# 2001 Munich
Fold and form procedures for the trenchless renovation of gravity drainage pipe systems have been used throughout the world since the late eighties. Fold and form procedures are classified as renovation by the European Committee for Standardization CEN. OmegaLiner®, a product combining the advantages of comparable procedures with a special material composition, has been marketed by Uponor Anger for several years. The material is modified PVC (PVC-U). The application of these procedures results in a “pipe within the pipe” (lining). Omega-Liner® is installed in the defective pipeline in a close-fit manner.
The article describes the application of PVC-U fold and form procedures based on the Omega Liner® technology and compares it to the PE-HD fold and form procedure ULiner that has been used by PRS Rohrsanierung GmbH for many years.