SmithGroup: Task Lighting Essentials

For Detroit-based SmithGroup, Inc., an A/E firm with its own in-house lighting design group, according to James Luckey, AIA, Senior Design Architect, a main goal with creating a nine-building campus in Van Buren Township, Michigan, for auto parts supplier, Visteon Corporation, was to attain "the absolute minimization" of energy costs. The first consideration was natural light. To allow as much light as possible into interiors, Luckey designed all of the 100,000- to 150,000-sq-ft buildings to be "…extremely narrow, 64 feet in width. We wanted this project to conform to the European standard, in which workers are never more than 10 meters from a window," he said.

Exposures are large: sills of 15-ft-wide windows are only 2 feet above floors; headers are 10 feet above floor height; ceilings at 1-ft 6-in. above the headers. We like, whenever possible, to push ceiling height," says Luckey.

Ambient lighting, via indirect pendants (95 percent upward, 5 percent downward), centered in 20-ft ceiling bays, 30 inches beneath ceilings, is at 25 to 30 footcandles and blends perfectly with the distribution of natural light. The uniformly illuminated ceiling plane increases the sense of openness and maximizes the impact of the high ceilings.

For "sparkle," SmithGroup used café and track lights. Each 50-square-foot workstation has one adjustable compact fluorescent task light and one furniture-mounted fluorescent light capable of providing 50 footcandles where it is needed.

"The use of task lighting allows higher intensities only where that level of light is needed, while also providing the benefit of personalized control," says Luckey. "In a computer environment, the goal is to minimize glare. This project," he says, "is in keeping with what we try to do with every project. If ceilings are shallower, we have no choice but to put lights in the ceiling plane, but we prefer not to."

At Visteon's new corporate campus, which opened in January 2006, workers have personal control over lighting within individual workstations; individual controls allow them to control floor-distributed heating and cooling as well.

"Overall, lighting consumption," Luckey says, "is one watt per sqare foot; lighting and miscellaneous power consumption, 2.25 watts per square foot-the figure excludes air-handling.

Perhaps more importantly," Luckey says, "ASHRAE 90.1 sets a standard of 94,842 BTUs (British thermal units) per square foot per year. Visteon Village consumes about 59,000 BTUs per square foot per year-a 37 percent energy reduction from the code allowance. That number includes under-floor heating and cooling consumption."

The SmithGroup delivered 25 to 30 footcandles of ambient lighting for the Visteon Corporation Michigan campus. Photo courtesy of Justin Maconochie Photography