Peter Hildebrandt 2015-04-20 15:56:15
Lighting design choices can cut energy and fuel costs, as illumination forms a substantial part of the energy usage equation. But illumination engineered efficiently and wisely can also make a huge difference in our lives and even the environment, especially that of the night skies. Some 80% of outdoor lighting is used for public illumination, according to Scott Kardel, managing director of the International Dark-Sky Association (IDA). The IDA is a non-profit organization founded in 1988. “Initially, we were focused on astronomy by people with a strong interest in astronomy,” he explains. “But it didn’t take too long for the organization to realize that there is a whole lot affected by light pollution beyond astronomy. Safety, security, energy, the environment, and health are all issues with a stake in the lighting debate, in ways that most people don’t understand. There’s this perception that if you need a certain amount of light to navigate, then more light will make you even safer—that is not necessarily the case.” The point of IDA, Kardel says, is not to turn off all the lights. “What we advocate for people to do is really only use the right amount of light when they need it, and it is shining where it needs to be. As the big picture is studied, it is found that generally those things are just not done. A lot of light is tremendously wasteful, because it is on when it’s not needed; in many cases, that light is also even brighter than it needs to be. A standard ‘acorn-style’ street lamp wastes some 70% of its light—light that goes everywhere but down on the street where it is needed. “We work with manufacturers to encourage them to do the right thing,” continues Kardel. “We also work with state and other governments to help them adopt outdoor lighting ordinances, as well as to issue standards, doing that with some LED lighting. One of the things that’s very exciting about outdoor lighting now is that we live in a time of tremendous technological change. We have a greater ability than ever before to control outdoor lighting in terms of brightness, time that it is on, and other controls that have never been possible before.” Solid-state LED lighting doesn’t take so long to come on as the old sodium lighting, and with timers, the LED lights can be on when the traffic is heaviest. The lights can even be set to respond when traffic goes from low to high. “All your life you’ve heard: ‘Turn off the lights when you leave the room.’ But in the outdoors, we don’t follow that advice,” says Kardel. “Many places around the United States have lights on all night, every night. We have the ability to smartly use lights only when we have to. We want to make sure we are not being excessive.” In the past, when lighting became less expensive, people simply used more of it, Kardel points out. “We educate to make sure you only use the right amount of light for the task. LED and controls give us that ability to look at that, hit those targets of how much light is really needed, and not go over that amount,” he says. “If you employ the proper use of lighting techniques, saving money is a natural occurrence. For stargazers and astronomers, I let them know that a better, stronger message is energy and financial savings—not simply a superior view of the night sky, though that is clearly a wonderful side effect. “The statistics the DSI is trying to highlight concern waste,” he continues. “In the past, we’ve been focused on ‘up light’—light that shines up into the night sky, as the primary source of light. Now up light is the least important. There is unwarranted illumination, lighting installed in an area which doesn’t need it, installed because that was the standard procedure. Controlling the waste from this light has made up some 25% of the energy savings. “Part of the issue needing to be discussed is just what is the purpose of the illumination: safety, commerce, or something else? A community must be willing to think through the process of when lighting is needed,” says Kardel. “Lighting traditionally was installed and shone from dusk to dawn; there was no control in any way other than the initial illumination level. New technology allows the illumination level to be adapted to the time of the night. Based on standards, the amount of light on a particular road is dictated by the amount of traffic—including pedestrian traffic. The problem is most planners don’t know that; there is no awareness that standards have evolved over time. They’re still thinking in 20th Century technology—lighting at the maximum level and leaving it on all night. “Now there is a choice to save energy, saving massive amounts of energy by dimming the lights to match the existing standards,” he adds. “For instance, after rush hour, lights may be able to be dimmed by 25%, as after hours there is no more traffic. A lighting curfew could be instituted, and the lights could go off at 10 p.m. and come on an hour before rush hour. With the latest LED illumination technology, lights are able to switch on and off quickly, unlike