Carol Brzozowski 2016-08-02 14:22:10
Perhaps nothing exemplifies the importance of LED color temperature in a work setting better than that of the International Space Station (ISS). Although astronauts are allocated 8.5 hours per night for sleep, half of them in a recent study slept less than six hours per a 24-hour mission day, and were unable to make up the sleep. Sleep deprivation occurred because of spacecraft lighting, interruptions, and excitement inherent in space flight, with their performance declining over time. Professor George Brainard, Ph.D., director of the Light Research Program at Thomas Jefferson University, collaborated with researchers at Brigham and Women’s Hospital to design and test new LED lights for the ISS crew that would allow them to sleep and perform better in space. The adjustable LED lights have three settings and use color to help astronauts sleep better and perform better during the day. They were tested in a special simulation center built in the Jefferson Light Research Lab before NASA started to relamp the Space Station. Brainard, who is also a member of NASA’s flexible lighting team, recently received NASA’s Johnson Space Center Director’s Innovation Award. The implications for lighting life on planet Earth pose promise, as do many space innovations. Already, color temperature has become an important factor in LED applications for a variety of settings. In analyzing the present status of LED adoption in the United States, the US Department of Energy (DOE) found that while the lighting technology is on a slow but steady forward trajectory—and in 2014 offered facilities some $1.4 billion in energy savings—it only represents 5% of the potential. LED applications with the greatest future energy savings include linear and low/high bay luminaires. Not all LED lights are the same, but rather exist on a scale of color temperature. Therefore, the choice of the right color temperature will have a bearing on the success of adapting LED technology in a facility setting. The LED range of color temperature is measured in degrees Kelvin (°K), which explains how the light source looks to the human eye, notes Josh Kurtz, senior vice president of sales at Orion Energy Systems. Orion Energy Systems offers numerous fixture options for many applications, including industrial manufacturing and distribution centers, office space, retail, and exterior lighting. The company’s retrofit lighting products are designed for numerous Kelvin temperatures, lumen packages, and other options. Cooler color temperatures with higher Kelvin ratings (3,600 to 5,500) will look more blue and white to the human eye, while warmer color temperatures with lower Kelvin ratings (2,700 to 3,000) temperatures will appear more yellow. For LED fixtures, the higher the color temperature, the more efficient the fixture, says Kurtz, adding that color temperature does not impact the lifetime rating or warranties for LED fixtures. In a 2015 Solid State Lighting Technology Development Workshop in Portland, OR, sponsored by the DOE, the argument was made that LEDs offer an opportunity to customize the spectrum during a presentation by Brainard and Dr. Stephan Völker, chair of Lighting Technology at the Berlin Institute of Technology in Germany. A proliferation of information exists on human circadian systems and the sensitivity of the photoreceptors that send signals to the central brain. Color-tunable luminaires are being promoted for health, productivity, mood, and fun. There are claims of increased alertness, improved sleep, and slowing of dementia symptoms. Factors affecting circadian health include light spectrum, intensity at the eye, the timing and duration of light exposure, its spatial distribution, and individual characteristics. “Fixture selection depends on application and what the customer is looking to achieve with the project,” says Kurtz. “The critical factor is to determine what is needed overall: are you simply replacing burned-out or under-performing fixtures? “Are you meeting a required light level in your facility? Or doing a retrofit project to reduce operating and maintenance costs? The best fixture choice is the fixture that best meets the needs of the project and saves the most energy while matching or exceeding required light levels.” Russ Sharer, vice president of global marketing for Fulham, contends that there is no “right or wrong answer” when it comes to color temperature choices for lighting. “We see a lot of people who are either replacing incandescents or fluorescents, and tend to go towards the 2,700; 3,000; or 3,500 end of the range of color temperatures because the light is most like what they’ve been working with,” he says. There is a body of current research on the influence of color temperature on productivity in the office space, says Sharer. “While they believe scientifically there is some connection between color temperature, circadian rhythm, and work efficiency, they haven’t really identified anything that says this is absolutely the right way for everybody, in every situation to do it,” he says. “In general, there is a lot of belief right now in starting with warmer temperatures that go down into the 2,700 and 3,000 range and then to brighten to the brighter 4,000 and 4,500 range during the day. That does seem to have some positive correlation to efficiency in many cases.” Toward the end of the day, as the sun begins to set, the office can revert to warmer color temperatures as a way of helping transition people out