Sewer line repair using the “CIPP” method is a relatively new kind of pipe repair. This method has only been around for ten or fifteen years, but judging from the professional plumber’s outlook, that is a long time. No major news stories are written about developments in the plumbing trade. TV news doesn’t cover plumbing. It’s left for the plumbing industry to educate the public and sometimes this is not done well.
CIPP or cured in place pipe repair is used by industry in chemical, sewer, water, and gas applications. The most common use in residential repair is sewer rehabilitation to repair damaged or leaking lines. A tube made of fiberglass or sometimes polyester is impregnated with resin between two sheets in a single tubing. The resin will eventually line the pipe. The tube is inserted into the pipe from a manhole or an excavation point close to the main public sewer. The resin tube liner is pulled upstream to the residence. When in place, the resin tube liner is inverted with air or water pressure, similar to blowing up a balloon. The pressure required for this inversion can be generated using different types of pressure vessels. Then steam, UV light, or sometimes hot water is used to cure the resin and form a tight fitting, leak proof, corrosion resistant, joint less replacement pipe. Compared to other methods like “dig and replace”, this is less disruptive because there is little to no digging. Buildings and landscape are left undamaged and pristine. This process can be done in pipes from four to one hundred and ten inches. The resin shrinks when cured and creates an annular space between the liner and the host pipe. To keep water from seeping back into that annular space, gasket sealing technology is used. Hydrophilic material is used for gaskets. This means water swelling with absorption. These gaskets are placed at the ends of the host pipe as well as in all external connections. Completed jobs are inspected by a camera on a cable that is run through the complete length of the interior of the plastic. This is considered to be one of several “trenchless” technologies and can be initiated on leaking or unsound sewer pipe. It can repair pipes with bends but considerations must be taken to prevent wrinkling and stretching. Special liners must be used for pipes with bends to keep the pipe from going out of round and to avoid wrinkling.
There are a few reasons to shy away from the CIPP procedure. Once a line is repaired by this method, it can no longer be snaked or cabled. It must be cleaned by high pressure water blasting. Curing can take up to 30 hours, which means running a temporary sewage line until the job is finished. Obstructions in the existing pipeline must be removed before starting the process. Also, liners must be produced for every job.
Taking into account these disadvantages, CIPP is a good choice to keep from tearing out landscape or buildings. It would not have grown into its recent popularity had it not been an excellent alternative. As use becomes more prevalent and more is known about CIPP, it will become a major way of repair.