Modern methods of construction is a term often used across the built environment to describe new construction techniques and has been increasingly promoted as the sector strives to improve the quality and sustainability of the buildings we build. Despite the considerable benefits, its use can introduce new fire challenges with buildings that have displayed outcomes that are not as resilient and robust as we might wish. Applying old thinking and guidance aimed at traditional construction techniques are not a secure path, therefore we need to look to additional measures. Tom Roche, Secretary of the Business Sprinkler Alliance (BSA), explains that embracing innovation and bringing new methods of construction to the design process brings new challenges and risks which must not be at the expense of building safety.
The design of buildings is ever changing and as the construction sector faces new challenges, it must gain positive benefits from the rapid rise in building innovation. New materials, products and building processes can open the potential for those benefits, but we must not miss the potential changes in fire-safety risks. For example, modern methods of construction (MMC) encapsulates a range of on-site and off-site fabrication practices. It could also be said that all construction techniques would have been a form of MMC at some stage; meaning the need to research, develop, refine their use and deal with any arising hazards. The increasing use of MMC and its economic and environmental benefits have been discussed for many years – greater efficiency, consistent quality, less waste, an increased productivity and faster build programmes are some of the reasons why MMC has become a focus. Although many will think of residential developments for these techniques, they are being used in a range of buildings from hotels to hospitals and care homes to offices.
Fire perspective
These construction methods also introduce other features into buildings such as concealed spaces, modular units, lightweight steel frames and new connection techniques. While not all MMC are combustible, there are a mix of materials which can include combustible elements such as insulation, textiles, structural and framing details. As a result, the combination of these elements can be challenging in a fire scenario and small fires can spread and have damaging consequences.
A fire in the 106-bed Moorfield Hotel in Shetland in 2020 is a stark reminder of the potential vulnerability of buildings which have been built using combustible materials. Structural insulated panels (SIPs) were used to create fully furnished hotel room modules which were constructed off-site and shipped to site for assembly. The fire started in a cupboard and spread to destroy the whole building. The materials and construction details led to a fire outcome many would not have considered possible within a modern building.
A fire starting in a small server room spread to ravage Weybridge Community Hospital in July 2017. The fire wiped out a community asset, the building’s timber frame construction and timber floors provided the flames with a path and sufficient fuel to develop into an intense and rapidly spreading fire that was witnessed by fire crews who first attended the site. Once again, we have an example of what was a modern construction technique, deployed to deliver a new community asset where a fire, reported to be electrical in nature, spread and destroyed the whole building. Again, the combination of materials and construction details lead to an outcome many would not expect in a relatively modern building of this type.
Given these fire outcomes, it is perhaps right to question whether we fully understand the performance of these new techniques in fire or whether we have blind spots. One element that strikes you is that small fires, either with the potential to escape into voids or passing through unseen spaces, is a theme. This means that their treatment and methods to prevent fire reaching them will be a vital concept. Research is therefore needed to fully understand the performance of these materials and their risks. It may mean redesigning or adapting these techniques. It also means considering additional layers of protection to avoid scenarios escalating to significant failure. It’s why active forms of fire protection such as sprinklers are often talked about as a significant safety layer to ensure that any fire is contained in the room of origin.
Whilst these fires highlight the potential outcome, we have little experience of performance over time, but there are some indicators of the need for close attention. A modular technique was used to create the Paragon Estate in Brentford. Featuring six residential blocks, the estate’s tallest – at 17 storeys – was one of the tallest modular buildings in the world when it was built in 2006, garnering awards for the development. Fourteen years later in 2020, 900 residents were forced to evacuate due to fire-safety concerns. There was no fire event but the fear of what might occur prompted action. Once hailed as being a development where ‘the use of innovative design and construction techniques can enhance quality’, it now sits empty with an uncertain future due to the reported defective fire and cavity breaks and a lack of compartmentation between flats.
Regulations and the pace of innovation
Regulations and building codes will lag behind innovation – their development cycles mean that they cannot simply respond – but this does not mean innovation cannot take place. In England the guidance is based on common building types and innovative construction techniques are possible by demonstrating that the functional statements of the regulations are met. This means taking a fire-engineering approach to bridge the gap to support the safe use of an innovation. In essence the designer needs to satisfy themself that these innovations have been researched, appropriately tested and their combination of safety measures deliver the desired outcomes.
The industry as a whole will continue to innovate in order to meet the expectations we require from the built environment. It will also build to a certain set of regulations and guidance, but we must question whether we are on the right path to deliver good outcomes as we try to keep pace with the ever-increasing speed of innovation. When it comes to modern methods of construction, are we fully aware of the hazards they can generate and the features we need to put in place to ensure we deliver the right outcome? Are we open to more holistic methods and combinations of protection for such schemes, including the use of sprinklers, to minimise the potential for damage?
For more information about the Business Sprinkler Alliance visit www.business-sprinkler-alliance.org
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