of their work day, Sharer says. “It’s a general trend, but no one has positively said this is absolutely the case in every situation in every work place,” he adds. Cory Ockunzzi, product manager for luminaires at Eye Lighting International, notes that in different areas of the country, there are different lighting preferences. “It seems like the farther north you go, the warmer the color temperature they like and the farther south you go, they like it to be a little cooler color temperature, mostly because they get more sunlight in the South than they do in the North,” he points out. Most outdoor applications tend toward 4,000°K, he says, adding that it’s due in part to being the “color temperature you get from the moon. It blends in a little better, and it’s a cleaner light.” Others prefer to replace the color of one type of bulb with the same color in another type. “When you’re replacing a high-pressure sodium, there’s a lot of yellow and a lot of amber in the light, so some people tend to try to get something that’s a little bit warmer or generally go to 4,000°K because they like that nice, crisp, clean white light. “A lot of applications with metal halide could be a higher color temperature, depending on the lamp that they’re using in the first place. Some of those go to 5,000°K.” John Casadonte, vertical marketing manager for Cree Lighting, says color choices depend on the detail of the work being performed in a given facility. Warehouses and industrial facilities have expansive lighting needs, spanning more than 17,000 square feet on average, and often featuring loading docks designed to handle delivery trucks at all times, notes Casadonte. As such, operational efficiencies are driving many of these facilities to LED lighting technology, he says, adding that it offers “immediate bottom line impact, helping industrial facilities control overhead energy and replacement costs, and boost bottom lines.” Cree Lighting luminaires are designed to cut energy costs by as much as 80%. In manufacturing work involving intricate details such as color coding, a specific-colored wire has to be attached to a certain device or two different components are being joined together. “You have to have some very distinct lighting to be able to provide as much clarity as possible,” notes Casadonte. “In those particular circumstances, you’re looking at a fairly cool light as close to 5,000 Kelvin as you could get, and that’s a pretty bright white light,” he adds. Kurtz concurs, saying the 5,000°K fixture gives the human eye the impression of natural daylight. Replacing lamps and hard-to-reach fixtures can cause costly interruptions–especially in high-ceiling industrial environments, notes Casadonte. LED lighting lasts up to 100,000 hours–or up to 11 years of 24-hour operation–eliminating recurring maintenance needs, and maximizing the number of operating hours on the line, he adds. Light quality plays a significant role in promoting visibility for a productive, secure work environment, says Casadonte. “OSHA recommends that a workspace be ergonomically arranged to reduce glare and excessive lighting, which can result in eye strain and headaches,” he says. Compared to outdated lighting technology, LED solutions can “significantly reduce energy consumption, allowing many manufacturers to take advantage of tax benefits and rebates through energy efficiency certifications like LEED while supporting sustainability goals,” says Casadonte. For example, The Penn State Berkey Creamery in University Park, Pennsylvania had outgrown its location many times. The most recent expansion took the company to the first floor of a new building where everything but the lighting in the creamery’s storage freezers was state-of-the-art. The 15,000-square-foot facility provides more manufacturing and service space, but the induction lights in the deep freezers were causing safety and efficiency challenges for employees, says Casadonte. Cree replaced outdated induction lights and fixtures with its Cree Edge canopy lights to fill the room with uniform, brilliant white light, Casadonte says. “Previously, the dimly-lit environment hampered workers’ ability to locate ice cream containers,” says Casadonte. “Now, they can maneuver easily around the freezers and quickly identify what they’re looking for. And because LED performance inherently increases in cold temperatures, these luminaires function better, last longer, make for a lower energy bill, and significantly reduced maintenance expenses.” In administrative offices or workplaces, the temperatures need to be a little bit warmer, says Casadonte. “Brighter white light tends to be more problematic and burdensome to people who are sitting in front of computers,” he says. “It’s just not the right temperature to do your job, so it varies depending on the actual application.” Mark Mackey, director of sales and marketing for KLS USA, which provides equipment to Bulb Daddy, says in an office environment, his company suggests a 4,000°K color temperature. “The 5,000 Kelvin light tends to be too bright for people working under that environment, and the 3,500 Kelvin is just not quite enough and tends to turn things a little bit on the pink side,” he adds. In office environments, KLS will replace a four-foot fluorescent bulb fixture with two LED 4,000°K color temperature bulbs, “so we’re reducing the energy and the amount of bulbs that are in the fixtures to produce the same amount of light, if not better,” says Mackey. Cool light is often used for