AGRU’s Close-Fit liner has been used in the trenchless renovation of a 5200m pressurised sewer sited in the few metres separating a busy main road and the Danube river to the east of Linz in Austria, in a project requiring the liner to be formed into a U-shape on site to allow insertion into the existing pipe.

The contract for rehabilitation of the 400mm diameter ductile iron pipe was awarded by the RHV water association to RTi-Austria. It involved lining the existing pipe with a PE 100-RC liner to restore the structural integrity of the pipe.

The liner is formed into a U-shape and pulled into place, before being restored to its correct shape. Normally the liner is folded at the factory and supplied on reels. The project required lengths of up to 620m, because of which the client required the pipes to be folded on site.

The pipe was supplied in 18m sections. These were butt welded on site into sections of between 400m and 624m. These were formed into a U-shape and held in this shape with straps. Pressurised steam was used to restore the inserted pipes to the original shape, providing close contact with the existing pipeline.