Should we be concerned at taking a ‘Cradle to Cradle’ approach’ for building materials sustainability, or just build and put our faith in future recycling technology? Let us look at what a ‘Cradle to Cradle’ approach is and why it is so important.
Most materials used currently in building construction can have a second life when they come to their end of use in a building, this is a ‘Cradle to Cradle’ approach to the use of building materials. This could be material reused for landfill from heavy-side construction or at the other end of the scale, an almost 100% recycling capability of materials in the case of metals. The dilemma that we currently face is that material manufacturers that supply products that are currently problematic to recycle into new products, prefer to adopt the ‘Cradle to Gate’ approach which means taking the stance of ‘take-make-consume-and-throw-away’. Producers of products made from metals on the other hand wish to embrace the ‘Cradle to Cradle’ approach, but it comes with a caveat in the case of metals, a high embedded carbon content due to energy costs in the extraction from ore, refining and product formation.
A great deal of work is being done, in the case of aluminium, where carbon embodiment has already been significantly reduced. According to a 2020 white paper, ‘Low-carbon Aluminium, Solution for Sustainable Construction & Renovation’, primary aluminium from China can be as high as 20kg CO2e (carbon dioxide emissions equivalent) per kg of aluminium; for average global production of primary aluminium this figure drops to 16.7kg CO2e per kg. A ‘low-carbon’ primary, currently is on average just 6.67kg CO2e per kg.
According to the white paper, the Carbon Trust is currently targeting 8kg CO2e for all primary aluminium, and reviewing the Carbon Trust’s own report ‘The Case for Low-carbon Primary Aluminium Labelling’ they suggest that just 4kg CO2e is possible to achieve and suppliers have now achieved this figure through using renewable energy sources like hydro power during production.
The production of recycled aluminium now means producers are guaranteeing a CO2e footprint below 2.3kg of CO2e per 1kg of aluminium produced.
The key here is that the current global figure for primary production will have already reduced since 2020 and continue to fall in future years as new technology is brought online.
The construction industry continues to move towards the ‘whole life’ use of materials including their reuse and recycling potential. Obviously some materials will have a single use, with limited second use, some materials will become better recycled as technology improves and some can currently be recycled indefinitely in the case of metals.
The framework for appraising the environmental impacts of the built environment is provided by BS EN 15978: 2011: (Sustainability of construction works — Assessment of environmental performance of buildings — Calculation method). It sets out the principles and calculation method for whole life assessment of the environmental impacts from built projects based on life-cycle assessment.
Today the drive in sustainability in construction is to consider the circular economy, the ‘Cradle to Cradle’ approach, with BS EN 15978 Modules C (end of life) and D (reuse and recycling potential) mandated for most products when preparing Environmental Product Declarations to the A2 version of BS EN 15804:2012 Sustainability of construction works – environmental product declarations – core rules for the product category of construction products.
Underpinning BS EN 15978 in the UK is the RICS Professional Statement which is currently being updated with consultation to begin in March 2023. It is expected that Module D will be changed from optional and will deemed as a mandatory requirement.
Aluminium is crucial to our modern lifestyles in all walks of life, not only construction. It takes just 5% of the original energy to produce it, to recycle aluminium back into new products of the same quality, indeed there is such a demand for recycled aluminium that its scrap cost is close to that of prime, or first use aluminium. Continuing to leave Module D as an option ignores this valuable materials importance in building construction.
Let us not forget that CAB are contributing to the ‘Cradle to Cradle’ approach with its own ‘Closed Loop Recycling Scheme’ which aims not only to encourage 100% recycling of aluminium, but to recycle within specific aluminium grades. This ensures that typical architectural extrusion grade aluminium, such as 6063, is recycled within a closed loop meaning the quality of the grade is maintained. More information on this scheme, which is open for members to join, is on the CAB website.
CAB remain at the forefront of the use of aluminium in the UK & Ireland and we will be keeping our membership informed of developments and pending changes in legislation. If you are not a member, why not consider joining the Association and be recognised as being involved in and helping to shape the future of our Industry. More information on our website at c-a-b.org.uk
