Over the past year, there have been significant changes to the Building Regulations and Approved Document B (fire safety) to the Building Regulations in England (ADB-2019). These affect the fire-performance requirements for external wall constructions on high-rise buildings, and consequently which products can be used in these applications.
Regulation 7(4) sets out what is considered a relevant and non-relevant building. It defines ‘relevant buildings’ as buildings which have a floor at least 18 metres from ground level and contain:
- one or more dwelling;
- an institution; or
- a room for residential purposes (excluding any room in hostels, hotels or boarding houses).
With some exemptions stated in Regulation 7(3), materials installed as part of the external wall, including insulation and specified attachments, must now achieve a European Classification (Euroclass) of A1 or A2-s1,d0.
It is important to note, however, that European Classifications are used on individual products and may not be wholly representative of the fire performance of the complete system build-up.
ADB-2019 permits an alternative route to compliance for ‘non-relevant’ buildings with a floor above 18 metres, via specific external wall build-ups which meet the performance criteria within BR 135 using large-scale test data from BS 8414.
BS 8414 is a rigorous large-scale test of the complete facade system, simulating a fire which breaks out through a window and providing accurate data on how the assembly can be expected to perform in the event of a fire.
Kingspan’s Kooltherm range of products are amongst the most advanced and thermally efficient insulation materials on the market today, with lambda values as low as 0.018 W/m·K, allowing for slimmer, lighter constructions. When exposed to a flame, the phenolic insulation core of Kooltherm products forms a black char which causes the insulation to self-extinguish when the flame source is removed.
Kingspan Kooltherm products for external walls do not achieve Euroclass A2-s1,d0 or better and cannot be used on ‘relevant buildings’. However, when tested to BS 8414, specific wall assemblies featuring Kingspan Kooltherm K15 Rainscreen Board and Kingspan Kooltherm K5 External Wall Board have been shown to meet the criteria within BR 135. These build-ups are therefore compliant with the requirements for ‘non-relevant’ buildings.
The use of Kingspan Kooltherm K106 and K108 Cavity Board is permitted for use in non-relevant buildings, providing the cavity is between two leaves of brick or concrete at least 75mm thick each and the cavity is closed at openings and the top of the wall (see Diagram 9.2 in Section 9 of ADB-2019 Volume 2 for further guidance).
Two further routes to compliance are available for ‘non-relevant’ buildings:
- Assessment-based Route – A report is prepared in lieu of a test where sufficient testing evidence is available from UKAS-accredited testing bodies. This should be prepared to the relevant standard for extended application for the test in question.
- Fire Safety Engineering Route – This requires a detailed assessment of all aspects of a building from a fire-safety engineer. In addition to considering the performance of the construction in a fire event, it also considers human behavioural aspects, fire prevention and active and passive fire-protection measures.
The Kingspan Kooltherm products listed above can be used with both of these routes.
For more information, go to www.kingspaninsulation.co.uk