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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

MAILING ADDRESS: 1120 SW 5th Ave, Room 1000, Portland, OR 97204

More Contact Info

Cured-in-Place Pipe-Lining (CIPP)

preparing to install the pipe linerCured-in-Place Pipe-Lining (CIPP) is a trenchless sewer repair method that requires little or no digging and significantly less time to complete than other sewer repair methods. In most cases, a section of sewer pipe that is several hundred feet long can be repaired in one day.  Work crews avoid digging, and instead access the sewer pipe using existing manholes. Crews insert a flexible liner inside the old pipe. The liner is inflated to press the outer portion firmly against the inside wall of the old pipe. The liner is exposed to heat or ultraviolet light (UV) to “cure” 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.

Limit Water Use During CIPP

If you live in a single-family home where crews will be repairing sewer pipe using CIPP, your sewer service connection will be temporarily sealed off by the liner once it is inflated. This will prevent any water leaving your home from flowing into the main sewer line while the liner is curing. After the liner has hardened completely, a robot will be inserted in to the pipe to cut a hole where your home is connected to the sewer, and your service will be restored.

To avoid water filling up your private sewer and backing up into your home, you may be asked to limit how much water you use for one day during the lining process. The contractor will ask that you not take showers or baths, wash clothes or dishes, and to turn off all sump pumps connected to the sewer. If you need to, washing your hands and flushing your toilet is okay. Large scale uses of water should be limited, however.

pipe liner

Unpleasant Odors

When heat (steam) 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.

While unpleasant for some, the amount of airborne styrene generated by the CIPP process is not a health risk at the levels observed by the City of Portland and tested and monitored by an independent industrial hygienist. The odor dissipates quickly once the process is complete.

How to prevent odor from entering your home during CIPP

If your home is connected to the sewer line being rehabilitated, you can help prevent the odor from entering your home or building by pouring water down all floor drains, sinks and tubs to ensure that a water barrier is maintained in each drain’s “P-trap” (see image). If this does not prevent odors from entering your home, you may need to temporarily seal the drain by placing a plastic bag filled with water over the drain or taping over it. These temporary measures will prevent the backflow of odors.

graphic showing how to properly maintain a ptrap

If there is already a strong odor in your home, opening windows can improve ventilation and help diminish these odors. If the odors are stronger outdoors, closing windows can prevent these odors from entering your home or business.

For more information about Styrene odors associated with CIPP

Cured-in-place Pipe lining (CIPP) is a tested method of sewer rehabilitation and repair that has been used by sewer utilities throughout the United States for decades. The odor associated with CIPP styrene can be smelled at extremely low levels, but because it smells like glue or plastic, it leads people to ask questions about how safe it is for the general public.

Though the odor is unpleasant for some, industry testing has shown that styrene exposure for workers and the general public resulting from CIPP installation is below thresholds for health risks. The Bureau of Environmental Services (BES) is committed to ensuring public health. As part of this commitment, BES hired an independent Certified Industrial Hygienists to conduct independent air quality monitoring and testing during CIPP lining. This independent assessment confirmed that exposure to the public is below all applicable thresholds for impacts to public health.

Independent Certified Industrial Hygienist Reports

Other information about Styrene

Performing spot repair

CIPP and Noise

Vactor trucks will be in the area during the CIPP process to operate vacuum pumps necessary to clean the pipes prior to the lining and maintain sewer service during the lining. Vactor trucks generate noise and may be in place for several hours at a time.

What to Expect During Cured-in-Place Pipe Lining

You can expect the following during construction:

  • Construction crews do most of the sewer lining work through manholes in the streets.
  • Spot repairs may require excavation prior to lining process.
  • Preparation and restoration will take a couple of days to complete, but the pipe lining process should only take one day at each location.
  • You may notice an odor during the pipe lining process, but it will dissipate quickly.
  • There may be inactivity between some phases of this process.
  • Typical work hours are 7:00 a.m. to 6:00 p.m. Monday through Friday, but the contractor may schedule work during the same hours on Saturdays.
  • To help reduce odor run water in all sinks and basins to make sure p-traps are filled, and cover floor drains with a wet towel or a zip bag filled with water. Be sure to cover the drain completely.