The journey of Fusion Building Systems began almost 20 years ago. Putting over 5000 buildings in the ground, they have a proven track record of delivering large and complex Light Gauge Steel (LGS) structures. Together with Aggregate Industries (part of Lafarge Holcim, the world’s largest cement producer and creators of Airium) and Crest Nicholson (a major UK home-builder), Fusion set out to be a catalyst in creating an integrated supply chain, which revolutionises both the performance of buildings, and the build process itself.

Plasterboard is the traditional way to provide fire, thermal and acoustic insulation of Light Gauge Steel (LGS) structures, but they are both labour intensive construction processes. With demand for 300,000 new UK homes per year (100,000 more than are normally built), there is a greater need for safe, effective and non-combustible insulation that can be carried out at scale and in a way that is more sustainable for the planet. And the Grenfell Tower disaster, and subsequent Hackitt enquiry, has rightly seen renewed focus on regulations around fire-proofing residential builds.

Hyb-ISS (Hybrid Insulated Steel System) is an innovative, lightweight solution to insulation and fire protection that can be built off-site in one streamlined, simple process. This novel insulation would mean more residential structures of up to ten floors could be built more quickly and more accurately - with faster and easier finishing, less resource and waste and vastly improved acoustic, thermal and fire-proof properties. This reimagining of insulation production and installation would be suitable for a third of the housing market, satisfying the demand for multi-storey housing and ensuring they are built faster, more accurately but, more importantly, with greater safety.

Fusion already had a track record in delivering large and complex Light Gauge Steel (LGS) structures and was investigating new thermal, fire and acoustic insulation products in collaboration with other supply chain and manufacturing partners. The team knew the light-weight insulation based on Airium performed well in sound and heat insulation tests. During a small-scale fire test, the partners realised its exceptional fire-proof qualities. It is difficult and time-consuming to carry out extensive, large-scale fire testing to get the adequate British Board of Agrément certificates to assure new building systems; sometimes taking as much as two years to be approved. Knowing they had a product that was fit for current market need and demand, the partners secured an Innovate UK grant of £222,868 which enabled them to develop the product further, and go on to carry out a full-scale fire tests on a floor and a wall. Currently Hyb-ISS is being tested for structures up to 10 floors, but if pilots and uptake go well, it could expand into the 10-floor-plus market, currently worth £1 billion per year.

With increased restrictions in the use of its current product offer, Fusion saw an opportunity to create an integrated, higher-performing, offsite product to meet demand for a platform approach to buildings. Fusion worked with Aggregate Industries, who sees its traditional market disrupted by Modern Methods of Construction (MMC), and Crest Nicholson, a house-builder interested in exploring the opportunities MMC could offer. Aggregate Industries is owned by Lafarge Holcim who are the world's largest producer of cement and has developed Airium, an innovative cement-based insulation. The collaborative believed that panels filled with Airium foam insulation could offer the sound, heat and potentially fire-proof insulation this new market needed, and set out to test it.

In the drive for affordable housing, the industry has overly relied on building systems that cost less but, as a result, compromise on quality. This can lead to homes that are inadequate or unsafe. Manufacturing solutions allow faster, more efficient construction but also need to ensure value throughout the building's lifecycle, and safety of residents. Hyb-ISS offers a manufacturable alternative to the use of LGS, that employs a safer insulation system and can be made offsite.

Hyb-ISS (Hybrid Insulated Steel System) overcomes the challenge of achieving high fire protection to a Light Gauge Steel (LGS) floor at scale. It is strong and very structurally efficient, at the same time being super-lightweight and solid. The product is a unique combination of load-bearing light gauge steel frames and a patented, low density, injectable mineral foam called Airium. Airium works by combining the aqueous mineral foam with cement-based slurry and distributed air bubbles. This clever combination creates a simpler but higher-level and fully fire-resistant insulation for multi-storey buildings up to nine floors. The structure can be built off-site in a single process, and includes external and internal load-bearing walls and floors. It is solid and yet incredibly light-weight, and uses 35% less plasterboard. It also allows faster and easier finishing for the client. The focus of the team is currently on developing products for four storey buildings and above, where non-combustibility concerns are greatest and where separating walls and floors is important for fire and acoustic reasons. Following successful floor tests, it's likely that the Hyb-ISS floor product will be quickest to market through standardised production. 

The journey of Hyb-ISS and Airium has involved some important partnership. Fusion, Lafarge Holcim and Crest Nicholson worked with NHBC, who explored the range of thermal and combustibility requirements as well as criteria to be satisfied for product approval; to the BBA, who advised on the use of Airium as novel insulation, fire-proofing and acoustic proofing product. Whilst assessments are being carried out on using Hyb-ISS as a component part of a build, BRE is helping explore and assess the benefit of it as part of a system-based solution and is working with the team on a pilot to test this current thinking. Future projects are on the horizon.

