Steel structures are considered very strong, stable and resistant to mechanical damage. For example, warehouse halls are made of them very quickly. However, this material also has a disadvantage, namely it can corrode. Therefore, steel structures require special protection. It is worth learning more about this subject.
Technical condition assessment of steel structures
Before you choose the right protection, it is necessary to assess the technical condition of the steel structure. This means that you need to analyze the load path, analyze the risk of potential hazards. A visual inspection is carried out, looking for potential damage or failure. Those performing the condition assessment also analyze how best to protect the structure. Non-destructive testing, which is just visual inspection, is taken into account, as well as destructive testing, which determines the condition of the material. This means that samples are subjected to deterioration and potential hazards are analyzed on the basis of these tests. Particularly important are corrosion, tensile or hardness tests.
Protection of metal structures – what should be kept in mind?
Metal structures require proper protection. It is important to realize that every year millions of tons of steel are used to build various types of structures, including even those belonging to functional architecture. Unfortunately, steel is prone to rusting, and it also quickly loses its properties when exposed to high temperatures. Fortunately, with proper protection, its performance can be enhanced. Fireproofing mortars, for example, are applicable. They consist of cement fibers, gypsum and vermiculite, among other materials. Importantly, they also feature an aesthetic finish. Of course, fireproof paints can also be used, which are particularly suitable for the surface of public buildings. Anti-corrosion painting is also extremely important. You can use the wet method, which is especially recommended for the protection or renovation of halls or bridges. Liquid paint is used, and the number of layers depends on the technical condition of the material, but also on the conditions to which it may be subjected. In areas where there is really high moisture, several layers are often used. It is important to remember the basic rule, namely that the next layer is applied only when the previous one has dried completely.
Choosing the right method for renovation of steel structures
Steel under the influence of moisture, but also water, can become damaged and rust. Although corrosion occurs gradually, the process can significantly accelerate. Sunlight combined with moisture has an effect on this. Anti-corrosion painting will work very well. A durable and flexible coating is used for this purpose. It can be applied directly to the rust. Another great product is primer paints, which are used for exterior steel structures. You can also opt for anti-corrosion primers that create a matte coating.
How to prepare the surface for painting with anti-corrosion paints?
Protection of metal structures is necessary to preserve their strength parameters, as well as safety. At the same time, you need to remember to properly prepare the surface. So, it is best to remove all dirt, as well as unevenness. You can also perform sandblasting of the substrate. There must be no dust or loose paint coating or mill scale on the surface. For cleaning, equipment with a rotary nozzle is most often used, and the pressure should not be lower than 300 bar. It is important to know that this cleaning method will also remove loose rust.
Which anti-corrosion paints to choose for metal structures?
The paint should be selected taking into account the corrosiveness of the environment. The EN ISO 12944-2 standard applies, where:
- C1 refers to an environment that is not very susceptible to corrosion.
- C3 refers to an environment that is moderately susceptible to corrosion. In it, there may be emissions of aggressive gases or temperature changes due to high insolation.
- The most susceptible to corrosion are structures where the corrosivity of the environment is high or very high, so C4 or C5.
It is precisely taking into account the corrosiveness of the environment that you need to choose anti-corrosive paints. You can choose from single-component ones, that is, ready to paint, as well as two-component ones that require mixing, consisting of a hardener and a base. The corrosion resistance of paint coatings can be short, that is, up to 7 years, medium, that is, from 7 to 15 years, and long, that is, from 15 to 25 years. Very long resistance refers to a durability of more than 25 years.
