Electric lighting is one of the largest single consumers of energy in shopping centers and other commercial buildings. Lighting systems also produce heat, which accounts for 15% to 20% of a building's total cooling load.
Architects and lighting designers keep these facts in mind when working together on shopping centers. For The Lakes Mall, a new single-level center near Muskegon, Mich., the developers, CBL & Associates Properties Inc., in Chattanooga, Tenn., commissioned architecture firm KA Inc., of Cleveland, and The Lighting Practice to create a friendly and attractive destination.
Opened in fall 2001, The Lakes Mall is a middle-market center anchored by J.C. Penney, Sears and Younkers, with Bed Bath & Beyond as a subanchor, and 60 shops and services plus restaurants. The Arts & Crafts style architecture of the mall is a nod to the Prairie School of design popular at the turn of the century. KA Inc.'s design resembles the residential, lodge-like architecture influence of the region bordering Lake Michigan.
Working closely with Darrell K. Pattison, design principal for KA, Inc., our team was responsible for designing the general and accent illumination for the interior common mall area, mall graphics, food court/food court seating area and restrooms, three exterior mall entrances and adjacent landscape areas.
High expectations
Developer clients such as CBL expect lighting systems that combine high efficiency, long life and low maintenance. Lamps that are rated at 10,000 hours, such as some metal halide and compact fluorescent varieties, reduce the frequency of replacement to effect savings in operating costs. When specifying fixtures and lamps for a shopping center interior, the amount of light (measured in footcandles, or FC) and the Color Rendering Index (CRI) of the light produced by the lamp sources create the image and environment that encourage visitors to stay longer, and potentially purchase more.
Energy codes, standards and demand-side management (DSM) programs have been developed to minimize lighting energy waste and assure the use of efficient lighting systems. DSM programs from utilities and government agencies provide incentives to encourage energy efficient solutions. Considerations for energy management for new buildings include: components (luminaires, sources and controls); space parameters (plan, space utilization); and operation/maintenance. Ballasts used in commercial fluorescent lighting installations must meet or exceed the minimum ballast efficiency factors (BEF) established by the National Appliance Energy Conservation Act Amendment.
The luminaire efficiency rating and labeling program is a voluntary program that permits easy comparison between the efficiencies of different luminaires. Labeling rules for incandescent, incandescent reflector and compact fluorescent lamps have been in effect since 1994.
A comprehensive lighting plan can be presented to a shopping center owner using such tools as CAD (computer aided design) graphics with areas shown as virtual reality with the proposed lighting in place. This technique helps the owner to foresee the spaces and understand how they will be lit by artificial illumination and natural light, as was the case with The Lakes Mall. A spread sheet shows all potential fixtures and lamps and their cost, along with information on the watts per sq. ft. in the constructed building. The Lakes Mall plan achieved a 1.8 watts-per-sq.-ft. level which is under the recommended practice of 1.9 watts per sq. ft.
Daylight from overhead skylights and clerestory windows bring daylight into the retail areas and the food court. The benefits from using daylight are both aesthetic and monetary. Studies show that people are more comfortable and productive in buildings where abundant natural light enhances the surroundings with a diffused brightness. And, a comfortable shopper is more apt to be in a good buying mood.
As an expense saver, daylight reduces the cost of maintaining a level of illumination that will meet visitors' visual needs in the public areas, which is about 20 FC.
For The Lakes Mall, Darrell Pattison has used both skylights and clerestory windows. He advises owners to consider a value-engineering study of first costs of clerestory windows as compared to skylights. This type of window prices out at approximately one-quarter the cost of skylights, which range from $45-$60 per sq. ft. A center's ambient lighting system can augment natural light using an electronic system that dims or increases the artificial illumination depending on outside conditions — sunny, overcast, etc. — and time of day.
Accent and decorative lighting fixtures for The Lakes Mall were designed in the Craftsman style to carry out the architect's concept for a familiar, residential-like theme for the center. Modern technology allows us to provide the good color and lively accent that was previously only possible with halogen sources.
To give the space drama and visual punch, we specified customized compact fluorescent lanterns and pendants that restate the architectural motif and add sparkle to the various walkways and courts around the center with metal halide accents. These articulate the space and integrate with the architectural details.
The food court captures a white-trimmed, clapboard-siding image of a Michigan lakeside family resort with wood-like porch structures and dockside lighting fixtures, while the building's exterior design features an exposed timber-like porte cochere and entrance towers that are reminiscent of a turn-of-the-century Lake Michigan vacation lodge. Light fixtures mounted on the piers and at the corners of the tower send a subliminal welcoming message to visitors, and guide them to the front entry doors beyond.
Helen Diemer, FIALD, is vice president of Philadelphia-based The Lighting Practice.
Energy savers
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The Lakes Mall utilizes a very efficient T8 fluorescent lighting system augmented by the punch from efficient high color rendering ceramic metal halide PARs. Metal halide takes the place of incandescent/halogen PARs in contemporary retail lighting.
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General lighting is provided by two types of multiple head metal halide 70watt PAR accent lights. Ambient lighting for The Lakes Mall that combines cove lighting and downlight/accent lights provides most of the final FC level for this enclosed retail space.
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Decorative wall bracket lanterns along skylight bulkheads use 26-watt compact fluorescent lamps and electronic ballasts. This type of fixture would normally be designed with incandescent lamps. Here, the compact fluorescent lamping saves energy while combining longer lamp life with strong visual appeal.
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Pyramid ceiling fixtures at the transition areas and in the center court also have 26-watt compact fluorescent energy-saving lamps.
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Exterior lighting uses 40-watt biax fluorescent for the uplights to make the towers glow. Metal halide PAR downlights were specified for accent lighting in the entrance canopies. Sconces and bollards were fitted with compact fluorescent lamps.
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