Buildings can be seen as a platform of opportunity – with a life expectancy well beyond the first needs of the client responsible for construction. In time, factories, offices and other buildings often change to accommodate new uses. While it is relatively easy to satisfy the original client’s five-to-ten-year need, the modern challenge in an environmentally sensitive world is to develop the platform for sustainable use. Among building finishing materials, aluminium has been the workhorse for decades. The Aluminium Federation of South Africa (AFSA) envisages that it will continue to play this role.
With the emergence of energy-saving considerations, the well established thermal break technology used overseas for decades seems likely to find its way increasingly into local thinking on the building envelope, the interface between the internal and external environments. Facades that do not form part of the building envelope can be designed to rejuvenate a building or to reduce the thermal load on the building, as with sun louvres, for example.
There is, however, much more to the use of aluminium in buildings. Just some examples can be seen in the use of reflective aluminium foil to keep internal temperatures at comfortable levels, and in office partitions which often include aluminium doors and frames with glass panels. One advantage of aluminium in this application is that it allows for easy modifications, as aluminium joints are normally mechanical. This means that aluminium structures can be readily demounted, to be moved or changed. Hidden from view, aluminium also forms flexible ventilation ducts that are attached to exposed louvres, carpet retainers and ceiling support structures. It is the basis of light reflectors and conductors. Looking around any building the myriad uses of aluminium will be noticed.
Much has been said about the embodied energy required to change porcelain (90% - 95% alumina) into aluminium, as this is what the smelting of aluminium involves. While it is true that the oxide bond is difficult to break (which is why aluminium is corrosion resistant), AFSA argues that due to in-process recovery and remelting of clean, unused metal, and because of the metal’s high strength to mass ratio, it is also true that the embodied energy in aluminium products is not significantly different to that in competing materials.