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Lamps & Fixtures in the Field

A Two-Lamp Revamp

BY REBECCA FALZANO

Lighting Research & Education
>New Lighting Industry Buzzwords
>What Can Be Taught And What Must Be Learned
>The Utility of Dimming For Load Shedding
>20 Years In The Trenches

With 230 sales offices throughout the country, real estate company Long & Foster has quite bit of space to light. When the firm decided to build its new headquarters in Chantilly, VA, the objective was to make the building as green as possible while keeping within the parameters of the total development budget. The solution: cut the number of lamps in half in the new space.
   According to lighting consultants Steven Glock and Kenneth Nalls (Glock Smidt Engineering, Forest Hill, MD), the first hurdle was steering Long & Foster away from the four-lamp fixtures they typically use in most of their office space. Glock and Nalls specified a fixture that would save energy and lower lighting costs without sacrificing light levels: a two-T8 lamp 32-W parabolic fluorescent unit (EnergyMax by Columbia Lighting). Drawing 67 watts, this fixture strikes a balance between light output and energy conservation as it requires 21 percent less energy than standard three-lamp parabolic units: 89 percent efficiency compared to 70 percent with a standard three-lamp parabolic fixture. In addition, the two-lamp fixtures provide comparable footcandles to the three-lamp parabolics—on average, about 68 fc in open areas. The fixtures combine a louver material and ballast to optimize light output and energy savings. “With these fixtures, we were able to get comparable light output with less wattage,” says Glock.
   Long & Foster occupies the top three floors of the five-story building, approximately 168,000 sq ft of space. The spaces outfitted with the new fixtures include department offices, an executive level, boardrooms, and a data center. In addition, the fixtures were mandated as the building standard for tenants on the other floors.
   ong & Foster estimated lighting will be on at least 10 hours per day, five days a week or 2,600 hours annually. With 1,964 fluorescent fixtures installed throughout the headquarters alone, if the firm had chosen a typical three-lamp parabolic fixture they would have consumed nearly 167,000 watts. The two-lamp parabolic fixtures, however, require approximately 131,000 watts, a savings of over 35,000 watts and thousands of dollars annually in operating costs.