Qualitative Assessment of Mechanical and Adhesive Service Connections for CIPP

Cured-in-place pipe (CIPP) was initially created to repair aging gravity sewer systems. The addition of glass reinforcing layers to the felt tube in the 1990s provided CIPP with the structural integrity necessary to be used in the rehabilitation of pressurized pipeline applications. The use of CIPP for pressure applications requires reconnecting and sealing existing service lateral connections. Improperly sealed service connections can result in leakage or migration of water into the annulus between the CIPP and the existing pipe that has been rehabilitated. This leakage is not often apparent during the initial quality and proof testing of the CIPP liner. Minor leaks in the annular space between the liner and host pipe can worsen over time, creating a pipeline that not only lacks the integrity necessary to comply with standard industry guidelines, but one that may also suffer from reduced operational functionality. This paper will review two of the most commonly accepted internal service reconnection methods, both mechanical and adhesive, as well as testing data that was generated during a 12-month research and development project into these two methods. This data will be reviewed and conclusions drawn in regards to the critical aspects required of these methods to ensure long-term, water-tight connections in pressure CIPP systems.