Aarsleff primarily uses close-fit lining for gas pipelines, but the method is also applicable to water and process pipes. Close-fit lining consists of long, fuse-joined PE pipes.

The launch and exit pits as well as all laterals and valves are exposed prior to installation. 

With a pulling device mounted at one end of the pipe the close-fit lining in question is pulled into the existing pipeline. Outside the launch pit the equipment for reducing the diameter of the fuse-joined PE pipes is placed. The diameter of the pipes is reduced immediately before installation. The entire installation is executed in one run.

After installation the new close-fit lining pipe expands to fit perfectly inside the host pipe.