Sustainable Aluminum
Essential to Building a Greener Skyline
By Rand Baldwin, CAE, President, Aluminum Extruders Council

AEC promotes the use of extruded aluminum as an environmentally responsible approach within the burgeoning green building industry, and in the manufacture of innovative products and equipment used to harness alternative energy resources. AEC communicates the sustainable benefits of aluminum extrusions to architects and builders via education/training endeavors, a public relations initiative, and by participating in events, policy-making, and certification processes that firmly establish and recognize aluminum extrusion’s green attributes. The inherent characteristics of extruded aluminum demonstrate that it is a premier green building materials choice. The following article represents some of the many ways extruded aluminum supports sustainability within the commercial building and construction sector.

© James Steinkamp, Steinkamp Photography. Photo used with permission of Goettsch Partners, Inc.

Green building isn’t merely a catchphrase; it implies a vital planet-preserving future for the commercial and residential building-and-construction industries. Architects and builders are aggressively pursuing advanced technologies based on sustainable design principles. Such tenets employ energy conservation, eco-friendly materials choices, and extensive reuse and recycling practices to create environmentally responsible buildings that are more productive, healthier, and profitable places to live and work.

Advanced green design and building technologies are proving highly effective in lowering construction costs and reducing operating expenses. According to the U.S. Departments of Energy and Transportation, buildings drain a staggering 39 percent of the nation’s total energy, while all transportation--including cars--consumes 27 percent. Green buildings are rapidly gaining in acceptance, as public awareness grows and the global community develops alternative energy sources and intensifies its efforts to ease global climate change.

Aluminum, one of the most abundant elements in the earth’s crust, is an ideal natural materials choice for sustainable buildings – not just in new construction, but also in retrofitting older buildings to improve their energy performance. Aluminum is specified by architects for curtainwall systems, windows and doors, reflective “cool” roofing, solar-panel framing, skylight framing, reflectors for interior lighting grids, elevator housing/framing, atriums, entryways, walkways, sun rooms, and heat exchangers for air conditioning systems in both commercial and residential applications.

Aluminum has always been a green building material, and continues to offer key attributes that architects and builders want in a sustainable building, namely durability throughout a long life cycle, structural strength in terms of elastic modulus/stiffness, and importantly, recyclability. At the end-of-life stage in a building, aluminum is 100-percent recyclable, and may be reused in building components without any loss in quality.

Aluminum can be recycled multiple times without any loss to its innate characteristics. Photo © 2006 Norsk Hydro ASA

According to Green California’s Environmentally Preferable Purchasing Best Practices Manual, in reference to its Recycled-Content Product Directory: “Recycled materials are used natural resources, and need to be used effectively again to avoid impacts on the planet…furthermore, recycling creates jobs.”

Thousands of green commercial, office, and residential structures using aluminum emit less carbon dioxide, and are boosting the U.S. economy in a tangible way. The construction market constitutes 14.2 percent of the U.S. GDP. The 2006 member survey of End Use Shipments of Aluminum Extruded Products, conducted jointly by the Aluminum Extruders Council (AEC) and The Aluminum Association, Inc., shows that total aluminum rod and bar, pipe and tube, and extruded profiles contribute 1.3 billion pounds of aluminum used in building and construction industries, primarily in doors, windows, and curtainwalls.

The United Nations (U.N.) Environment Program states that aluminum used in manufacturing construction materials that are taken from recycled sources uses less “embodied energy” than materials having no recycled content. Embodied energy is the energy required to extract, process, and transport raw materials during the construction phase, and disposal at the end of useful life. When aluminum is recycled multiple times, its life cycle impact on the environment is greatly reduced. And it is important to note that aluminum can be recycled repeatedly without losing its integrity.

The U.N. assessment finds the most important factor in reducing embodied energy is designing long-life, adaptable buildings with durable, low-maintenance recycled materials. The recycling of aluminum building products means that older buildings can be deconstructed rather than demolished, averting landfill dumping costs and adverse environmental impacts. In an Australian study reported by the U.N. Environment Program, recycling aluminum materials for reprocessing and reuse represents up to a 95-percent cost savings.

