Fire Safety

FIRE SAFETY OFFSITE-BUILT BALCONY SYSTEMS FACE UP TO HIGH-RISE FIRE SAFETY ROLE

The grim lesson of the horrendous fire that engulfed London’s Grenfell Tower on 14th June 2017 is that fire safety applies as much to the exteriors of multi-storey residential buildings as it does to the interiors.

The Grenfell fire killed 72 people as flames spread through the external cladding of the 24-storey building. The incident and the ensuing public outcry led to a significant tightening of Building Regulations with an outright ban on combustible cladding materials.

But this was not the only cause for concern in high-rise buildings. Before and after the Grenfell incident, a significant number of apartments in London and other parts of the United Kingdom were damaged – some quite severely – by fires accidentally started on balconies. Despite frequent warnings from fire chiefs about balcony fires, these were often attributed to accidents with smoking or sparks from barbecues, which ignited nearby furnishings or other combustible materials.

While some incidents clearly stemmed from residents’ actions, questions were also raised about the design and choice of materials used in balconies.

Tall apartment buildings continue to mushroom in areas of heavy residential demand with balconies giving the high-rise lifestyle a welcome hint of the outdoors. Unsurprisingly, perhaps, balcony systems themselves came under the spotlight.

As a leading specialist in offsite-manufactured systems, Sapphire Balconies contributes extensively to the post-Grenfell debate on fire safety. For example, Andrew Parsons, Sapphire’s Founder, helped to write BS 8579, the benchmark for balcony design throughout the United Kingdom.

In addition to advocating use of fire-safe materials, Sapphire has recommended that balconies should incorporate Class A non-perforate soffits, even before Grenfell. Soffits not only have the aesthetic benefit of screening support arms and drainage systems from view, but have shown in many balcony incidents that the use of them has helped to inhibit the external vertical spread of fire by deflecting flames and heat. Soffits also restrict the flow of oxygen and contain embers if items on a balcony are burning. This has now been recognised and added in to Part B regulations in their June 2022 amendments.

Sapphire’s Cassette balcony system uses steel support arms that are bolted to castin anchors. A thermal break is usually incorporated to minimise cold bridging. However, with the move to thinner slabs and minimal floor finishes, there is less space for traditional linear cavity barriers to pass over or under the balcony support stubs. Sapphire set out to solve the industry problem of ad hoc and often-untested site-assembled, fire-stopping solutions. Its own solution – the Sapphire StubGuard – has had numerous third-party independent testing. StubGuard is already available for use, subject to fire engineers’ and any project-specific approvals.

Sapphire says there is a valid case for overturning the ban on laminate glass, which, under the combustible cladding ban, is ‘effectively outlawed’ in facades over 11m in height, when it was not mentioned on the exemption list. In the whitepaper Sapphire wrote for the UK Government, Nick Haughton, Head of Marketing – UK & Global at Sapphire, contends that laminate glass for balcony balustrades is not a fire – or general – safety risk but, in fact, a safety benefit.

It says, prior to the ban, laminate glass was widely preferred over metal railings – especially at height where its screening creates a more comfortable environment for users, as well as protecting furniture and plants. The possibility of obscure interlayers means laminate glass can also provide privacy, while still allowing light into the apartment.

As a prominent housing association discovered after specifying metal railings for its balconies to reduce fire risk, residents installed makeshift windbreaks with plywood sheets and other material cable tied to the railings – an aesthetically-poor and much more hazardous solution.

Sapphire says although many industry leaders feel the ban on laminate glass was inadvertent, it also feels that the benefits of laminate glass far outweigh the reasons for the ban.

It says: “Thankfully, the Department of Levelling Up Housing and Communities has now started to relook at the new regulation and its overall impact on building safety.

“We recommend that clients and all professionals research the current situation, and fire safety generally, when specifying balconies.”  www.balconies.global