Steel structure; Steel structure;

Designing steel for re-use

In recent years Arup has worked with major players in the UK steel industry to examine the possibilities for a more sustainable use of this vital, but carbon-intensive material. The research shows that designing for re-use can deliver up to 25% savings on steel costs per tonne. I believe designing steel for re-use is a potential solution for reducing carbon emissions whilst perhaps also building a more resilient commercial future for the steel industry.

Today’s demolition and dismantling process misses an opportunity to make smarter use of existing steel and to take a more responsible approach to its embodied carbon footprint. Typically, when a building is demolished the steel goes to scrap before being melted down, milled, transported and stored, and eventually being reprocessed into something new. These are carbon intensive processes at every level.

Whole life resource efficient design suggests a better way. In this alternative method, the building is designed to enable re-use from the outset - traditional steel recycling is not the objective. This means the initial design embodies principles that enhance a building’s re-use potential. 

Re-use starts with enabling easy and cost effective deconstruction using a minimum number of fixings that can be removed mechanically, not chemically. The structure should be simple and elements should be specified with an eye to ensuring re-use, a degree of standardisation across the structure will also assist re-use. 

An information trail for passing on data to the end of a building’s life is also critical. Steel sections’ individual properties would be labelled at first production, from the virtual Building Information Model (BIM) and specification through to physical tagging of each individual piece. This process would embed details on the steel’s stress, strength and fatigue (amongst other characteristics) for easy use when the building is disassembled, facilitating easier re-purposing with only the smallest of re-fabrication activities.

Given that the majority of the cost and carbon in making steel comes from the primary and secondary materials and energy used in the furnaces, this new process creates opportunities for producers to bring a product to market at a much lower cost and significantly reduced carbon footprint. Plus, the re-use process differentiates the product in a heavily over supplied market. 

Building for the future

Planning for later re-use is therefore commercially compelling and meets corporate social responsibility goals. Prologis, who build and run large distribution centres for retailers have already embraced this idea. With an ongoing need to build simple, replicable and sustainable structures, they’ve designed buildings where the steel is designed for re-use, either for their own purposes or for purchase and use by third parties.

This circular economy concept has also gained a foothold in the ship-building industry. Given that up to 98% of a container ship is steel, and the demanding nature of its limited lifespan, it’s easy to understand companies’ focus on value for money. In response, global shipping giant Maersk has developed the product passport, tagging as many elements of a decommissioned ship as possible so that parts can be recycled without losing structural quality or value. If it works for shipping, why not the built environment?

Designing steel for re-use is still a relatively new idea. But in a world where globalised price fluctuations and over-supply can have sharp effects on a producer’s bottom line and competitiveness, having innovative, forward-thinking ways of harnessing and retaining resources and their value efficiently, should improve a steel maker’s commercial position. In theory the steel maker might not even relinquish ownership of the steel resource and could instead expand their product and service model to re-fabrication and supply of end of life steel.

For now, making disassembly plans mandatory for all buildings could be an easy way of recording the necessary information to enable a circular economy approach. 

Arup is continuing to explore this alternative steel production scenario with partners in the industry and I’d be interested to hear your thoughts on the applicability of this approach.