Successful use of ductile cast iron pipes in renovation using long pipe relining

The comprehensive renovation of the long-distance Thallwitz-Leipzig fresh water pipe, which daily transports 24,000 m³ of fresh water to Leipzig, has to be carried out in individual sections.

At the beginning of last year, the decision was made to prepare and put out to tender the section most at risk of pipe ruptures, which is located in the residential area of Leipzig-Mölkau, in the form of single-phase planning. This section will be renovated using the so-called “long pipe relining” process. In this renovation method, new pipes are pushed into the already existing, damaged pipes. This modern and very economical process has today become one of the best-proven methods of pipe renovation.
 
For the renovation of the pipe in Leipzig-Mölkau, the client, the “Kommunale Wasserwerke Leipzig GmbH”, decided on ductile cast iron pipes to DIN EN 545 from Buderus, which are lined on the inside with cement mortar, and have a zinc protection with coating as the outer protection.

The decision in favour of these pipes was made largely because of their long service life, the proven connection technology, the ease of handling during installation and their generous safety reserves.
 
After the old DN 1100 grey cast iron pipe had been mechanically cleaned and flushed out, the sleeve gaps sealed and the heels levelled, the Buderus DN 900 pipes could be pushed in without any problems. The subsequent integrity test of the new pipe was passed at the first attempt. Due to the excellent co-operation between all those involved in the construction, the planned construction time of two months was reduced by three weeks.