older lights that took 20 minutes to start up. Street lighting designers didn’t have the flexibility to do that. Now they do, but the problem is they don’t know it.” “Shielding all the light going up into the sky, you could save another 10% on your energy bill,” according to Kardel. Glare is one of the most important issues in the quality of lighting, yet gets the least amount of attention in lighting design. If poles are being spread out to save on money, than upping the amount of light from each fixture along the highway will create even more glare, brightness that can impair the driver’s view. If accidents, in turn, happen because of the illumination, the lighting is not improving conditions—we shouldn’t be doing lighting in that case. “We’re saying you could reduce energy by 60 to 70% if you are willing to do the whole package,” he says. “Also, if you change your lighting type to a certain LED, you can save on carbon emissions, energy, and a whole lot of money in a way that will improve on visibility.” Kardel recommends warm temperature LEDs that reduce the perception of glare. Savings at a Night Sky-Friendly Place The spectrum strongly affects light pollution, according to Christian Luginbuhl, longtime astronomer—now retired—from the US Naval Observatory in Flagstaff, AZ. Yellow lighting, such as the commonly used high-pressure sodium, and in Flagstaff low-pressure sodium, produces a much fainter sky glow than white sources like LEDs: as little as one quarter or less. It is sometimes claimed that people don’t like yellow lights. “But in Flagstaff, people have always been very accepting of yellow light, even low-pressure sodium lighting, understanding that it causes much less light pollution for astronomers,” says Luginbuhl. In recent years research, some done by Luginbuhl, has also shown that yellow light causes much less light pollution for stargazers as well. Yellow light turns out to be “night friendly” light. Luginbuhl goes on to note that white LED lighting is very aggressively promoted in the market today, with apparently very little awareness of or sensitivity to the light pollution consequences of this spectrum choice. He points out that yellow LEDs are technologically possible and reasonably efficient, but as the industry is focused so sharply on white light, there is not much market interest in yellow lights, and therefore very few are being sold. The consequence is that, as communities switch from yellow (usually high-pressure sodium) lighting, to white LED lighting; even if there are moderate reductions in outdoor lighting amounts, sky glow levels are dramatically increasing. In Flagstaff, Arizona light pollution locally is well managed. Luginbuhl studied how much the lighting codes in Flagstaff had changed the amount of light that was being used outdoors. As a result of that study, they were able to see both that the growth of light pollution had been reduced, and that substantial energy is being saved. Due, in part, to the existence of a number of observatories in the area, Flagstaff has done one of the best jobs of any city in the US of controlling light pollution. In 1958, the city adopted the first regulation anywhere in the world intended to protect night skies from unnecessary light pollution. It has dramatically reduced the amount of unshielded lighting, which shines light all over the place—including upward into the sky. Since the 1980s, the city has also limited the amount of light permitted to an amount reasonable to address utility, safety, and security, but limiting the tendency to compete using over-bright lighting. Flagstaff has shown, with 25 years of experience, that limiting lighting amount has not resulted in any increase in crime, something that may seem counterintuitive. Further, businesses built under these new standards are saving 35% or more on energy costs for outdoor lighting every year, according to Luginbuhl. Tucson has more observatories and telescopes, as well as a long history of trying to address lighting issues. “They have nearly a million residents, while we have only about 67,000, as of 2012,” states Luginbuhl. “Though professional astronomy is very important in the Tucson area, astronomy and night sky protection are not as deeply rooted in the wider community as they are in Flagstaff. Because of that, there is more resistance to lighting regulation in Tuscon, and much more difficulty effectively applying the regulations and maintaining adherence with so many lights.” Protecting Major Light-Sensitive Investments, Including Our Workforce Monrad Engineering, Tucson AZ, has worked on lighting issues around the country and the world since 1982. The company’s founder, Chris Monrad, helped to write the city of Tucson’s outdoor code in the mid 1970s. A collaboration between the firm and the IDSI stretches back for decades. He speaks of common sense approaches when it comes to lighting. These include accurate targeting of light, avoiding the placing of light where it’s not required, using the correct amount of light for the job, timing and shielding. These are