A Piercing Tool Program on Target for Gas Service Installations
July 20, 2011Trenchless technology has always been closely associated with the gas industry. The piercing tool, specifically, has become a common sight on gas service line installation projects — and with good reason. The piercing tool allows companies to save time and money on both new service installations and rehab and replacement programs.
Brownsville, Wis.-based Michels Corp. is one of the largest contractors in North America and highly proficient in all market segments of trenchless technology. Since 1959, the company has been a driving force in the trenchless construction industry, developing several new technologies and incorporating others into its repertoire along the way.
The use of piercing tools at Michels dates back to the early 1980s, but it was in 2000 that Michels made a concerted effort to achieve a larger presence in the gas industry.
“Michels’ natural gas installation methods utilize every aspect of underground construction, from trenching and plowing to directional drilling and pneumatic boring,” said Michels superintendent Craig Beckstrand. “In 2000, we felt that we needed to get a stronger foothold in the gas industry and hired some key personnel to achieve this. In 2003, we were awarded the Minnegasco contract, which today is known as CenterPoint Energy.”
Having the right equipment is an important part of any gas service installation program. For their gas service and mainline work, Michels crews use 2- to 4-in. diameter Grundomat piercing tools from Aurora, Ill.-based TT Technologies, a trenchless equipment manufacturer.
“In any and all applications, the method in which it is installed is critical not only for the homeowner, but also to our customer, CenterPoint,” Michels superintendent Darwin Faldet said. “Grundomats have been a key component to Michels’ success. The tools provide crews with incredible precision. They’re fast and maintain grade and accuracy.”
Michels is recognized internationally for its innovation, efficiency and reliability. Michels began doing business in 1959 as a gas pipeline construction company providing construction and installation of natural gas distribution systems to Wisconsin utilities. Over the last 52 years, the company has been involved in virtually all aspects of underground and overhead construction.
Today, Michels is one of the top 10 utility construction companies in North America and ranked No. 43 on Engineering News-Record’s Top 400 Contractors List for 2011. It is also one of the largest design and outside plant construction telecommunication contractors in the United States.
Michels has installed pipe up to 60 in. in diameter and has established numerous industry records with increasingly longer and challenging horizontal directional drills. Michels’ gas service line installation program with CenterPoint Energy is a good example of how this contractor’s knowledge and skill lead to efficient cost-effective solutions for its customers.
CenterPoint Energy serves more than 5 million metered customers from its corporate headquarters in Houston. The company operates in five primary business segments: electric transmission and distribution, natural gas distribution, interstate natural gas pipelines, field services and competitive natural gas sales and services.
With about 8,900 employees, CenterPoint Energy and its predecessor companies have been in business for more than 130 years. The company sells and delivers natural gas to 3.2 million homes and businesses in six states: Arkansas, Louisiana, Minnesota, Mississippi, Oklahoma and Texas. Its business in Minnesota and Texas includes the high-growth areas of Houston and Minneapolis. CenterPoint maintains 107,287 miles of main and service lines within its territory.
Piercing Tool Program
Approximately 70 percent of the work Michels does for CenterPoint is completed in the seven-county Twin Cities metro area, with the other 30 percent coming in various towns and cities throughout the state of Minnesota. Because of the harsh winter weather, the Minnesota construction season spans from early-April through mid-December. Most of the work — roughly 90 percent — is rehab and replacement, while new construction makes up the remaining amount.
Michels predominantly uses piercing tools for road crossings and restoration-sensitive areas.
“A typical service line installation for a new service or upgrade averages around 50 ft in length,” said Michels shop foreman Barron Anderson. “In extreme situations, they may reach 70 to 80 ft in length. Because CenterPoint’s service area in Minnesota is so large, soil conditions can vary greatly from job to job.”
Dealing with the variety of soils makes the accuracy and power of the piercing tools extremely important. For this program, TT Technologies has developed an interchangeable head for Michels that allows crews to react to changing soil conditions on the fly. This becomes a cost-savings that eventually gets passed on to Michels customers.
According to TT Technologies piercing tool specialist Bill Brennan, the soil conditions can be challenging.
“Inside and around the Twin Cities metro area, you can encounter almost every possible soil condition,” Brennan said. “So what we’ve done is given them the ability to switch from a reciprocating head to a solid head quickly and easily. This is especially helpful in fine, granular soils that don’t provide much in terms of tool-ground friction. In those situations, a fixed-head Grundomat is often a good option. It [has] been a highly successful program.”
Keeping Tools Running
Michels maximizes efficiency by taking advantage of TT Technologies’ program of providing them with multiple loaner tools. This allows Michels to avoid downtime by simply inserting a loaner when a tool needs maintenance or goes down.
According to Brennan, Michels crews take good care of their tools in the field as well. Flushing is one of the easiest, yet most effective maintenance procedures for a piercing tool.
“When boring in wet, sloppy soils, a lot of dirt and debris can be pulled into the tool,” Brennan said. “When left unchecked, that debris can cause performance and eventually wear problems with the tool. Flushing the tool consists of pouring a cleaning agent into the air hose and running the tool above ground until all the debris is flushed out. In the past, diesel fuel was commonly used as the cleaning agent — maybe a cup or so in the air hose. But today, many contractors use our environmentally-friendly, bio-degradable lubricant to clean their tools.”
The piercing tool can be used to install PE service lines and mains in several ways. For service lines and mains up to 2 in. in diameter, crews commonly pull the new PE in when removing the piercing tool’s air hose. For the typical 5/8-in. service line installation Michels performs, the new pipe is attached to the air hose once the crew completes the bore and removes the tool. The new service is then pulled into place as the air hose is removed. In favorable soil conditions, smaller services are pushed into place by hand.
Another way to install HDPE pipe is to attach it directly to the piercing tool using a threaded PE pipe adapter. This is typically done with larger diameter pipe ranging from 2 to 6 in.
Finally, when installing small diameter pipe (5/8-in. through 1 1/4-in.) the pipe itself can be used as the piercing tool’s air hose by using an air nipple. By making the product pipe function as the air hose, the crew simply removes the tool once the bore is complete and everything is in place.
Jim Schill is a technical writer based in Makato, Minn.