18/1/2021
After the terrible fire at Grenfell Tower in London, many municipalities and building owners in the Netherlands are concerned with the fire safety of the façades of their buildings. Efectis is regularly asked to assess a facade and express an expectation of how it will react when exposed to a fire.
We base this assessment on the requirements set in the Building Decree and NEN 6068 with regard to fire spread between compartments. On the basis of those requirements, it often comes down to parts of the façade having to comply with fire class B, which is a relatively light requirement in comparison with our neighbouring countries. This fire class is determined by the Single Burning Item (SBI) test with a burning power of 30 kW. A real fire or a container fire against a façade can easily have a capacity of 1 MW or more. Additionally, in an SBI test we do not look at connection details at window frames or in other places.
When we are asked for an assessment for a façade, however, we do look at those details, because those connection details can allow the fire not only to pass in front of the façade but also to spread in the façade. We also look at combinations of materials. We regularly receive test reports of materials that are used in façades that comply with class B or if a non-combustible metal such as zinc is to be found on the outside of the façade. In such a case, we look more than just the behaviour of that one material. Has the foil been tested in combination with an insulation material? What material is behind the zinc façade? Test reports often show that a material such as a vapour-permeable foil has been tested free-hanging, stating that the classification is not valid in combination with another material. That is why we at Efectis advocate testing as much as possible in an “end-use situation”, as the standard also prescribes.
If we are unable to express an expectation about the fire behaviour of a façade or if a party does not agree with the expectation that we express, it is of course possible to perform an (indicative) SBI test. We regularly do this with existing façades. These tests often show that the combination of materials performs worse than a single material.
Unfortunately, this is frequently discovered only in existing façades and advice is rarely requested in advance. Thinking in advance about the structure of a façade can prevent the need for proof to be provided afterwards or, worse, the need for parts of the façade to be replaced.
Contact: René de Feijter – rene.defeijter@efectis.com