Earlier this year, I published an article in which I discussed the fact that the 2020 editions of the Domestic and Non-Domestic Technical Handbooks (official guidance for compliance with the Building (Scotland) Regulations 2004 (the “Regulations”) had removed direct reference to a party’s ability to demonstrate “alternative” compliance with the Regulations by using a solution based on British Standard 8414/BR135, which was previously included in the Handbooks.
The BS 8414/BR135 path was still open to applicants at the time, and I wondered whether the removal of a direct mention to it in the Handbooks could be the first step toward the elimination of the “alternative” route entirely. I was wrong, of course, and the route remains open today. The Scottish Government has stated that this is indeed their aim with the publication of The Building (Scotland) Amendment Regulations 2022, which will change the Regulations, and that only stringent compliance will now be permitted under the new regulations.
Materials will be subject to stricter controls.
When the modifications take effect, the Regulations will require that any materials that “form part of an external wall cladding system… are of European Classification A2-s1, d0, or A1, classed in accordance with BS EN 13501-1:2018” be used in the construction of the exterior wall. These limits will apply to all residential high-rise buildings as well as other high-risk structures (such as hospitals and care home). In Scotland, the word “high-rise” refers to any structure that is 11 metres or more in height (rather than the 18m figure used elsewhere in the UK).
If cladding systems have passed a large-scale fire test in accordance with British Standard 8414, they might escape the need to adhere to the severe requirements of this standard in the past. Essentially, this meant that combustible materials could be used in an external walling system, provided that the system as a whole passed the fire testing procedure. This loophole, on the other hand, has since been closed.
Metal composite materials are prohibited.
A further provision of the amended regulations is the outright prohibition on the use of “highly combustible metal composite material” in the construction or renovation of structures of any height. An outright prohibition on “Grenfell style” cladding, which is comprised of panels made up of two metal sheets and a filler core, has been instituted following the devastating fire at Grenfell Tower. If the core has a “gross calorific value of greater than 35 MJ/kg,” it can no longer be used on projects in Scotland because it has exceeded the threshold. When a substance has a high “gross calorific value,” it basically indicates how much energy it would give to a fire. As a point of comparison, diesel has a calorific value of approximately 45 MJ/kg and dry firewood has a calorific value of approximately 16 MJ/kg.
However, others have argued that this prohibition does not go far enough in terms of prohibiting the use of potentially hazardous products. According to critics, by restricting the restriction to only the “worst” class of metal composite materials, an opportunity to provide more comprehensive protection has been wasted. The ban also applies only to metal composite materials; other potentially hazardous materials, such as high pressure laminate (HPL) materials, do not fall under the purview of the prohibition.
It will be interesting to see whether, like the prohibition on combustible cladding on high-rise buildings, these limits will become more stringent over time.
What happens next?
The modified Regulations will become effective for all projects for which a Building Warrant application is submitted on or after June 1, 2022.
Early in May, updated editions of the Domestic and Non-Domestic Technical Manuals that reflect the new regime will be available online.