A close fit lining with PE pipes means renewing a pipeline efficiently, durably and environmentally friendly using a factory-made PE pipe. This pipe is deformed (folded) thermomechanically in the production process. The maximum length of the pipe to be coiled up is determined by the outer diameter of the pipe. Depending on the nominal width, several hundred meters of new pipe can be installed in one run thanks to its reduced cross-section. By passing steam and pressure through the new pipe, it expands to its original round form and fits tightly in the old pipe, being statically autonomous.
Before commencing the rehabilitation, the existing pipeline is cut off. Following a camera inspection, obstables and incrustations are removed from inside the old pipe. If necessary, a provisional pipeline is installed to ensure supply of the users during the construction process. After that, the liner is pulled into the existing pipe with a motor winch. The liner pipe is then heated with hot steam which activates the ‘memory effect’. Passing steam and pressure through the close-fit-liner causes it to unfold and fit tightly to the inner wall of the old pipeline. After the joints are connected safely through electrofusion sleeve welds, the rehabilitated pressurized or non-pressurized pipeline can be reconnected to the grid.
The new pipeline can be commissioned after a successful pressure test and flushing of the pipe.