Corrosion resistance of substructure
Corrosion resistance of each element of substructure has huge impact on the overall resistance of a system. Corrosion resistance tests are also very significant factor of product admission for use in construction process. This applies especially to metal elements. Subframe systems for ventilated facades are usually made of aluminium – material that is very resistant to atmospheric factors. Nevertheless elements of the system are fixed to the building and each other with different screws and anchors. Very often those elements are made of galvanized steel and therefore they anti-corrosion resistance is lower in moist conditions.
Galvanized steel made anchors are allowed to be used if they are coated with an additional bitumen protective layer and hidden in insulation. Using galvanized steel screws and self-drilling screws to connect other elements of substructure in locations exposed to humidity and moisture is a bit risky at best. Corrosion resistance class is determined by PN-EN ISO 9223:2012 norm. Corrosion class of an element is the first thing to do in order to establish corrosion class of an environment in which the element can be used. There is six such environments classes: C1, C2, C3, C4, C5-I and C5-M. Majority of constructions take place in C3 environment (medium polluted urban and industrial areas) and C4 environment (industrial areas and seaside with medium salinity).
BSP elements have been tested by ITB (Building Research Institute) for anti-corrosion resistance. All of our elements are B durability class by PN-EN 1999-1-1:2011 norm and can be used without additional coating in environments of C1, C2 and C3 corrosion classes by PN-EN ISO 12944-2:2001 norm. Coated (anodized) elements they can be used in C4 class environment as well.
BSP KW PAS passive brackets that are partly made of special plastic have been tested as well. They have the same anti-corrosion class as other aluminium elements of BSP system which are C3 and C4 when additionally coated.