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The ZMU Austria pipes were laid on some 300 linear meters.

Tiroler Rohre GmbH (TRM):

Use of ZMU Austria Pipes in Aggressive Soils

Aggressive soils such as clay or peat have corroded the snow pipes laid in a swale near Hintermoos. That’s why the Hochkönig ski resort is presently shifting to ZMU Austria coated pipes from TRM.

 

A drop in pressure in the pipeline system was recorded by snowmaking experts in the Hochkönig ski resort during a routine inspection before the 2018/2019 winter season. The cause was quickly found: a pipe in a swale near Hintermoos had externally corroded after twenty years of operation.

 

The corrosion was caused by the clayish, peaty soil with pH values of three to four. “We promptly exchanged the pipe. But it was immediately clear to us that we needed long-term solution,” reports Hartwig Moßhammer, Chairman of Aberg-Hinterthal Bergbahnen AG.

 

 

 

That’s why the cable car team sent the damaged pipe and soil sample to TIROLER ROHRE GmbH, (TRM) asking if they had any special product suitable for aggressive soil like that near Hintermoos. “We were offered their new ZMU Austria pipe with the guarantee that the affected 300-meter-long section will remain corrosion-free over the long-term,” says Siegfried Egger, authorized officer at Aberg-Hinterthal Bergbahnen AG.

 

The ZMU Austria pipe was developed as a result of a two years’ cooperation between TRM’s research department and an Austrian cement producer. It features an innovative fiber reinforced cement mortar used for external coating. “The pipe’s highly alkaline outer coating offers the highest degree of chemical protection preventing any kind of corrosion in soils up to the pH-value of ten,” explains TRM’s Marketing Manager,
Christof Mairinger.

The aggressive soil is present only in a 300-meter-long section. Photos: SI/Surrer

The fiber reinforced cement mortar also demonstrates a very high sulfate resistance, making this new pipe system suitable for highly aggressive, contaminated or sulfate-containing soils.

 

Mairinger refers to one very special quality of the outermost surface of the cement coating: “Through carbonation occurring during contact with the surrounding environment, the cement further hardens on the surface and builds a thick, resistant and water-repellent layer.”

 

All these positive qualities also convinced the Hochkönig cable car team. 300 meters of the ZMU Austria pipes were preventively laid parallel to the old route regularly covered with artificial snow. “It is more cost-efficient than exchanging damaged pipes one by one. By doing this, we satisfy our maintenance obligation in the best possible way,” says Moßhammer, explaining the complete exchange of pipes in the swale.

The use of shrink-on collars offers additional protection from corrosion.

Knowing that the pipes’ cement coat-ing prevents corrosion increases even further the cable car team’s already quite high trust in the ZMU Austria pipe with its additional cement mortar coating. “Another advantage is the mechanical protection which, for us, does not really play any role but it can be very interesting for our colleagues from the cable car industry,” says Egger.

 

The five-millimeter-thick fiber reinforced cement mortar coat protects the pipe from any damage during storage, transport and installation. “This new all-rounder, ZMU Austria, is virtually predestined for application in alpine and even hard-to-access, rocky terrain. Thanks to the pipe’s mechanical robustness, just about any excavation material can be used for backfill, including even rock inclusions up to 100 millimeters in size,” elaborates Igor Roblek, TRM’s sales representative responsible for the region.

 

The advantage is that no additional bedding or backfill material is needed. In addition to that, no waste disposal costs are incurred as the excavated material can be recycled.

The cement mortar layer of the ZMU Austria pipe is available in the blue color typical for TRM’s pipes.

“The economic benefit is clear. But environmental aspects also need to be mentioned:  thanks to the recycling of the original excavation material, the natural soil structure at the relevant spot remains unchanged,” adds TRM’s head of sales, Walter Korenjak.

 


Handling the excavation material is not a problem at Hochkönig, the snowmaking team themselves handle its laying. “It is in our experienced team’s own interest to work very carefully – after all, they are the ones who will subsequently have to work with the snowmaking pipes,” emphasizes Moßhammer. And his colleague Egger adds: “I know of many ski resorts which would also greatly benefit from the ZMU Austria pipe.”  ts

Siegfried Egger

Aberg-Hinterthal Bergbahnen AG’s Authorized Officer

“We have sent TRM samples of the pipe and the soil and asked them if they had any special product suitable for such aggressive soil. They promptly offered us their new ZMU Austria pipe. Its cement mortar coating efficiently prevents corrosion. As our planning is long-term and success-oriented, the decision in favor of the ZMU Austria pipe was easy to make!”