Vanessa Rae, Marketing & Sustainability Director at Knauf Insulation, discusses the role of fire safety in sustainable design.

For buildings to be fit for the future, fire safety must be viewed from both legislative compliance and as a measure of sustainability, so it makes sense to use non-combustible insulation as standard (LSE Marshall Building pictured).

When it comes to the sustainability of the built environment, the UK is on a knife edge. Legislation, such as Approved Document L, is driving up energy-efficiency standards, but there’s a growing chorus warning that net zero targets will be missed if embodied carbon is not addressed.

At the same time, questions are being asked about the environmental impact of demolition and new build when many buildings could be repurposed. But this is only possible if buildings are safe. To achieve an optimum lifespan, they must be designed to last, adapting to changes in use or tightening regulations. Therefore, fire safety must be considered one of the foundational pillars of sustainable design.

Chart showing the levels of embodied carbon for different insulation materials.  Mineral wool has the added benefit that it is non-combustible.

How fire impacts sustainability
While a building’s fire safety strategy rightly focuses on the prevention of injury and loss of life, it must be acknowledged that building fires also have a devastating impact on the environment. CO2 and other pollutants are released into the atmosphere and chemicals contaminate land and water. For example, soil samples collected 140 metres from the Grenfell fire site still contained levels of carcinogenic chemicals and other harmful toxins 160 times higher than in other urban areas – 16 months after the fire occurred.

Fire destroys a property and its contents. Fire-damaged materials are usually sent to landfill and new resources are used for the repairs or rebuild, adding to the carbon footprint of the building. But as we’ve seen in recent years, the threat of fire can also lead to remediation works, as they have in the wake of the cladding scandal. In extreme cases, inappropriate fire design can even lead to total demolition – something that’s hardly sustainable.

The simplest way to mitigate fire risk and the environmental impact of fire is to specify materials such as non-combustible insulation regardless of the height or type of building.

Going beyond minimum standards
When designing for sustainability, fire safety must be baked into the design. Architects must take steps to futureproof the building – after all today’s minimum standards may be considered lapse tomorrow. For example, until December 2022, in England, combustible materials were only banned in the external walls of relevant residential buildings over 18-metres tall. Now, the definition of relevant residential buildings has widened to include hotels and hostels. The ban has also been expanded to cover certain external wall build-ups of all residential buildings between 11 metres and 18 metres – unless a full-scale fire test has been undertaken.

Buildings must also be designed to stop fire spread. Certain structural elements must achieve specified periods of fire resistance to compartmentalise the building and create dedicated escape routes. As well as preserving life and reducing injury, this limits fire damage, especially when combined with the use of a sprinkler system. After all, a fire that is contained can be extinguished more quickly, reducing the scale of repairs required and lessening its impact on the environment.

Using non-combustible insulation in the build-up prevents the spread of fire hidden in the build-up.

That’s the theory, but it’s not always the reality. If combustible materials have been used within the system and the building fabric has been compromised by poor installation, maintenance, or damage post-occupation, then it’s possible for fire to spread internally within the build-up. The consequences could be catastrophic.

So how do you futureproof your projects? The simplest way is to specify non-combustible materials, such as insulation, for every height and type of building.

Both thermal performance and fire safety were important factors for specifying Knauf Insulation Rocksilk® Flat Roof Slab for Landmark.

Specifying mineral wool insulation as standard
Designing for sustainability means taking a holistic approach and specifying insulation that delivers on multiple levels. As well as thermal and acoustic performance, insulation must have minimal impact on the environment during manufacture and in use, and help to prevent the development and spread of fire.

The good news is you don’t have to compromise. Glass and rock mineral wool insulation are made from materials that come from either naturally abundant sources or are recycled. In contrast, materials such as rigid boards are produced using oil-based ingredients. Compression packaging also means more mineral wool insulation can be shipped in one go, reducing handling, storage, and transport related emissions, making it ideal for projects where embodied carbon is a factor.

And crucially, mineral wool insulation is non-combustible with the best Euroclass A1 or A2-S1,d0 reaction to fire classification. This is important because a product that does not combust will not emit pollutants during a fire, nor contribute to its spread.

Essentially, a building is its designer’s legacy and to fulfil that legacy, it must be fit for purpose. With this in mind, architects must focus on sustainability as a measure of fire safety, ensuring the insulation products they specify go beyond the minimum standards for compliance and contribute to the building’s resilience, allowing it to adapt to future needs.

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