Robust cast iron pipes for the Feldkirchen drinking water network
Regular servicing and maintenance of a drinking water network pays off. This is also one of the reasons why the urban area of Feldkirchen in the Federal State of Carinthia is particularly anxious to replace their ageing pipes or pipelines whose dimensions no longer correspond to current requirements. Therefore the municipality is responding to a recommendation by the Austrian audit office which advises communities that they should renew around 2 to 3% of their network of drinking water pipelines each year. This is because the funding authorities have also responded to this recommendation and suuport those communities with a higher rate of funding that maintain their pipeline network constantly.
Ratio of resident number to supply area
The lasting financial advantage is only one aspect of the reason why the urban community checks the performance of their water supply network regularly; the topography of Feldkirchen is another one. The community counts barely 15,000 residents spread over an area of around 77 km2, which equates to a considerable spread in relation to population numbers.
Feldkirchen has a large arsenal of supply sources available to it – with 17 pumping stations, ten wells and one deep well plus 15 elevated tanks with a volume of 3,500 m3, 4,000 domestic connections across a 230 km long network of pipelines are supplied. The piping network is being recalculated for the planning of a new housing project.
Calculation of pressures and volumes
What volumes of water are required at peak times, whether these can be transported by the existing piping network or whether adaptations are necessary were the results of the hydraulic pipe network calculation. For example, a need for adaptation in the form of an enlargement of the pipeline cross-section was identified in one area of the main supply pipeline in the network.
In order to guarantee the security of supply of drinking water and water for other purposes, both for the town and for the newly developed land around it, it was decided to extend the existing system and the constantly ongoing extensions for new-builds and new developments.
Uninterrupted water supply
The particular challenge for the renovation work completed to date was guaranteeing the water supply for the town and the surrounding area even during the construction work. So the first construction stage to be completed was the one which ensured the supply of the urban community from the deep well; those in the outlying settlements of the urban community of Feldkirchen were supplied from the small wells.
The particular challenge for the renewal work was guaranteeing the water supply for the town and the surrounding area even during the construction work. Various different alternatives were considered for this, which also carefully scrutinised the scheduling of construction stages so as not to disrupt the traffic too much.
Installation of various valves and hydrants in the piping network.
Crossing the railway was the greatest challenge
The contractor CCE-Ziviltechniker GmbH, together with the urban community, decided to use ductile iron pipes from Tiroler Rohre GmbH in nominal sizes DN 100, DN 125, DN 150 and DN 200. There was one construction phase, where DN 200 pipes were installed, which proved a particularly tricky task for those in charge: Crossing the railway line, where it was not clear whether it would work, because there was only use of an abandoned rainwater drainage channel, that didn’t run straight but slightly curved.
The robust DN 200 ductile iron pipe can be deflected up to 4 degrees. Thanks to this flexibility of the joint, the pipes could follow the curved course of the rainwater channel. Feldkirchen saved money here was there was no need to use fittings and the work could progress more quickly.
5,750 m cast iron pipes from Tiroler Rohre GmbH have been installed in the last three years. They replace the ageing PVC pipes.
From PVC pipes to ductile iron pipes from TRM
In the nineteen sixties and seventies, a great deal of housing development occurred in the whole of Austria. In the course of this, in Feldkirchen too, a network of pipelines came into being, for the most part in PVC pipes. In the last two decades these PVC pipes have come to the end of their useful life and have gradually been replaced by ductile iron pipes. Quality material, a long working life and the good hygiene properties for drinking water all speak in favour of the cast iron pipe system. “Quality counts“, says water engineer Werner Drolle with satisfaction, and also the service and the reliability of Tiroler Rohre GmbH were convincing.
Products from the home market preferred
Whenever possible, the municipality goes for home-produced products and when selecting products, it is not just a question of the cheapest price but of the quality. “The price-performance ratio must fit,“ explains Feldkirchen‘s deputy mayor Siegfried Huber. Added to this is the fact that with good support by experienced sales representatives, smooth progress of work is guaranteed. Until now 5,750 m of TRM cast iron pipes has been laid in the Feldkirchen network of pipelines.
Author: Patricia Pfister, Fachmagazin zek kommunal
Contact person at Tiroler Rohre GmbH: Igor Roblek