Cured-in-place pipe, better known as CIPP, is a trenchless technology that allows plumbers to repair and replace existing plumbing by placing a liner inside of an existing line. The liner is textile permeated with a liquid resin compound. Workers insert this liner into the host pipe. Once in place, it cures into a hard state, forming a new pipe within a pipe, seamless and able to adapt to any pipe condition. Liners can also be added to tubes with several bends, as the liner is pliable when it is inserted.

Once the liner is in place, it takes up to four hours for it to harden. However, once cured, this method of pipe repair offers many significant benefits to the areas which utilize them.

History and Growth of CIPP Use

The technology used in the early days of CIPP dates back to the 1950s. However, it was not until 1971 that someone used it for this purpose. Eric Wood, a London man, needed to repair a leaking pipe underneath his garage floor. Not wanting to destroy his floor, he developed a method of inserting a tube within the broken pipes. After fixing his pipes, Wood applied for a United States patent using patent number 4009063. The United States Patent Office granted the patent on February 22, 1977.

While CIPP was common in Japan and Europe in the 1970s, it did not become commonplace in the United States until the 1980s. As technology improved, use of CIPP went from being solely for large diameter pipes to use in smaller diameter pipes. By the 1990s, this technology was upgraded, making it feasible to use in residential homes and commercial businesses.

Since its conception in 1971, workers have installed over 50,000 kilometers, or over 30,000 miles, of CIPP worldwide during their trenchless rehabilitation projects. As more companies become certified in installation, the amount of CIPP continues to grow.

Benefits to Using CIPP in Water Mains

Construction professionals dealing with different mains rehabilitation causes have been known to be able to use CIPP safely and efficiently to fix them throughout the world. However, it is most common to find it in water mains because of the added protection the pipe within a pipe method offers. Additionally, this repair process is intended to last 50 years and is quicker to complete than traditional water line repairs.

Pipes using CIPP help to prevent water main breaks. The design of a pipe within a pipe strengthens the existing tube. It also contributes to offset any joints or gaps in sections where parts of the plumbing may be missing.

CIPP also serves to protect the water and consumers drinking it or coming into contact with it from harsh contaminants, specifically, existing lead pipes and asbestos-laced pipes, which can release lead and asbestos respectively through the water supply. Trenchless CIPP goes further to rehabilitate asbestos-laced pipes, as traditional trenching, removal and replacement of these pipes exposes them to air where the asbestos particles can then cause health problems for workers in the vicinity. This removal process is also more costly and time consuming, requiring construction companies to seal the area properly and use hazmat suits for protection. (Learn more in "Asbestos Cement Pipe: Why its a Problem and How Trenchless Can Fix It.")

Trees can be a major issue for water mains. Tree roots can travel for quite a distance in search of water. Even a tiny crack in a pipe allows a fine, hair-like root to enter. Over time, that root grows and breaks the plumbing further. The dual wall design of CIPP helps to eliminate, or at least significantly reduce, root infiltration within the tubing.

CIPP improves the overall flow rate of the pipe. While this might seem counter-intuitive, as you are reducing the overall diameter of the tube, the liner's surface has characteristics that allow water to flow more quickly, providing a better flow from the main line to the faucet and greater pressure from fire hydrants. This increased pressure and flow from hydrants can lower homeowner insurance rates in some areas. The increased flow rates can also result in lower pumping costs for cities.

The Growing Popularity of CIPP in Water Mains

Despite the innovations in CIPP, its use in drinking water lines is still lagging, but many cities are learning the added benefits of having these lines and are attempting to add them to their water main infrastructure through trenchless construction.

In addition to preventing water breaks and root infiltration, CIPP reduces the potential for water contamination through the surrounding soil. To begin with, CIPP is a trenchless repair, meaning the pipe does not have to be dug up to insert the liner. Previous methods required the plumbing to be excavated using conventional trenching which allowed soil, and any contaminants in the ground, to enter the water supply. You may have sen this in action before when you've turned on the faucet and brown water came out. By eliminating this step, contaminants do not enter the stream during repair. The added layer of pipe eliminates the possibility of soil contaminants reaching the water supply even if the external tube has cracks.

Drinking water delivered via cured-in-place pipes reaches consumer homes and businesses in a clean state. Rust and soil from old pipes are kept out by the liner.

Cured-in-place pipes also allows for faster repairs without disturbing the ground above, saving cities time and money as they make the necessary repairs.Thanks to its design, CIPP strengthens water lines and provides cleaner, clearer water to the public.