Corrosion is a natural process in which a material is gradually destroyed by a chemical or electrothermal reaction. Corrosion often occurs when metal comes into contact with water and oxygen.

Metals only occur in nature as ores. In order to make them into a usable material, oxygen is removed during the transformation process. However, the material strives to return to its original state. In other words, metal corrodes upon contact with oxygen in order to return to its original oxidized state.

In wind turbines, this process is particularly accelerated by salty air and moisture, as found in offshore wind farms. Salt water promotes the formation of electrolytes, which accelerates chemical reactions on the metal. These reactions lead to the formation of rust, which impairs the structural integrity of the metal parts and can ultimately lead to their failure.

There are a total of six corrosivity categories. They are categorized based on locations of the buildings and the corrosion potential prevailing there.

• C1 = insignificant: heated buildings, thickness reduction of unalloyed steel ≤ 1.3 µm
• C2 = low: atmosphere with low contamination and unheated buildings with condensation; thickness reduction of unalloyed steel > 1.3 - 25 µm
• C3 = moderate: Urban and industrial atmosphere with low SO2 contamination, coastal atmosphere with low salt contamination and production rooms with high humidity; thickness reduction of unalloyed steel > 25 - 50 µm
• C4 = strong: industrial atmosphere and coastal atmosphere with moderate salt pollution; thickness reduction of unalloyed steel > 50 - 80 µm
• C5 = very strong: industrial areas with high humidity and aggressive atmosphere, coastal atmosphere with high salt load; buildings or areas with almost constant condensation and heavy contamination; thickness reduction of unalloyed steel > 80 - 200 µm
• CX = extreme: Offshore areas with high salt load, industrial areas with extreme humidity and aggressive, subtropical or tropical atmosphere; industrial areas with extreme humidity and aggressive atmosphere; thickness reduction of unalloyed steel > 200 - 700 µm

Corrosion can cause significant damage to wind turbines, affecting their structural integrity as well as their safety and efficiency. One of the greatest dangers is the structural deterioration of load-bearing parts such as towers and flanges. This leads to cracks and, in the worst case, to breakage of these components, which can jeopardize the stability of the entire system.

Another significant problem is the safety risks that can arise from corroded parts. Particularly in offshore wind turbines, where repairs are difficult and costly, the failure of critical components can cause dangerous situations for technicians and the turbine itself.

Corrosion also leads to increased maintenance costs, as wind turbines in such extreme environments require more frequent inspections and repairs, especially when no truly effective corrosion protection is applied. Repairing corrosion damage is time-consuming and expensive, making regular maintenance necessary to extend the life of the turbine and avoid unexpected failures. The environmental impact of flaking paint and rust particles is also a problem. Therefore, environmentally friendly protective measures is necessary to minimize such negative effects.

Last but not least, corrosion-related damage leads to considerable downtime when damaged parts need to be repaired, replaced, or new corrosion protection measures need to be taken. Every minute that the system is out of operation means financial losses due to lost of energy production.

To protect metal coatings and steel from corrosion, so-called corrosion protection systems are used. One of such systems could be the composition of two or more layers of coatings that differ in their functions and thickness, depending on the location of the wind turbine.

Such coatings can consist of paint or film that prevent the metal from coming into direct contact with water, oxygen and other corrosive substances. Conventional corrosion protection systems are not always efficient or flexible. Painting work, in particular, is extremely dependent on the weather conditions on site and requires drying time in addition to surface preparation work and the application of various layers.

In comparison, the self-adhesive corrosion protection film RENOLIT CP Advanced offers significantly more efficient and reliable protection. It is not necessary to apply a primer, nor do drying phases have to be maintained, so that downtime can be reduced to a minimum. What's more, the film is also environmentally friendly. It does not release any volatile organic compounds (VOCs) and does not cause any contamination like in the case of dripping paint.

Regular inspections and maintenance also help to detect and repair corrosion damage at an early stage. Nevertheless, up-to-date, truly effective corrosion protection remains the best option for keeping corrosion in check and maximizing the operating time of the wind turbine.

The application of RENOLIT CP Advanced is simple and efficient: First, residual paint and rust spots must be removed, the surface must be thoroughly cleaned. Then, the film can be applied bubble-free using a squeegee right after cleaning the surface without additional primer, as the corrosion protection effect is integrated directly into the film.

Corrosion protection feature is available immediately without the need for a drying time. The uniform film thickness and the thick adhesive layer enable simple and effective application, even on rough or uneven surfaces.

The wind turbine can be put back into operation right after application of RENOLIT CP Advanced.

Yes, after detailed training and instruction, you can apply the film quickly and easily.

The thickness of the film is ≥430 μm.

The film is produced in the color RAL 7035 (light grey).

The color RAL 1023 (traffic yellow) is also available on request.

The film is designed for use in a temperature range between -30 and 70°C.

The film can be processed at temperatures from 10 to 35 °C.

Like conventional coatings, there is no fixed upper limit for air humidity. Instead, it is important to ensure that there is no visible condensation of air humidity on the surface if there are differences between the air and surface temperature.

Yes, the RENOLIT CP Advanced film is certified in accordance with the BAW standard and ISO 12944-9 CX (protection duration: high) and offers long-term corrosion protection of 10 years and more.

CX represents the highest corrosivity category. This means that the film even protects steel and metal coatings in areas where the risk of corrosion is extremely high. These include industrial areas with high humidity, a high salt content and a particularly aggressive atmosphere. This makes it the ideal corrosion protection for the offshore wind sector.

RENOLIT CP Advanced is more environmentally friendly than conventional paint for a number of reasons. Firstly, the application of the film does not release volatile organic compounds (VOCs), which are harmful to the environment and human health. VOCs are a common problem with paint as they escape into the atmosphere and contribute to air pollution.

Secondly, with film application there is no risk of paint or other environmentally harmful substances dripping into the sea or soil. This is particularly important for offshore wind turbines, where protection of the marine environment is a priority.

Thirdly, the film is quick and easy to apply, which greatly reduces the need for extensive surface treatment work and drying phases. This means that less energy and resources are consumed overall to create corrosion protection for wind turbines. Therefore, RENOLIT CP Advanced protects both the environment and the health of the people applying the corrosion protection on site.

Yes, RENOLIT CP Advanced is highly UV-resistant. The film has been specially developed to withstand the extreme conditions in onshore and especially offshore environment, including intense UV radiation. The UV resistance has been proven by extensive tests, such as the 15,000 hour xenon test in accordance with ISO 4892-2.

These tests ensure that the film maintains its protective properties even after many years of exposure to sunlight and does not degrade. As a result, RENOLIT CP Advanced offers reliable long-term protection for your wind turbines.