The impact of insulation fire performance reclassification
Compliance with the fire performance requirements within the Building Regulations is a key aspect of any project, and with the implementation of the Building Safety Act 2022 the focus on compliance will only become greater.
This month’s question to all roofing system manufacturers and roofing contractors is: “are you ready for this scrutiny?”
Much has been written about the fire performance of flat roofs, but as ever the devil is in the detail and whilst you may think you have a fire performance classified roofing system, some recent changes to the classification of product fire performance may render a classification report invalid. Let us explain by first going over some old ground.
BS EN 13501-1 Fire classification of construction products and building elements – Classification using data from reaction to fire tests
This is the classification standard for a standalone product as supplied, so in the case of an insulation board it is for the product as it is when you take it from the wrapper. That product can be classified from Class A1 to Class F.
BS EN 13501-5 Fire classification of construction products and building elements – Classification using data from external fire exposure to roofs tests
This is the classification standard to roof assembly, i.e. the full build-up deck to surface finish. The roof assembly can be classified Broof(t4) to Froof(t4).
Whilst these two classification standards are totally different in test method requirements and classification of the results, they do have a link that is important to be aware of so as not to fall foul of accidentally misinforming a client about building regulations compliance.
Within the BS EN 13501-5 classification report will be a list of the products tested within the assembly. The test result will be specific to this exact roof assembly only, unless it forms part of an Extended Application Report (EXAP). This means that if the test is for say 200mm thick insulation from a specific manufacturer, then you cannot change to a different thickness insulation or different manufacturer as this would render the test invalid. This is something generally understood within the industry; BUT there is another nuance to the classification that could be missed and that relates to the BS EN 13501-1 classification for the standalone products within the roof assembly
If the manufacturer changes the BS EN 13501-1 classification of a standalone product used within the roof assembly tested, then the BS EN 13501-5 classification report becomes invalid. Not a problem I hear you say, a manufacturer would not change the rating of their standalone product. Unfortunately, that is not the case. A number of insulation products have been changed from Class E to Class F during 2022 rendering testing with the Class E board no longer valid. Always check the fire certification information against the latest Product Data Sheets to protect yourself.
Next month: Point loadings on insulation boards.