Updated guidance from façade engineering groups aims to provide greater clarity on fire safety requirements for cladding and external walls.
The Centre for Window and Cladding Technology (CWCT) and the Society of Façade Engineering (SFE) say new guidance, which is free to download, will provide a consistent interpretation of the new regulations for combustible materials in the external walls and on specified attachments of relevant buildings.
“Changes made to Regulation 7 of the Building Regulations in November 2018 introduced a ban on combustible materials in England,” a statement from the CWCT and SFE said.
“This legal requirement is deliberately simple and with limited exemptions and requires all materials used in the external walls of certain high-rise buildings to achieve a reaction to fire classification of A2-s1, d0 or better. The regulations and associated guidance in Approved Document B (ADB) were revised again in June 2022.”
Whilst the Regulation itself is simple, “modern building envelopes are not”, the CWCT and SFE added, saying it became apparent that additional guidance was required to provide a consistent interpretation of the regulation.
“Key to the Regulation are the exemptions that are provided; however, the exemptions do not fully recognise the complexity of modern facades and leave some ambiguity and uncertainty over combustible materials which may or may not be used, and in what circumstances they may be used,” they continued.
“Whilst the exemptions acknowledge the vital role that certain combustible materials presently play in the performance of modern facades, it is important to recognise the industry has responded to the ‘ban’ and developed new materials that fully meet the Regulation. Where such materials exist without compromising other aspects of performance, it will almost always be appropriate to use them in preference to a more combustible alternative.”
Changes to Approved Document B
The revised guidance reflects the recent changes to the Regulation and Approved Document B and feedback the CWCT and SFE have received since the guidance was first published. Further clarification is provided on testing, plus there are new sections on windows and parapet walls, and revised guidance on waterproof membranes, amongst other changes.
The CWCT is an independent industry-funded centre of specialist knowledge and expertise that publishes standards, guidance and technical publications. The SFE is a division of the Chartered Institution of Building Services Engineers (CIBSE) and is a joint initiative with Institution of Structural Engineers (IStructE) and the RIBA.
