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Part 2: Light Pollution, Efficiency are Concerns with Outdoor Lighting
By Desiree J. Hanford
July 2010 -
Lighting Article Use Policy
Reflectors not only direct light to a certain area but they also can help control light trespass and light pollution. The former is where light shines in an area where it's not wanted, such as in another property's windows. The latter is light that essentially shines upward, intentionally or not, into the atmosphere.
One of the first steps a building owner or manager should take is to find out if a municipality has ordinances covering light trespass. Some do, says Daniel Fernandez, director of product management for Juno Lighting's AccuLite and Navalite brands, and more and more are adopting them or at least considering adopting them.
"It really goes back to light design," says Tim Hill, marketing manager of Streetworks for Cooper Lighting. "There are many tools and optical designs that give you the ability to control light, such as forward throw optics or spill control optics. They cost more than basic optics, but a bad lighting design is a bad lighting design."
Light pollution can also be a result of poor lighting design but can be easily addressed. As with trespass, some municipalities have ordinances that attempt to limit light pollution.
"Light pollution is becoming more and more important," says Paul. "It's being able to control your sources, putting reflectors around high intensity discharge (lighting) and putting the light where you want it."
Several types of fixtures and lights can limit light pollution, including LED, high intensity discharge and compact fluorescent, says Fernandez, noting that it's a matter of not having any light above the 90-degree line.
Although safety and security are at the forefront of most discussions regarding outdoor lighting, energy efficiency is a close second. The benefits of energy efficient lighting may go beyond energy savings, potentially reducing maintenance requirements and lamp lumen depreciation, and delivering higher lumen levels in the targeted lighting zone, says Lavoie.
Induction and LED lighting are the two "leaders" when it comes to energy efficiency, says Paul.
"LED will probably be the most expensive and induction a bit less versus high intensity discharge, which might be half (the cost) of an LED fixture," he says. "But you need to consider the maintenance costs. With LED and induction, you're talking about not changing the bulb or ballast for 10 years versus three to four years for HID."
Although a metal halide lamp is more energy efficient than LED, LED is directional and so more of the light can be used and not lost or be trapped in a fixture, says Fernandez.
Induction lighting is ideal for street lighting, parking lots and garages, says Sara George, vice president of sales and marketing, North American Energy Group. Induction lighting can also be retrofit by using existing light poles, she says.
Sensors are another way to control energy costs, Paul says. With proximity sensors, lights could be set at 50 percent of their capability at 3 a.m., increasing to 100 percent only if something triggers the sensors. "You may use more expensive equipment, but you use it more intelligently," he says.
"Good quality lighting takes some pre-thought and work, but it's worth it," says Gotti. "The most important point is the decision that you're going to do a good job of lighting and you're going to get help if you don't understand it."
Desiree Hanford is a freelance writer who spent 10 years as a reporter for Dow Jones. She is a former assistant editor of Building Operating Management.
Part 1: Quality and Quantity Key to Outdoor Lighting