Compact fluorescent lamps are gaining sway in the marketplace for outdoor lighting as alternatives to incandescent or HID lamps. While specifiers still look to HID lamps for street and area lighting, CFLs are growing in popularity in various niches for outdoor use. Though growth is steady, there is diversity of opinion among lighting manufacturers whether the impact is a rumble or a boom.

More economical than HID lamps,including first costs,and with better color rendering, uniformity of color among lamps, CFLs' characteristics make them suitable for a variety of tasks, including accent lighting for residential and commercial applications, and battery pack-backed emergency lighting. The lamps can sit in a broad range of fixtures such as post tops along walkways, wall mounts that illuminate facades, and in bollards and step lights that illuminate pathways and stairs.

While there is a trend toward miniaturization in outdoor lighting, there is also a trend toward white light, noted Ted Simpson, marketing manager of HID, Philips Lighting. As he sees it, CFLs are an effective way to get long-lasting white light in a moderately sized fixture.

In addition to casting the white light that many people find flattering on a person or product, CFLs also boast practical maintenance features,not least of which is relative longevity,that make them suitable for parking garages and small parking lots and other areas that benefit from maintenance at longer intervals. And lamp manufacturers are developing larger wattages that could work in a wider range of outdoor applications, with fixture manufacturers developing products to match. Some of the lamps are screw-based, with the ballast integrated into the unit; others are pin-based, with the ballast external to the lamp and integrated into the fixture.

Bill Peel, market development manager in Lithonia's Outdoor Product Group, said: "Some of the general lamp benefits derivable from CFLs that are driving business are the improved color, instant on, instant restrike, comparable lamp life, and the fact that CFLs, as a light source, are at least a little more visually comfortable, with less glare effect than an HID gives. They are also economical as replacement lamps."

CFLs provide an appropriate soft accent for many applications. "The lamps are suitable for accenting a commercial building where you need instant on, or in post top units that can lead pedestrians to an entrance or into a parking garage," said Ben Prichard, market development manager, Holophane Lighting. "They are also options for security where an installation needs good color but not a lot of intensity." And in residential applications such as fa?ade lighting, Prichard said CFLs could cost less and give the added security of longer life when compared to incandescent lamps.

Compact fluorescents use about one quarter of the power an incandescent uses for the same light output. For example, an 18-watt compact florescent lamp is comparable to a 75-watt incandescent. "In residential applications, where fixtures may remain on all night, that energy-saving aspect could be attractive," said Rich Hanlon, compact fluorescent marketing manager, Osram Sylvania. In commercial applications, especially in California where energy concerns remain high, "some retail chains interested in keeping energy costs down have started using CFLs because they give nice light output with acceptable power consumption," he added.

Other industry representatives are aware of the advantages, such as Kichler Lighting product manager Jeff Dross, who noted that end users like the compacts' natural color, which steers clear of the cold blue look that many people associate with fluorescents. And DayBrite product manager Rob Freitag said, "Traditionally, HID lamps have had a much higher lumen package than CFLs. But recent developments are creating greater lumen packages, with higher wattages, with a relatively small tube length, enabling CFLs to compete with HIDs in higher wattages."

For example, Philips Lighting plans to introduce its new high-output compact fluorescent, PL-H, early next year. Suitable for use in outdoor fixtures such as post tops, the lamp provides the white light that end users want while reaching HID output, said Simpson. The lamps will likely will be available in lumen outputs of 4,000, 6,000, 9,000 and 13,500 (at 60, 85, 120 and 180 watts respectively), and are anticipated to carry a rated life of 20,000 hours and a CRI of 85, with about the same energy efficiency as a metal halide lamp.

Patrick Walker, Cooper Lighting marketing manager, said her company is excited about the emerging high-output compacts. "These lamps are starting to reach the efficacy levels of standard metal halide sources. Historically, one of the detracting characteristics of CFL, especially when considered for outdoor applications, was its lower lumen/watt ratio versus metal halide and high-pressure sodium lamps. But with the introduction of high-output CFL lamps, that ratio is getting much closer."

To help ensure reliable performance in almost any climate, CFLs use amalgam, a mercury alloy. Paul Hafner, manager of Philips Lighting application center, said amalgam helps the lamp maintain light output close to its advertised rating over a broad temperature range. This is accomplished by controlling the lamp's vapor pressure. Thus, CFLs provide good light output even in cold-weather applications, such as post-top luminaires. They are then paired with special electronic ballasts and designed into a fixture, making them suitable for all but the most extreme North American climates.

In the coldest climates, CFLs could present some limitation. At extremely low temperatures, fluorescents can take longer to start and warm up to an acceptable light output. Incandescents have no correlation to temperature and carry ratings reflecting that, noted Sylvania's Hanlon. CFLs suitable for outdoor use are usually rated at zero degrees Fahrenheit,the lowest-rated instant-on temperature,even though the products would likely continue to start (and then warm up slowly to provide higher light output) at lower temperatures, he said.

