 |
|
|||||||||||||||||||
|
||||||||||||||||||||
|
|
 Lighting designer Nancy Clanton helps energy-strapped California rethink outdoor illumination. The Metropolis Observed October 2001
This year Clanton's California project will undertake research on what makes people feel secure in nighttime public spaces. Rachel Weissman spoke to Clanton recently about how her work in the Golden State, if successful, could lead us to rethink what constitutes well-lit and safe public space everywhere. How will you cut California's outdoor lighting use in half? We want to get a baseline assessment of what California is using now--whether it's for parking lots, retail stores, fast-food restaurants, gas stations, car dealerships, hotels, or office buildings. Besides watts per square foot, we also measure light levels--foot-candles [the equivalent of illumination from one candle at a distance of one foot]--and glare. There are three types of glare: the first is discomfort--which is totally subjective. Then there's disability--when a light is so bright you honestly cannot see someone coming toward you or details like stairs, a rock, or ice on the road. The third is "obnoxious glare"--I love that term. If light is going over the property line by a certain amount, research has shown that there will be a complaint. It's not just the watts but the time that fixtures are on. In the guidelines we'll ask people to turn off all but ten percent of their lights an hour after they close. I've been at many office lots where the cleaning crew may be there late, and even though they park close to the building, all the lights will be on in the lot. The lights in the back don't need to be on, and could be triggered by motion. Then the most important thing we're doing is filling out subjective evaluations about the site, which are being answered by our surveyors and the general public. The first question is, "Would you feel safe being here during the day?" This weeds out the bad neighborhoods. If someone says they would never get out of their car in this place during the day, then we can't use that response. The second question is, "Would you feel safe here at night?" We ask other questions like: "Is the lighting spotty?" "Can you see colors?" "Is it too glaring?" We're trying to look at the reasons why people feel safe and secure at night. Have you learned anything from the questionnaires yet? I'm beginning to think that reducing glare has more to do with the perception of safety than increasing watts does. That makes sense, because our eyes adapt to the brightest thing in our field of view. Anything around a glaring light is going to be darker. If we shield the lights, everything else gets lighter. All of a sudden we need less watts to light the same place. Who are the biggest lighting polluters, and why? I think they are gas stations, car dealerships, fast-food restaurants, and maybe huge regional malls. It's from advertising and fear of litigation. Some owners say, "What if a mother's coming out with a small child? We want all vehicles to see them." I agree--but why is it that you say you need ten foot-candles when we can achieve that with one foot-candle? Could you describe a talk you gave recently at the Lightfair International in Las Vegas titled "Dark Sky--What Is It? Why Is It So Important?" And isn't Las Vegas a pretty ironic location for such a talk? [Laughs] Yes it is. It does glow in the desert. The talk was about a lot of things we've just mentioned. Preserving dark skies is a by-product of good lighting. If you are using correct light levels, minimizing glare and using uniformity, then you haven't overlit places--and the light is not bouncing off the pavement and going up into the sky. And by using shielded luminaires that shine the light down, you've eliminated sky glow potential. It's a win-win situation. The night sky is something many of us grew up with--the ability to see the Milky Way every night. Many children really cannot see stars at night anymore, because the sky glow is so bright. It's being ratcheted up. We're seeing fewer and fewer stars as our cities are increasing, and it will be difficult to reverse. I met a city planner who grew up in New York who never saw stars until she moved to Colorado. There must be some reason we see all of that. I get quiet when I'm looking at millions of stars and think: I really am small. Light trespass is when illumination spreads from its intended source and invades places such as our bedrooms. What are its physical effects? Light suppresses our production of melatonin. Part of the process of going to sleep is having darkness. Then we start producing melatonin, which we need to fight cancer. If we are exposed to light at night, our bodies might stop producing it. The debate is still on about how much light will trigger suppression. Some say a night light will bother you; others say anything more than full moonlight will suppress production. I'm very interested in it as far as streetlights in a residential community--if they are too high and too bright and coming into second-story bedroom windows. I look at elderly people, many of whom have sleeping disorders: the more they can get total darkness at night, the better. You recently designed lighting for a prison yard in Vermont that would avoid polluting the night sky. How does it differ from the norm? Everyone thinks you need floodlights in prisons, which gives you a sense that Big Brother is watching. But blasting light doesn't necessarily increase vision. There's a lot of research data that shows that you see motion better in silhouette. We're perceiving in a different way than we think we are. So we asked: Why do we have to light up the whole yard? How do you light a prison where the guard is always invisible and the prisoner doesn't know where the guard is? Light can act as a barrier--the more light you have on a surface, the harder it is to see through it. So you light the perimeter fence from the inside of the court. We put lights at the eaves and aimed them at the facades of the buildings. The yard will feel dark, but in reality the guards will see any activity there as silhouettes against the wall. And the prisoners can't see through the fence. We're using a lot less light just by putting light where it's most useful. If your California project is successful, do you think other states will be likely to follow it? If so, do you see a radical change coming in the way we light our outdoor public spaces? And how soon? Yes, yes, and I hope soon. We have to get the baseline data, which will be pretty well finished by this time next year. Concurrently we will begin writing standards for outdoor lighting in California. Many other states are waiting to see what California is doing. When it catches on, I think the first thing you're going to notice is that the use of very bright lighting fixtures is going to decrease--your standard building-mounted wall pack will disappear. Even sooner you'll notice a difference in streetlights. Most municipalities will use full cutoff lamps so light does not go up into the sky. Then you'll see a trend in minimizing floodlighting, whether it's used for parking lots or other large areas. Energy prices will have to go up quite a bit before we really see the impacts. Twenty years ago very few people heard about light trespass or pollution. City planners are looking at it now. In Denver, Qwest put up this huge blue sign on the top of their building. When they turned it on, Denver turned blue. Fortunately it happened three days before a light-pollution bill came up. So it really brought the issue home. |
