Defining, Understanding Lateral Rehab Options

Part 2 in a series
By Jeff Griffin, Senior Editor | May 2011, Vol. 66 No. 5

Sectional lateral CIPP lining
When inspection and evaluation reveals that only an isolated section needs repair, sectional CIPP repairs can be made by pull in place, push in place, or inversion methods.

Pull-In-Place Method -- A resin-saturated liner is positioned on a pneumatic plug, inserted through a clean out and pulled to the point of repair. The plug is inflated until the resin is cured, then the plug is deflated and removed, leaving behind the finished cured-in-place sectional liner.

Push-In-Place Method -- This method involves positioning a resin-saturated liner on a pneumatic plug, inserting it through a clean out and pushing it to the point of repair. The plug is inflated until the resin is cured and then deflated and removed leaving behind the finished cured-in-place sectional liner.

Inversion Method -- A resin saturated liner is moved into position by attaching it with a frangible connection to an inversion bladder. Swelling compression gaskets or other approved seals can be attached to each end of the liner in cases where severe leaks are present. The inverting bladder carries the liner through a clean out and positions the liner at the exact location of repair. Prior to curing, an inspection camera can be inserted into the bladder while pressure is maintained to determine proper placement.

Lateral renewal by CIPP Lining
Lateral lining is defined as rehabilitation of the lateral from the lateral access point continuously to a specified point, typically the sewer main. CIPP lining is also used to renew a portion of the lateral from an access point to a point near a building foundation. Technology providers have developed four distinct installation methods to accomplish the lateral lining objective.

Double Inversion Method -- An excavation is made, and a section of lateral pipe is removed. A predetermined length of resin-saturated liner is inverted into the lateral pipe using air pressure. When the liner is fully inverted, the end is open allowing the inflation pressure to release. A bladder then is inverted inside the liner causing the liner to be repressed tightly against the pipe until the resin is cured.