Please note that the regulations and guidance mentioned in this article may have been updated since writing. Please visit our Fire Regulations page for the latest information.
So called ‘non combustible’ and ‘limited combustibility’ materials have been the focus of considerable discussion following the tragic fire at Grenfell Tower.
Some have argued that the current building regulatory system should be stripped back to allow only these materials to be used on high-rise constructions. Before such a drastic course of action is taken, however, it is critical to consider whether it would actually improve the fire safety of our buildings.
Simplicity over safety?
As we discussed in a previous article, under current regulatory guidance façade systems comprising ‘limited combustibility’ or ‘non-combustible’ insulation materials are able to bypass large scale, full system testing. Instead, they can take a tick-box route which is arguably much less rigorous
The so called ‘Linear Route to Compliance’ is outlined in ADB2 Section B4-12 - Construction of external walls, for England and Wales, and THB2 for Scotland. It allows façade systems which use ‘non-combustible’ (Scotland) or ‘non-combustible’ and ‘limited combustibility’ insulation (England & Wales) to be deemed compliant on buildings over 18 metres, so long as performance requirements for the façade cladding panels are also met. Façade cladding panels must be either non-combustible, low risk / Class 0 or Class 1 depending on country, position on building and location of the building in relation to its ‘relevant’ boundary.
There are several potentially serious issues with this approach.
A fit test?
‘Non-combustible’, ‘limited combustibility’, ‘Class 0 / Low Risk’ and ‘Class 1’ classifications of insulation and façade materials are made solely through small scale tests on isolated product samples.