Successful steel reuse in the UK – key aspects why it happened

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International HISER Conference on Advances in Recycling and Management of Construction and Demolition Waste

21-23 June 2017, Delft University of Technology, Delft, The Netherlands

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Successful steel reuse in the UK – key aspects why it happened Michał P. Drewniok1, Cyrille F. Dunant2, Julian M. Allwood3, Jonathan M. Cullen4 1,2,3,4

University of Cambridge, Department of Engineering, Trumpington Street, Cambridge, CB2 1PZ, UK, E-mail: Michal.Drewniok@eng.cam.ac.uk

Abstract

With growing pressure on the construction industry to be more resource efficient, to reduce waste and to lower embodied carbon, material reuse strategies are critical to meet targets, especially for steel. Indeed, steel recycling is an energy and carbon intensive process, offering only approximately 50% energy savings [1] and 75% [2, 3] over new production, while steel reuse eliminates both. Unfortunately, there are many barriers preventing steel reuse happening at a large scale. Indeed, only 7% of heavy structural sections and tubes are currently reused compared to 93% which are recycled in the UK. Using information collected during interviews with actors across the supply chain in the UK, we could establish the cost of steel reuse. We found that steel reuse is only slightly more expensive than new steel when considering all additional costs. This paper presents case studies which were described to us during interviews or which we found in the literature where steel reuse was successful. We tried to analyse where savings were found to make it viable. Finally, we propose three main strategies to enable steel reuse at scale.

Keywords: steel reuse, structural steel, sustainability in construction. Introduction

Steel reuse compared to using new steel made in primary or secondary production is an excellent way to reduce the CO2 emissions connected with construction. It saves both the energy and the carbon required to melt the scrap and form the steel back into a useable product [4]. Unless used steel sections were fatigued or subjected to fire, they keep their properties. Thus, they can be used after the end-of-life of a building in other structures. Table 1 shows different scenarios for reuse. These can be in the same building, in another but on the same site, or on a different site. In some cases, a whole building is reused but the most common cases are parts of building or single elements being reused. Unfortunately, steel reuse is rarely happening. In studies by EUROFER, and by Samson and Avery [6, 7] it is reported that only around 7% of heavy structural sections and tubes, 15% of steel piles (sheet and bearing) and 10% of profile steel cladding in construction in the UK were reused in 2012, whereas respectively 93%, 71%, and 89% were recycled. It is therefore thought that many barriers prevent steel reuse from occurring on a larger scale [8, 5]. Only a few of these barriers appear to be practical in nature: availability, timing, and testing [8]. However, all barriers are linked to supplementary costs. In a survey, we found that actors in the supply chain believe steel reuse is more expensive than new steel. However, Dunant et al. [9] calculated the full cost of reusing steel sections to be only slightly higher than new elements. The difference is approximately 80-145/t [5]. This represents between 7.6% and 10% over the cost of new steel (Fig. 1). The cost components causing reused steel to be more expensive are related to reconditioning, fabrication, transport and testing.

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Using the information collected during 30 interviews across all the supply chain, supplemented by a review of literature, we found successful case studies which suggested where cost reduction might be found to make reuse viable.

Table 1. Characteristics of different types of reuse [5].

Successful steel reuse – Case studies

Even though steel reuse in the UK is not common, there are some successful examples. Table 2 presents such cases as described during interviews or found in the literature. Based on these findings, we can observe that the three main strategies enabling steel reuse are:

- Refurbishing or extending existing buildings; - Reuse of a whole building or large parts thereof;

- Reusing elements left on the demolition site after the deconstruction of a building previously standing there.

All these strategies show cost components reduction connected to steel reuse, such as lowered material, fabrication, testing or transport costs.

Insite

(thesamebuilding)

Onsite

(other building but in the same site)

Differentsite

(other building but in the other site)

AllBuilding Reuse

The same purpose Relocation – the same function

Other purpose Relocation – the other function

Partofthe BuildingReuse

(componentsystem

reuse)

Unmovable parts (e.g. reinforced

concrete foundations)

Reinforced concrete footings (especially

prefabricated)

Rebuild_{or extend existing}

buildings_{(e.g. frames, trusses,}

roof structures)

Build,_{rebuild or extend from components derived}

from_{other buildings (e.g. frames, trusses, roof}

structures) Use as temporary structures Use_{as temporary} structures Use in agriculture buildings

Reuse e.g. façades, envelopes, sandwich panel systems for existing and new buildings

ElementReuse

(steelelements)

Rebuild, extend or repair

(replacement) from reuse steel

elements

Build, rebuild, extend or repair (replacement) from

reuse steel elements

Use as temporary structures Use as temporary structures Use in agriculture buildings

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Figure 1. Differences between new and old steel use [5]. Table 2. Savings observed in analysed case studies.

Conclusion

Steel reuse in the UK is a very narrow market. The main reason seems to be high cost, real and perceived. Indeed, taking into account all cost components, we found that steel reuse is more expensive than using new steel. However, the difference isn't large, only 10% over new

-450 165 375 175 50 -330 120 245 145 45 -500 -250 0 250 500 A d d it io n al c o st f o r st ee l re u se £ /t

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steel. We found case studies through a literature review and interviews where the costs of reconditioning, fabrication, transport, and testing where reduced, making steel reuse profitable. Finding such viable strategies to make reuse profitable will contribute to develop steel reuse into a widespread practice hopefully leading to significant savings in emissions. Acknowledgement

This research was founded from Innovate UK founds, project “Supply Chain Integration for structural steel reuse", ref 132106 and EPSRC Material demand reduction, ref. EP/N02351X/1.

Work made in cooperation with Michael Sansom from Steel Construction Institute (SCI), Simon Corbey from The Alliance for Sustainable Building Products (ASBP) and Howard Button from the National Federation of Demolition Contractors (NFDC), all contributions for which we are thankful.  

References

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[6] EUROFER survey of NFDC Members, July 2012.

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