Published In November 2000
While cause and effect drives science, cost and effect is increasing what drives specifying for outdoor lighting. Those two factors—initial and maintenance/replacement cost and effect of the light provided by lamps and fixtures on an area or building—can be of paramount importance in the efficiency and perceived success of a lighting installation. End-users are always happy when overall life cycle cost is as low as possible without sacrificing quality or quantity of light. Using pulse-start metal halide lamps for a variety of outdoor applications can save on energy expenditures while providing excellent lighting, overall. Metal halide lamps, which can be used in fixtures that aim them precisely, are increasingly used for a wide variety of outdoor installations. These include roadway and parking lot lighting, various decorative and other architectural applications, and sports lighting, where metal halide has been the predominant light source (and the white light it provides is much appreciated) for the past 15 or 20 years. While the metal halide market continues to grow in general, the pulse-start metal halide market has experienced the most technological advances recently. This is because of introduction of lower wattages (down to 50 watts, which is suitable for wall washes and bollards) and higher wattages, though these are not yet widely available in this country in high enough wattages for most sports lighting applications. “Pulse-start technology is probably the fastest growing area of metal halide right now because it is a more efficient metal halide product,” affirmed Craig Witsoe, product general manager of North America high-intensity discharge (HID) products at GE Lighting. Unlike standard metal halide lamps that dim over time, pulse-start metal halide lamps burn brighter for the life of the lamp. Though fluorescent and incandescent lamps have very high lumen maintenance over the life of the lamp—e.g., fluorescent has up to 95 percent lumen maintenance—standard metal halide has only 65 percent lumen maintenance and dims over time. But metal halide lamps with pulse-start technology can offer up to 75 percent lumen maintenance. Pulse-start technology, while increasingly popular in lower wattages for a few years now, is showing up in higher wattages as well. In pulse-start technology, the fill pressure of the metal halide arc tube is much higher than the pressure in standard metal halide, enhancing the lamp’s performance by increasing the lumen maintenance and increasing the metal life of the lamp. This helps to reduce warm-up and re-strike times for these systems. However, as the fill pressure in the tube is increased, the lamp is harder to start, requiring a high-voltage igniter. Pulse-start lamps use a 3000- to 4000-volt pulse from a matching ballast to start the lamp; hence the term “pulse start.” Lower-wattage lamps, developed in the 1980s, typically had the higher pressure and the necessary pulse igniters within them because their arc tubes were too small to include the third starting electrode used in standard larger metal halide lamps. While the higher wattages in metal halide—which were the first to enter the market—did not initially have pulse-start technology because there was room for the third electrode, manufacturers, specifiers, and end-users have increasingly seen the benefits of including pulse-start technology in higher-wattage lamps, as well. Because the pulse igniters to start the lamps are in the ballast, special ballasts are needed for pulse-start metal halide lamps. Until fairly recently, the color appearance from metal halide lamps would change over time because the unavoidable, even minute, varying of chemical compounds involved in the manufacture gave some lamps diverse hues. Manufacturers are addressing this and are developing products that achieve better color rendering and uniformity among lamps. Philips, for example, in its MasterColor metal halide line, recently developed a method of manufacture, involving ceramics, that ensures there is no variance in the chemicals used in the manufacturing process, making all the lamps in a particular line almost clones of each other. “Color appearance is just about identical from lamp to lamp,” explained Steven Goldmacher, director of public affairs at Philips. Instead of using a glass arc tube, he noted, “Philips uses a polycrystalline alumina (PCA) and the fill elements are added in precise doses.” Available in ED-17s, reflector parabolic aluminum reflectors (PARs), and single-and double-ended linear versions, the lamps, which have typical life cycles of 12,000 to 15,000 hours, can replace lower-wattage standard metal halide lamps, incandescent, and halogen lighting sources, for landscaping and other applications. Well suited to facade lighting and outdoor lampposts, the line features higher wattages than previously available, with sustained color rendering index (CRI) of 92, which the company notes is the highest in the industry. Starting at 150 watts and running up to a soon-to-be-released 400-watt version, the lamps are available in 3000K to 4000K color temperature. Other companies, as well, offer ceramic pulse-start technologies for lamps useful for color-critical applications. GE Lighting’s product, for example, is called Constant Color CMH. Sylvania