Whilst they are not yet enshrined in Building Regulations, fire safety measures for balconies are now widely stipulated by building warranty providers. Architects and developers should be mindful of this at the design stage of their projects. Steve Howard of balcony and decking specialists, Neaco, explains…
Visit the centre of any major city and balconies will probably be visible in most directions. It’s estimated that there are over 45,000 high-rise apartments in London alone, with flats comprising just over 50% of the capital’s residential accommodation. Given this proliferation, it is no surprise to read reports that highlight the frequency of associated risks such as fires. In their 2016 document ‘Fire safety issues with balconies’, BRE Global reported 24 cases of balcony fires since 2005. In Part B of the Building Regulations there are no fire safety requirements specifically relating to balconies (with the exception of balconies providing a means of escape) but housebuilding warranty providers are increasingly concerned about potential risks, especially post-Grenfell, and many are requesting balcony design modifications with reference to Part B4 which refers to the spread of fire on building exteriors. It has encouraged a wider obligation across the residential sector to ensure that all construction and refurbishment projects are built in line with these new demands.
Timber decking is an obvious risk and BRE Global’s report includes case studies identifying discarded cigarettes on decking as the cause of fires. Neaco discuss balcony specifications with architects across the UK and many tell us that decking material is the primary safety concern for warranty providers. Their most commonly requested revision is the replacement of timber with more fire-resistant materials. Wood-polymer composite decking, comprising a combination of plastics and timber fibres, is not considered to be sufficiently fire-resistant and is often rejected too. Glass reinforced plastic (GRP) is in essence an oil-based product with a combination of materials and components which all react differently when exposed to fire. The polyester resins are made up of carbon, hydrogen and oxygen atoms and, like all organic compounds, they will burn.
Realistically, this leaves steel and aluminium as the only viable alternatives. Aluminium has the advantage of being 1/3 of the weight of steel and it can accommodate spans of up to 2m between joists. Aluminium is also a superior material for fire safety. Its thermal conductivity is four times faster and therefore a greater heat input is necessary to bring aluminium up to a given temperature than required for steel. Aluminium has an A1 Fire Rating – the highest achievable score for non-combustibility - and it also eliminates the need for timber joists, thereby significantly reducing fire risk.
Steel is the preferred substitute for timber joists and this brings further implications to the design and specification of balconies. Extensive steelwork is expensive and it makes economic sense to reduce the amount of required support by using decking that is lightweight yet high in load-bearing capacity. The structural efficiency of aluminium decking is ideal in this respect.
What’s more, aluminium is corrosive-free, extremely durable (with a design life of 60-100 years) and 100% recyclable. It can be easily machined to provide special features which serve the needs of balcony decking, including anti-slip surfaces. This ability to provide slip resistance is another aspect which makes aluminium safer than timber, which over time becomes increasingly slippery underfoot.
As a company which uses aluminium for the manufacture of our architectural systems, Neaco is a passionate advocate of its many benefits and especially its value in reducing fire risk. By specifying aluminium’s use in balconies, architects and developers can streamline the regulatory approval of their design schemes and, more importantly, improve the safety of their buildings.