As we decarbonise construction in line with the UK’s net zero 2050 targets, attention is turning to the challenges of moving to a more circular economy. Michael Sansom, Associate Director, Steel Construction Institute (SCI), outlines how a new website portal could help the steel sector.
Steel construction systems are already highly circular, benefitting from steel’s intrinsic ability to be recycled, again and again, without loss of properties. For example, current endof-life recovery and recycling rates for structural steel in the UK is >95%. The challenge for the steel construction sector therefore is how to move from recycling to reuse.
A new initiative by the SCI will facilitate the reuse of structural steelwork through the collection and aggregation of data on new and reclaimed structural steel products – we are also assessing how this could be adopted and applied to the light gauge steel sector.
SCI has developed a prototype website portal for collecting and sharing information about steel reuse and for trading reclaimed steel structures and components. In terms of the functionality of the portal, it has been developed to address both:
• Reuse today scenario, i.e. a traditional ‘sell-buy’ exchange but devoted specifically to reclaimed structural steel
• Development of a database of new structural steel in newly constructed buildings, i.e. facilitating future deconstruction and reuse.
Both of these scenarios contribute to a circular economy and can substantially reduce environmental impacts. Not only are the production impacts of making new steel avoided but by reconditioning and reusing reclaimed sections in the UK, the transport impacts of importing new steel and exporting steel scrap are avoided. Currently the UK exports around 75% of steel scrap for recycling overseas. Studies suggest that greenhouse gas emission savings of around 95-97% are achievable through reuse compared to primary steel production.
There are also potential economic benefits. Although new steel and scrap steel prices fluctuate, a review of the price differential between new and scrap structural steel between 2002 and 2018, shows an average price differential of £313 per tonne. This represents the potential profit opportunity of reusing, as opposed to recycling, steel sections. There are also many case studies of whole structure reuse where significant cost savings were achieved relative to using new steel.
In terms of reuse today, the prototype portal enables sellers and buyers to make contact and exchange information both pre and postdemolition. Pre-demolition building information provided includes:
• Age of building
• Scheduled demolition date
• Size of building
• Overview of section sizes, grade, sub-grade, etc.
• Contact details to enquire about the building.
Post-demolition it is assumed that the building has been deconstructed with a view to reusing the reclaimed members, i.e. care has been taken to deconstruct the building carefully with a view to preserving the structural steel members. Post-demolition, more information is readily available, for example, section designation, length, etc. If testing is required, the results should also be made available.
Buyers can search the database of available reclaimed sections using the following search criteria:
• Section type; e.g. UB, UC, PFC
• Postcode and search radius
• Section size from a dropdown menu of standard section sizes.
To facilitate future reuse, the portal captures and stores detailed information on new steel buildings to enable them to be refurbished, extended and potentially reused in the future. Data fields relate to building or project information plus elemental information.
Project information is inputted manually and elemental or product information is provided electronically to the portal via uploaded IFC files of the erected structure. The whole building structural models are held confidentially and securely until such point as they either due to be refurbished, structurally extended or when they are scheduled for demolition. At this time, the building information becomes searchable via the portal and the elemental information will be placed in the database of reclaimed sections and made available for purchase. Over time, this database will grow to provide a virtual stock of steel elements with all associated properties and provenance, to facilitate mainstream reuse.
Because of the factory-based nature of structural steel and the widespread use of BIM by the sector, the product information required to facilitate future reuse is readily available and it is simply a matter of collecting, storing and retrieving this information effectively. As a minimum, the following information is to be stored in the database for each structural element:
• Section designation, length and weight
• Steel grade and sub-grade
• Product and execution standard
• Mill certificate
• Environmental product declaration (EPD).
To date, development of the prototype reuse portal has focused on hot-rolled structural steelwork; these members being durable, dimensionally stable and importantly robust. Consequently, they offer the greatest potential for reclamation and reuse. Light steel structural elements including 2D (panels) and 3D (modules) are highly reusable, and we need to start collecting and storing the relevant properties, as described above for hotrolled sections.
There are other aspects relating to the reuse of light steel systems that also need to be explored such as how we can standardise our systems to facilitate reuse. It is time for all of us to think about our carbon footprint, both personally and professionally, and proactively think about what steps we can take to help tackle the ongoing climate emergency.
To read the full article, go to Offsite Magazine
