Safety turbine maintenance using ZARGES work platforms

The client

The torrents of water that flow through the pipes of the E.ON Hydro Power canal power plant in Töging am Inn are colossal. Up to 340 cubic metres of water, at least 340,000 litres, roar through the pipes every second. This represents sufficient force to generate huge amounts of eco-friendly electricity.

This had already been recognised by experts back in the 1920s and the decision was taken to exploit the immense power of the River Inn. But the power plant in Töging itself is not the only facility that is part of the hydroelectric plant. The canal that brings the water to Töging branches off 20 kilometres upstream. At its end is a 110-metre long surge tank with 14 downpipes leading to the powerhouse. Each of these pipes is over 50 metres long and measures 4 metres in diameter. In the 5 years it took to complete the entire building project 7,000 workers transported more than 14 million cubic metres of earth and processed 400,000 cubic metres of concrete and 11,000 tons of steel. The costs amounted to 23.12 million gold marks.

In Töging, water drives the 14 turbines in the powerhouse at a fall of 30 metres. From its commissioning in 1924 until 1999, the power plant generated around 40 billion kilowatt-hours of eco-friendly electricity. This was initially consumed almost exclusively by the nearby aluminium works, but since closure of the works, the electricity produced has been fed entirely into a three-phase network.

The Töging hydroelectric plant is part of E.ON Hydro Power's eco-friendly power generation operations. 16 staff ensure that everything runs smoothly and attend to the maintenance of the turbines and generators. This is a major challenge particularly on the Inn because the river contains a lot of suspended solids – even an average quantity of suspended solids amounts to around 13 tons per day, leaving behind traces as it flows through the turbines.


For the above reason, one turbine a year is shut down and completely disassembled for major overhaul. Over a period of three months, workshop fitters then replace all worn parts, clean the turbine and re-seal it. A multitude tasks need be completed in the process.

Previously, scaffolding was erected to carry out the work on turbine parts measuring up to 4 metres high. This was not only complicated, but also inflexible. Erecting and dismantling the scaffolding was laborious and even small changes in height required its re-erection. Furthermore, space for the scaffolding was not always available in the powerhouse. “A directive from E.ON Hydro Power forbid working from single ladders,” explains Robert Eder, the hydro-power team leader on the Inn. “But we need both hands free and stability, for example, to scrape off the old gaskets and replace them with new ones.”

Technical special features

Expert advisers from the ZARGES sales team demonstrated the newly developed ZARGES ZAP work platform to the E.ON Hydro Power staff. The platform combines the flexibility of a ladder with the safety of scaffolding. The stable and height-adjustable ladder parts support a secure platform with peripheral guardrails. “ZAP saves us a lot of work,” reports Robert Eder after its initial use. Access is much safer and easier than using scaffolding. Workers have firm footholds on the work platform and can work freely with both hands while having space to store tools. 

The work platform can be adjusted to the desired height quickly and easily and, thanks to integrated castors, it is also easy to move. “Everyone who's worked with it thinks it's brilliant,” says Robert Eder. 

ZAP is now being used in the E.ON hydroelectric plant in Töging not only for turbine maintenance, but also for a multitude of other tasks. “It takes no more effort to set up than a standard single ladder,” says Eder. The staff are impressed by the high degree of safety provided by ZAP.


“As flexible as a ladder, as safe and comfortable as scaffolding” is the slogan for Zarges ZAP work platforms which fill the gap between ladder and scaffolding. ZAP offers optimal convenience and maximum safety for long-term, strenuous tasks at heights.
The new work platforms can be folded like a ladder and easily transported thanks to integrated castors. They are set up on-site and are ready for use in less than a minute. Thanks to the generous platform area with all round guardrails, they offer a stability and maximum safety, particularly for tasks requiring both hands free. 

The Zarges ZAP work platforms come in two different versions: with a telescopic platform ladder which can be adjusted upwards and downwards with the familiar, tried-and-tested push-up ladder principle; or as height-adjustable platform steps with large, non-slip steps for easy access. Both versions are height adjustable. Working heights of up to 4.20 metres (for platform ladders) or 3.20 metres (for platform steps) can be set instantly. 

The ZAP series from ZARGES is currently being extended:

  • ZAP work platform: A height-adjustable platform up to a working height of 5.60 m which can be folded up to save space.
  • Z600 ZAP stepladder: A stepladder with five non-slip steps and a large standing platform enclosed in a safety cage. Additional stabilisers are optionally available to give even more stability.
  • Z500 ZAP telescopic platform ladder and Z500 ZAP platform ladder: Competitively priced alternatives for maximum stability. Successful products with slightly fewer features but with the same high safety and quality standards.

Interview with Robert Eder, Competence Team Leader at E.ON

Z-experts forum:What was it that led you to purchasing the ZARGES ZAP work platform?
Robert Eder:We attach great importance to work safety at our company and directive has been in place for some years to the effect that ladders may be used only for gaining access to a work platform. Maintenance work on our turbines also required major effort in the erection and dismantling of scaffolding.
Z-experts forum:What tasks is the ZAP used for?
Robert Eder:We use the work platform not just for turbine maintenance. They also provide high standards of safety for many other tasks too, e.g. inspecting cranes and other work at heights. We need two free hands and a secure footing for much of the work we do. A platform with all-round guardrails is therefore the perfect solution.
Z-experts forum:How have staff responded to the new access system?
Robert Eder:Everyone who's worked with it thinks it's brilliant. Having used the ZARGES work platform once, they want to use again and again. It is quick and easy to set up, is effortless to transport and fold up and neatly stored. As the boss, I feel better when workers have a secure footing and both hands are free to do the tasks.
Z-experts forum:Is one ZAP actually enough for the multitude of tasks in the hydroelectric plant?
Robert Eder:The experience has in fact been so positive and the staff's enthusiasm so great that we are already considering buying another ZAP. We will in any event be passing on our experiences to the company group so that our colleagues can also have the greatest possible safety when working at heights.


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