Use of corrosionproof fasteners for the installation of sandwich panels

Sandwich panels are fastened to a supporting structure with screws. This kind of facade cladding is time-tested and reputable. But there is a little detail you have to know to extend the lifetime of a facade by 2 or more times. That’s what we are going to talk right now.

Screws of carbon steel.Self-tapping screws or screws for panels fastening will be used for many years to come. And now the task is to extend the lifetime of these components. Fasteners commonly used in Russian and most other countries are made of carbon steel coated with Zinc or another corrosion-resistant material. It may be high-grade gReycoat coating, or, possibly, a cheaper one. But in Germany it has been forbidden to use such screws as fasteners. Notably, it was legislated. So, they began to use stainless steel screws instead.

Stainless steel screws. Stainless steel differs from the simple one in the fact that its composition includes chrome. Its percentage composition is 15-17%. Chrome covers the steel with a thin anticorrosive film that recovers, if damaged. Moreover, stainless steel also includes nickel, which further enhances its corrosion-resistance.

Compare the benefits. Two companies decided to estimate the benefits of such change: manufacturer of sandwich panels Stroypanel LLC, and fasteners manufacturer Gunnebo Industries. They came to the conclusion that usage of self-tapping screws made of stainless steel doubles a facade’s lifetime. While a facade fastened with carbon steel fasteners lasts for up to 20 years (assuming that high-quality European screws are used), the same structure fastened with stainless steel screws lasts for 45-50 years. And in the latter case it’s not a screw that will cause a structural failure eventually, it’s a sandwich panel.

At that, the cost of the facade increaes by just 1%. Thus, this design will pay its way quite fast. The estimation was made for environments aggressively affecting a construction. For mildly aggressive environments the use of high-grade carbon steel self-tapping screws is preferred. For they are cheaper. In this case, they will easily last for 30 years and more. But what should we do with chemical and food production plants, hospitals and other buildings affected by aggressive environments? These are the cases, when screws of high-chrome steel should be used.

Facade-cladding panels faced with stainless steel. After the research Stroypanel and Gunnebo Industries decided to carve out a premium niche within the facade-cladding systems industry. Moreover, they decided that high quality of fasteners is not enough. Coating a facade-cladding panel with a polymer is a good option, but only if environment conditions are neutral. But if a facade cladded with polymer-coated sandwich panels is affected by an aggressive environment, then stainless steel fasteners extend its lifetime by mere 2.5 times. And eventually the panels themselves will collapse.

It was therefore decided to initiate manufacture of stainless steel-faced sandwich panels in addition to conventional ones. Of course, this increases the cost of the facade by half, but the structure’s lifetime is increased multifold. Eventually, this leads to substantial profits. Besides, buildings cladded with stainless steel-faced sandwich panels have original hi-tech look.

Beware of imitations. Sandwich panels and fasteners made of stainless steel are conquering Europe and are likely to become popular in Russia. But be careful and check the percentage composition of all the components the steel is made of. Fakes always were, are and will be. Therefore it is necessary to be especially careful with products imported from Southeast Asia and China. These are the regions you should expect the fake “alternatives” to come from, with forged datasheets and at a low cost. Obviously, use of such panels in construction may lead to quite dire consequences.





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