Kelly Westwood from Knauf Insulation discusses the critical need to combine fire safety and sustainability in buildings of the future
COP26 in Glasgow brought a renewed focus and urgency to the long-term sustainability of the built environment. This is reflected in updated Building Regulations, which came into force in June this year, as well as in the response by RIBA, which has set 2030 targets for operational and embodied carbon.
For buildings to be sustainable, they must also be resilient; i.e. designed to last, adapting to changes in use or tightening regulations. Fire safety must be considered one of the foundational pillars of sustainable design.
The impact of fire on sustainability
As well as the potential for injury and loss of life, building fires have a devastating impact on the environment. Fires emit CO2 and other pollutants into the atmosphere and release chemicals that contaminate both land and water. This is evidenced by soil samples collected 140 metres from the Grenfell fire site. As long as 16 months after the fire occurred, they were found to still contain levels of carcinogenic chemicals and other harmful toxins 160 times higher than other urban areas.
As well as releasing pollutants, fire can destroy a building and its contents. In the clear up, fire-damaged materials are usually sent to landfill. New resources need to be used for the repairs or rebuild, accumulating more embodied carbon into the building’s lifetime footprint.
Even if a fire never occurs, inappropriate fire design may necessitate remedial work, as is the case with the tower blocks identified in the wake of the post-Grenfell cladding scandal. Fire risk may even result in whole properties being deemed unsafe, leading to their premature demolition – something that is hardly sustainable.
Go beyond Building Regulations
It is essential that every building is designed to be fit for purpose throughout their intended lifespan. This means fire protection measures must not only meet the minimum standards outlined by existing legislation, but go beyond them to effectively future-proof the building – something that is already required for non-domestic buildings as part of the BREEAM In-Use certificate.
Building regulations already ban the use of combustible materials in the external walls of certain buildings over 18 metres in England and Wales (11 metres in Scotland). Key structural elements must also achieve a specified period of fire resistance to prevent the passage of fire from one area to another. This is achieved by designing the build-ups of the roof, walls and floors to compartmentalise the building.
As well as creating dedicated escape routes for occupants, compartmentalisation works in conjunction with sprinkler systems (if installed) to help limit the fire to a confined area. This minimises its spread and means it can be extinguished quickly, which reduces the scale of any repairs or rebuilding work required after the fire and the impact on the environment.
But problems occur if the structure has been compromised due to poor installation or by any damage caused to the building fabric post-occupancy. If combustible materials have been used within the build-up, it would then be possible for the fire to spread within the structure itself – with devastating consequences.
The simplest way to mitigate this risk is to specify materials such as non-combustible insulation regardless of the height or type of building. Look for the Euroclass reaction to fire classification, which measures whether a UKCA and CE marked material will ignite, produce smoke or flaming droplets. The ratings range from F (easily flammable) to A1
Mineral wool insulation as a standard specification
Of course, when designing for a sustainable future, architects must specify insulation products with minimum impact on the environment through either manufacture or use. But they also need to adopt materials and systems that reduce risk by preventing the development and spread of fire.
Mineral wool is non-combustible, having the highest possible Euroclass A1 or A2-S1, d0 reaction to fire classification. This is important because a product that does not combust will also not emit pollutants, as well as not contributing to the spread of a fire in a building.
This means that as a specifier, you don’t have to compromise. As well as being non-combustible, 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. Glass mineral wool can also be compressed so there is more insulation per pack or per pallet, meaning fewer trucks on the road and therefore less transport emissions. This makes it ideal for projects where embodied carbon is a factor.
For buildings to be ‘fit for the future,’ it’s not enough for fire safety to be considered from the point of legislative compliance alone, it must also be viewed as a measure of sustainability. Where insulation is concerned, there is a trusted solution for every application that already delivers on both criteria – non-combustible mineral wool.
Kelly Westwood is head of construction projects at Knauf Insulation