basics of lighting no matter where light is being used, stresses Monrad. “With rising gas prices in the late ’70s, came a push to use better, more lucrative strategies with lighting, too,” explains Monrad. “People started to pay attention to lighting issues; saving money made fiscal sense. Beyond saving energy and money, we’ve always known that the spectrum of the light source matters, too. Mercury vapor was acknowledged back in that same time—pre-1975—as more damaging to astronomical interests than sodium light sources.” Paying attention to UV content was important to astronomers; such light has been banned in the state of Arizona since 1988. Other factors that come into play include: poor lighting maintenance, poor color rendition, and the fact that mercury vapor lighting has relatively no efficiency, compared to high-pressure sodium lighting. The bulk of the US uses low-pressure sodium or high-pressure sodium LED in commercial applications. “All of a sudden, spectrum is important, because the type of LED used may lead to a lot of glare content,” adds Monrad. “It’s well-documented that the blue spectrum is an unnatural spectrum in all of evolutionary history after sunset. Up until 150 years ago, there was no electric light. Stars, the moon, and fire were sole light sources; people went to bed with the chickens and cows, as well as got up with them the next morning.” You may recall the feeling you had when an oncoming vehicle had blue headlights when you passed it head-on at night, according to Monrad. This feels bad because that frequency of light has never been experienced in evolutionary history. It is a visceral, physiological reaction. Such lights are good, but only under certain conditions and if you are not exposed to glare as a result. “There is a direct relationship between blue LED light from electronic sources, and the disruption of circadian rhythms,” says Monrad. “Once that happens, the body’s endocrine system is disrupted, potentially leading to problems with sleep and digestion, as well as other ailments. I think if you plotted the rise in nighttime computer use against the recent rise in diabetes, insomnia, or depression, you would find a strong correlation. Sleep deprivation is a huge human health risk.” Changing from high-density sodium (HDS) to LED causes more sky glow, and animals—unlike humans—don’t have blinds to pull down at night. As with us, there has been no blue light in their nighttime spectrum until recently. Monrad points out that the city of Tucson has a very successful outdoor lighting code. They’ve managed to keep light pollution increases below population increases. “It [the code] has done its job in promoting and maintaining the lifespan of the billion-dollar professional observatories in southern Arizona,“ he says. “These facilities have a lot of economical value—over 200 million dollars annually. This includes the billion-dollar infrastructure within 75 miles of Tucson, including allied industries that support the observatories, research taking place at the University of Arizona, science engineering startups, and an optics cluster that is located in Tuscon.” Much of this revolves around the fact that the city has excellent night sky view possibilities for these observatories. Yet, visitors are still within an hour-and-a-half drive of an international airport. No need to travel to Hawaii, Chile, or the Canary Islands: A direct flight into Tucson or a two-hour drive from Phoenix yields some of the most magnificent night sky views in the world. The area telescopes, in turn, are continuously being upgraded, provided with the newest instruments and new adaptive optics. But they will only continue to make those investments in the upgrades as long as they have some level of confidence that this area’s natural dark sky asset will be protected. The area’s outdoor lighting code is now coming up on 10 years and has been through a number of revisions and refinements over the years. “But in every case, the code gets stronger, pushing the lighting design and manufacturing industry into a best practice situation,” explains Monrad. “Pushing industry to come up with equipment and optical systems that put light on the target, control the ability to turn the light on and off at will, as well as being able to provide the most desirable spectrum of light is good for business. “The payoff transcends money savings; ‘visual comfort’ due to lighting systems is often ignored when businesses install lighting systems,” he continues. “The greatest expense of any company is their payroll. Whether it’s outdoor lighting or indoor plant lighting, lighting for airport ramps or railroads, if you don’t put in illumination systems sympathetic to human vision, you may have various problems. Among these are worker fatigue, worker dissatisfaction, and worker agitation. Glare, especially, is never good. It is unsafe at any speed.” It is good to save money on energy, but paying attention to visual comfort is vital as well. It’s not about what you see on the meter, but how people perceive the light and how it helps