is also in the process of introducing a full line of ceramic pulse-start metal halide products. In most cases, the amount of color shift among metal halide lamps in a particular installation is not an issue, but in color-critical applications it could be. When one lamp burns out, end users could “use group relamping in order to minimize any differences in perceived color,” Robert Roller, Venture Lighting vice president of market development, suggested. Osram Sylvania recently expanded its line of METALARC PULSE START lamps to include an exclusive 320/350-watt pulse start metal halide lamp that can run on a 320- or a 350-pulse-start-watt ballast. The lamp design can operate on a 277V linear reactor or constant wattage auto transformer (CWA) ballast at 320 or 350 watts, simplifying stocking to two sizes for distributors and at facilities, notes Bob Ponzini, Sylvania product manager. The lamp will soon be available as open fixture and enclosed fixture rated in BT28 and BT37 configurations. The new Osram Sylvania METALARC SUPERSAVER, an energy-saving retrofit lamp running off standard metal halide technology, does not require a ballast change. Electricians can, for example, use a 360-watt lamp as a direct replacement for a 400-watt metal halide lamp, saving 40 watts per fixture while yielding the same light output, he pointed out, increasing system efficiency. Venture Lighting Uni-Form Pulse Start Metal Halide System-lamp, ballast, and controls—uses a formed arc tube body and ballasts that run on 277-volt systems which, Roller noted, contributes to higher efficiency than otherwise. The lamps are available in 50- through 450-wattages in open or enclosed styles, clear or coated versions, 2700K, 3000K, and 4000K color temperatures; and CRI options of 65 through 75. The reactor ballasts save approximately 50 percent of energy consumed, compared to older, CWA ballasts, Roller pointed out. For example, he explained, a Venture 350-watt pulse-start metal halide lamp installed with a reactor ballast, will yield more lumen output than a standard 400-watt lamp and will save a total of almost 80 watts of electrical energy over a 400-watt lamp over its life. Venture also has pulse-start ballasts for those installations where 277 volts are not available. GE PulseArc Multi-Vapor metal halide pulse-start lamps, for new installations, for example, are rated up to 30,000 hours if the lamp is cycled once per 120 hours for standard systems. (Manufacturers recommend that the lamps be turned on and off at least once a week for about 15 minutes for certain operating safety issues. The 750-watt GE PulseArc lamps, which operate on energy-saving ballasts and have a shorter warm-up time could, GE Lighting notes, provide energy savings up to $440 per lamp while providing comparable light and longer life than 1000-watt standard metal halide lamps. The crisp white metal halide light is, he pointed out, well suited to parking areas. For retrofits, using similar technology, GE’s new StayBright Multi-Vapor lamps feature an integral pulse-start technology that provides PulseArc-like performance on standard CWA ballasts. The lamp can serve as an easy direct replacement of existing metal halide lamps because the starter circuit is integrated within the lamp, allowing an installer to plug it into an existing CWA system without changing the ballast, essentially giving pulse start performance on a standard metal halide system. Available in both clear and coated 400-watt versions, they deliver 22 percent more light over life (mean lumens), the highest maintained lumens of any standard CW/ CWA system, notes the company. GE also has a new 750-watt PulseArc lamp, suitable for outdoor retrofits, which can be used, along with 750-watt pulse start ballasts, in place of 1,000-watt universal metal halide lamps and ballasts. Though the lamp starts at 80,000 lumens, rather than over 100,000 lumens, it stays brighter over time, with a less steep drop-off in lumens, the manufacturer points out. “It lasts about one-third longer, minimizing maintenance costs, and could save users up to $440 in energy savings over the life of the lamp, based on the average energy rate of 10 cents per kilowatt hour,” Witsoe pointed out. As the lamp manufacturers come out with new lamps, the fixture manufacturers follow suit with products that can accommodate those lamps. Ruud Lighting’s Square Dome was designed to accept a metal halide lamp in a vertical, rather than horizontal, position. Featuring a domed top and squared off sides, the fixture maximizes lumen output, notes Doug Paulin, product manager, because a lamp that is rated for all orientations puts out the least amount of light in the horizontal orientation and the most in the vertical orientation. Moreover, vertical-burn-only lamps are optimized for even more lumen output than universal-burn lamps in the vertical position, he pointed out. Vertical lamp orientation can be desirable in such outdoor lighting applications as parking lots, shopping centers, and strip centers. The fixture comes in three reflector configurations that offer different beam spreads for perimeters of parking lots, for single-fixture pole mounts, and for back-to-back pole mounting. Designed for pulse-start lamps, the system—which costs 10 to 15 percent more but provides 15 to 20 percent more