Great Glazing: National Public Radio Headquarters
Photo by Anice Hoachlander
|Photo by Anice Hoachlander|
The basics: The designers of National Public Radio’s headquarters building in Washington, D.C., transformed a 1927 warehouse building into a new state-of-the-art, LEED Gold home for the broadcasting organization. Glass proved a critical design element for the 330,000-square-foot project that is part renovation of the four-story warehouse, and part new construction of a seven-story office block.
A glass wall surrounds the entrance lobby, and on the upper floors, a curtain wall system with colorful glass fins allows natural daylight deep into the structure.
Sensitivity to cost remained ever present, pushing the team to carefully research and restore many building components, such as repairing approximately 50 percent of the cast-in-place concrete façade and replacing inefficient windows with high performance replicas.
The players: Architect, Hickok Cole Architects; structural engineer, Thornton Tomasetti; civil engineer, VIKA Inc.; building envelope engineer, Simpson Gumpertz & Heger; general contractor, Balfour Beatty; contract glaziers, CBO, Galaxy Glass & Aluminum Inc., Physical Security; glass fabricator, curtain wall and fins, Viracon; glass fabricator, replacement windows, Oldcastle BuildingEnvelope; glass manufacturers, PPG Industries, Pilkington; interlayer supplier, Solutia.
|Photo by Adrian Wilson|
The glass and systems: The NPR building features replicas of the original windows, with an added laminated inner lite for acoustical performance. The windows replace the 1927 punched windows, ranging from 15 feet to 22 feet wide by 8 ½ feet tall. The ground floor windows feature 1 ¼-inch insulating glass units with PPG Solarban 60 low-emissivity glass, heat-strengthened, with replica mullions and muntins located in the air space. Windows on floors two through four feature 1-inch IGUs.
Hickok-Cole designed the office block, floors five through seven, as a clerestory to sit above the historic roof line, allowing light into the newsroom below. The design team specified Viracon VE 19-2M low-emissivity IGUs for the office block. The entrance glass wall consists of the same glass in 1 ¼-inch IGUs, measuring 75 feet long by 29 feet high.
The NPR building features a dynamic glass fin system surrounding the clerestory level with a spectrum of six different colors as an abstract expression of sound waves and a representation of the client’s brand. The fin system utilizes 1 1/16-inch Pilkington Optiwhite heat-soaked ultra-clear low iron, fully tempered float glass, with a Saflex Vanceva PVB interlayer laminated between the glass lites to create the various colors of the fins.