Aarsleff applies the PI liner for trenchless rehabilitation of pressure and process pipes as well as for inverted siphons that due to uplift pressure cannot be emptied of water.

The PI liner is composed of a strong, reinforced preliner and an Aarsleff Tube.

The preliner is placed closest to the host pipe wall. Inside the preliner is the Aarsleff Liner. The preliner serves as protection against infiltration. The Aarsleff Tube combines with the preliner to provide strength to the new pipe.

The installation is carried out from a scaffold placed above an excavated launch pit. First the impregnated preliner is drawn into the pipeline. The Aarsleff Tube is then inverted into the pipe by means of water pressure. When the tube is in place it is cured with hot water. After the curing, the tube is hard and abrasion-resistant with a smooth surface.