output, according to the manufacturer—allows an installation to either use 15 to 20 percent fewer poles or 15 to 20 percent less wattage. GE Lighting Systems Dimension 1000 Luminaires, for retail and commercial complex parking lots as well as car lots and tennis courts, feature vertical full-size (BT56) lamp mounting and accept 250W, 400W, and 1000W metal halide lamps. Available in cutoff and noncutoff configurations in various light patterns, the units have one-piece door assembly that provides no-tool access to the optical department. All reflectors are field rotatable. McGraw-Edison Vision VXM architectural area luminaire, available in 100- through 400-watt metal halide and high-pressure sodium lamp sources, features sharp cut-off and maximum visual uniformity, with segmented optics that have been optimized to provide increased throw to the side while minimizing reflected downward illumination. This orientation, notes the company, permits increased pole spacing. The fixture features a hydroformed reflector system available in Type II, III, IV, and V cut-off distributions. All reflectors are field rotatable in 90-degree increments and the luminaire features both toolless entry and a quick disconnect electrical power tray for easy maintenance. Any reflector can be replaced with a different light distribution should traffic patterns change, according to McGraw-Edison. McGraw-Edison Galleria large area luminaires, featuring a vertical lamp as well as a horizontal lamp orientation, accepts pulse-start metal halide sources in a variety of wattages, from 400W to 1000W. The vertical lamp gives optimal uniformity and allows six times the mounting height spacing, rather than the more traditional four times the mounting height, the company points out. Well-suited for parking lots, shopping centers, and large retail applications, the luminaires are available in full cutoff and semi-cutoff models. Sterner Lighting Systems Infranor Capella-5d luminaire accepts both metal halide and quartz sources and is suitable for lighting facades, signs, banners, sculptures, or foliage. Three different rectangular beam patterns (narrow, medium, or wide) are available, with the quartz rectangular beam at 5 degrees wide in the vertical distribution, and 95 degrees wide in the horizontal distribution. Other features include die-cast housing, swivel and yoke mounting styles, and electronic ballast options. HADCO is coming out with a new series of outdoor architectural lighting fixtures, Profiler outdoor luminaire for area parking lots, that offers architecturally shaped cutoff luminaires. Available for pulse-start as well as high-pressure sodium lamps, the pole fixtures, sporting cast aluminum housings, have companion up or down wall wash units and companion floodlight fixtures. As the fixtures offer rotatable optic systems within the housing, the fixture orientation is essentially independent of the light pattern, noted Randy Miller, commercial sales manager. This freedom of movement allows for greater versatility of fixture placement, enabling orienting of the fixture one way and the light pattern in another direction, he pointed out. The pole fixtures offer toolless entry and quick disconnect of ballast when change is needed. McPhilben Outdoor 301 Series up/down wall cylinder combines uplighting and downlighting in a single compact lamp and ballast configuration. The new fixtures feature highly specular spun and faceted reflectors that can, the company notes, produce a variety of light levels and distributions to accommodate diverse lighting design objectives for traditional and contemporary applications. The uplight and downlight components use twin spun specular Alzak reflectors that provide symmetrical distributions. The spike downlight provides a very narrow spot beam at nadir that can, for example, create a strip of illumination on the wall or column for a strong, dramatic lighting statement; the spike uplight provides a very narrow spot at the zenith. HOLOPHANE MirroStar horizontal luminaires, which accept 400-watt pulse-start metal halide and 400-watt and 1000-watt metal halide, as well as 400-watt and 1000-watt HPS, achieve full cutoff and are suitable wherever high-wattage area lighting is required. The fixture includes a removable ballast tray with toolless disconnect to facilitate quick change-out, which could be particularly appreciated in areas where a bucket truck would otherwise be required, points out the company. Quality Lighting’s large-scale rectangular shaped Paradigm outdoor area and roadway lighting fixture, which accepts metal halide as well as high-pressure sodium lamps, has rounded edges and a raised and curved top. The fixture, which can be pole or building mounted and is available in five distribution patterns, is well suited for illuminating corporate and university grounds, retail sites, and public parks, according to the company. Optional Edgeglo windows on three sides of the curved top are available with either clear or colored lenses. Mounting arms can be specified to accommodate single-, dual-, or quad-fixture heads. The FELDMANS provide Web content for companies and write for magazines, trade associations, building product manufacturers, and other companies on a broad range of topics. They can be reached at firstname.lastname@example.org or (914) 238-6272.