Safety regulations affecting cladding and roofing can be confusing and lead to misunderstandings. Lisa Grosse, brand manager at Cedral, offers some clarity on building material fire classifications – which ones should be relied upon and which should be avoided.
It’s important for architects and specifiers alike to have a sound working knowledge of relevant safety regulations affecting cladding and roofing. However, be it British Standards (BS), Euroclass (EN) or the older Class 0 certification, it’s easy to see how misunderstandings can creep in when assessing product safety. Indeed, our technical advisory team continues to get several enquiries each week on the topic of fire ratings, which even now causes confusion.
We are aware how important it is to understand the characteristics and features of building materials for projects. Cedral has a long-standing commitment to ensuring our fibre cement facades and roofs comprehensively meet the fire performance classification A2-s1,d0 to EN 13501-1:2018 standard. But what do these letters and numbers actually mean? Here we explain all of the fire classification ratings and how they should be used, including Class 0 and why you should avoid it.
In a Euroclass of its own
The European standard of fire safety is the Euroclass system, recognised as the standard of fire safety across Europe. It was introduced by the European Union in 2000 to remove trade barriers between member states and ensure consistent quality levels. It classifies the reaction to fire (the behaviour of materials when exposed to heat or fire) and evaluates multiple aspects such as ignitability, flame spread, heat release, smoke production and propensity for producing flaming droplets and/or particles. The European standard is EN 13501-1, which is met by all Cedral materials. While we are no longer within the Eurozone since Brexit, these regulations still apply to building products sold in the UK.
Top of the class?
The European classification ranks construction materials in seven classes according to their fire behaviour – A1, A2, B, C, D, E and F. It also classifies these materials with regard to smoke development – s1, s2 and s3 – and the formation of flaming droplets/particles – d0, d1, d2.
A1 refers to non-combustible materials, A2 is non-combustible in Scotland and of limited combustibility in England and Wales, while B, C and D range from limited to medium combustibility and E and F designate a high contribution to fire.
‘s’ refers to the total smoke emitted during the first 10 minutes of exposure to fire. s1 materials produce little or no smoke, s2 emit quite a lot of smoke and s3 produce substantial smoke.
The ‘d’ part of the classification covers the number of flaming droplets and particles that are produced within the first 10 minutes of fire exposure, with d0 designating no droplets, d1 some droplets and d2 quite a lot of droplets.
No more Class 0?
UK fire classification Class 0 indicates the surface spread of flames and not the combustibility of the material itself when involved in a fire. It was introduced in the UK Building Regulations on fire safety in 1991 and remained in place after the Euroclass system was introduced in 2000, even though Class 0 does not demonstrate the same performance as the Euroclass system. For example, combustible materials can still achieve a Class 0 classification That’s why it is vital to always refer to the newer ratings and not Class 0.
Class 0 is an out-of-date national product classification and should not be used to determine the fire safety of building materials because it says nothing about the combustibility of the material in a fire.
If you would like more advice on fire classifications for buildings, Cedral’s dedicated technical advisory team can offer expert help. We can support your project from the initial design concept through to build completion and beyond.