Cured in Place Pipe (CIPP)

Definition - What does Cured in Place Pipe (CIPP) mean?

Cured in place pipe (CIPP technique) is a trenchless technology rehabilitation method to fix and repair existing water, gas, chemical and wastewater pipelines. CIPP has no joints. It is a seamless, pipe-within-a-pipe and can rehabilitate pipes ranging from 4 inches to 110 inches. It is an ASTM approved method for rehabilitating cracked, damaged or broken pipelines.

Cured in place pipe is also known as cured in place pipelining.

Corrosionpedia explains Cured in Place Pipe (CIPP)

Cured in place pipe (CIPP) rehabilitation technology uses an internally placed flexible lining material that provides both corrosion mitigation and structural improvement. The CIPP lining process can rehabilitate virtually any type of pipe including clay, cast iron, Orangeburg, PVC, ABS, HDPE, concrete or corrugated metal pipe.

CIPP liners are constructed from non-woven polyester felt with an exterior polyurethane coating in tubular layers. A specified amount of catalyzed thermosetting resin mixture is impregnated into the felt during a process called wet-out. The felt acts as a resin carrier and adds flexibility and strength to the finished liner. After wet-out, the CIPP liner is transported to the installation site in a refrigerated truck. At the installation site, the CIPP liner is positioned in the host pipe by either inversion (air or water) or winched in place. Once in position, the liner is inflated by air pressure or by a water column, which presses the material against the host pipe wall. When fully inflated, steam or hot water is circulated within the liner to start the thermosetting resin's hardening cure. After the cure has completed, the liner is slowly cooled to prevent shrinkage.

This technology was invented in England, but has seen frequent use in many parts of the world. Used at more than 20 sites in the United States, several water utility owners expressed their willingness to use the technology.

CIPP shows improvement over traditional rehabilitation methods using cement mortar lining (e.g., Class IV fully-structural solution versus Class I non-structural solution). Long-term tests are ongoing.

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