# 2001 Munich
The use of the no-dig method of renovating waste water sewer pipes is becoming steadily more common in the area of sewer systems, in spite of ever declining budgets.
But maybe for this very same reason, other contemporary terms such as “pipeline integrity” are also becoming more important.
Against this background, the development of optimal materials for this special pipe systems market has taken on a special significance.
This report describes the properties of a material mix especially developed for use in the renovation of pipes and refers, in particular, to material behaviour during installation and after commissioning of the renovated pipe.
Furthermore, it pays particular attention to the fold-and-form plastic pipes made of the universally-known high-density polyethylene (PE-HD) and a modified PVC (mod.
PVC)1,2 which has been specially developed for the so-called Close-Fit-Relining method.
The latter thermoplastic consists mainly of polyvinychloride and has been modified with ethylene co-polymerisate. This report will demonstrate:
• That this special material works in an optimised and application-oriented temperature range and can thus be processed more quickly and safely than conventional polyethylene.
• Why the annular space between the inliner and the old pipe can be reduced to a minimum.
• That the thermal expansion coefficient is reduced.
• That the forming properties of this material are optimal for application.