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Mon 5 Nov 2007 11:41 AM

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Footprint in the sand

Aluminium is shaping architecture in the Middle East, for better or worse.

Aluminium, the third most common element in the earth's crust behind oxygen and silicon, is often heralded as one of the world's most dynamic building materials. Aluminium's strength-to-weight ratio is unparalleled and its functionality, after mining, smelting and extrusion, allows for forms and shapes that were previously unthinkable.

Of the approximate 230,000 metric tonnes of aluminium produced by Dubai Aluminium Company Limited (DUBAL) in 2007, 90% is slated to be used in architectural applications in the Middle East and northern Africa.

Aluminium will not be replaced. There will never be another metal that offers all the benefits of aluminium – Ali Khalaf, Reynaers.

Because aluminium is the base material for myriad models of curtain walls, façade cladding, window/door frames, interior cabinets, exterior shading devices and air-conditioning systems, the case is often made that its functionality trumps its somewhat large environmental footprint.

While it's true that aluminium is uniquely versatile as a building material, the scope with which it is being used in regional architecture is raising concerns about the amount of embodied energy that goes into mining and manufacturing primary aluminium. And, when one considers that bauxite ore is a non-renewable resource and that it makes up just 8% of the earth's crust, as with oil, we are becoming dependent on another finite resource.

Formability

After alumina is extracted from bauxite ore it is smelted to produce primary aluminium. This final product can be cast, rolled, forged or extruded according to the specifications of a project or the intricacies of an engineer's mind.

Once aluminium is produced, it can be curved, tapered, welded, formed or cut into geometric shapes that challenge architectural rules and confound the imagination. It is this very characteristic that makes aluminium such an ideal material for contemporary architecture. According to a recent report from the European Aluminium Association (EAA): "The extrusion process offers an infinite range of forms and sections, which allows designers to integrate numerous functions into one profile."

Without the capability for such extreme shaping, those iconic buildings that dominate the skylines of so many cities would be impossible to build. Without aluminium frames that bend, twist and cantilever, those award-winning structures that serve as inspiration for current and future architects would never have made it off the sketch-room floor.

Lightweight

According to Ali Khalaf, managing director of Reynaers Middle East, "There is a big weight difference between [aluminium, steel and titanium]. Aluminium is a lot lighter than steel, which puts less stress on the structure. Titanium is quite light too, but it's very expensive."

Moreover, if we can assume that aluminium weighs 35-45% less than steel and costs much less than titanium, it will always be more energy-efficient to use aluminium in a project than using the same amount of either of its closest competitors.
The lightweight nature of aluminium puts less strain on a building's supporting structure, which ultimately affects the long-term performance of the building. Given that the decision to decommission a building begins with the appearance and safety of its facade, an infrastructure that consists mostly of lightweight aluminium has a greater chance of retaining its shape and performing its function for a longer period of time.

On the other hand, aesthetics cannot be the only consideration. In the Middle East, aluminium refineries and production plants are generally located in sparsely-populated areas. In order to get the final product to its market destination, aluminium requires significant energy in terms of transport. If we consider transportation a part of the overall ‘embodied energy' of producing a building material, aluminium, whether shipped or driven, is an energy-intensive material.

Recyclability

It is often cited that aluminium can be recycled infinitely without a measurable loss of metal quality or properties, and that at the current level of production, bauxite reserves will last for hundreds of years.

Landmark buildings such as the $US 8 billion Burj Dubai…will incorporate an estimated 1,400 tonnes of aluminium extrusion billets – Walid Al Attar, DUBAL.

The International Aluminium Institute (IAI) - an international body whose members comprise 75% of the world's aluminium industry - illustrates the science behind those claims: It says that one kilogram of recycled aluminium can save up to eight kilograms of bauxite ore, four kilograms of alloy chemical products and 14-15 kilowatt hours of electricity. It also states that 11.6 million tonnes of the world's demand for aluminium is coming from recycled products. And, that when aluminium is recycled, it requires just 5% of the amount of energy used to produce the original material from bauxite ore, and the process emits just 5% of the greenhouse gases.