Some fixture manufacturers see CFLs becoming stronger in commercial rather than residential markets. Dick Liepold, Progress Lighting product management consultant, noted CFL fixture-lamp combinations cost about twice that of incandescent versions, causing CFL sales to lag in the residential market, where first cost is often a decisive factor. However, in the commercial sector, he sees a trend toward specifying lanterns and post tops that are adapted to work with CFLs because they offer good color and cost.

Ian Ibbitson, vice president and general manager, Architectural Landscape Lighting, does not yet see compacts making much of a dent in HIDs' share of outdoor lighting. Optical performance, he said, is limited by their size, cold-weather problems and relative inability to focus. Though all of the company's fixtures support CFLs, he sees the lamps as best suited for building-accent and smallscape floodlighting applications, where the beam control is usually not an issue and where white light is required.

Lithonia's Bill Peel said CFLs can be used in lower wattages in fixtures mountable at lower heights than HIDs, making them well-suited to pedestrian scale areas (10 to 15 feet versus 20 to 30 feet for parking lots and roadways). Lower pole heights and smaller luminaires, he added, create a sense of proper scale in pedestrian spaces, along walkways and paths, and in common areas between buildings. "Because the light-emitting surface is larger than with smaller, more-focused lamp sources, it is a little harder to control the light output of the lamp, though fixture optics can address that challenge," he said.

Walker, at Cooper Lighting, sees CFLs as a smart alternative to emergency lighting, an arena that "has just gone off the map this past year." HIDs, unlike "instant-on" CFLs, take too long to strike or restrike to be suitable as emergency light sources. They have other problems, as well.

"Because local building codes are increasingly requiring an emergency pathway light outside any door that has an exit sign inside, the market has seen an increase in the use of CFLs for battery-backed emergency lighting wall packs or building-mounted fixtures," Peel said. When people emerge from a building in an emergency, they need to see their way to the street. Specifiers can accomplish that by using a mixture of CFL-equipped fixtures,wall mounts, bollards and step lights,close to the egress.

Cooper Lighting is adapting fixtures for even higher lumen packages, including 70-watt CFLs that satisfy egress codes. "It's logical to integrate higher-wattage compact fluorescents into what is traditionally the 175-watt size shoebox fixture with a 5,200-lumen package (equal to that of a standard 70W metal halide lamp). Fixtures can be mounted at 12- to 15-foot mounting heights and still meet the one foot-candle UBC emergency lighting requirement in the areas close to exits," Walker said.

Over the last several years, lamp manufacturers have reduced the outer-jacket size of HID lamps to the extent that the reduced jacket, once considered a specialty, is now a de facto market standard. As a result, fixture manufacturers can reduce reflector and enclosure sizes so an installation can make smaller luminaires look more in scale at lower mounting heights. CFLs with higher lumens, however, come at the price of larger-sized lamps.

"As the CFLs get larger, the fixtures get larger as well, so the challenge to a fixture manufacturer becomes how to accommodate the larger CFLs when the HID trend is toward downsizing," Peel said. Partially in consideration of the CFL lamp-size issue, Cooper Lighting predominantly uses the 57-watt compact fluorescent, rather than the longer 70-watt high-output CFL, to design or retrofit a fixture around.

"The lumen package of the 57-watt CFL lamp exceeds that of a 50-watt standard metal halide lamp. So from an efficacy standpoint, the CFL comes out on top. And end users get a color rendering of 82, compared to 70 for a standard metal halide, making CFLs legitimate players, at least in some ranges," Walker said.

"The 70-watt high-output CFL is quite long, compared to 70-watt metal halide or high-pressure sodium lamps, and therefore is more difficult to package in a smaller product. Lighting specifiers are accustomed to a certain size of product for the lumen package they are receiving. Forcing an increase in fixture size without noticeably improving the light output is generally ill-received by the design community."

Other alternatives, however, are attractive. Prichard, of Holophane, sees excellent possibilities with induction fluorescent lighting systems.

Induction lighting's attractive characteristics,100,000 hour-rated life, uniform illumination, and high efficacy (lumens per watt),render it suitable for general illumination of parking lots, building approaches, architectural elements and signs. Compared to HID lamps, induction lamps are a bit larger and offer less of a point source, making it challenging for fixture manufacturers, Prichard said.

Walker anticipated that, "The reality is, in the future, outdoor lighting will no longer be defined by HID sources, but by a mixture of light sources, especially the high-output CFLs, particularly for post tops, wall lights, step lights and bollards. People have embraced fluorescent lamps, albeit in traditionally indoor environments, for the high-quality white light that they emit. With the higher-lumen packages now afforded by the high-output CFLs, it is possible to deliver that quality of light to the outdoor environment without sacrificing performance." EC

The FELDMANS write for various magazines and Web sites. They can be reached at wfeldman@att.net or 914.238.6272.