The Harry S. Truman Building is the State Department’s Washington, D.C. headquarters. Its main corridor spans two city blocks and contains more than 150 lighting fixtures. But that’s just a sliver of the building, which contains 34,000 fluorescent lights with ballasts in its 2.6 million-square-foot structure.
The Office of Facilities Management Services manages the State Department buildings, and as greater emphasis is placed on making the government more energy efficient, the FMS sees lighting control as a leading tenet for creating more efficient buildings. Achieving greater energy efficiency is a primary goal of Donald Traff, division chief of the Domestic Environmental and Safety Division for the FMS.
Keeping the lights on is the single highest operating expense for a typical office building — exceeding that of even HVAC — so to improve energy efficiency in the Truman Building, Traff focused first on lighting systems. After a great deal of research, Traff chose to work with lighting manufacturer Lutron Electronics. Lutron, in turn, partnered with Washington-based Eco Electric to design and build an integrated lighting system that delivers a solid return on investment.
In total, 156 lights were retrofitted by changing the sockets and incorporating dimmable ballasts to control the fluorescent bulbs, testing fluorescent dimming as a lighting strategy. Dualtechnology (infrared and ultrasonic) sensors also were installed and programmed to detect when sections of the corridor were empty, so lights would automatically be shut off until someone entered the space, testing occupancy sensing as a lighting strategy. The long corridor was split into four zones and occupancy sensors were placed to provide uniform coverage throughout the extended hallway. New, high-performance lamps also were installed at a color temperature that enhanced the wall colors to provide a more pleasing appearance.
“For this first project, I anticipated energy savings of 30 to 40 percent and am completely shocked we reached 70 percent energy savings using dimming and proper bulb selection,”Traff said.
Additionally, FMS immediately achieved 70 percent lighting energy savings by dimming the corridor lights using a high-end trim feature, allowing them to set the maximum light level to a value of less than 100 percent. The human eye can barely distinguish between a 100 percent light level and an 80 percent light level, for example, and setting lights to less than 100 percent can significantly reduce energy costs. Further significant energy savings are achieved when the corridor is empty and the lights are reduced to 10 percent.
“It may seem low, but a 10 percent light level is still three times the minimum for emergency evacuation standards,” Traff said, “so we are able to establish a higher safety guideline while saving energy.”
Unexpectedly, State Department employees noticed and commented on the lighting improvements. “Once the project was complete, we immediately got compliments about the new paint on the walls and freshly waxed floors — neither of which happened,” Traff said. “The lighting change actually made the corridor appear brighter, even when the bulbs were dimmed 70 percent.”
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