Published In April 2001
Several recent advances in fluorescent lamp technology—and in the design of fixtures to match—provide specifiers lighting commercial space ample opportunity to closely match specific user requirements. These options attend not only to energy efficiency, but also to user comfort. For example, T8 linear fluorescent lamps and T8 fixtures (with three lamps per fixture as the approximate standard) are now considered commodity items for new construction or renovation. Having replaced the larger T12 lamps and the basically standard four-lamp fixtures that held them, they are no longer the trimmest choice. Smaller, yet, T5s have entered the mix and are making their mark. While T5s will not, at least in the foreseeable future, replace T8s as standard fixtures, T5 (high-efficiency) lamps and T5 HO (high-output) lamps are increasingly common choices of designers and specifiers for selected applications. T5 lamps can offer higher efficiency and better optical control because the light can be more easily directed and more evenly distributed. Therefore, usable in smaller system wattages, they are finding various niches in the marketplace. While T8s, at 1 inch, are smaller in diameter than the older T12s, which were 1½-inch diameter, and are nearly 20 percent more efficient (a 32-watt T8 lamp gives out pretty much the same amount of light as a 40-watt T12 lamp), the T5s measure just 5/8-inch in diameter. Plus, they are a couple of inches shorter than T8s and T12s. The shorter length and smaller diameter, in turn, offers fixture manufacturers expanded options for design. Somewhat more costly than T8s, the T5s provide about 10 percent more efficiency than T8 lamps when used in a fixture specifically designed to take advantage of T5 technology, yet offer about the same life-span. Although existing 48-inch strips can be factory-modified to accept T5s (with the modifications bringing the sockets closer to the center of the fixture), the fixtures that take best advantage of the T5 characteristics are those that are, in fact, designed from scratch for the new, smaller lamp. Three major manufacturers are selling the T5 and the T5 HO lamps in the United States: Osram Sylvania (which offers the T5 Pentron line), GE Lighting (which sells the T5 with Starcoat line) and Philips Lighting (which offers the Silhouette line). The T5 HO version, such as the T5/HO Starcoat, for instance, can deliver up to 92 percent more light than the high-efficiency T5 for applications that call for higher light levels. The T5s (high-efficiency lamps) are available in four wattages, ranging from 14 watts to 35 watts. Numerous manufacturers have developed fixtures to accommodate T5 and T5 HO lamps. For example, Aerial, by Metalux, is an architecturally styled low-profile (2½ inches deep) two-lamp T5 standard output fixture for direct lighting that, taking advantage of the narrowness of the lamp and the thinness of the ballast, offers shallow surface mounting. The fixture is well-suited for general illumination applications, including any renovation where the ceiling is solid or where there is not enough ceiling height for indirect lighting. Offering shielding media that address a variety of performance and aesthetic needs, the fixture has a center downlight optic that comes with a white baffle, a specular parabolic, or frosted acrylic lenses. While most of the light comes out of the center optic, some light filters down through the architectural “wings” that taper outward on either side, noted the manufacturer. While indirect lighting for commercial space was traditionally an expensive option usually reserved for primarily owner-occupied spaces, indirect lighting with T5s has become a more cost-effective possibility for standard office spaces. And, because shielded or indirect lighting generally cuts down on the glare and improves the quality of light, it is possible for an application to use, in effect, even lower light levels than would be needed with direct lighting. In fact, T5s are increasingly popular for fixtures designed such that at least part of the lamp is shielded from direct view, for cove or perimeter lighting, and for task lighting. Because so much light comes out of such a small diameter lamp, fixture manufacturers are able to use louvers, baffles, or cutouts to create various fixture styles that purposely shield either all or varying amounts of the lamps from direct view, noted Robert Horner, product group marketing manager, fluorescent, at Osram Sylvania. In an open office, a designer might specify indirect lighting in rows, either surface- or pendant-mounted, and bring the office to a basic ambient light level of between 30 and 50 footcandles, rather than 100 or more footcandles, and then supplement that with task lighting. T5s can be used in direct/indirect fixtures. A direct/indirect fixture is, typically, a suspended T5 that has a ratio of uplight to downlight that varies according to the exact needs of the space. (There are also recessed direct/indirect fixtures, but these are generally more expensive.) The term “total indirect lighting” applies when the bottom of the fixture is totally enclosed. When it is partially opened up one way, with a louver, lens, baffle, or cutouts, some of the light then goes straight downward, directly, creating a balance between the two types of lighting. “It is often a matter of aesthetics,” Horner explained. “Some people like it better when the fixture has a bit of light emanating from the bottom.” Lithonia Lighting offers the Avante line of recessed direct/indirect fixtures suitable for surface or pendant mounting, which use T5s and T5 HOs, for direct and indirect general area lighting. The fixtures, available with a variety of shielding options, offer a mix of directional and diffused reflected light that yields balanced illumination between the task and proximate walls, along with enhanced visual comfort and minimized shadows. Companion decorative wall sconces are available. T5s can also be used effectively in factories and other industrial applications. The new High-Intensity Fluorescent Monopoint luminaire, from Holophane, for example, combines specular reflectors with T5 HO lamps, allowing the fixture to serve as an alternative to traditional high-intensity discharge (HID) sources one-for-one, noted the company, without sacrificing light output or initial efficiency. Light output can range from 11,000 to 36,500 lumens. Lithonia also offers a low-profile fixture for T8s. The SP8, Specification Premium T8 Lensed Troffer sports a low-profile, lighter-weight ballast and low-profile, V-shaped ballast cover contoured, said the manufacturer, to reduce shadowing. Featuring an A12 reverse prismatic lens that, the company noted, controls light distribution and creates uniform illumination across the lens and less lamp image. The fixture sports a