Using recycled building materials saves substantial total energy otherwise used for material production. Producing recycled aluminum building materials reduces pollution emissions and energy use, taking only five percent of the energy needed to produce raw aluminum from bauxite.

Jerry Powell, Editor, Resource Recycling says, "Many construction materials are hard, if not impossible, to recycle, and this is a negative factor when wishing to undertake a sustainable construction project. This is not the case, however, for aluminum as a building product. The sizable energy savings attained when scrap aluminum is remelted makes the recovered metal very valuable."

Four Seasons Solar Products LLC, Holbrook, NY, is North America’s premier sunroom manufacturer, producing year-round sunrooms, conservatories, enclosures, and skylights for residential and commercial applications primarily using thermally broken aluminum extrusions with an aluminum glazing track system. Of their residential sunrooms and conservatories, 85 percent are ordered with aluminum extruded framing. Four Seasons also manufactures entrances, atriums, walkways, and enclosures for stores, libraries, hospitals, hotels, restaurants, colleges and schools, and office complexes.

Aluminum extrusions are especially well suited for sunrooms and atriums, such as this area in a banquet hall. Photo courtesy of Four Seasons Sunrooms.

James Ruppel, Four Seasons Marketing Director, notes “We use roughly five million pounds of recycled aluminum per year. Four Seasons is committed to providing the most energy efficient glass building additions on the market, both to help the environment and to assist our consumers in reducing use of fossil fuels and the cost of heating and cooling their glass building additions. We as a company are always looking to the best materials with which to construct our additions, and aluminum continues to play a leading role in that area.”

From a green design perspective, aluminum’s reduced cost over a longer life cycle offers architects a viable economical choice. A whole-buildings approach allows flexibility for balancing U-factors; for example, thermally-broken aluminum window frames may be used in combination with increased insulation, HVAC efficiency, ambient lighting, high-tech glazing, etc., providing more options in designing the building envelope.

Gaylord Texan Resort and Convention Center in Grapevine, Texas, features an atrium made with earth-friendly extruded aluminum. Photos courtesy of Naturalite Skylight Systems by The Vistawall Group

Aluminum resists the ravages of time, temperature, corrosion, humidity, and warping, adding to its incredibly long life cycle. Extruded-aluminum-framed windows with thermal barriers effectively insulate against condensation and are rigid and stable, operating smoothly with minimal maintenance and a tight fit. Extruded aluminum alloys accept durable anodized finishes, which are inert materials that are not combustible and pose no health risks.

Energy efficiency in cooling buildings is also being redefined by all-aluminum microchannel heat exchangers used in commercial and residential air conditioning units. This advanced technology delivers greater cooling capacity in a same-sized unit, compared to traditional copper-tube/aluminum-fin technology. Microchannel heat exchangers employ a metallurgical interface with greater thermal efficiency and corrosion resistance.

The aluminum extrusion industry is actively engaging LEED-certified architects and builders, seeking to make extruded aluminum a priority materials choice for a vast array of commercial applications. Steven Nilles, AIA, LEED AP, Partner at Goettsch Partners, Chicago, has designed green Chicago high-rises using aluminum extruded curtain wall panels, ceiling lighting systems, and elevator cab framing.

More than one million pounds of aluminum, including extrusions, were used in the construction of this green-design building at 111 S. Wacker Drive in Chicago. © James Steinkamp, Steinkamp Photography. Photo used with permission of Goettsch Partners, Inc.

Nilles says: “Aluminum has found a key place in the construction of these modern buildings for several reasons. Aluminum is extremely light weight in relation to its strength. This allows us to do more with less material. It is aesthetically flexible, allowing numerous finish and color opportunities. Aluminum is inherently recyclable and can be taken from the buildings in the future and brought back into the resource stream. Many of these concepts tie directly into sustainable design initiatives that the construction industry has embraced. Sustainability is now the investment of choice, and green building products give an exceptionally good return on investment.”

Earth-friendly extruded aluminum has the inherent characteristics essential to sustainable construction. Aluminum Extruders Council members are depended upon to serve the needs of the green building industry, and continue to provide advanced technologies and innovation for a variety of aluminum building components.