Application of CIPP (cured in place pipe) for water pipe rehabilitation

The need for rehabilitation of water system is rapidly growing in many Korea cities. For the rehabilitation of water pipeline, the open-cut method has been prevalent in Korea. But long duration of works, traffic interruption and environmental impact raised the cost. So many trenchless methods such as epoxy lining, ceramic mortar lining, CIPP, slip-lining and others have been developed and used for the cost and environmental advantages. Among them, CIPP has high rehability for pipe rehabilitation as semi-structural and safe lining method. This time, new CIPP method for water pipe rehabilitation was developed and applied to the real site. The safety of liner for drinking water was confirmed in the previous study. So curing for branch pipe and connection of lined pipe to unlined pipe was developed with pilot pipeline test. For the application of developed CIPP, pilot test was executed with 300mm and 1,200mm ductile iron pipe with fittings. And developed CIPP method was applied to the water pipes with diameters of 350mm, 600mm, and 800mm buried in 1930's at the G water treatment plant in Seoul. The rehabilitation work was executed by the following steps. First, inside condition of pipe was investigated using expert robot and scales of pipe were washed out by scraping. Applied CIPP is consisted of unsaturated polyester resin and polyethylene tube, inserting by air pressure and curing with misting hot water. In case of water pipe, connection technique is very important because high water pressure is maintained inside pipe. For the connection of lined pipe to unlined pipe, flange method was used. From the success of rehabilitation with CIPP, the application of CIPP can be expended for the rehabilitation of water main.