Rehabilitation # 2004 Milan
An old 1550 mm diameter heavily corroded water pipe, was in March 2003 relined in Kolkata, India by using 1400 mm SDR 30 PE pipework. In all, 1 km of pipe was rehabilitated. To facilitate the installation of the PE pipe and maximize the insertion lengths, extensive planning for a slip-lining operation was carried out. The PE pipe was pulled into the steel pipe in three sections, with lengths between 240-430 metres and each pipe section weighing between 50 – 90 tonnes. Limited mechanical equipment was available; basically just a winch with 30 ton pulling capacity. By utilizing the flexibility properties of PE pipes and optimal locations for insertion and receiving pits, the insertion lengths could be maximized. Even an unexpected misalignment of the existing steel pipe was eventually overcome. The whole installation was carried out in less than two month time and to a relatively low cost.