21st Century steel in a low carbon, built environment
Jo Clarke* continues our series on the future of steel and explains the role of steel in construction as the industry aims to meet carbon targets.
21st century steel in construction
Over 50% of world steel is used in construction. Steel’s inherent properties such as strength, versatility, durability and 100% recyclability allow for improved environmental performance across the whole life cycle of buildings.
The versatility of 21st century steel means it is used for many different building elements including structural sections, roof and wall cladding, building services and fittings.
Of the many benefits of steel, it’s relatively lightweight compared to other structural materials such as concrete and this is beneficial for transportation, resource efficiency and assembly, as well as impacting on the type and extent of foundations needed.
It is even possible to use 21st century steel as an alternative material to concrete for foundations and it can be used to manufacture lightweight offsite solutions for buildings. As well as reducing waste materials, offsite manufactured solutions minimise onsite labour and the associated costs and carbon generated by onsite activities, as well as reducing overall construction time.
21st century steel in Active Building demonstrators
The current high embodied carbon of steel makes it an increasingly difficult choice of material as we address carbon targets. The good news is there are ways to reduce the carbon footprint of steel and low carbon steel solutions are already being developed.
Our Active Building demonstrators have provided an ideal opportunity to showcase innovative low carbon steel products, enabling feedback on their performance in a real-world environment.
One of the aims of our demonstrators was to show the benefits of UK steel and how innovative 21st century steel products could be used to create sustainable buildings.
Steel framed panelised building system
We constructed our Active Classroom using a novel steel-framed panelised system utilising Welsh manufactured light gauge steel developed by a small company seeking to showcase their system on a real building.
The simplicity of their system allowed the whole building to be erected with very little time, effort or equipment and in theory their design allows the building to be deconstructed, and the panels reused on another building at the end of the building’s life.
As the panelised system was lightweight and required no additional structural supports, we designed the building to sit on a series of steel screw pile foundations, instead of using concrete.
At the end of the building’s life the screw piles can be removed and reused for another building. The lighter panels and foundations meant they were easier to move, reducing time, transportation and fuel use.
21st century steel walls and roof
The outer skin of the Active Classroom showcases Tata’s novel, pre-commercial Colorcoat Prisma® cladding. Their three-layer manufacturing technology creates a robust, chrome free pre-finished steel product in a range of colours.
We selected colours to match the surrounding landscape and buildings on Swansea University’s Bay Campus. The south elevation is black to maximise the absorption of solar energy as a renewable heat source.
Internally Tata Coretinium® was used as a wall lining providing magnetic ‘idea walls’ within the teaching space.
We used a precommercial building integrated photovoltaic roof manufactured by Welsh company BIPVCo. This comprises a series of thin-film PV panels bonded onto steel roof sheeting to form a lightweight, electricity generating roof covering, with very low impact aesthetics.
Steel speeds up construction time
All the steel-based systems we used sped up construction time considerably. From the steel foundations, to the panelised superstructure, and the energy generating roof, onsite operations and the associated carbon emissions of a construction site were significantly reduced.
The ease of erection of the steel intensive building and lack of wet trades meant construction could continue in all weathers, helping us meet our tight programme.
Reuse of steel
As we strive to meet carbon targets, steel producers must seek ways to significantly reduce the embodied carbon of steel. One way to do this is to maximise its reuse.
Tata Steel are introducing a “Tag and Track” system marking their product range with a QR code to maintain a record of where every element is used, to ensure steel is used fully for its entire lifetime.
Their plans include creating materials passports and collecting in-use performance data from all their products, providing full product provenance. This would allow more reuse of steel, reducing the amount of new steel needed and the carbon emissions, energy and resources of steel production.
Designers can assist the reuse of steel products through designing bolted connections, rather than riveting or welding, for example; and using standardised sections and components.
Recycled steel has approximately one fifth of the carbon footprint of virgin steel and uses roughly one third of energy used in producing new steel.
Globally and in the UK the demand for steel currently exceeds the supply from demolished or scrapped steel. As more steel is used, the proportion of recycled steel to virgin steel will increase.
21st century steel in a low carbon built environment
To meet our carbon targets, we all need to think carefully about the way we use resources. The beauty of 21st century steel lies in its versatility, the role it has to play in offsite construction, its reusability and recyclability.
Building designers, contractors and the whole construction supply chain have a massive part to play in ensuring resource efficiency. The choice of materials and how those materials are deployed has a substantial impact on the whole-life carbon of buildings.
There is a real opportunity for 21st century steel to lead the way in developing low-carbon solutions for buildings. Our Active Classroom is a successful demonstrator of this.
Contributed by Jo Clarke, January 2022
*Jo is Design Manager for SPECIFIC IKC, and is a multi-award winner for her Active Building demonstrators