Aluminum has long been a popular choice for exterior wall design—since the mid-1930s, architects have incorporated aluminum products due to their economy, strength and timelessness. The Empire State Building was one of the first buildings to incorporate aluminum into major structures. It’s the most abundant metal on earth and 100% recyclable. Now more than ever, sustainability is such an important consideration for each new project. Aluminum contributes to LEED points, is easier to ship and doesn’t go into landfills. Choosing aluminum alloys can also result in lower greenhouse gas emissions.
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Choosing the right panel for your project is imperative and there are several things to consider.
Location—Is your project in a high-wind or harsh environmental location? It’s best practice to give careful thought to what gauge metal is right for your project. Quite often, a thinner gauge is specified to save on cost than is appropriate for the wind loads of that location. Having those conversations before finalizing the specification will insure you have the right metal thickness for your rainscreen or panel product. If your project is in an area where a Miami-Dade tested product may be required, be sure and ask your panel manufacturer for a rainscreen product that has passed the TAS 1/TAS 2/TAS 3 AAMA testing and has a Florida Building Product number.
Economy—Achieving a unique and elegant look while staying within budget can be challenging. There are many factors to consider when choosing a wall panel; however, weighing the long-term benefits of aluminum over other materials is key. Aluminum is extremely durable, low-maintenance and weather resistant. It has a natural resistance to corrosion and can weigh up to 65% less than steel while providing equal strength. The strength of aluminum even increases at extremely low temperatures.
Non-Combustible—A solid plate panel is often the best choice for a wall system. When taking into consideration requirements such as the NFPA285, solid aluminum metal wall panels by their very nature are a non-combustible option and work with many NFPA285 tested wall assemblies, insulation and fasteners. For more information, see ASTM E 136-11 standard test method results for behavior of materials in a vertical tube furnace using test material 3003. To achieve the strongest panel finish, require an AAMA 2605 PVDF coating which self extinguishes.
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AAMA Testing—When considering rainscreens for your project, always ask the manufacturer if their system is AAMA tested—specifically the 508-14 proves weather resistance by testing the panel system for static and dynamic water infiltration, and shows achievement of pressure equalization between the interior of the rainscreen assembly and the exterior wall. Several other tests are part of that process which include the ASTM E283-04. This test determines the rate of air leakage under specified pressure differences. Next is the ASTM E1233/E1233M-14 which is the method for testing water penetration by cyclic static air pressure difference. Another test is the ASTM E331-00—this is the standard test method for water penetration by uniform static air pressure difference. Lastly, the 501.1-05 is the standard test method for water penetration of windows, curtainwalls and doors using dynamic pressure. A manufacturers’ passing test data report proves they’ve achieved a true rainscreen system.
Flatness—It is important to choose the proper aluminum thickness to avoid oil canning, edge wave and stiffener read through. Common aluminum plate thicknesses are 0.08-inch, 0.09-inch, 0.125-inch and even 0.19-inch and 0.025-inch. Consult with your panel manufacturer as to which thickness to specify based on your maximum panel face and project location wind loads. To avoid flatness challenges, the thinner gauge 0.063-inch should only be used on panels that have a smaller width.
Scott Samson is the national sales manager for American Metalcraft Inc., Villa Rica, Ga. With over 30 years in the architectural aluminum product industry, Samson is happy to answer any technical questions and provide additional information. Email scott@americanmetalcraft.com, or visit www.americanmetalcraft.com for more information.