How Aggressively Can You Clean a Newly Lined Pipe?

From caustic cleaners to cable machines, here are some tips on what’s wise to stick down a pipe post-lining

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“I told my customer that her new sewer lining process took some special care and that she couldn’t use caustic drain cleaners or any cable machines to clean the line in the future. After I left, I questioned myself and now am wondering if I told her the right thing?” 

In order to provide the best possible answer, I decided to do a little internet research to see what other information is out there. I read so many “expert” opinions that it was hard at times not to laugh out loud.

If you’ve been in the drain cleaning industry for a while, you’ve learned that when a new cast iron pipe gets plugged, you can use pretty much any method — regardless of how aggressive it is — to remove the clog. Give that same pipe 40 years of service with it becoming heavily corroded and thinned out, and your aggressive methods aren’t such a good idea. While you may have used a toothed cutter to remove the debris earlier, that cutter may now do more harm than good.

Conversely, you most likely wouldn’t use an aggressive toothed cutter in a new PVC or ABS drainpipe in the first place. You could still use a drain cleaning cable machine, but you’d most likely choose something less intrusive than a toothed cutter. You may also employ a jetter to remove the clog. One of the websites I looked at stated that a jetter could cut plastic pipe. Yes, a jetter can cut plastic pipe, but the unit would need to produce pressures for PVC, ABS and CIPP in the neighborhood of 35,000 to 40,000 psi. Most jetters used for typical drain cleaning maintenance operate in the 2,000 to 4,000 psi range.

So how aggressive can you get in plastic pipe? I’ve used chain knockers, taking care to limit the diameter that the chain knocker can extend, as well as a centering device to keep the chain knocker centered in the pipe. I’ve also seen toothed cutters used — again, smaller than the actual pipe diameter and centered with a centering device. Standard hooks on a cable machine are fine to use. Any sewer jetter with most tools can be used. Root saws not so much, but you shouldn’t be seeing roots in lined pipe.

What about caustics? Drano, among other caustics, can be used in plastic pipes. If you use these products, most are composed of various forms of sodium hydroxide. We’ve tested 10 percent, 20 percent and 50 percent solutions of sodium hydroxide. In 12 months of testing, there’s been no degradation of the CIPP liner.

One of the articles I read said that the Drano product would eat through or soften metal or plastic over time. I wonder how it can even be bottled if it eats through everything? If your customer wants to try that type of product because it makes them feel better, tell them they are good to go. Although most of the time it doesn’t work exactly as they expected and they still need to call for a repair.

About the author
John Heisler is the owner of Pipe Lining Supply and Quik-Lining Systems Inc. He has 20 years of experience in the CIPP lining industry and over 40 years in the underground construction industry.


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