With the ever-increasing awareness of climate change mitigation, built environment professionals are showing an increasing preference for perceptively sustainable product solutions, whether for structural elements or aesthetic purposes. Unsurprisingly, it’s led to an increasing appetite for timber-based materials, due to their often assumed, sustainable credentials. In turn, metals, such as aluminium, iron and steel have been avoided due to apparent carbon intensity. Analysing the true sustainable status of any material needs to go beyond measuring carbon produced from merely sourcing, manufacturing and distribution. Any evaluation must take into account the availability and renewability of the resource, whole-life embodied carbon and performance qualities, including insulation and thermal conductivity. In construction, the sustainability of materials is dependent upon designing-in permanency or reusability. Timber: The pros and cons So, let’s take timber as our first example. It’s universally known that trees act as a natural carbon store, meaning the timber produced from them has essentially locked the carbon into its matrix. By its nature, it reduces greenhouse gas emissions. However, we must consider timber’s full life cycle too, i.e., the embodied carbon from production through to the material’s fate at the end of life. Less appreciated is that the carbon stored in timber only remains locked into the wood for as long as the timber is in use. If it rots or is burned for energy, then all this stored carbon returns to the atmosphere where it releases its delayed contribution to global warming. Currently, it’s estimated that half of all construction timber ends up in landfill, with 36% recycled and 14% burnt for biomass (Arup, 2014). It’s important to indicate that the 36% of timber that is recycled can only be downcycled into products such as particle board or mulch for composting, downgrading the quality of the timber. So, until timber’s end-of-life is addressed, the carbon footprint across an entire lifecycle does not intrinsically, or positively, contribute to environmental sustainability. Aluminium: The pros and cons Let us then make the comparison with, aluminium, a product integral to the glass partitions we manufacture at Optima. The first major difference between aluminium and timber is that the latter is a renewable resource in a way the former cannot be. A finite amount of aluminium exists in the earth, whilst timber, such as that sourced for the Forest Stewardship Council (FSC), is continually replenished with the planting of 2 or 3 trees for every tree felled. However, in turn, aluminium, despite the limits of virgin material, is infinitely recyclable, retaining its inherent structural and performance properties. It’s this recyclability whilst maintaining the characteristics that make it a valuable construction material that highlights its strong sustainable capabilities. Furthermore, advancements in recycling techniques and a greater understanding of sustainable construction mean that aluminium for buildings, fixtures and fittings is now recycled at a rate of 92-98% (Alfed, 2022). Eliminating carbon emissions through reuse or recycling Reusing or recycling aluminium not only eliminates the carbon emissions released from extracting and manufacturing virgin alternative materials but also reduces the number of materials in landfills. This minimises the energy required to produce new aluminium. In fact, an energy saving of 95% can be achieved from recycling aluminium when compared to the same quantity of aluminium made from virgin materials (Hydro, 2020). So, you see, there’s more than initially meets the eye for both materials, so it’s best not to make a knee-jerk decision when specifying sustainability. It’s important to look at the whole supply chain from cradle to gate and beyond. Indeed, we should be approaching this from a more circular approach and, regardless of material, looking at ways in which we can reuse and repurpose products, extending their lifecycle for as long as possible. Furthermore, if the materials in question (either aluminium or timber) are manufactured or designed for reusability, their sustainable credentials are boosted even further, as the energy used for reusing or recycling is eliminated, lowering embodied carbon. Decarbonisation in design is paramount Any reduction or delay in the release of carbon dioxide into the atmosphere is a welcome move, and clever product design will make the most of any construction material used. It’s something that prompted us to switch to the most sustainable grade of aluminium on the market, Hydro CIRCAL, for our glass partitioning systems. With the lowest embodied carbon aluminium available, Hydro CIRCAL allows us to provide our clients with the high-quality glass partitions they expect from us now manufactured with low-carbon aluminium. Not only have we adopted aluminium made from a minimum of 75% post-consumer recycled content, but we have also launched the Reuse Service to ensure we maximise the opportunity for reuse in all our products, facilitating an almost infinite number of lifecycles. As a market leader in sustainable glass partitioning solutions, we are developing several innovations that will support our clients in specifying glass office partitions sustainably. Ultimately, designing-in reusability as a primary consideration builds in a greater degree of sustainability. The true potential of materials such as aluminium is unlocked when we integrate reusability into their very fabric. In this era of rethinking and rebuilding, it’s time to mine the Anthropocene and embrace a circular economy, ushering in a new age for construction. Decarbonisation and driving sustainability are part of our business strategy at Optima and we are committed to developing products and processes that promote the circular economy and guide us on our journey to sustainable development. About the Author Managing Director, Christian Mabey joined Optima back in 2006, and he has played a central role within the business, especially when it comes to growing the Optima brand outside of Greater London. Joining Optima with the intention of building a nationwide network of Dealer Partners, Christian has helped to grow the Optima brand so that it has become the specifier’s system of choice throughout the UK. This has been achieved principally by developing regional networks that enabled nationwide access to Optima’s unrivalled portfolio of market-leading acoustic partitioning.