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Lamps Help Transform Georgia State Capitol
December 5, 2007 - Lighting
Before undergoing a lighting renovation, the Georgia State Capitol building and its glittering gold dome stood tall on the Atlanta skyline during the day. But at night, the building and dome lost much of its luster with a lighting scheme that created uneven lighting.
The rotunda primarily was lit with 400–watt, high–pressure sodium lamps from an extremely steep angle, resulting in deep shadows above the curve of the dome and at the upper cupola. A mix of lower-wattage, metal-halide lamps, and high–pressure sodium lamps combined to create hot spots and uneven colors on the stone and gold leaf.
CD+M Lighting Design Group was hired to work with the principal architecture firm, Lord, Aeck & Sargent Architecture, to create a new lighting scheme in conjunction with a $70 million building rehabilitation. CD+M then collaborated with GE Consumer & Industrial’s lighting business to supply the lamps.
The lighting scheme had a number of goals, including emphasizing the newly restored limestone and brilliant gold leaf materials on the dome with a palette of complementary colors, while also highlighting a wide variety of architectural details.
Numerous adjacent buildings, 50–foot-tall trees, and a landing pad for the governor’s helicopter presented some unique challenges for fixture placement. They could not be placed close to the helipad, and the team had to seek approval from the governor’s office due to concerns about glare during takeoffs and landings.
A combination of about a dozen each of GE’s 1,000–watt Multi–Vapor® metal halide lamps and 1,000–watt Lucalox® high–pressure sodium lamps in narrow-beam floodlights balance the color of limestone and gold surfaces. More than 40 narrow beam uplights manufactured by Hydrel Lighting were furnished with GE low–wattage ConstantColor® CMH® ceramic metal halide lamps to accentuate columns and moldings.
To help overcome some of the mounting challenges, CD+M turned to Phoenix Lighting, manufacturer of the building floodlighting system. Phoenix created computer models of the building to determine the best locations for long–throw spotlighting of the rotunda and to confirm illuminance levels 360 degrees around the dome.
Close proximity of buildings on three sides forced the use of a complex series of mounting locations and aiming angles. Using poles, rooftops and building facades, all lighting equipment was carefully concealed from view at street level so the building would appear to glow from a distance.
“The finish, color and architectural elements can now be viewed at night for the first time in the history of the building,” says Susan Turner, AIA, a principal at Lord, Aeck & Sargent. “The lighting is much more even now, adding both subtle and dramatic touches that showcase this architectural gem.”
The lighting team also considered ease–of–maintenance issues when designing the lighting scheme. All fixtures mounted on the Capitol rotunda can be maintained from two primary inside service points. More than one-half of the building’s floodlights are accessible from adjacent rooftops, and the remaining fixtures are accessible from a cherry picker that can be parked alongside each mounting location.