Aluminium has been at the core of residential and commercial buildings for over a hundred years and aluminium’s role in the construction industry is vast and diverse. Now aluminium products are helping more and more with the transition to a low carbon economy and the need for greener, more sustainable buildings within a circular economy framework.
A green building structure is defined as a structure that is environmentally responsible and resource-efficient throughout its life cycle. Some of the key features of green buildings include consumption of non-toxic/recycled material, optimal use of natural resources, increased use of renewable energy, minimum interference with the landscape, and indoor air quality.
Solar panels and other sources of energy production are considered active strategies in green buildings, while processes and materials that improve energy efficiency are considered passive strategies.
Two common passive strategies impact lighting and energy loss. Firstly, leveraging natural light during daylight hours reduces energy consumption and ensures an air-tight seal around windows and doors which prevents excess energy loss when heating or cooling.
Secondly, using materials that are sustainable in their sourcing, repurposed, reused, recycled, or long-lasting, reduces the overall energy consumption of the structure.
Nevertheless, materials still have to be sourced, manufactured, and shipped to the building site. Therefore, green building strategies need to take these aspects into account as well to include factors such as the energy used and the cost of transporting the building materials to the site. Aluminium is not only strong and infinitely malleable, but also light compared to other alternative building materials making it an attractive green building choice.
Aluminium’s high strength-to-weight ratio makes aluminium structures lighter by 35% to 65% compared to steel, while providing equivalent strength. The development of the modern skyscraper has mostly depended on the use of aluminium. Since modern lightweight aluminium alloys can easily support the weight of heavy glass spans for fenestration, thus maximizing the building’s capability for using natural sunlight.
Aluminium can be made into any form, shape, size, and gauge without compromising material integrity and performance, making it ideal to create lightweight and strong buildings and interior components. These properties also make aluminium ideal for very complex extrusions and castings.
Fuel consumption to transport aluminium to the building site is much lower than the transportation cost of heavier building materials. Moreover, fewer materials may be necessary to support lighter aluminium components versus steel counterparts, and buildings using aluminium weigh less overall than those built with steel without compromising on the structure’s overall strength.
In addition to its physical properties, aluminium is one of the most recycled materials on the planet. The International Aluminium Institute studies demonstrate that about 75% of all aluminium produced in history is still in use today. Further, recycled aluminium saves around 95% of the energy required to mine and process new aluminium.
Unlike steel and many other metals, aluminium is highly resistant to corrosion. It does not rust, and it holds up to extreme weather conditions. These characteristics mean that aluminium products in a home or building will last longer. Aluminium products in buildings usually have a designated service life of multiple decades, causing fewer needs for repair and furthermore at the point of replacement the aluminium can be recycled.
Aluminium products only need to be cleaned routinely to remove dust. Additional maintenance should not be required resulting in a major cost saving and also an ecological advantage because cleaning and maintenance of aluminium products in buildings does not usually involve chemicals or toxic agents.
Reflective properties are an essential aspect of green buildings. Reflecting light energy rather than absorbing it reduces the energy needed to cool the building. Coated aluminium reflects more than 95% of solar energy directed at it. This means that depending on the orientation of the building and where aluminium is used, there is potential for significant energy savings.
Looking at the wider environmental impact it is no secret that mining and refining operations for all raw materials come at a high cost to the environment. Since aluminium does not occur naturally in the earth’s crust, the process of refining bauxite ore in the production of aluminium inevitably has an impact too. However, the aluminium industry is constantly working to reduce this impact, including recycling caustic soda, introducing better management of bauxite residue, undertaking rehabilitation initiatives such as planting replacement trees, and restoring the natural habitat when mining is finished.
The industry worldwide is also continuing to decarbonise the electric power used in aluminium smelting. A third party critical reviewed life-cycle assessment (LCA) published in January 2022 demonstrates that since 1991 the carbon footprint of primary aluminium productionhas been lowered by 49% and processes to recycle aluminium saw a 60% reduction in North America. During the same time period, the energy needed to produce primary and recycled (or secondary) aluminium has dropped by 27% and 49%, respectively.
Carbon footprints differ across regions and producers worldwide. However, clean energy is becoming cheaper and more reliable. Governments and businesses around the world recognised this and are now focusing on developing more clean power.
When aluminium is used in building designs, it means supporting an industry that is mindful of its practices and continually working to improve its processes to reduce the impact on the environment and increase energy efficiency.
The on-going drive for more green buildings has transformed the way buildings are now planned and created. Aluminium continues to have a key role in this transition journey and remains at the core of this positive shift in the creation of sustainable structures.
