Ranked among the 10 largest convention center ballrooms in the nation, Kansas City, Missouri's Bartle Hall Ballroom is, needless to say, enormous, encompassing a vast 46,450 square feet. Even more monumental was local lighting design firm Derek Porter Studio's task of lighting the large-scale space so it could yield numerous environments for a variety of functions while capitalizing on daylight to conserve energy and introduce natural light into the space.

Just one part of a multiphase expansion of the convention center, the new state-of-the-art ballroom not only provides more flexible space to the facility's repertoire of offerings (for events including exhibits, lectures, performances, and galas), but also strengthens the convention center's role as an anchor for the revitalization of the downtown area, which is experiencing unprecedented growth with the new Sprint Center arena, a nine-block entertainment and residential area known as the Power & Light District, and the Kauffman Center for the Performing Arts.

In a departure from traditional “black box” ballrooms that offer no context to site orientation or exterior surroundings, daylight pours through clerestories on the north, east, and west sides of the room. Translucent stretched-fabric panels measuring 8-, 15-, and 30-feet, respectively, on the north, west, and east sides of the ballroom border the ceiling perimeter, diffusing the sunlight as it moves across the space over the course of the day. “Being time-based, the light is always changing and revealing the exterior condition in various ways, so you really feel the dynamic changes of the room and how natural light sculpts and gives orientation to the space,” explains Derek Porter, principal designer and owner of Derek Porter Studio. “We purposefully wanted those shadows and projections to move across the translucent ceiling surface so you see the exposed structure inside the light-well, revealing the temporal presence of daylight as well as diffusing the direct sunlight entering the room.”

The natural light has proved to be Porter's favorite element of the design. “Feeling the light move through the space naturally and diffusely through the stretched fabric is just magical,” he says. Providing both visual animation and orientation while offering energy conservation and substantial functional illumination, the daylight footcandle level (with no electric lighting) ranges from 60 footcandles underneath the stretched-fabric panels to 20 footcandles in the middle of the room. However, for those events requiring a specific theatrical scene with electric lighting, motorized blackout shades in the clerestories can be employed.

Working independently of and in concert with the natural light, electric lighting can be used to create seemingly countless illumination combinations. A variety of light sources and fixtures were used to meet the diverse programmatic needs, providing both general illumination and task lighting, including 250W PAR38 recessed halogen downlights; photocell-controlled dimmable 18W, 26W, and 42W compact fluorescent downlights; 14W and 28W T5 and 54W T5HO linear fluorescents that run continuously and transversely across the ceiling; and 39W and 150W T6 ceramic metal halide wallwashers. To keep the focus on the design, fixtures were carefully incorporated within the ceiling and other interior design elements.