Design of CIPP Pressure Liners Using the HDB Method

Rehabilitation of water distribution pipes using CIPP (cured-in-place-pipe), a fiber-resin composite lining system, is a viable alternative to pipe replacement. This paper will discuss the challenges of using the well-established thermoplastic hydrostatic design bases (HDB) design method for CIPP pressure pipe liners. For example, HBD curves for thermoplastic pipes are developed using 25 mm/1 inch or 50 mm/2 in. extruded tubes. Since CIPP liners are constructed with reinforcement layers and resin the construction of small tubes for HDB testing is not possible. At the University of Waterloo, a new test facility has been constructed to develop HDB curves for CIPP lining systems, as well as, test specimen subjected to pressure cycles. HDB test results for 150 mm/6 in. diameter Insituform's InsituMain CIPP liner will be presented along with short-term burst test results for other commercially available CIPP pressure liner products. The paper will conclude by proposing a standard methodology for HDB testing of CIPP pressure liners and determining the liner pressure class/pressure rating.