How To Test To See If A Pipe Is Linable

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Pipe Before Cleaning

“I have a job that looks pretty difficult. I am nervous that if I try to line the pipe, it may not go. My camera gets stuck when I pull back, but goes in okay. It’s cast iron and I know I need to clean it, but didn’t want to get in too deep to “own” a job that isn’t doable. Any suggestions?”

Your question is pretty typical when it comes to pipe rehabilitation. Here’s a low cost test to help you decide whether to tackle the job with lining or propose an alternative method of repair. Assuming the line is semi-clean in that there are no obstructions that you can’t negotiate such as built up scale or roots, you can use a piece of old calibration tube from a previous job and shoot it into the pipe. You will learn a couple of things right away. If it goes without a problem, you are pretty well assured you can line the pipe. If the pipe needs cleaning, pull out the calibration tube you shot in and proceed to clean the pipe.

Your next hurdle is to clean the pipe without breaking or destroying it. Some of the piping is old and brittle and may not take a lot of destructive cleaning methods. Here’s an idea if you want to keep those destructive methods of cleaning in check but still use them, you can center them with centering axels or center brushes. These tools include chain knockers, sanders, wire brushes, and carbide cutter heads. If you keep them centered in the pipe, you can remove scale and roots without banging the edges of the cutters against the wall of the pipe. They will move to the diameter of the pipe, but are restrained from a full blow to the walls of the pipe. A high speed cable drives these devices extremely well and work very quickly for cleaning.

Once the cleaning process is complete you can now reprove the ability to line the pipe by installing your old calibration tube again by shooting it back into the pipe. Again, if it goes, you can be pretty well assured that the liner will follow the calibration tube. Leaving your calibration tube in place you can go ahead and shoot your liner through the pre-liner old calibration tube with a pretty high level of confidence it will go.

Floor Cuts

If, at any point, you can’t get your calibration tube used as a pre-liner into place, your options are to look for other solutions. These may include opening up the area in the wall or floor where the test pre-liner stops. It’s much easier to patch an access point than replace an entire wall or floor.

One last consideration is risk. When tackling these jobs, add some margin into your job for risk. What if you have to dig it up? What if you break a pipe during cleaning? Have you explained the risks to your customer and your plans if things don’t go as planned? If you keep your customer educated to your risk concerns he or she won’t be shocked when things don’t go well. Don’t be afraid of these jobs. They are the ones no one else wants, but if you manage them and manage the risk, you can succeed.

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