Sewer Lining Program

Cured-in-Place Pipe (CIPP) Sewer Rehabilitation

Cured-in-Place-Pipe (CIPP) lining is a method of trenchless sewer rehabilitation and repair that has been used by sewer utilities throughout the United States for decades. The “trenchless” pipe repair can be installed in significantly less time than other sewer repair methods, is less damaging to roadways, and is less disruptive to the public.  CIPP lining requires little or no digging, as crews access the sewer pipe using existing manholes. In most cases, a section of sewer pipe that is several hundred feet long can be repaired in one day. A flexible liner is inserted inside the old pipe. The liner, which contains a hardening agent called resin, is inflated to press the outer portion firmly against the inside wall of the old pipe. The liner is exposed to heat using hot water or steam to “cure” the resin in the pipe. During curing, the liner gradually hardens against the inside of the old pipe forming a rigid, smooth surface that seals cracks and restores the old pipe to near-new condition. Openings for building service connections and laterals are then cut out of the lined pipe with a small robotic cutter.

Odors - When heat is used to cure or harden the liner during CIPP, people who are nearby may smell an odor that is often described as being similar to plastic or glue. The odor is from the chemical styrene, which is in the resin of the liner. The resin is the part of the liner that reacts with heat and hardens. The odor associated with CIPP styrene can be smelled at extremely low levels, so it leads people to ask questions about how safe it is for the general public.  In response to inquiries received regarding the odor of CIPP installation, Engineering reached out to the CIPP lining contractor who provided the below information sheet titled "What's that Odor?" published by the National Association of Sewer Service Companies (NASSCO).

What's that Odor?/DocumentCenter/View/27925/Styrene-Odor-Information-Document-10-22-2020

As stated in the information sheet, if you detect an odor in your home, it is likely entering through the pipe that connects your home to the public sewer main.  A "U" shaped pipe called a P-trap is located at all drains/plumbing fixtures and is designed to keep sewer gas and other vapors out of your home or building.  Floor drains/plumbing fixtures may dry out at the P-trap and allow sewer vapors to enter your home or building.  However, some of the oldest buildings in the City may have been built without proper plumbing or permitting, allowing odors to enter the home.  Odors can usually be quickly dissipated by opening windows or doors.