Major Sewer Improvement Effort

CIPP Process/FAQs

Construction Process

The Process

The sewer rehabilitation method of the SRI and NRI will employ a cured-in-place-pipe (CIPP) lining process. This process allows the contractor to rehabilitate the existing sewer pipes "in place" rather than a traditional method of replacement which would require complete excavation and replacement of existing pipes, causing extended disruption of streets and surrounding neighborhoods and businesses.

The pipe lining process begins with installing a bypass sewer system to pump the flow of sewage from the section of pipe that will be lined. Once the bypass is in place, the existing sewer pipe will be cleaned, using a high pressure water hose and inspected with a video camera to verify that the pipe is cleaned and record the condition of the pipe.

A flexible liner is then placed into the existing sewer. Heated water or steam is forced into the liner, causing it to be pushed tightly against the walls of the existing sewer pipe. The heat from the steam or heated water causes the liner material to harden (cure), thus creating a new pipe inside the existing sewer walls.

The Lining and Curing Process

You may notice a smell like that of new plastic during the pipe repair process. This odor may be caused by an ingredient that is used to make many types of plastics and resins, including many household products. This ingredient is called styrene.

The process used in sewer repair or rehabilitation is called cured-in-place pipe (CIPP). The CIPP process involves installing a resin-saturated felt tube that later hardens into a strong "pipe-within-a-pipe". Styrene is a component of the resin that makes up the outside of the new pipe.

Styrene can be detected by its smell even when there are very small amounts of it present. As a result, persons living along the sewer lines may notice the distinct plastic smell during the new cured-in-place pipe process. You can minimize the possibility of odors migrating into your home or business by making sure your sewer connections are in proper working order and that you frequently run water into all the drains in your home or business, especially seldom used floor and laundry drains. This exercise will ensure that your property's plumbing traps, which are designed to constantly hold water, have not dried out. They're called traps because they do just that: trap water inside, preventing sewer gases from coming back into the building.

The release of styrene during the typical sewer rehabilitation process is in such small quantities that it does not pose a significant risk to human health or the environment. It has been proven that styrene exists only briefly in the environment; it is destroyed rapidly in the air and disappears quickly. Levels are continuously monitored during the installation process.

Pima County