visual tasks because it produces higher contrasts than warm light, says Mackey. “If you have a manufacturing situation, you would want more light so you would go to the cooler temperature,” he says. “If you’re in an office environment where you’re looking at a screen and you have a typical eight-foot ceiling, it would still be a cool light at 4,000, but not extra cool.” Cree Lighting would never consider going any higher than 3,500°K or 4,000°K for an educational institution, classroom, or administrative office, says Casadonte. “But if I were in the labs of that same institution, I probably would be at 5,000 Kelvin because of what they are doing within their responsibilities,” he adds. Ockunzzi says he’s seen various studies indicating that at 5,000°K for office settings, “people tend to be more productive in general, but it’s mostly what you’re used to. Most offices have moved to a 3,500 Kelvin lamp for in the office area. Some are 4,000 Kelvin.” While lighting color choices have to do with personal preference, there are current studies showing that the higher color temperatures “do increase productivity, but there are also studies that show that higher color temperatures at the end of the day will make you stay awake longer because it messes with your sleep and wake cycles,” says Ockunzzi. For health care lighting needs, the color temperature for Cree Lighting’s SmartCast CR Series LED troffers are designed to deliver a customizable lighting experience at the push of a button. “This technology allows for superior color quality and consistency while providing greater flexibility to control illumination for patient needs at no additional cost,” notes Casadonte. The “smart” lighting technology is intuitive and intelligent, utilizing embedded sensors acting in concert with software to adapt to its surroundings, such as dimming or increasing the light as needed. Cree TrueWhite technology is designed to deliver clean, bright light and accurate color to assist in diagnosis and treatment, and create a tranquil environment. Outside, Cree LED lighting is used to provide safety and security for parking structures and exterior grounds. “The health care industry is amidst one of the greatest core changes in the last 25 years, shifting from a clinical view to a focus on hospitality,” says Casadonte. “As a result, improving patient satisfaction and well-being while controlling costs is critical, and new roles have emerged creating specific considerations for LED lighting.” Building professionals are tasked with creating welcoming, productive, and energy-efficient environments in new facilities and through upgrades, Casadonte points out. “LED lighting solutions that easily integrate into building design and deliver performance, aesthetics, and cost-effectiveness are critical,” he adds. Meanwhile, facility leadership focuses on margins, as executives work to ensure that facilities run efficiently and minimize financial waste while creating the best hospitality experience, notes Casadonte. “Cutting-edge technology and sustainability initiatives, such as LED lighting, support cost-management demands, as well as patient experience and community perception,” he adds. Facility managers focus their concerns on creating safe environments while ensuring day-to-day operations and maintenance is streamlined, notes Casadonte, adding that long-lasting LED lighting offers virtually no maintenance for years. Patient care is the top priority for clinical and medical staff, with the ability to treat patients safely as a top concern, which is addressed by high levels of light and color rendering index (CRI). For example, Watson Clinic in Lakeland, FL, replaced its 75-W halogen lamps with LR6 LED downlights to deliver attractive ambient light, provide energy savings, elevate the look of health care spaces, and improve the bottom line, notes Casadonte. Watson Clinic is also using Cree CR22 and CR24 LED lights with Cree TrueWhite technology. The Cree LED troffers “create quiet ceilings that are better for patient and staff comfort, and the operating budget,” says Casadonte. “Watson Clinic patients have been noting how much brighter and cheerier the lobby areas seem, and staff has particularly appreciated the improved lighting in the clinic’s diagnostic exam rooms.” For education lighting needs in administrative offices, high-ceiling gymnasiums, classrooms, and fields, LED lighting “continues to be the most energy-efficient solution for indoor and outdoor lighting, offering better light over traditional light sources, increasingly attractive price, improved performance, and long lifetime,” says Casadonte. “Many LED light fixtures lower the total cost of ownership compared to incumbent light sources, providing better illumination and significantly reducing maintenance costs,” he adds. Studies have shown that lighting can have a direct effect on mood, productivity, and even decision-making skills, says Casadonte. “With two-thirds of the brain devoted to visual processing, optimal classroom lighting is more than a utility. It is one of the instructor’s most powerful tools for teaching,” he says. The Cree LED lighting technology offers user-friendly control integration to provide teachers with flexibility over their classroom surroundings, says Casadonte. The LED lighting frees up facility personnel, limiting classroom disruptions to replace short-lived fixtures, “while providing better, more consistent illumination than often flickering or buzzing fluorescent lighting,” says