Phil Slinger from the Council for Aluminium in Building provides expert insights on the current green credentials provided by aluminium production, and how EPDs and collaboration are supporting its specification
Aluminium has enjoyed an extensive recycling lifespan since its commercialisation in the 1880s with the advent of the Hall–Héroult process for the economic production of aluminium, in fact, 75% of all the aluminium produced since that time is still in active use today. Aluminium has an enviable scrap value and ‘clean’ scrap can cost almost the same as new ‘prime’ aluminium. The industry demand for recycled aluminium today is driven by the demand for ‘low-carbon’ aluminium, as recycling aluminium uses just 5% of the energy needed to produce ‘prime’ aluminium from surface mined bauxite.
Today ‘low-carbon’ aluminium can be produced at less than 3.0 tCO2e (tonnes of CO2 equivalent per production tonne) when prime is mixed with 60% to 70% of recycled aluminium. The process of reducing carbon in production is ongoing with some producers now gearing up to produce aluminium using hydrogen energy. No more than a couple of decades ago we were specifying the use of ‘prime’ aluminium for projects at 20.0 tCO2e carbon content.
As you would expect, there is a high demand for this ‘low-carbon’ billet which comes at a premium. In reality all new aluminium used globally, across all industries, on average contains by volume one third recycled aluminium. The dilemma we face, is the difficulty in obtaining scrap, which is due to the aluminium product still being in active use which is down to aluminium’s in use life expectancy. Some of the oldest installed aluminium windows, installed at the Bodleian Library in Oxford, are over 80 years old and still going strong.
Today we recycle a higher percentage of our scrap aluminium as extraction rates from deconstruction of our structures has increased to almost 100%, such is the value of the metal. In fact, many aluminium supply chains now see our cities as ‘urban mines’ for the future extraction and re-use of aluminium used in both construction and transport infrastructure.
What is new today is the ability to easily recycle aluminium back into their original ‘grades’. Pure aluminium is relatively soft and rarely used in production, it is normally formed into an aluminium alloy which contains other materials that give the alloy special characteristics. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are many globally recognised grades of aluminium alloy which are placed into a long list or ‘series’ of different characteristics which are used in various applications. For wrought aluminium used in the architectural aluminium extrusion process, we generally use an alloy grade 6063. The ability to recycle in a single grade is helped by using modern, handheld alloy analysers. These XRF (X-Ray Fluorescence) analysers perform a quick, non-destructive analysis of scrap so grades can be grouped together for recycling.
Keeping the grades segregated means that the scrap aluminium has a higher value to a reprocessor ensuring that former architectural installations can be collected and made back into windows, doors and curtain walls. CAB (Council for Aluminium in Building) introduced the first ‘Closed Loop Recycling’ initiative for aluminium used in construction in the UK. The scheme has since been adopted by other Associations.
Environmental Product Declarations (EPDs) are now becoming more widely accepted and indeed being requested from product manufacturers by main contractors during the tendering and design processes. An EPD is designed to inform the recipient about a product’s environmental and human health impacts during its life cycle, and should follow recognised standards such as the ‘core rules’ in BS EN 15804+A2. Based on a product’s Life Cycle Assessment (LCA), the aim of an EPD is to inform the reader about a product’s environmental impact in a standardised and transparent format for specified life cycle stages and a given performance.
While it is possible to develop EPDs for any type of product or service, it is the construction sector that has one of the most advanced EPD systems. EPDs can be based on a company’s ‘specific product’ or compiled to offer an ‘average product’ EPD from a range of suppliers of similar products, such as provided by a membership association like the Council for Aluminium in Building.
As stated above, an EPD is a standardised document produced from a Life Cycle Assessment (LCA). An LCA is defined as a ‘systematic analysis of the potential environmental impacts of a product or service during its life cycle’. Often a company’s ‘specific product’ LCA can carry sensitive company data which cannot be made public. However, the resulting standardised and independently verified EPD produced from the LCA should not divulge this sensitive information, so is usually safe to promote and circulate.
As an association, CAB also continues to develop to meet the rapidly changing fenestration landscape that seeks to achieve thermally efficient fenestration systems to meet our need for sustainable ‘low-carbon’ homes, businesses and public spaces. Aluminium can be easily and cheaply formed into intricate shapes that together with thermal insulation strips and infills allows Passivhaus certified products to be easily produced to meet future demand for thermally efficient products, but it is not only material and product development that need to be sustainable, businesses also need to be sustainable. A further recent CAB initiative ‘Journey to Net Zero’ forms the path ahead for the Industry both in business processes and products. There are significant challenges adopting this challenge and the time has never been better for the Industry to draw together to drive achievable change in the coming years.
The membership drive explains the support services offered by the Association, but more importantly, it is about belonging to a ‘family’ where businesses meet and network, to the benefit of the whole industry creating one voice for future change.
Should you wish to learn more about the use of aluminium, please contact CAB directly, and why not consider joining the association and be recognised as being involved in supporting your industry and helping to shape its future? More information is available on our website (c-a-b.org.uk).
Phil Slinger is CEO at the Council for Aluminium in Building (CAB)