5 October 2017
By Tercia Jansen van Vuuren
Using BREEAM to assess the sustainable sourcing and use of aggregates
Last week, the draft of the eagerly anticipated BREEAM UK New Construction (NC) 2018 was launched for consultation. Whilst there are many changes that will hopefully continue to improve the way we promote and assess the sustainability of new developments, here at KLH Sustainability, we are most excited about the proposed changes to assessment issue WST 02 in the ‘Waste’ category.
The new WST 02 is entitled ‘Use of recycled and sustainably sourced aggregates’, branching out from the previous topic of simply ‘Recycled aggregates’. Over the last year, KLH Sustainability, on behalf of The Crown Estate conducted extensive research into the UK aggregate industry and consulted with key members about a revised methodology for assessing aggregate use in construction. Out of this work, we proposed new criteria and assessment methodology to the BRE for the WST 02 assessment issue. Our proposed criteria have now been published in the draft 2018 manual, and we are excited about the prospect of how it can be used to evaluate and improve the sustainability of aggregates used on projects.
Why does it matter and why change the credit?
Aggregates are low value, high bulk material and are vital in nearly every construction project. We have previously written about the availability of recycled and secondary aggregates, and the potential consequences of trying to drive recycled and secondary aggregates up the value chain. We introduced an alternative approach to the assessment of sustainable sourcing and use of aggregates, highlighting how aggregates should be evaluated holistically.
New proposal for WST 02
Our new methodology aims to recognise and minimise social and environmental impacts of aggregate selection, sourcing and use. Three key assessment criteria, deemed significant for the aggregate industry, are used:
- local availability of aggregates – this uses the regional Abiotic Depletion Potential (ADP) of the aggregate type depending on the region from which it is sourced (see our explanation on ADP here);
- social cost of transportation – a monetary value is determined based on the cost of externalities associated with freight transport, such as accidents, congestion, and noise. Different modes of transport and types of roads have different social costs;
carbon footprint – carbon emissions are calculated based on the aggregate type and the CO2e emissions from the mode of transport selected and the travel distance.
The assessment is based on the points achieved per aggregate source, with points awarded in each of the three categories. Using the tonnes of aggregate per source, a final weighted average for the project is calculated, giving a project Sustainable Aggregate Points score.
If it all sounds complicated, don’t worry, we produced an easy-to-use tool for use with the BREEAM credit that does most of the work for you!
We hope that this new, broader method will encourage project teams to recognise the holistic impacts of aggregates and engage with the industry to identify and test alternative sources, as well as encourage the maximum reuse of aggregates obtained from site-won material. As noted in the draft BREEAM UK NC 2018 manual, this new methodology recognises that “primary aggregates can still be considered a sustainable option, where locally sourced, sustainably transported and from a region where that aggregate type is abundant.”
We welcome comments on the proposed changes to the WST 02 assessment issue and want to hear your thoughts on whether this will stimulate a positive change in industry, and how it could be improved. The formal BRE consultation closes on Friday 3rd November 2017, so please make sure you submit your comments before then and feel free to let us at KLH know your thoughts.