The Lindab Blog

Corrosivity classes and warranties – a jungle to master

By Zeina Lindström, May 07 2018


It is easy to get dazzled by marketing campaigns with products that can handle the toughest environment when it comes to corrosivity (C5). Many believe these products have to be the best and that you really get quality products in place if you were to mount these.

What many people do not know, is that to technically be able to say that a product fulfills C5, the standard only demands 2 years of testing. If the product is approved after these 2 years, you can brand the product with the C5 standard. This becomes a bit irrelevant and meaningless, unless you are pleased with the product lasting for only 2 years of course. 

First you have to figure out what the environmental preconditions are, which corrosivity class, you are about to mount a product in (there are tables available with examples of environments in C1 to C5) and then check how long the warranty period is in that particular environment. It happens that technical data sheets state one thing, but when you check the warranty, it can actually exclude the environment that is used in the marketing campaign. What then happens is that you get a crash between the standard (2 years) and the warranties, where anything between 10-50 years can apply.

Poor knowledge

As more and more companies are trying to benefit from the industry's poor knowledge about this matter, a sort of competition in corrosivity has emerged, resulting in inaccurate quality and deceiving promises.

So, watch out for this, and check all the facts before you fall for the simple tricks. Make sure to always mount the right material in the right environment so that we get long lasting buildings, it benefits everyone involved as well as our climate.

Warranties always include terms and conditions that need to be fulfilled for the warranty to apply, and they are there for a reason. We simply know that products last longer if mounted correctly, maintained and washed regularly.

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5 tips regarding corrosivity classes and warranties

  • Find out which environment the products you are purchasing are to be mounted in
  • Check the warranty period in that particular environment
  • Read the terms and conditions of the warranty, making sure there is nothing in your case that the warranty would not apply
  • Always rinse off products mounted in so called rain shadow at least once a year
  • In case of doubt and questions always contact your material supplier before you mount – it is easier to straighten things out before the products are mounted incorrectly

More information?

Do you want to know more about sheet metal, such as colours, paint systems, rust protection, base materials or warranties for that matter? 

Contact us!  

Topics: Corrosivity classes, Warranties, Building components

Zeina Lindström

Zeina is Steel Quality & Material Development Manager at Lindab Group
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The Lindab blog aims to give you an inside track to our company. We would like to share our knowledge from over 50 years of production for the construction and ventilation businesses.