The American Institute of Graphic Arts is the country's leading professional organization for graphic designers. Founded in 1914, the AIGA now has 22,000 members who are served from the organization's national headquarters in New York's Flatiron District. Named the National Design Center, the building contains two exhibition spaces, a library, archive and office space for the director and staff who run the national organization. The AIGA commissioned Biber Architects to renovate the second and third floor office spaces. Prior to the renovation, the two floors were long, narrow and dim, lit by windows only at one end and furnished in a standard desk-and-cubicle layout. The spaces were a world apart from the building's expansive first floor public gallery with its 20-foot high ceiling and mezzanine.Our mission was to visually connect the second and third floors. Fortuitously, the second level originally had been the building's top floor and once held skylights that were covered as upper stories were added. Taking advantage of this pre-existing condition, the openings were re-established and crossed with a pair of glass bridges and a section of illuminated glass floor. Constructed of large sheets of etched glass lit from below, the bridges established a simple, central circulation path that leads visitors to a large conference room at the front of the building.The openings create a visual and spatial connection between the second and third floors and give the office the buzzing, collaborative atmosphere of a design studio. Without the circulation pattern the bridges offer the layout would have been hopelessly inefficient. The bridges also serve to give some separation between visitors and the staff and they help tie the building together thematically as they recall the split-level structure of the first floor with its high ceiling and mezzanine.Angled walls punctuate the bridges, contributing wall space for the exhibition of graphic work and giving staff a place to pin up images near their desks, but out of view of visitors. The office looks remarkably neat as a result. The large conference room at the front of the building is separated from the rest of the floor by a floor-to-ceiling glass partition allowing the entire floor to share the light from its only windowed wall.The lighting fixtures, custom ductwork, desks and storage spaces were also designed by Biber Architects. Desktops and counters are covered in a fiber paper laminate, as paper is the surface most associated with graphics.