them do their job, according to Monrad. “Lighting is to help you see, and if you’re putting too much light in an area, under-lighting, or not putting the light where you need it, you are not maximizing your investment. Worker satisfaction leads to less absenteeism, better morale, and a much healthier workplace on many planes.” Growing Into Today Nancy Clanton has been involved with energy concerns since 1981. “The idea of energy efficiency was not even a topic that was on anyone’s radar back then. The first experience that I had was with President Clinton’s work with the Rocky Mountain Institute to integrate more efficiency and energy saving into lighting at the White House. “What I didn’t realize was how important an impact that would have, as well as how ahead of things that initiative turned out to be—that was a huge eye-opener. Some of the people there were the founders of USGBC [US Green Building Council], in turn, leading to a meeting at Big Sky where discussions started with wondering, ‘what do you think green means to you?’” Clanton realized how little training architects received in lighting, including daylighting as well as getting buildings to work completely on their own. Her company has knowledge on daylighting and energy savings with lighting, as well as an ethic to keep challenging one another. “It’s more than just energy-modeling, more cooperation and brainstorming,” she says. “We’re not a production firm. We enjoy working on buildings other people have given up on, and how you get there with energy saving could take a million different paths. We are constantly looking at new ways of doing things.” Clanton is perpetually looking at standards and recommendations, testing or questioning them as to what is the basis for such advice. They know what is needed in buildings and about glare, so when a lighting requirement per square foot comes out, they ask what it’s based on, the quality of the light, or how many layers of light are involved. “We can get by with many of our designs using far below one watt per square foot and be more like 0.2 watts per square foot because of the integration of controls,” she says. “Because of that balance, you can do excellent lighting design that’s not energy-driven, but the result is maximum energy savings —starting with quality design.” When over-lighting happens, light, in turn, reflects off the pavement or the ground, and that light is adding to sky glow. The best strategy, according to Clanton, is to not over-light, but light to what is needed. “Our lighting standards in this country are too high. There is little research on where our lighting standards are; they are more consensus-based. “We delve into ‘let’s develop research-based lighting standards,’” she adds. “Anchorage, Santa Fe, Seattle, and San Diego are client cities for which we’re studying visibility through target detection and community subjective evaluations. This occurs on a closed off mile and a half of roadway. The testing evaluates different lighting spectral distribution types. Looking at the effectiveness of lighting is a better predictor than simply studying uniformity and lighting level.” Clanton has focused on using well-filtered lighting. The color of light can contribute to sky glow. Blue light is absorbed into the atmosphere. That’s why the sky is blue during the day; at night, blue light is absorbed into the atmosphere—we just can’t see it. “If we go with warmer colors of light, such as red light which is not absorbed, this type of light does not contribute to sky glow,” says Clanton. “Just the type of light selected can make a huge difference for people sleeping, for animals, and all by moving it more toward the longer wavelengths or the red light, in the middle of the night. Higher light levels do not necessarily mean safer environments, she adds. “Police departments come with us, look at lighting, and then end up not choosing the highest lighting level but the highest quality of lighting. We’re trying to get involved in standards writing and lighting policy. We’re on the Roadway Lighting Committee of IES [Illuminating Engineering Society], proposing research symposiums to get the researchers together to figure what our metric should be.” Clanton is working on smart, intelligent lighting systems through cities and getting them ready for this advanced technology. This can be based on the street lighting, on traffic counts, or the car itself could trigger streetlights—or even a smartphone. “You can get lighting responsive to the people using it, instead of just having the lights on all the time,” she says. “I’m a member of several IES technical committees. We need to ask what the technical basis for existing and new recommendations are. If the technical basis is lacking, then develop research-based data. As an example, we’re working on California’s Title 24, reviewing the baselines for interior and exterior lighting.” Over-Lighting Complaint Changes One Town’s Lighting Model Plymouth, MN, a western suburb of Minneapolis with 73,000 people, has had the Dark Skies Association’s model