Upon learning that an inferior shop primer had been used on structural steel for a new lobby atrium at the Bloomberg School of Public Health, the project’s architect contacted Tnemec to prescribe a remedy for the fabrication faux pas. “We had to deal with the shop primer that was on the steel and the condition that it was in,” recalled Tnemec coating consultant Todd Guntner. “The structural steel was exhibiting excessive rusting. Since the atrium was occupied space, sandblasting the primer was prohibited and only a waterborne, low-odor coating system could be used.”
After determining that the shop-applied primer was too weak to support the epoxy and urethane coatings originally specified for the project, Guntner selected a hydrophobic acrylic polymer coating system as the ideal solution. “The architect knew Tnemec as a quality company and trusted that whatever we recommended was going to give them the performance they required,” Guntner noted.
Surface preparation involved hand power tool cleaning in accordance with SSPC-SP3 to remove the rust. “It was a labor intensive job in a very confined area,” acknowledged Guntner. The rusted areas were coated with Tnemec’s Series 18 Enviro-Prime, an advanced technology acrylic primer. “Quite a bit of rust was removed, so the applicators almost ended up putting on a full coat of primer,” Guntner said. “They then came back and spray applied a full coat of Series 30 Spra-Saf EN, another acrylic coating from Tnemec.”
Both Enviro-Prime and Spra-Saf EN contain rust inhibitors and provide long-term corrosion protection. Spra-Saf EN is formulated to provide good gloss and color retention on structural steel. “Acrylic coatings protect against ultraviolet light and this system had proven its durability before on exterior structures exposed to weathering,” Guntner added. “After more than five years, this coating system is doing very well and is providing the owner with the performance and life expectancy they wanted. As you walk into the lobby area and look up, there’s this beautiful glass atrium steel that looks outstanding.”
Bloomberg School of Public Health is located on the Johns Hopkins University medical campus in East Baltimore. The eight-story urban building features a contemporary design, which is a contrast to the older architecture found on the campus.