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The Corrosion Protection Film RENOLIT CP is an effective Means Against Bolt Corrosion


Worms, 22nd June 2022 – The RENOLIT CP high-performance film has once again proven itself in a practical project: Last week, repair work was planned for two wind turbine towers at a wind farm near Hanover, Germany. Severe corrosion on the flange areas and weld seams had brought the experts from WP Energy to the field: they applied around 45 square meters of the protective film, thus renewing the legal corrosion protection requirement for wind turbines. The RENOLIT CP film, which is certified according to ISO 12944-9 CX, offers long-term corrosion protection of 10 years.

Prevention with RENOLIT CP

Wind turbines are regularly inspected and checked for safety – at least every four years. The sensitive flange areas are often the Achilles’ heel of steel towers, as water can enter the tower at the flanges and especially around the bolts – a breeding ground for corrosion. So the better the flange areas are protected, the better the corrosion protection.

RENOLIT CP can also be applied as a preventive measure,” explains Ralph Gut, General Manager at RENOLIT, “preferably from the factory or when the towers are still new. Because wherever there are gaps, the danger of corrosion lurks. Especially around the flange areas, it makes sense to apply our film preventively: The film effectively prevents water ingress and can save high costs that would be incurred in the case of major repairs.” 

Film instead of paint

Although all towers are given a protective paint coating from the factory, as soon as spalling, flaking or even slight damage occurs – for example due to weathering or impacts from the technicians’ tools – the effort required to seal this damage with a new coating is comparatively very high. The application process with RENOLIT CP, on the other hand, only requires a few steps: After the surface has been cleaned and the primer has been applied and dried, the film can be applied. In the case of paint, three coats are often necessary for comparable protection, including the respective drying time. Thanks to only one drying time of the primer and the film as the top coat, RENOLIT CP can be applied more quickly and independently of the weather. This enables more flexible repairs, reduces downtimes and saves costs.

“Another option would also be to inspect existing towers before the legal deadlines expire to see where there is potential for corrosion – and take countermeasures at an early stage,” adds Christin Otto, Key Account Management at WP Energy. “Thus, the corrosion protection film can also be used as a 2-in-1 measure to protect the metal areas on the tower and save the flange area from a costly overall bolts replacement that would be necessary due to a single corroded bolt.”

About RENOLIT CP

The high-performance film was specially developed for the application on wind turbines – it protects the steel and metal coatings of the towers from corrosion. RENOLIT CP is an efficient alternative to conventional paint. The product has been established on the market since 2020 and is distributed exclusively by RENOLIT partner WP Energy (part of the WP Group), which also applies the protective film on the wind turbines. The film has an unprecedented durability of 10 years, which is confirmed by ISO 12944-9 CX certification. In addition, RENOLIT CP is environmentally friendly: the film does not emit any volatile organic compounds (VOCs), and thanks to the long durability of the corrosion protection system, hazardous waste and VOCs are significantly minimized during the 10-year period. This reduces harm to people and the environment, as well as health risks. In addition, the dripping of paints or pollutants into water bodies is prevented.