Pipe reduction

Trenchless rehabilitation of gas, water and effluent pipes

The pipe reduction procedure exploits the existing cross section of the old pipe to an optimum degree (close fit). Old pipe materials can be renewed with this technology. Commercially available PE 100 RC tubes are used for the new pipe. The pipe reduction procedure can be employed for nominal diameters from 100 mm to 1,000 mm. Cutting lengths of 200-300 m can be achieved without an intermediate trench, but house service connections and shaped fittings need to be dug out and replaced. Commercially available top loading connections, electrically welded sleeves or multijoint couplings are used for connection.

Comprehensive quality assurance is state of the art in every respect for a modern trenchless technology such as the pipe reduction procedure. In addition to TV inspection and pipe cleaning, the use of state-of-the-art equipment such as CNC-aided welding plants, data loggers, etc. is standard at Swietelsky-Faber. All data relevant to quality, such as welding parameters and, especially, tensile forces acting on the new pipe, are electronically recorded and documented. Experienced personnel with specialised training in the pipe reduction procedure and ÖVGW-certified plastic pipe fitters are the guarantee of superior-quality workmanship.

The pipe reduction procedure is a uniquely cost-effective pipe renewal technique involving only minimal cross section reduction. The old pipe section must be cleaned prior to commencing pipe drawing operations. The success of cleaning is checked through TV inspection and documented on DVD. It should be ensured in this respect that the required cross section for the new pipe is achieved in the entire renewal section. The new commercially available PE 100 RC tube is welded outside the drawing pit and then drawn through a reduction taper. The pipe with the reduced cross section can now be drawn into the existing pipe using a hydraulic drawing machine. As soon as the pipe is drawn in completely, it automatically returns to its original diameter (memory effect) and presses closely against the wall of the old pipe as a result without complicated thermal evaporation (close fit). This renews the old pipe, while the loss in cross section is merely equivalent to the wall thickness of the new PE pipe. It goes without saying that the pipe reduction procedure also offers all the advantages of trenchless techniques: the most rapid possible work realisation, protection of the environment and local residents through the minimising of excavation work and, naturally enough, the preservation of parking and traffic surfaces. This results in a considerably improved on-site CO2 balance sheet.