Aluminium is utilised for a host of applications in building and construction and is the material of choice for curtain walling, window frames and other glazed structures. It is extensively used for rolling blinds, doors, exterior cladding and roofing, suspended ceilings, wall panels and partitions, heating and ventilation equipment, solar shading devices, light reflectors, solar panels, solar collectors and complete prefabricated buildings.
The building and construction industry is today faced with many environmental challenges - from its impact on climate change to its choice of materials and methods of waste disposal.The growing understanding that the entire life cycle of a building and its fittings must be considered and balanced against the realities of design, function and economy has seen aluminium fast become the material of choice.
Its properties mean that intricate, stable and lightweight structures can be designed without concern, as even thin structures do not warp. Aluminium is a material that has given architects and designers the physical means to achieve creative innovations in design. Aluminium allows a high degree of prefabrication with a variety of finishes before components leave the factory, which reduces the workload at the construction site.
Design, function and economy
Architects and designers have been aware of aluminium's unique qualities for more than 100 years. As well as being one of the most abundant metals in the world, aluminium's formability, high strength-to-weight ratio, corrosion resistance, and ease of recycling make it ideal for a variety of architectural products.
Wide Choice Of Alloys
Aluminium in its pure form is a very soft metal, and hence not suited for building applications. Thanks to the addition of alloying elements such as copper, manganese, magnesium, zinc, etc. and thanks to suitable production processes, the physical and mechanical properties can be varied in a wide range to satisfy the requirements of a large number of different applications.
The extrusion process offers an almost infinite range of forms and sections, allowing designers to integrate numerous functions into one profile. Coated sheets and composite panels may be manufactured flat, curved, shaped into cassettes, or sandwiched with other materials. In addition, aluminium can be sawed, drilled, riveted, screwed, bent, welded and soldered in the workshop or on the building site.
Long Service Life
Aluminium building products are made from alloys that are weatherproof, corrosion-resistant and immune to the harmful effects of UV rays, ensuring optimal performance over a very long period of time. In 1898, the dome of San Gioacchino’s Church in Rome was clad in aluminium sheets, which are still in pristine condition today, more than 100 years later.
Apart from routine cleaning for aesthetic reasons, neither bare nor painted aluminium requires any maintenance, which translates into a major cost and ecological advantage over the lifetime of a product.
Hundreds of Surface Finishes
Aluminium can be anodised or painted in any colour, to any optical effect, using any number of surface touches, in order to meet a designer’s decorative needs. Such processes also serve to enhance the material’s durability and corrosion resistance, as well as providing an easy-to-clean surface.
High Strength-to-Weight Ratio
This unique property allows architects to meet required performance specifications, while minimising the dead load on a building’s supporting structure. This is a key advantage for cladding and roofing applications. Furthermore, thanks to the metal’s inherent strength and stiffness, aluminium window and curtain wall frames can be very narrow, maximising glazed surface and solar gains for given outer dimensions. Moreover, the material’s light weight makes it easier to transport and handle on-site, reducing the risk of work-related injury.
This characteristic feature makes aluminium a very efficient material for light management. Aluminium solar collectors and light channels can be installed to lower energy consumption for artificial lighting and heating in winter. Aluminium shading devices can be used to reduce the need for air conditioning in summer.
Aluminium is a good conductor of heat, which makes it an excellent material for heat exchangers used in energy efficient ventilation systems or in solar thermal heat collectors. While it may be a disadvantage in window and façade applications, this property is overcome by an appropriate profile design and the use of thermal breaks made of low conductivity materials.
Aluminium does not burn, and is therefore classified as a non-combustible construction material (European Fire Class A1). Aluminium alloys will nevertheless melt at around 650°C, but without releasing harmful gases. Industrial roofs and external walls are increasingly being made of thin aluminium cladding panels, intended to melt during a major fire, allowing heat and smoke to escape and thereby minimising damage.
No Release οf Dangerous Substances
Several studies have proved that aluminium building products do not present a hazard to occupants or the surrounding environment. On both sides, today’s studies prove that the alloys used, their surface treatments (either coating or anodising) and the materials used are all neutral. Aluminium building products have no negative impact, either on indoor air quality or on soil, surface and groundwater.
Where high security is required, specially designed, strengthened aluminium frames can be used. While the glass for such applications may well be heavy, the overall weight of the structure remains manageable thanks to the light weight of the aluminium frame.
Text: European Aluminium Association, International Aluminium Institute
Photos: Green Architecture