Anyone who has been tickled pink, green with envy, or had the blues understands the affect color can have on emotions, so it’s understandable why the CNA Center in Chicago is considered a “hot” property with its red exterior featuring a fluoropolymer coating system from Tnemec. “Whenever you see the Chicago skyline, there’s this lone red building,” according to Tnemec coating consultant Chris Wascher. “From a color perspective, it’s one of a kind.”
The building’s owner wanted to select a coating system that offered the best available life expectancy, so mock-ups of different products were left on the building and evaluated over several months. “They wanted to compare the various coating systems after being exposed to a year’s worth of freeze/thaw cycles,” Wascher noted. “The mockups were evaluated for aesthetics, as well as adhesion, and the coating system that best kept its gloss and color was the Tnemec system with Series 1072 Fluoronar as the finish coat.”
The project was completed in two phases. The first phase consisted of overcoating the exterior steel substrate on the top 42 stories of the 44-story high-rise, as well as aluminum and galvanized louvers located mid-way up the building and on its top two levels. Surface preparation on steel substrates in the first phase was in accordance with SSPC-SP2 Hand Tool Cleaning or SSPC-SP3 Power Tool Cleaning. Existing paint on the aluminum was removed using an environmentally friendly paint stripper. Exterior steel in phase one was spot-primed with Series 135 Chembuild, a modified polyamidoamine epoxy, followed by an intermediate coat of Series 73 Endura-Shield, an aliphatic acrylic polyurethane. The finish coat was Series 1072 Fluoronar, a high-solids fluoropolymer, in the custom color “CNA Red.” Aluminum and galvanized metal substrates were primed with Chembuild and finished with Fluoronar.
The second phase involved removing all exterior coatings from the building’s lower two levels down to bare steel in accordance with SSPC-SP6/NACE No. 3 Commercial Blast Cleaning. “Rather than just overcoating these areas, they wanted to start from scratch,” Wascher acknowledged. The prime coat used on phase two exterior steel was Series 90-97 Tneme-Zinc, a zinc-rich, aromatic urethane, followed by an intermediate coat of Chembuild and a finish coat of Fluoronar in CNA Red.
Overall, more than 2,300 gallons of coatings were required for the 1.3 million square foot red tower, which was built in 1972. “The ease of application and quick cure times for the coatings made it possible for the applicators to maximize their time,” Wascher added. “They absolutely loved the way it looked.”