ordinance in effect for 10 years. The event that triggered the whole change happened when a new commercial development in the area mistakenly put in too much lighting. A neighbor complained, which led to the reworking of Plymouth’s lighting regulations. The neighbor who complained had just learned about the Dark Sky Association’s model ordinance. “The individual who lodged the original complaint had come upon the model ordinance during the course of his travels out west, and he suggested that was what the city needed to adopt,” explains Barb Thomson, planning manager for the city of Plymouth, MN. “The council said ‘OK’, so I started researching, and eventually we hired Nancy Clanton, who was one of the authors of the original version, to help us. “She visited Plymouth and met with the Planning Commission and the City Council—with this being completely new territory for everybody. She showed examples of good lighting and bad lighting, making the point that more lighting is not necessarily good lighting.” The way in which lighting is designed is actually the greater path to security, efficiency, energy savings, and safety. That made all the difference in the world, according to Thomson. “To actually see examples really brought out the old adage, a picture is worth a thousand words,” she says. “We were eager to make the model work for Plymouth, and we did.” Recently, the city had some issues, because more and more people were changing over to LED lighting. The original ordinance was based on watts per square foot, but LED watts are not equivalent to standard lighting watts. The Dark Sky Association had already revised the model ordinance to address this issue, so Plymouth is now working with lumins per square foot. “Nancy [Clanton] helped us to make the changes to go that route, and, in October 2013, we put the changes into effect. There are a lot of things that go into making good lighting, and more is not necessarily one of those things,” continues Thomson. “Our ordinance affects lighting of commercial, industrial, institutional, and multiple family housing developments. We have limited regulations for single-family neighborhoods as we have not had issues in these areas.” One of the biggest issues in the community was over-lighting from commercial and industrial uses bordering residential areas. While Plymouth had made progress in addressing offsite lighting impact, the recent addition of the back light, uplight, glare (BUG) provisions to the Dark Sky’s model took controlling offsite impact to a new level and insured that the lighting being installed would not impact neighbors. That’s a big thing, according to Thomson. “When we put these into effect the first time, some years ago it was a major change from what we had before,” she says. “We received virtually no push back from people, and the people we were dealing with were the commercial/industrial developers in town—it was an amazingly easy and smooth transition. “One thing about the Dark Sky Initiative ordinance is that it’s akin to a math exercise—it’s not hard to figure out what you need to do. That might be part of why we did not have a lot of issues.” Implementing the new lighting ordinance took two to three years. However, once the city started down the path of the Dark Sky model ordinance, the process took only a few more months; it was not difficult at all. Thomson feels there have been many benefits from what they’ve done in Plymouth. “We help the natural environment with the darker skies in the area. It’s more efficient; there was a lot of over-lighting in the past. Over-lighting was causing light-trespass and glare on other properties. “Controlling that problem has been one of the good results we’ve had because that was where our problems initially started. That was the one that bubbled to the surface and caused us to do something, and controlling light intruding on other peoples’ properties was one of the good things coming out of this work.” BE Peter Hildebrandt writes on engineering and scientific subjects. SIDEBAR When Changes in Technology Alter Well-Known Landmarks Musco Lighting, for more than 40 years, has been a global leader in LED lighting technology. The LED lighting on the new East Bay Bridge will now cost vastly less than the older lighting on the former suspension bridge. At six NCAA arenas, their lighting technology has dramatically reduced energy consumption. The company does lighting for everything, from Little League fields to Olympic Games. Musco Lighting has a very diverse transfer base, including projects such as the Charlotte Motor Speedway, the first NASCAR track ever lit, done with Musco technology, which helped them to gain the system specifics for motor speedways. That was back in 1992. In April 2014, they lit another track at an international speedway. “Our new Light Structure Green System has been able to reduce glare by 50%, and energy consumption by 50%,” explains Jason van Eyk, marketing representative for Musco. “This is a technology that we released in 2005.”
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