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NUCA contractor Arby Construction, New Berlin, WI is
replacing 5/8-inch diameter copper gas services with
1-inch CTS utilizing the trenchless Mini-Grundotugger pipe replacement system from Associate NUCA member
TT Technologies,
Aurora, Ill.
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With numerous, aging copper
and plastic service lines in need of replacement, the
gas industry is always looking for new replacement techniques
that limit disruption and speed installation times. Trenchless
equipment manufacturer and associate NUCA member TT Technologies,
Aurora, Ill., is working with the Gas Technology Institute
(GTI), Naperville, Ill. to develop new techniques and
methods for effectively and efficiently replacing these
small diameter gas service lines.
NUCA contractor Arby Construction,
New Berlin, WI, has partnered with TT Technologies
and GTI in order to utilize the latest in trenchless
pipe splitting technology to replace numerous copper
gas services for Nicor Gas, Naperville, Ill.. Arby
crews are using the new Mini-Grundotugger static pipe
splitting system (patent pending) to split and replace
5/8-inch diameter copper gas services and replace them
with
1-inch CTS.
Started in 1956, Arby Construction has grown from a small
telephone contractor to one of the largest underground
construction contractors in the United States. For
the gas industry, Arby Construction offers complete installation
services for all sizes of pipe for gas distribution systems.
Nicor’s roots, like Arby Construction’s, date
back to the 1950s. Founded in 1954, Nicor Gas is
an investor-owned natural gas utility that serves nearly
two million customers in northern Illinois, excluding Chicago. Nicor
Gas is the largest natural gas distribution company in
Illinois and one of the largest in the United States. The
company maintains a 29,000-mile distribution system that
is connected to seven interstate pipelines. In addition,
Nicor Gas transports and stores natural gas for customers
that purchase their own gas supplies. These commercial,
industrial and residential customers total 129,000.
With a service area that is
growing, a large portion of fieldwork is devoted to upgrading
exiting systems and performing new service installations. Nicor
contracted Arby Construction to complete a large portion
of this service upgrade.
The trenchless pipe replacement system replaces the
host pipe by simultaneously splitting the existing
service line while pulling in a new PE service line.
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TT Technologies Product Specialist
Brian Mattson said the trenchless application is ideal
for this type of work. He
said, “These services are pretty much all main to
meter. They’re running under lawns, landscaped
areas, driveways, and sidewalks. By using the trenchless
splitting system, Arby is able to save a lot of time and
money in terms of excavation and restoration. Plus,
customers are back up and running the same day.”
Mattson said there are three
different models available, for the specific splitting
situations. He said, “The
Mini-Grundotugger 250
offers 6,000 lbs of pullback and is typically used for
host pipe diameters of 1/2- to 5/8-inch, the 313 offers
9,000 lbs of pullback and is used for host pipe diameters
of 5/8- to
3/4-inch and model 375 offers
12,000 lbs of pullback and is used for host pipe diameters
up to 1-inch. Each machine utilizes a different cable
diameter. The 250 uses 1/4-inch cable,
the 313 uses
5/16-inch cable and the 375 uses 3/8-inch diameter cable.
Depending on the existing pipe
material, the unit’s
specially designed splitting head and expander split the
host pipe. Then you can either pull in the new pipe
directly behind the expander or retrieve the split service
first, then pull in the new service.”
Arby crews try to accomplish 10 service line replacements
per day and have all customers back up and running
the same day.
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Most of the services that the
Arby crews encounter are between 30 and 75 feet in length. According to Arby
Construction Area Manager Mario Lipira, splitting times
vary depending on soil conditions. He said, “The
time of year and soil conditions have a lot to do with
how fast we can split and replace service. If conditions
are wet you can see between 5 and 10 services per day. If
soil conditions are dry and hard only 1 to 3 services per
day.”
The MiniTugger System can be used for both small-hole (keyhole)
and traditional trenchless work for the replacement of
copper or plastic service lines. The system replaces
the service line by simultaneously splitting the existing
service line while pulling in a new PE service line. The
existing service line is split and expanded to allow
for the subsequent replacement service to be installed. The
existing service line can act as a conduit for the replacement
service that aids in the installation of the new service
line.
The
Mini-Grundotugger requires
only small entry and exit pits to facilitate the
replacement of the existing gas service lines. Restoration
is dramatically reduced with the system.
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Lipira said, “On a typical job first you identify
existing copper or Aldyl-A services for replacement and
where the service tee is located in both the parkway as
well as under pavement including sidewalks. Then
you keyhole by using either a coring rig for pavement or
spade or vacuum excavation if it’s on a lawn to expose
the service tee.
Once that’s done, the system is set up at the service
tap hole. The splitter head with new PE service tubing
and tracer wire attached are configured at the service
riser tap hole. Once the winch line is pushed through
the existing service, the splitter head and replacement
service is pulled back. Typical launch and exit pits
are 3 feet by 5 feet. We try to get 10 services done
per day.”
Cost-saving opportunities are one of the most attractive
benefits of the system, especially when it comes to excavation
and restoration requirements. Mattson said, “Not
only can this tooling be utilized through a keyhole in
pavement applications, but also through a small hole
excavation in the parkway, minimizing not only excavation
requirements, but also, final restoration needs.
Minimal disruption through the use of the trenchless
pipe replacement system has pleased homeowners
in Nicor’s service area.
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In fact, for crews working in
the parkway, they should be able to simply spade out
a 15- to 18-inch ‘coupon’ of
sod that could be directly placed back into the excavation
for restoration. If the crew then simply added some
grass seed around the edges of the coupon, similar to grout
for a pavement core, this process could eliminate a trip
by an L&P contractor, saving even more hard costs. Some
of the soft costs should include improved public and municipality
appeal due to less disruption of the property.”
Lipira said, “Using the trenchless system has really
helped us limit restoration and the associated costs. It
has also helped reduce customer complaints and callbacks. When
you avoid tearing up sidewalks and driveways, residents
are usually
very pleased.”
Jim Schill
Technical Writer
Mankato, MN |
