Trenchless Piping Methods

By Tim Daly


If you are a homeowner, then you’ve probably received a number of letters from fly-by-night insurance companies explaining to you how much you need water main insurance. The brochures explain how much money the repairs will cost, not only because of the plumber’s expenses, but also how much it will cost to have a backhoe and operator spend a day digging up your entire front lawn. Add to that, the expense of re-grooming and landscaping your yard, and it’s enough to almost scare you into buying the insurance.

The repair of the water main pipe to your house of the sewer pipe running out of your house, does not have to be the headache it once was. These repairs are not cheap by any means, but with the video capabilities of many plumbers and the trenchless piping methods available, it is not as awful as you might expect.

A reputable plumber will be able to use video to find the exact location of a ruptured sewer pipe, and then use trenchless technology to repair or replace the pipe and only make one or two small holes near the ends of the pipe. While they may or may not have the video capabilities for the water line, they can still use trenchless technology to repair or replace the pipe, and do the entire job in a day or a day and a half at the outside.

Much of the trenchless pipe repairs for residential users involves pipelining technology where they reline a section of pipe—or in some cases an entire pipe, if it’s determined to be old and in danger of suffering a major break. This involves taking a form of plastic liner, with an adhesive like epoxy spread around the outside of the liner. An inflatable bladder is sent into the pipe until it reaches the area where the repair is needed. Once in place, the bladder is inflated, pushing the liner and adhesive outward where it adheres to the existing pipe. After it has set been up for the prescribed amount of time, the bladder is deflated and retrieved. The newly lined pipe will have a smaller inside diameter, but the difference is negligible.

The other popular method in residential trenchless piping is called pipe slitting, or pipe bursting, depending on the size of the pipe being replaced and the tool used to accomplish the feat. What happens in this method is basically a cutting or bursting tool is fed into one end of the pipe, and as it is forced through the existing pipe it cuts it and pushes it outward. As it’s making the cut, it is also pulling the new pipe into place behind it. When the pipe is all the way through, the tool is removed, and the pipe is tied into both ends and put into service. The old pipe is left to rot away in the ground, and the new pipe is run in the exact same place as the old pipe.

Now imagine you’re an engineer and you’ve got to get a water pipe run from the main on one side of a super highway, to the factory your firm is building on the other side of the highway; or you’re planning an oil pipeline that is going to have to cross a rather large river, and you don’t relish the idea of trying to build an entire tunnel under the riverbed, or bring the pipe over the water including all of the supports that would have to be built in the riverbed to hold the pipe (not that environmentalists would let you). It is for reasons like this that trenchless technology was developed.

Early trenchless technology mostly centered on vertical pipes to bring oil out of underground wells to the surface. In the 1970’s and 80’s the idea of horizontal trenchless piping started to take hold, and the technology has continued to improve as the industry grows.

The technology employs the same ideas that mining companies, as well as tunneling projects for transportation use; the only difference being the size of the tools used. It is sometimes called the Jack and Bore method, but more commonly referred to as micro-tunneling.

Much of pipeline trenchless technology for commercial or industrial use involves running pipes in areas that do not have pipes already run. To do this, a lot of ramming or boring work is done in which a ram rod, or boring tools, is used to cut a hole through the ground following a predetermined path. Often times, the pipe is connected to the tool making the hole, and pulled through as the tool travels onward; sometimes the pipe that trails the boring tools is actually used to push the tool. With these methods, the digging tool can be stopped, while lengths of pipe are welded as necessary to go the distance.

This is another example of the pipefitting industry advancing with technology. Going forward, the modern pipefitter will need to understand computers and complex machinery more than ever. Gone are the days when a pipefitter just needed heart and muscle to get the job done. If you’re a young apprentice, study hard and stick with it. The future looks bright ahead, and you’re in a trade with a seemingly unreachable ceiling.

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