Exterior Lighting: Use Best, Not Brightest
Part 4: Case Study: Exterior LEDs Balance Safety, Security and Green at Walmart
Case Study: Exterior LEDs Balance Safety, Security and Green at Walmart
By Desiree J. Hanford - December 2011 - Lighting
Many different types of technology are used for outdoor lighting, the most common being HID (high-intensity discharge). LED (light emitting diode) lighting is viewed by many lighting experts as the most efficient in terms of energy and longevity. Some retailers, including Walmart, have also turned to LED lighting in an effort to balance safety and security with being environmentally responsible. Nearly three years ago, the retailer began working with its counterparts to develop specifications and common standards for outdoor lighting.
LED's higher color rendering, higher vertical footcandles and excellent distribution provided a safe and secure atmosphere for customers with lower energy consumption than the incumbent HID technology. LED's superior optical control meant the retailer could have an "excellent cutoff to reduce light trespass and off site glare, which are expectations from our neighbors," says Ralph O. Williams, senior systems engineer for Walmart. Instead of lighting that went from light to dark to light, producing high contrast, Walmart found that it could use LEDs and keep its lighting uniform. "It was still bright enough to be inviting and for customers to feel safe, while reducing energy use by over 50 percent," he says.
Walmart conducted several tests using LEDs for site lighting and eventually installed them at a new store in Leavenworth, Kan. The retailer surveyed its customers and found that they felt safe and secure with the new technology. Walmart did some retrofits on stores closer to its headquarters in Bentonville, Ark., all of which were "closely reviewed for customer and operations expectations," says Williams. The LED technology passed those tests. With that success in the books, Walmart began rolling out the use of LED lighting nationally this year.
"The energy savings, lower maintenance costs and long life are the appeal to LEDs," Williams says. "In most sites, Walmart will burn lights all night every day of the year, so that's important."
— Desiree Hanford