ceramic metal halide (cmh) lamps were first introduced in 1994 after Philips engineers essentially borrowed a ceramic arc tube from a sodium lamp and put it in a metal halide lamp to create something entirely new. The final product delivered a crisp, white light and better color appearance and color control than standard metal halide lamps. These qualities make CMH lamps ideal for color critical areas in commercial applications, where a high-efficiency, long-life alternative to incandescent and halogen lamps is desired: for example, accent and recessed lighting in retail spaces. While still primarily used for indoor lighting applications, ceramic metal halide is also becoming popular for high-end outdoor installations.
Ceramic metal halide receives the strongest praise for its excellent color qualities. 'These lamps offer good color stability, color consistency from lamp to lamp and wattage to wattage, color rendering with 80-plus CRI and an excellent red component, along with improved lumen maintenance,' says Bob Nigrello, HID product group marketing manager for Osram Sylvania. The company provides CMH products like Powerball to fixture manufacturers Lithonia, Cooper, B-K Lighting, Greenlee and Custom Lights.
What is more, points out Adolphus Bailey Jr., marketing manager for Philips Lighting, ceramic metal halide provides consistent white light with the efficiency of HID lamps. Philips' MasterColor line of CMH lamps have been used for landmark projects like the Chicago Water Tower, San Francisco's City Hall and the top of the Chrysler Building in New York City. 'Crisp, white light creates a pleasing environment, both indoors and out. In addition, the high CRI afforded by ceramic metal halide lamps delivers a feeling of safety and comfort,' says Bailey.
Manufacturers of outdoor fixtures are also excited about this light source. 'Where else can you find something with so much energy, crisp white light, great CRI, and re-strike times that are under five minutes, in such a small and robust package?' says Michael Stevens, senior marketing specialist, SOURCE Cooper Lighting Center. The company's recently introduced INvue Lighting, and its established Lumiere and McGraw Edison brands, include both fixtures designed for CMH lamps and fixtures that can house a CMH lamp as an option.
CMH lamps are generally selected for outdoor applications where color quality and stability are critical. The lamps are available in a number of configurations, including ED17, PAR, T4 and T6 envelopes. The lamps offer long service life, good lumen maintenance and improved re-strike and warm-up times. While they are optimized for use with electronic ballasts, models that accept magnetic ballasts are available for retrofit of high pressure sodium lamps. Manufacturers are also introducing higher wattages, expanding the market for CMH lamps into applications where more light is needed.
'Ceramic metal halide lamps are ideal for lighting graphics and façade materials where true color rendition is important, along with indirect outdoor lighting, such as canopies, where good or warm color is flattering to people,' says Zach Zaharewicz, with Elliptipar. Zaharewicz estimates that about 25 percent of Elliptipar fixtures now include a CMH option.
'In landscape lighting, the traditional metal halide color is far too cool for most spaces,' says Ronald S. Naus, vice president of sales and marketing for B-K Lighting, which chose ceramic metal halide as the exclusive light source for its HID floodlighting line. 'People want to see warm color tones in the landscape, which makes ceramic metal halide an ideal choice. Consider the lighting of palm trees, for example. There is a brown trunk and green fronds. A traditional metal halide would accent the green leaf but wash out the brown trunk. Ceramic metal halide brings out both elements.'
A bright future
The percentage of CMH outdoor fixtures is small but growing. Naus and Ibbitson estimate that 5 to 10 percent of all outdoor fixtures in the United States use a CMH source. Naus believes, however, that ceramic metal halide has captured perhaps 40 percent of the decorative outdoor and landscape lighting segment.
'As more companies showcase their facilities and as more cities re-energize or reinvent themselves through the use of lighting, ceramic metal halide lamps lead the way as a viable option,' says Bailey.
'This technology is gaining lots of attention very quickly,' says Stevens. 'With the ED envelope and the PAR envelope, this lamp can be used in older-style fixtures provided they feature pulse-start technology. With the higher wattages becoming more readily available, the market for ceramic metal halide lamps is growing very quickly.'
B-K Lighting's Naus would like to see specifiers choose outdoor fixtures that are designed specifically for ceramic metal halide. 'A user should look for a product optimized for use with ceramic lamps,' he says. 'Frequently, manufacturers will use one type of reflector for several lamps. Good ceramic reflector systems are designed specifically for that lamp type. Using a quality brand will ensure that the optical system does its job for a long time. As a contractor once told me, 'It costs just as much to install a cheap fixture as a good one.''
As with other premium sources, CMH lamps have tradeoffs. The primary catch is initial cost. 'Although this lamp type has come down considerably in cost, it is still higher in price than standard metal halide lamps that you would find at the commodity level,' says Cooper Lighting's Stevens. 'However, you definitely get what you pay for.'
Craig DiLouie is principal of ZING Communications, a marketing com-munications and consulting firm specializing in the lighting and electrical industries. A former publisher of Architectural Lighting, he is the author of many books and articles on lighting and electrical engineering.