Zimmer Gunsul Frasca Architects
The Challenge: What kind of system would allow light into an atrium, without casting glare on adjacent work spaces, at the new EPA regional headquarters in Denver?
The Solution: The new 305,000-square-foot U.S. Environmental Protection Agency regional headquarters in Denver has a skylit atrium that, at nine stories, is too tall for the daylight filtering in to reach the ground levels during much of the day. It was clear to the architects at Zimmer Gunsul Frasca Architects (ZGF) that a system of fins would be useful to direct the light and that, for budgetary reasons, these fins would have to be fixed—there wasn't enough money for a motorized system to follow the angle of the sun.
The central question for ZGF became whether the fins should be placed above or below the skylight. The firm built a scale model with the fins situated above, but realized that this was going to direct a certain amount of glare onto the workstations situated around the atrium, making what should be prime office seating into a problem, in terms of the use of computer monitors and temperature levels. By moving the fins below the skylight, the architects were able to better diffuse the daylight and shield those adjacent workstations from glare.
ZGF tested several different shapes and forms—including flat panels and eggcrate–style louvers—before they arrived at the final set-up: a C-shaped reflector with a smaller radius at the top and drooping corners at the bottom. The design team termed it the “butterfly-wing solution.” ZGF also tested a variety of materials, from stainless steel to architectural textiles, but each came in over budget and under performance goals. The team ultimately selected material from a Portland, Ore., sailmaking shop and employed a Denver theatrical rigging company for installation. With some creative thinking, the ZGF team was able to achieve the maximum performance by alternative means and still come in under budget.
The R+D Awards jury appreciated the amount of time and energy spent figuring out the most appropriate materials and forms for the atrium sails. Extensive thermal imaging demonstrates just how successful the system is.
“I thought this project was really innovative,” said juror Victoria Meyers. “And it does provide a new technology, which is interesting, because that technology is very simplistic.”
The nontraditional end result reveals just how determined the firm was to go beyond the easy solution to find the right one. “It does what it's asked, and no more,” said juror Reed Kroloff. “And it does it in a very elegant manner.”
PROJECT Atrium Daylight Control System
CLIENT United States Environmental Protection Agency
ARCHITECT Zimmer Gunsul Frasca Architects, Portland, Ore. (John Breshears, Larry Bruton, Amy Cortese, Andre Covington, Mark Perepelitza, Doug Sams, Eugene Sandoval, Kristina Thomson, Peter van der Meulen, project team)
HELIODON TESTERS University of Oregon Energy Studies in Buildings Laboratory, Portland (G.Z. “Charlie” Brown)
FABRICATORS North Winds Canvas, Portland (Kerry Poe, Amy Poe, Kyle Norman, Anika Olsen)
INSTALLERS Rhino Rigging, Denver (James Acuna)