Comprising around 8% of the earth’s crust, aluminium is the third most common element and the world’s most abundant metal. In an era of eco-conscious design and construction, it is also becoming increasingly abundant in the fabric of man-made environments, where many of its natural attributes are ideal for sustainable development.
In more general terms, aluminium’s versatility and performance qualities make it the most widely used metal after steel. It can be found in foil and packaging, ladders, high pressure gas cylinders, sports equipment, road barriers and signs, furniture, lithographic printing plates, helidecks, offshore rigs and all types of transport including aircraft, passenger and freight rail cars, commercial vehicles, military vehicles, ships and boats, buses, bicycles and motor cars.
The properties which have made it so prominent in these applications have also resulted in its use in construction, including roofing, foil insulation, cladding, doors and windows, shop fronts, handrails and balustrade, architectural hardware, guttering, decking, grating, solar shading louvres, modesty screens, bridge and cycle paths, ventilation grilles, walkways, treadplates and industrial flooring. These properties are many and varied:
High strength–to-weight ratio
Aluminium is one of the lightest engineering metals with a weight of around one third of steel’s and a superior strength-to-weight ratio. Its combination of high strength and low weight is ideal for applications such as roof access walkways, which need excellent load bearing without placing undue strain on the roof structure. Being light and easy to handle also saves on manpower, enabling better cost management in construction.
When aluminium metal is exposed to air, it forms a protective oxide coating which is corrosion resistant and can be further enhanced with surface treatments such as anodising. This is beneficial for any building but especially valuable in environments where corrosion levels are high to severe, such as coastal, industrial and heavily populated suburban areas.
Aluminium is an inert metal and completely impermeable. It is non-toxic and does not release any odours or taint products in contact with them. These properties help to maintain a building’s aesthetic quality and reduce pollution.
Aluminium does not burn or aid combustion, providing an obvious advantage over building materials such as timber.
Aluminium is a good reflector of both visible light and heat. This makes it an ideal material for light fittings, solar shading louvres and insulation.
When preparing an architectural specification it is essential to consider the responsible sourcing, effectiveness, durability, and the potential recycling of any material. This is where aluminium scores highly: its recyclability is unparalleled. Unlike a fossil fuel – which is consumed when used – aluminium has an extremely high residual value.
The use of recycled aluminium over virgin aluminium is economically and environmentally unarguable. If not done properly, the mining and smelting of aluminium can have an environmental impact; the impact of using recycled aluminium is minimal in comparison. It takes 14,000 kWh to produce one tonne of new aluminium but only 5% of this to re-melt and recycle the same amount. Aluminium can be recycled over and over again without loss of performance – there is no difference in quality between virgin and recycled aluminium alloys. It can also be up-cycled if necessary.
Aluminium offers a wide range of properties which make it a superior choice for various building materials, but the most compelling of all is its remarkable recyclability. At present around 60% of aluminium metal is recycled at the end of its lifecycle but there is room for vast improvement in this percentage. Designers and specifiers should not only seek to incorporate a greater proportion of aluminium content into their developments; they should also seek building suppliers who can verify that their aluminium products are manufactured to a high percentage of recycled material. It is perfectly feasible for certain building applications to be manufactured from between 85% and 100% recycled aluminium.
Aluminium is a vital component in the creation of high quality architecture and infrastructure – it is also a key resource in the creation of a sustainable future and its positive influence can substantially increase with carefully managed design and procurement.