Given the 375,000-square-foot building’s location among 20 acres of restored wetlands, “Our quest, first of all, was to develop high performance in a transparent facade,” said founding principal Mark P. Sexton, who will deliver a talk on the project at next month’s Facades+ Miami conference. “If you’re working in the Everglades, the idea of your workspace being as transparent as possible [is obvious].”
But transparency comes with a couple of challenges, namely solar gain and glare. In order to preserve views while maintaining alignment with the Government Services Administration‘s 2030 Zero Environmental Footprint project goal, the architects relied primarily on two technologies: frit glass and integrated sunshades. Of course, building orientation was also key; Krueck+Sexton positioned the double-bar plan so that the major facades face south and north, the minor facades east and west.
To tackle the potential for thermal gain associated with floor-to-ceiling glass, Krueck+Sexton started with a product with a low-e coating. Next, they added a graduated frit that is heavier at floor and ceiling but more open at the vision plane. But even with the frit, said Sexton, “there was still too much glare on the south side of the building compared to the north side. It’s one of the issues of high performance. You can control solar heat gain with these coatings, but then the glare becomes the big problem.” When one side of an office is flooded with natural sunlight, he explained, the occupants on the darker side tend to compensate with artificial lighting—thus negating the environmental benefits of all of that daylight.
The architects also developed a system of sunscreens that cut back on both direct sun and glare on the south facade. “It became, in a way, eyebrows for the building,” said Sexton. He compared the shades to a tuned airfoil on an airplane or high-end automobile: “The performance is enhanced by the additive nature” of the shade. The result is a dynamic envelope with sunshades appearing as geometric mesh interwoven among the intersecting planes of glass.
Hear more about the FBI South Florida Headquarters project September 10-11 at the Facades+ Miami conference. Register today and sign up for an exclusive Miami-area field trip on the conference website.