The Advancement of Powder Coating in Specifications

Posted on Tuesday, February 28, 2023

By Sheila LaMothe

In 1936, Louis Skidmore and Nathaniel Owings began their architecture journey in a small Chicago office. Joined by their engineer friend John Merrill in 1939, the firm, dubbed SOM, would become a global influence designing the first glass and steel office building in New York City, Chicago’s Sears Tower and John Hancock Center, and more recently One World Trade Center and Dubai’s Burj Khalifa, currently the world’s tallest building. But what kind of influence has this design and engineering powerhouse had on powder coating? Specifier Rowan Georges shares insights on the specification of powder in SOM projects.

It Takes a Village
At SOM the specification process is a collaboration to ensure all aesthetic and technical requirements are addressed. The firm has found this is best achieved through a team approach consisting of design partners, designers, technical advisors, spec writers, etc. Rowan notes that depending on project type, size, and location, a team could have from ten members to as many as forty. He stresses that aesthetics and function cannot be divorced from one another because as beautiful a color, gloss, texture, or sheen a coating may have, it has to perform.

The project team is armed with a set of standards used as a starting place. As one might expect, for exterior coatings AAMA 2605 is the standard to avoid corrosion, fading, and other environmental impacts. While interiors may not require the 2605 standard, durability is still important. For example, high rise buildings have a lot of exposed interior metal.

Therefore, the previous AAMA 2603 standard for interior architectural coatings has been bumped up to 2604. In addition to need, the evolution of powder coatings has driven this move because powders that meet the 2604 standard are now more readily available. Rowan notes he sees architects following this trend in transportation facilities and other structures with high touch metal surfaces. That’s not to say that powders meeting AAMA 2603 have been eliminated. Should budget be a concern, or a more exotic finish be required, the standard can be downgraded to 2603 in some cases. Rowan points out that there is a much wider range of specialty finish powders that meet 2603 than 2604 or 2605 and this should not go unnoticed.

Watershed Moment
Historically, SOM was one of the strongest proponents of liquid coatings for architectural applications. Liquid, typically two or three coats, was the spec, but that all changed in 2010. Rowan shares what turned out to be a pivotal experience while on a project team for a building in Mexico City. The curtain wall for the project included coated aluminum from a fabricator in Europe. SOM specified a liquid coating for the curtain wall, but the supplier was adamant that they would not change their coating line to fit SOM’s spec. They were going to get powder coated extrusions, as is the norm in most European markets—period. Having never worked with powder for exterior fenestration systems before, the team said they needed time to investigate powder coating and requested samples so they could see how the extrusions would look from an aesthetic perspective. “We hated them,” recalls Rowen. “The samples were very flat and not shiny enough.”

Putting their aesthetic concerns aside, the team delved into the technical aspects of powder, prompting them to restate to the supplier the strict requirement that the coatings meet the AAMA 2605 standard. Quick to respond, the supplier noted that the powder coating absolutely met AAMA standards as well as all European standards and added that it was actually illegal for them to use liquid coatings in their city because of the VOCs and environmental concerns. “That kind of started the whole chain of events for us,” shares Rowan. “As we became more aware of the environmental benefits of powder over liquid, SOM stepped into the forefront specifying powder before it became the norm—well, I guess it’s still becoming the norm,” he adds.

Today the SOM master template lists powder as the preferred coating for all exterior fenestration specifications— firmwide. That’s not to say liquid has been eliminated completely, but according to Rowan the team takes a long hard look before they move forward with a liquid coating over powder. In fact, SOM invested the last three years in a global initiative to decarbonize and dechemicalize their specifications. The results of this research support SOM’s selection of powder as the default coating for exterior envelope specifications including curtain walls, sky lights, store fronts, entrances, and more.

The SOM team looks at every single spec in each project to ensure they are specifying the right materials to address decarbonization and dechemicalization. This might lead one to inquire about the firm’s pursuit of green building certifications such as LEED (Leadership in Energy and Environmental Design). Rowan states that whether or not a project intentionally pursues LEED certification, it is a byproduct of SOM’s approach to design. Their goal is to make the industry go beyond LEED and similar certifications. “We want to think holistically about what we are doing to address the climate. Eliminating carbon, for us at least, is low hanging fruit. Powder coating is something that is achievable right now so, we should just do it regardless of whether or not a project is targeting LEED certification,” he explains.

Pushing the Technology Further
While environmental concerns were and will continue to be the driver of specifying powder over liquid, architects long for aesthetic improvements. “Powder is on par with liquid when it comes to durability and performance, but with its specular nature liquid remains unmatched when it comes to special finishes, especially metallics, and particularly when you get into 2604 and 2605,” states Rowan. It’s a discussion SOM has had with all of the major powder manufacturers since their introduction to powder 12 years ago in Mexico City. “We continue to push and push, and manufacturers are listening. Progress is being made, but there is more work to be done,” affirms Rowan.

Rowan cites two New York City projects, one complete and the other under construction, that illustrate the aesthetic advancements in powder coatings that meet the 2605 standard. Hudson Yards is the largest private real estate development in the history of the United States and the largest in New York City, surpassing Rockefeller Center, built in the 1930s. A mixed-use tower designed by SOM, 35 Hudson Yards, opened about five years ago. Its exterior features glass and limestone along with extrusions coated in a warm, darker metallic bronze powder finish to match the actual bronze incorporated in the building. While the finish is not as specular as a metallic bronze liquid PVDF coating, Rowan acknowledges, “with the building color palette, it works.”

The second project, currently under construction, is a state-of-the-art municipal public health lab which also incorporates copper/bronze powder coated extrusions. The award-winning facility will comply with the city’s new ambitious resiliency and sustainability regulations.

Rowan considers these two building projects of note because not only are they all powder, they are also examples of powder coat finishes where the design specs called for a metallic finish. He also believes that the entire Hudson Yards project was a significant catalyst for powder coating specification in New York City. Other major architects involved in the Hudson Yards development specified powder and Rowan feels this has and will trigger others to do the same moving forward.

While powder coating is the default in SOM’s master specifications firmwide, Rowan definitely sees its prevalence on the east coast where SOM has a major presence, but notes it is on the rise in other regions. With high profile projects throughout the world, the firm would like to think they have an impact on the growth of powder specification in all regions. SOM has presented the findings from their three-year global decarbonization/ dechemicalization initiative nationally at the Construction Specifications Institute Conference and locally through a variety of avenues to spread the message and push the industry to lower carbon emissions throughout the building industry. Powder is a small piece of that puzzle but it’s important, nonetheless. Steadfast in their commitment to the environment, Rowan asserts, “We will always push for a lower carbon footprint. Yes, powder is more environmentally friendly than liquid, but can it do better? We want to see regular metrics and constant improvement.” I think the powder coating industry is ready to accept that challenge.

Sheila LaMothe is editor of Powder Coated Tough magazine.