In the 1950s, asbestos cement (AC) material became popular in the pressure pipe industry because of its good performance and durability. Used until the mid-1980s, AC then became a banned material worldwide.
Today, similar to Australia, thousands of kilometres of asbestos cement (AC) pipes are still being found in Europe, with the rehabilitation solutions for this aging material still being limited.
RTi Asia Managing Director Edmund Luksch says NordiTube provides two liner systems, which can be used to rehabilitate AC pipes successfully.
“The NordiFlow fully structural lining technology (Class A system) is independent from the AC pipe and able to carry all internal loads (pressure and vacuum), as well as all external loads (soil, ground water, surge, traffic loads available for DN 150 -DN 1400),” Luksch says.
“R-tec Close-Fit Liner systems, pre-folded PE Pipes, are factory made Class A systems – allowing structural liners to carry all loads (DN 150-DN 400).”
In 2021, NordiTube Technologies SE and its Hungarian installation partner Agriapipe Kft were awarded a 5.5 km of DN 400 AC sewer water main, running from a treatment plant to a reservoir.
NordiTube’s expertise, together with the fully independent Class A NORDIFLOW – which gives 100 per cent vacuum resistance and keeps the maximum flow capacity – introduced a very competitive price to make the final decision for the end customer easy.
Luksch says as an international tender, to be able to rehabilitate the AC pipes, the pits and pipes needed to be prepared so no AC fibres could leave the area.
“Therefore, the pipe section which had to be taken out needed to be in a sealed environment / tent, which operated with a low negative pressure and a special filter system that could catch all loose fibres,” he says.
“The workers who were in contact with the material needed to have special protection equipment and masks. All AC parts needed to be packed in special sealed bags and treated by a certified company.”
The host pipe ends had been prepared with a piece of steel pipe (or flange) which had the same ID as the AC pipe. These parts were essential to fix the liner end seals.
Luksch says 50 per cent of the lining had installation lengths greater than 250 m and had been done with the NORDIFLOW pull-in liner, including an an external coating.
However, the other 50 per cent were installed with the NordiFlow Inversion System in combination with a pre-liner.
The project was successfully executed and the new stand-alone NordiFlow Liner is now in service.
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This article appeared in the December edition of Trenchless Australasia. Access the digital copy of the magazine here.