variety of soil conditions. Soils types
include sandy loam, clay and rocky. With such a variety
of soil types, crews rely on the accuracy and dependability
of their piercing tools. Accuracy is a necessity to ensure
efficiency.
Bogrand
said, "Well I’ll tell you in ideal ground conditions
we’ve done 200-foot bores. That’s usually in an
extensively landscaped situation where we’re running
tool fairly shallow in good ground conditions. If it’s
running straight and true we’ll just go ahead and
keep adding hose. The guys call them glory shots. Most
of the time, though, typical installations range between
40 and 70 feet."
Typical
Installation
According to Bogrand, approximately
80% of all Potelco’s
piercing tool work is gas service line related. A recent
gas conversion project for Puget Sound Energy in Kent, WA
highlights the piercing tool’s abilities.
The project in Kent was a commercial gas service line installation
for a strip mall. The Potelco crew needed to install a
300-foot, 1 1/4-inch Medium Density Polyethylene (MDPE)
gas service line. The bore traveled from the mainline,
under a roadway, two sidewalks and landscaped area adjacent
to a parking lot, to the mall’s meter manifold.
Bogrand
said, "The
soil conditions in the area are very unforgiving. In
addition, we had to deal with a nicely landscaped area
and several changes in elevation, so we decided to divide
the run into sections. The first shot went from the main
under the sidewalks and the street, approximately 50
feet. After that we divided the subsequent shots into
40-foot lengths."
The three-man
Potelco crew used a 2-inch diameter Grundomat-P 55 from
TT Technologies for the job. After the first shot under
the road, the crew disconnected the air hose from the tool
and compressor. At the launch pit a pipe pulling cable was
connected to the hose and pulled into the completed bore
path as the crew removed hose at the exit pit.
At that point,
the exit pit became the launch pit and a new exit pit was
excavated approximately 40 feet away for the next bore.
Each pit measured approximately 3 feet wide and 6 feet long
at varying depths throughout the run. After each bore the
crew repeated the process of pulling in pipe pulling cable,
connecting each section of cable together once in place.
After the series
of bores to the mall was completed, the Potelco crew pulled
the new 300-foot, 1 1/4-inch service in place with the pipe
pulling cable. According to Bogrand each bore took approximately
20 minutes to complete. Once installed, the crew tied the
line in the steel gas main using a welded service tee with
a transition for plastic pipe.
Piercing
Tool Praise
The piercing tool has earned
a respected place in the Potelco toolbox, and for good
reason according to Bogrand. "The
piercing tool is absolutely essential for our business.
Our productivity would definitely be lower without it. You
know we’re so used to them you start taking them for
granted. But if you think about it, there are just all
kinds of pluses to the tool.
You
can put it in the ground and get it on its way and
the crew can be doing something else. The crew can
be working on the tie in or something like that. It’s always moving; it’s
like having another person on the crew."
Underground Construction, October 2001
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