Casadonte. For safety and security indoors and outdoors, “well-lit spaces help visitors travel between buildings and parking lots, dormitories, bus stops, and other facilities with confidence,” says Casadonte. “A well-designed, high-quality LED lighting solution can provide superior light coverage that minimizes shadows and dark spots as well as improves visibility and sense of safety. LED lighting can also improve the performance of other safety systems, such as security cameras, by enabling clearer images.” Case in point: North Carolina State University, as part of its campus-wide sustainability efforts, installed Cree’s CR22 LED architectural troffers equipped with SmartCast Technology on the first floor of its North Hall, located on the main campus. “Delivering up to 5,000 lumens of exceptional 90+ CRI light, the compact, lightweight design easily accommodates recessed, surfacemount, or suspended installations, making the CR22 troffer a perfect fit for North Hall’s needs,” says Casadonte. Typical retrofits are replacing fluorescent tubes with LED lights, says Sharer. “Or you can replace the light source and the power source, which gives you a more energy efficient way to do it, or replace the entire fixture,” he says, adding the color temperature choices in doing so range from as low as 2,700 to a high of 5,000. Much is being done in the realm of daylight harvesting for new installations and retrofits in that a sensor is used to help occupants judge how much light is coming in from windows, says Sharer. “You’ve got natural light coming in and you are dimming the real light to make sure you have the right amount of footcandles on the desktop, while at the same time being as energy efficient as possible,” he says. “The general consensus is that the more natural light people get, the better it is for their circadian rhythms and health and productivity,” says Sharer. Sharer says that sometimes in addition to color temperature, a better quality of light can be obtained by doing an LED retrofit. He references a compact fluorescent upgrade to LED in a Las Vegas hotel which has resulted in a number of positive comments because people are better able to see the color of the paint and carpeting. “The quality of light is as much a component as the temperature of light,” says Sharer. An accompanying factor to color temperature is the number of bulbs used. The Illuminating Engineering Society (IES) offers recommended footcandle levels for various applications. In helping end users make the best choice, Orion encourages a site field verification “where we do a test hang to ensure that the color temperature of the new fixtures matches or complements the existing fixtures,” says Kurtz. “This process is important, especially for retail facilities where merchandising teams can run into issues if the new fixtures don’t match their existing color temperatures,” he says. To help facility owners and operators figure out the right type of lighting needed, many energy companies will typically be helpful in identifying existing fixtures and the temperature of the bulbs in those fixtures, Mackey says. “When we’re asked those questions, we ask, ‘what is the height, the applications, and what do you have in the fixtures,’” he adds. “There’s a lot of information you need prior to making a good decision.” Facility operators should contact lighting designers when making such choices for spaces, with consideration for the room size, ceiling height, wall color, and the presence of any obstructions, says Ockunzzi. “Some people put in fixtures until they get the right amount of light,” he adds. “If you have somebody design it, they will take those parameters into consideration.” Labor costs are reduced through the use of LED because of their longer lifespan, notes Mackey. “A lot of people don’t want to replace the lights until they can take several of them out at one time because they don’t want to have an electrician at $80 an hour come out and replace a ballast or a tube,” he points out. “With LED, you don’t have a ballast. Typically, the warranties are pro-rated five years, so you have a better efficiency with labor costs, too. “And you have lights that are on. You’re not waiting before you end up having to call the electrician to come in and replace all of the lighting. The better lights you have, the more productivity you’re going to get.” Casadonte points out that one advantage institutions, planners, and architects now have is that with LED technology being more prevalent in installations, “the solid state lighting aspect of LEDs really does allow you so much more controllability. “You can install a product and have it alter its color temperature without having to replace certain levels,” he adds. In a residential setting, a homeowner might use a 2,700°K for the living room and a 5,000°K for the kitchen, buying two separate bulbs. “In the commercial space where there are so many different people working and so many different possibilities of what would affect somebody’s work productivity, to have something that can color change in those environments without having to replace a light or a lamp or anything along that line is really huge,” he says. “It’s really the next level of thinking beyond converting from incandescent or fluorescent lighting to LEDs. It introduces a whole new advantage to the technology, and what we can do for it.” BE Carol Brzozowski specializes in topics related to energy and technology.
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