• Aggregate Industries
• BBA
• BRE Centre for Innovative Construction Materials
• Crest Nicholson
• Fusion Building Solutions
• Lafarge Holcim
• MTC
• NHBC

As well as over £200,000 of funding, Transforming Construction (delivered by UKRI) has introduced the collaborative to MTC and BRE to help test, assess and manufacture the innovation and develop a viable system-based, rather than component-based, pilot. The team has also been introduced to Modulous (a partner on another IUK MMC demonstrator) to help develop and commercialise offsite-built Airium-filled panels being used in houses in South East London.

Hyb-ISS is a lightweight solution to insulation that can be manufactured and built offsite in a single process, meaning more housing structures of up to nine storeys can be built more quickly and accurately, with faster and easier finishing, and using significantly less resources. Its vastly improved fire resistant properties mean it would satisfy the need for new multi-storey buildings that are safer. Hyb-ISS is also 20% lighter than current alternatives and so use less materials, having considerably less impact on the environment. From schools to hotel rooms, universities to high rise apartments, Hyb-ISS offer could extend to bigger scale build, other construction markets, and new overseas opportunities helping the UK lead the way in systems-based innovative insulation.

Nobody wants to see a tragedy like the Grenfell Tower disaster happen again and so the safety of homeowners and tenants has to be paramount when building new multi-storey constructions. Hyb-ISS puts people's safety at the heart of new builds. Its vastly improved fire properties mean it supports houses that are safer in fires, and have considerably less impact on the environment. And the fact that it can be manufactured and built offsite in a single process, means build processes are smoother and site workers can work safely, and without unnecessary delays from on-site insulation. It also opens the industry up to a need for new systems-based skills and roles, creating job opportunities.

Hyb-ISS overcomes the challenge of achieving fire protection to a Light Gauge Steel (LGS) floor at scale. It combines the proven structural efficiency of LGS with an innovative cement-based insulation technology, Airium. This clever combination creates a simpler but higher-level and fully fire-resistant insulation. And as the solid structure can be built off-site in a single process, including external / internal load-bearing walls and floors, it makes handover on site quicker, requires less need for specialist on-site labour and supports faster and easier finishing for the client.

The product can be built off-site in a single process, so reduces the total time needed to complete the building. Following a full-scale fire test on an Airium/LGS floor at Exova Warrington, the team were able to prove high levels of fire protection. With a target of 60 minutes, the test achieved twice that showing 120 minutes of protection (the requirement normally for buildings over 30m or nine storeys). Hyb-ISS Airium/LGS floor weighs 75kg/m2 so is significantly lighter than current alternatives for multi-storey buildings. The structure and foundations required to support the floor are less, due to the lower mass, and this translates into lower costs. So, for example, composite metal deck/concrete (160mm) weighs 320 kg/m2 so is 4 times heavier than Hyb-ISS; Hollowcore 200mm with 65mm screed (265mm) weighs 400 kg/m2 which is 5 times heavier than Hyb-ISS; and concrete frame, plus 65mm screed (315mm) weighs 730 kg/m2 which is 10 times heavier than Hyb-ISS. Currently Hyb-ISS is being tested for structures up to 10 floors, but if pilots and uptake go well, it could expand into the 10-floor-plus market, currently worth £1 billion per year.

Assurance
Following a full-scale fire test on an Airium/LGS floor at Exova Warrington, the team were able to prove high levels of fire protection. With a target of 60 minutes, the test achieved twice that showing 120 minutes of protection (the requirement normally for buildings over 30m or nine storeys). This was a strong performance for a first attempt, and the team are already exploring opportunities to improve the fire performance, as well as reduce the cost of the floor product.

Cost
There are two factors that will improve the cost benefits of Hyb-ISS compared to current alternatives for multi-storey buildings - weight and fire resistance.

Firstly, the Hyb-ISS Airium/LGS floor weighs 75kg/m2 so is significantly lighter than current alternatives for multi-storey buildings. The structure and foundations required to support the floor are less, due to the lower mass, and this translates into lower costs. So, for example, composite metal deck/concrete (160mm) weighs 320 kg/m2 so is 4 times heavier than Hyb-ISS; Hollowcore 200mm with 65mm screed (265mm) weighs 400 kg/m2 which is 5 times heavier than Hyb-ISS; and concrete frame, plus 65mm screed (315mm) weighs 730 kg/m2 which is 10 times heavier than Hyb-ISS. Secondly, there is greater market value for a solid floor product that provides inherent fire resistance across multi-occupancy structures of three storeys or more. Currently Hyb-ISS can meet requirements for up to nine storeys currently and has potential to be used in private sale and private rental apartments, student accommodation, hotels, care homes and schools. The team's work on business models has begun to try to capture these comparative benefits on cost. If pilots and uptake go well, it could expand into the 10-floor-plus market, currently worth £1 billion per year.

Emissions
The raw materials used in Hyb-ISS – steel and cement - both have high embodied carbon. However, the unique way the materials are used radically reduces the quantities required, compared to conventional means of creating structures. And as Hyb-ISS is only 20% of the weight of the current concrete floor alternative used in Light Gauge Steel (LGS), this will translate into reduced carbon emissions, which will be tracked as the project progresses.

Time
Hyb-ISS dramatically improves finishing time and this will reduce the total programme time and increase productivity. Time savings will be a key metric measured as this project progresses.