Published In May 2001
As an electrical contractor, you may feel like you’re walking a tightrope when selecting and installing lighting systems for modern retail stores. You want to provide retailers’ desired look and feel while meeting their requirements for long life and operating efficiency within budget. As always, you strive to get the job done as quickly as possible—without callbacks—while ensuring a high level of satisfaction. While America continues to transform more urban space into big-box stores, retailers are taking advantage of industrial and warehouse facilities by converting them into large stores with more space and merchandise. This trend has also spread to the suburbs, where store sizes range from 25,000 to 150,000 square feet. These big-box stores are creating unique lighting challenges. Higher ceilings and demand for energy efficiency have made many fluorescent lighting systems—popular since the 1960s—obsolete. Looks are everything Fluorescent systems used in the past dissected almost every aisle. In contrast, luminaires installed in most big-box stores are simple, uncluttered, and unobtrusive. Many retailers are using high-intensity discharge (HID) sources, which can create a daylight atmosphere while emphasizing key merchandise. Uplight, which is a form of indirect illumination, eliminates glare and promotes uniformity by reducing the contrast between the light source and the surrounding area. An element of uplight improves the luminance of the ceiling and vertical surfaces, including signage, labels, and vertical displays. Because too much indirect illumination results in a drab, gray environment, lighting fixtures typically supply 50 to 90 percent downlight. This direct illumination creates depth and defines texture while helping focus customers’ attention on what the retailer wants them to see. Color rendering, which is the ability of the light source to represent the true colors in an object, also contributes to the appearance of the merchandise. The closer the color rendering index (CRI) is to 100, the more natural product colors will appear. Retailers and designers are choosing lamp sources with as high a CRI as possible, and that have the same color-rendering capabilities as daylight. Modern lamp technology Retailers and their customers tend to prefer the white light provided by metal halide lighting systems. A metal halide system may have nearly equal measured footcandles as a fluorescent system. However, customers in the area illuminated with the metal halide units will have the perception that they can see better because the area appears crisper and the products have more definition. Pulse-start metal halide lamps are the most efficient metal halide lamps. Not only do they provide the white light retailers prefer, but they offer more light over life. A pulse-start lamp will produce 110 lumens per watt (LPW), compared to 80 LPW provided by a standard metal halide lamp. One pulse-start metal halide lamp will also provide the same lumens as a dozen or more 32-watt T8 fluorescent lamps. While pulse-start lamps are initially more expensive than conventional metal halide lamps, retailers benefit from lower installation, operating, and maintenance costs. Still in the introductory stage, ceramic arc tube metal halide lamps offer even greater color rendering capabilities and excellent lumen maintenance. The new lamps bring out the red color in merchandise, which is often hard to achieve. Sound in the retail environment A buzzing light fixture can disrupt the music from a high-quality sound system or garble an intercom message. Galvanized shelving or ductwork or a metal deck ceiling will amplify the noise. Designers and contractors are eliminating this problem by installing lighting fixtures with encapsulated ballasts. The potting compound used in these ballasts reduces and absorbs ballast noise while acting as a sound barrier. Easier installation Whereas many HID fixtures have an adjustable light center that requires you to determine where to install the reflector in relation to the lamp, some manufacturers are offering luminaires with fixed light centers to eliminate guesswork. Fixtures with flexible wiring systems that use a distribution cable are facilitating installation and maintenance. This not only offers flexible layout, but it also allows the fixtures to be removed for maintenance without disrupting business or interrupting circuit power. RIES is director of commercial lighting at Holophane. For more information,call (614) 345-9631 or e-mail him at firstname.lastname@example.org.