Aluminum – The ABCs of Green Building Materials
Used in a wide variety of ways in the building construction market, aluminum is a very versatile green building material, especially when it’s recycled.
Everything from huge external building structures to delicate window blinds can be manufactured from this lightweight, durable, and corrosion-resistant metal.
Doors, windows, and awnings are popular products made from this material, as well as parking canopies, warehouses, and other commercial outbuildings.
Solar panels typically rely on low-weight aluminum framing components in solar installations on residential and commercial rooftops.
Popular Use Rose With the Empire State Building
The first wide use of aluminum for building and construction occurred in the 1920’s. Although used primarily for decorative details on art deco buildings, by 1930 the use of aluminum rose with the construction of the Empire State Building in New York. It was used in the famous spire, as well as major interior structures in this landmark building.
The original steel window frames of the Empire State Building had to be replaced in 1994 because of major energy inefficiencies. Window frames were deteriorating, allowing water and air to leak in. With the approval of the Landmarks Preservation Society, a total of 5,460 windows were replaced with new energy-efficient aluminum frames.
By comparison, steel weighs 35 to 65 percent more. But, because contemporary high-strength, low-weight alloy frames are able to easily support the weight of broad spans of heavy glass, modern buildings can now maximize the use of natural sunlight.
Utilizing this advantage, the Houston George Bush International Airport (IAH) offers spectacular views of the jet taxi grounds and the runways because of wide glass spans supported by high-strength aluminum framing.
A Key Component in LEED-Certified Green Buildings
Aluminum is also a key component in LEED-certified green buildings. Aluminum roofs that are properly coated can reflect nearly 95 percent of the solar energy that strikes them. This dramatically improves the energy efficiency of a building, especially in comparison with steel and iron.
The first LEED-certified building in California was the Capitol Area East End Complex in Sacramento. The Aluminum Association (AA) states, “This certification was awarded in part due to a high-performance, nonreflective aluminum curtain wall that conserves energy by maximizing the use of sunlight.”
“Aluminum-intensive LEED-certified buildings have won awards for Platinum, Gold and Best-in-State sustainability across the country,” adds AA.
Recycling is the Key to Green Value
This is an easily recycled metal and explains its important value as a green building material. It’s 100 percent recyclable, and in the process of recycling, aluminum loses none of its high-strength, low-weight, or energy-efficient properties. Likewise, it can be repetitively recycled with no loss of quality.
Aluminum collection is also commonly the most valuable component of municipal recycling programs.
The Original Manufacturing Process is Not So Green
Compared to the energy required to produce new aluminum, the recycling process reduces energy use by over 90 percent. This is an important factor in assessing its value as a green building material. That’s because the original manufacturing process is not all that green. In fact, it’s downright awful.
Up to six pounds of bauxite ore are needed to produce one pound of aluminum. A huge amount of electricity and heat are required in the process, which typically comes from burning fossil fuels. Greenhouse gas emissions in the process contribute to air pollution and global warming.
Waste produced in the process also contains traces of heavy metals and other chemicals such as fluoride and chlorine, which must be disposed of properly as hazardous waste.
Offsetting the Negative Aspects of Aluminum
Offsetting the negative aspects of original production, recycling offsets a huge amount of energy consumption. Producing aluminum from recycled content requires only around 5 percent of the original energy needed to produce it from bauxite ore.
For every one ton of recycled content produced, four tons of bauxite ore are saved. Likewise, recycling it offsets 95 percent of the carbon dioxide (CO2), sulfur oxide (SOx), and nitrogen oxide (NOx) emissions released in original production, and offsets 97 percent of the water pollution.
Almost 75% is Still in Use Today
Fortunately, recycling aluminum is popular and easy, all across America. This has led to substantial reductions in the amount being produced from raw ore. In fact, AA states that almost “75 percent of all aluminum produced is still in use today.”
In 2008, a survey of aluminum producers indicated that “the total recycled content of domestically produced, flat rolled products for the Building and Construction market was approximately 85%.” The 2008 survey also reported that an average of around 60 percent of total content is from post-consumer sources.
Today, AA points out, “Thousands of concrete and steel-reinforced bridge decks now require rebuilding due to their age and condition. Aluminum will be a critical building material in this new infrastructure. The metal and its alloys are lightweight, durable, corrosion resistant and infinitely recyclable.”
–- Don’t forget – Watch for new posts every week in our new series, The ABCs of Green Building Materials. And if you’d like to give a shout out for a project highlighting great green building materials, please add a comment below!