Smithsonian National Museum architect Adolf Cluss and his team faced the challenge of designing a building that would provide the “perfect light” for exhibition purposes, while also shielding exhibits from overexposure to harmful ultraviolet rays and extreme temperatures (in particular, the oppressively hot Washington, D.C. summers).
Cluss employed a complex system of windows, clerestories, monitors and skylights to illuminate and ventilate the building; he also designed the windows to utilize two panes of thick glass, with an air space in between to allow for insulation. The double-paned glass concept was fairly unusual in Cluss’s time, but is now common in 21st century construction. Ground glass was used in the exterior panes of all exhibition hall windows to diffuse the light entering the museum. The glass was imported from Belgium, a leading producer of the material at the time. Stained glass was used in selected areas, notably at end-walls of Halls; they were marked with compass points, to assist visitors in navigating the vast building. Large, clear glass windows in the towers, pavilions and Rotunda provided both necessary daylight and aesthetic value.
Cluss remarked later that the museum’s 8,361.27 square meters (90,000 square feet) of floor space were lit by 1,170.58 square meters (12,600 square. feet) of glass, equal to 1/7 of the floor space for glass; this was substantially more than the 1/9 of floor space that was considered adequate for proper exhibit display.