Bring on the Night
- By Amy Milshtein
- November 1st, 2006
It’s a no-brainer. To keep your people and buildings safe you light footpaths, streets, parking lots, and façades as brightly as possible all night long, right? Wrong, actually. Today’s outdoor lighting designers find that less is more and the creatures of the night remain thankful.
These nocturnal beings include the International Dark-Sky Association (IDA, www.darksky.org). Started in 1988 by a small group of astronomers, the IDA became troubled about the loss of the dark night sky. They have since grown to 11,000 members in 75 countries whose concerns include astronomy along with energy conservation, human health, wildlife wellbeing, and the security of people and property.
Colleges are anxious about the safety of their students, and rightly so, commented Nancy Clanton, president, Clanton & Associates in Boulder, CO.But they overreact and throw up way too many lights. This has the obvious effect on a school’s astronomy department whose students can no longer participate in constellation labs. However, the ripples move farther than that.
Too Much of a Good Thing
Bright lights done wrong create a lot of glare, which can blind pedestrians and drivers.The Department of Justice did a study on crime prevention, and several pages were devoted to lighting, reported Bob Gent, vice president, Board of Directors, IDA. The results were mixed at best. People feel safer when an area is highly lit, but they may not be safer. As an example, he points to brightly illuminated ATM machines. Yes, you can see the machine and surrounding area, but a criminal hiding in the bushes can see you as well.
Bright lights done wrong can also create light trespass. This is where light illuminates areas beyond its intended target. If the light trespasses into dorm rooms or off-campus houses, human health can be affected. Sleeping in a dark room produces melatonin, which regulates the immune system, said Gent. Melatonin suppression has been linked to increases in cancers and other illnesses.
Finally, bright lights done wrong can be an environmental hazard. Not only for the obvious energy drain. Plants and animals need the dark as much as humans. Reports abound of sea turtles unable to find a dark beach to lay eggs and migrating birds being confused by brightly lit skyscrapers.
Striking a Balance
If this information leaves you in the dark, don’t fret; a balance that satisfies everyone can be struck. Lighting manufacturers now offer products with full or partial cut off. These cut offs direct the illumination exactly where you want it and cut it off where you don’t, avoiding light pollution.
Five years ago we had a limited pallet of cut-off lights, said Robert M. Corning, partner, landscape architect, ASLA, Geller DeVellis, Inc. Now almost every fixture offers it. Even historic-looking acorn fixtures come with cut off.
The lamps inside these fixtures continue to evolve as well. Color choice has moved from orange to full-spectrum white. Orange light impairs peripheral vision, said Clanton. White light is safer and more inviting.
More and more campuses are installing a new product called induction lamps. While these lamps costs about $200 more than metal halide lamps, induction lamps last up to 20 years. Light poles cost between $3,000 to $5,000 each, so the extra $200 to not change a lamp for 20 years makes sense, Clanton observed. Induction lamps give off warm, inviting light, they turn on and off instantly, and are so reliable that a school’s liability goes way down. Their only disadvantage is they are a bit larger than other lamps, but they still fit in most fixtures.
Location, Location, Location
No matter which lamp or fixture a designer chooses, deciding where to put the light poses the next challenge. Major pedestrian arteries will obviously be lit, while secondary paths may remain dark to discourage use. Even pools of light should direct walkers to their destination which, according to Clanton, should be, softly illuminated. Some jurisdictions have codes that demand a light at every door, but you don’t want to direct people to a side door that could be locked. Instead she suggests illuminating façades to clearly define the front entrance.
Another code lighting designers are paying attention to is California’s Title 24. Last October, institutions had to be circuited to reduce energy by 50 percent. The next step is actually reducing that output.
You can’t comply by simply turning off every other light; that creates pools of dark and light and just isn’t safe, said Clanton. Having lights that dim during curfew hours but brighten as pedestrians approach would meet the criteria and still provide security. Clanton reported that the major outdoor lamp makers are coming out with dimming models within the year.
Another technology that continues to improve is stadium lighting. That’s one area where light trespass has been a real problem, said Corning. Now the light can be pinpointed right onto the field or the stands. The levels can even be adjusted for a practice, which doesn’t need full lighting.
Sports lighting has come a long way, Gent concurred. You can have 100 foot candles in the park and a few yards away project only one foot candle. The problem comes when they forget to turn the lights off when the game is over.
Centralized lighting controls can help turn the power off or on as needed. Run through a computer, PDA, or even a cell phone, controls have evolved along with fixtures and lamps. You now need less staff to make even more sophisticated adjustments, said Steve Beede of Lutron Electronics, Inc.
No matter the adjustments made, the new paradigm of less is more should reign. A full moon is 1/100th of a foot candle and we can read a newspaper at that level, explained Clanton. Most campuses should light to one-half a foot candle. As long as the illumination is even our eyes can adapt.
And that leaves the night healthy and dark.