Intent

It is the intent of this specification to provide for installation of a tubular resin impregnated sleeve affixed to the walls of a lateral pipe (“Lateral section”) at the junction between the pipe and main sewer. In addition the sleeve should seamlessly extend into the main pipe (“the flange section”) thus creating a watertight Tshaped profile.

General

The method involves the impregnation of an absorbent carrier material; the attachment of the material to a inflatable former; the insertion of the former into the pipe; the remote identification and location the lateral; the inflation of the former; and the curing of the resinated carrier leaving behind a T shaped internal sleeve, consisting of a flange section in the main and a section up the lateral.

Before Video (15 MB)

After Video (24 MB)

Testing

Visual Inspection

On completion of the work a CCTV survey should be carried out and the repairs must be verified as per below:

 1. The flange section in the main should be watertight internally.

2. There reduction in the main pipe diameter should be no more than 15% of the original pipe diameter.

3. The junction between the flange and the lateral sleeve must be watertight. A certain amount of wrinkling at this interface is acceptable provided it is no more than 15% of the diameter of the lateral pipe.

Pressure Testing

If required by the owners bid documents, testing may take place by placing a plug in the main sewer and inserting a proprietary push rod plug down the lateral. The “T” section is isolated an air is fed into the isolated section.  Test criteria and acceptable losses to be determined by the engineer in consultation with the contractor

Design Considerations

The design is based on the assumption of a partially deteriorated pipe. The CIPP is designed to support the hydraulic loads due to groundwater, since the soil and surcharge loads can be supported by the original pipe. The groundwater level should be determined by the purchaser and the thickness of the CIPP should be sufficient to withstand this hydrostatic pressure without collapsing.