Pipeline &
Gas Journal
December issue 1999:
Innovative Utility
Reducing Construction
Costs With Coil Pipe Technology
by Ricky D. Dye, Division Manager, Mountaineer Gas Company, Huntington, WV
With all of the competitive changes that have taken place in the natural gas industry in recent years, distribution companies have been forced to revisit practically every phase of their operation in hopes of becoming more efficient and reducing costs. Deregulation in the industry has certainly had a competitive effect on the energy business.
One area that Mountaineer Gas Company has scrutinized closely is pipeline construction for new and replaced mains. Like many other distribution companies, Mountaineer Gas contracted a large portion of its construction work to local pipeline contractors. A few years ago, this trend began to change. Because of the necessity to stretch budgets as far as possible, Mountaineer had to assess where true savings could be made. We soon discovered that utilization of our workforce was indeed the most cost-effective means.
While using Mountaineer personnel was a great experience for our labor force, we were still very lean in number of employees. Mountaineer needed to search for ways to work even more efficiently.
Traditionally, Mountaineer would perform all of its installations using medium density PE pipe consisting of 40-foot joints. Though far less expensive than its steel counterpart, this still consumed a substantial amount of time and labor. Recently, however, this has all changed with the introduction of large diameter coil pipe. The extensive use of coil pipe yields dramatic savings due to the significant decrease in fusion activity, labor, and transportation costs. We have 15 trailers at Mountaineer that we use on a near-daily basis. For the 1998 construction season, we installed 289,041 feet of PE pipe. Of that total, 255,822 feet (or 88 percent) was coil. This was the most footage installed in Mountaineer history.
Reducing Fusions
One of the most obvious advantages associated with coil pipe is the drastic reduction in fusions needed during installation. Conventional stick pipe requires a fusion in at least 40-foot increments, which demands more labor and slows production. Considering the length of coils available on the market today, many jobs can be completed without any fusion activity. Typical lengths of coil pipe available are:
2'' - 4000'
3'' - 2400'
4'' - 1280'
6'' - 450'.
Less Labor-Intensive
Most fusions require around 20 minutes to complete when total setup and cool down times are considered. Using that as a gauge, the amount of time dedicated to fusing comes to 8.3 hours for every 1,000 feet of pipe installed. This is computed as follows:
1000 / 40' = 25 fusions
25 x 20 min. = 500 minutes on fusion activity
500 / 60 min. = 8.3 hours per man for fusion activity.
If properly captured and utilized, the labor saved in fusion activity alone can result in significant monetary savings. In many cases, the savings in labor from one installation will offset the initial price of a coil pipe trailer.
Minimum Of Storage Space
Stick pipe is traditionally stored at a pipe yard and requires a substantial amount of space. When needed at a job site it must be handled several times and transported with special equipment. Stick pipe is labor-intensive.
Due to the ability to store large amounts of pipe on a coil pipe trailer, a whole new system of inventory management emerges. Using a multiple trailer concept, a trailer can be dedicated for each size of pipe used. The trailer is always loaded and ready for use while occupying a very small amount of yard space. In essence, inventory becomes mobile, compact, and never needs to be rotated. With foot markings now being placed on the coils, the task of tabulating quantities on hand becomes much easier.
Pipe storage at the job site is always a problem, especially with stick pipe. Many jobs are in densely populated areas with limited safe storage. With coil pipe the amount of space needed is drastically reduced. The need to layout 40-foot lengths for joint fusing is also eliminated.
Transportation Savings
Transporting 40-foot joints of stick pipe to the job site is a cumbersome task requiring special trailers coupled to large trucks. With a coil pipe trailer, the entire job requirement of pipe can be hauled in one small package and can even be transported by a half-ton pickup. A coil pipe trailer takes some of the headache out of job preparation and planning.
Aids In Directional Boring
Coil pipe and coil pipe trailers are especially suited to directional boring activity. The trailers allow the pipe to be stored and ready for use at the job site, and it does not require additional manpower or workspace to layout and fuse the necessary footage. Having no fusions in the pipe run is also beneficial in the pullback operation since the pipe has not been cut, fused or weakened.
Mountaineer’s Approach
Mountaineer Gas began experimenting with large diameter PE pipe in fall 1997, and purchased three trailers for use in January 1998. Although savings from the use of coil pipe were obviously significant, a more efficiently designed trailer was desired. A trailer that was more user-friendly and easier to load and operate was needed. With that in mind, Mountaineer developed its own version of a coil pipe trailer. In April 1998, Mountaineer’s Pipe Master trailer made its first test run.
The Pipe Master trailer incorporates an all-aluminum design and is user-friendly with a unique sideload feature. Aluminum requires much less maintenance and minimal effort to keep its fresh appearance. Steel requires periodic painting which can be unsightly and expensive.
Loading a coil pipe trailer can be tedious work. In fact, some trailers can take 30 minutes or longer, depending on the degree of difficulty in removing and installing the parts on the trailer. Some trailers load from the top, or rear, which in many cases poses a safety risk. It also places a need on more specialized equipment and additional crew to do the loading since the height needed for loading is usually above the normal lifting range of most backhoes and many forklifts.
The Pipe Master features a side-hinged, swing-out gate that opens 180 degrees toward the front of the trailer. This means that the pipe must only be hoisted around 40 feet in order to be loaded. This is well within the lifting range for virtually any kind of full-sized backhoe or forklift. The entire loading operation requires only one person and is usually completed in 10 minutes.
A conventional steel trailer would add as much as 2,000 pounds to the overall package, which in turn forces the use of a larger truck for towing. The Pipe Master weighs only 2,700 pounds and has a GVWR of 7,000 pounds, which leaves 4,300 pounds for payload. A fully loaded trailer can be transported with nothing more than a small pickup. Most of the larger coils being produced today weigh in excess of 3,000 pounds and this number will continue to increase as the coil sizes being manufactured continue to grow in length. Its use with the right coil pipe trailer should directly benefit our industry as we work to be more competitive. Without question, coil pipe is one of the greatest breakthroughs for efficient and cost-effective pipeline construction. P&GJ