If it is indeed the case that aluminium can be recycled forever without losing its tensile properties, a worldwide aluminium management strategy should be implemented to monitor the industry and identify locations with recycling potential. Manufacturers, builders and developers could then be offered incentives for using recycled rather than primary aluminium.

If the world's aluminium were managed sustainably and developers could offer documentation to prove that certain developments were built with recycled aluminium - similar to the world's FSC-managed forests - the architecture industry could take a massive step toward achieving truly ‘green' buildings.

Obviously, aluminium's recyclability gives it a tremendous advantage over other building materials. At the moment, however, individual companies are being left to set their own environmental goals, and all too often, these voluntary goals take a back seat to bottom lines. Although there is a basic ideology in place, the Middle East's aluminium industry has not yet reached a place where environmental responsibility trumps corporate profits.

Panel performance

Although aluminium will melt at around 650ºC, like most metals, it will not burn. In the event of a fire, aluminium panels do not release toxic chemicals into the atmosphere and, for this reason, are often used to construct industrial roofs and external walls.

As aluminium panels are usually painted or anodised to comply with aesthetic requirements, this process also enhances the material's natural durability and corrosion resistance. "Because of the humidity in the Middle East, if you don't protect the surface, it will corrode," says Khalaf, Reynaers. "The paint we use comes with 10, 15 and 20-year guarantees for non-fading and non-corroding. Paint is used not just for colour, but for protection as well," he says.
If a building's façade looks nice, is durable and resists corrosion, it requires much less maintenance and likewise requires fewer maintenance-oriented chemicals. Fewer chemicals on a structure mean fewer toxins in the soil or surface water after rain, which adds another element of eco-friendliness to aluminium panels.

"Aluminium panels are a bit like a car. They all hope to achieve the same function but they all use different designs, different technology and adhere to different speculations to do so," says Khalaf.

Need for understanding

Aluminium is light, strong, affordable, flexible, reusable and indigenous to the region. That much is undisputed. In fact, because of these characteristics, it's difficult to make a case against using aluminium in architecture. Rather than discourage the use of aluminium, efforts are better spent on familiarising oneself with the realities of its production.

Over a car’s life, every tonne of aluminium used instead of traditional heavier materials will save 20 tonnes of carbon dioxide equivalents in the atmosphere – ALCOA Website.

Aluminium in the Middle East is a burgeoning industry in a region that has only just begun to take seriously its carbon footprint. That said, however, manufacturing primary aluminium is a process that is extremely energy inefficient and one that is guilty of emitting a significant amount of greenhouse gas.

For example, in 1997, the base year of the Kyoto Protocol greenhouse gas emission targets, the process of manufacturing primary aluminium was directly responsible for emitting 110 million tonnes of CO2 into the atmosphere. Moreover, 50 million tonnes of those emissions were made up of perfluorocarbon compounds (PFCs), which are 6,500 times more potent and destructive than CO2.

An extensive look at the numbers shows a dismal reality. But, in 2005 it was reported that PFC-specific emissions per tonne of aluminium had been reduced by 74% between 1997 and 2004. This equates to a reduction of three tonnes of CO2 per tonne of primary aluminium.

While steps are being taken - including the UAE's recent ratification of the Kyoto Protocol and the launch of the IAI's 12-step Aluminium for Future Generations Sustainable Development Programme - areas like China, Eastern Europe and Russia continue using older smelting technology, which contributes greatly to the industry's overall carbon footprint.

The way forward

The major environmental concern regarding aluminium involves reducing the negative affect of production on air emissions, water discharges, waste disposal and the dispersion of toxic substances.

The architecture industry within this region has realised that the built environment can significantly contribute to or detract from these areas of concern and it is in the process of taking action.

This represents a unique opportunity for the aluminium industry with respect to architecture. As the push for evermore green facilities becomes the norm in this region, the aluminium industry, provided some progress is made with regard to reducing CO2 emissions, could find itself in the somewhat unfamiliar role of being part of the environmental solution.

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