compact socket with a rotating collar, enclosed contacts, and an audible locking click on the door latches. Buyers can opt for a polyester coating on the aluminum finish of the louver that keeps the fixture at less risk of anodizing from finger oils and offers anti-static properties that keep dust from accumulating. Ballasts Today’s electronic ballast technology allows for smaller and lighter packaging than in the past, allowing for lower-profile fixtures. Certain manufacturers, including Advance and Magnetek, offer low-profile universal voltage electronic ballasts, considered “smart.” Computer chips in them, for fluorescent lamps, automatically adjust to incoming voltage, from 120 to 277 volts, while maintaining constant voltage to the lamp. An integrated circuit (IC) in the ballast, combined with the proper circuitry, determines the proper voltage. The T5 ballasts incorporate shut down circuits as a safety feature. The ballast senses end of lamp life and will shut down the output to the lamp. Advance and Sylvania offer dedicated voltage low-profile ballasts for linear T5 lamps. Advance also has a low-profile universal ballast (Intellivolt) for T5 HO lamps that operates from 120 volts to 277 volts. Sylvania also makes a dimming ballast, the Quicktronic, for 100 percent to 1 percent dimming, for T5 HO lamps. Advance noted that a full line of low-profile T5 HO dimming ballasts will be available later this year. Sockets In selected products, some fixture manufacturers are using a new type of socket that sports a rotating locking ring to prevent inadvertent grounding of the fixture that would blow the ballast. When the socket is open, the pin can only go directly down the center avoiding electrical contact until the lamp is twisted and the locking ring snaps into place. Also, the new socket is configured so that the installer cannot, by mistake, push the pins down the side of the socket and snap the socket off. Every socket has two test points to allow the electrician to check the circuitry or ensure the ballast is putting out what it should without having to laboriously remove the lamp to test the circuit, as has to be done with the older-style sockets which have no exposed leads. Supplemental lighting For new construction in office buildings, another approach is useful for accommodating the trend in commercial lighting toward lower levels of general illumination. This approach supplements direct overhead lighting (and perhaps less of it) not only with indirect lighting (perhaps using metal halide lamps as part of the mix), but also with lighting, including task lighting, from floor and table lamps. Because a lot of the supplemental lighting can be wired on the floor, less work overhead—in and on the ceiling—is required. Task lighting, for example, is particularly useful in commercial space where a fair number of employees sit at workstations or in front of desktop PCs. Workers looking at computer monitors throughout the day do not generally appreciate overhead lighting that generates a glare on their screens. Rather, they prefer lighting that is concentrated wherever they are doing paper tasks or other non-computer related work. Portable, decorative floor and table lamps that use metal halide for focused spotlighting, such as Venture Lighting’s Microsun line, uses one vertically mounted 68-watt metal halide lamp, which takes a bit of time to warm up. Two 25-watt angled incandescents that can provide instant illumination, can be very effective in achieving the light level that people require close to the task. “It is, however, key that the installers put in enough receptacles to accommodate portable fixtures all around a space,” suggested Bob Roller, Venture Lighting’s vice president, market development. Against a white or off-white ceiling, indirect lighting can work as well as direct lighting coming down from the ceiling if metal halide lamps are used, said Steve Goldmacher, Philips Lighting’s director of marketing. Lighting designers are often able to use a lower general light level—and therefore less energy—by relying on task lights at the desks of individuals who require a specific light at specific times. With careful lighting design, it can be an effective option, especially for facilities where worker cubicles are often moved to accommodate changing tenant needs. (Stationary ceiling fixtures may provide ample light with one cubicle configuration, but not another, requiring floor- or desk-based lighting anyway.) At least one cube manufacturer has devised systems that use a light installation that sits in the corner of the cubicle—where two partition walls come together—and aims the lighting straight up. The fixtures are part of the cube system, effectively making the cubes self-sufficient in terms of lighting. These systems often use 50- to 400-watt metal halide lamps, such as Philips high-wattage MasterColor metal halide lamps, for general lighting. “Using this type of lamp can reduce the amount of energy because the number of metal halide lamps is less than the number of fluorescents,” Goldmacher pointed out. For specific desk tasks, a cubicle occupant could use an MR-16 halogen downlight, perhaps in a capsule on a fixture arm, Goldmacher mentioned. Narrow spot and narrow flood halogen lamps can direct light effectively and are often used by retailers, Goldmacher pointed out, to help attract customers’ eyes to specific locations, or by restaurants, where you don’t need a lot of light in the aisles, but rather directed light on each table. Fluorescent disposal To satisfy the EPA’s toxic characteristic leaching procedure (TCLP), or various state regulations that regulate disposal of mercury lamps from generators of high levels of hazardous waste (impacting about 17 percent of linear fluorescent lamps), several manufacturers produce fluorescent lamps with levels of mercury low enough that, at end of life, do not require special disposal for most states. (Minnesota, Vermont, and Maine as of mid-2002, and Connecticut and the incinerator counties of Florida, for instance, have additional requirements that come into play under varying circumstances.) These low-level mercury fluorescents are well-suited to retrofits in many types of facilities, including hospitals, schools, and other buildings originally built with those kinds of fixtures, because the retrofit would be relatively easy and the product would satisfy the facility owner’s disposal concerns down the line. Philips Lighting’s ALTO Reduced Mercury Fluorescent Lamps, for example, have the same life-span and are priced the same as standard fluorescent lamps, while satisfying end of life and disposal issues in states that require passing the TCLP test. The lamps also meet California’s total threshold limit concentration (TTLC) standard. The company recommends them for new construction as well as retrofits. “Eliminating mercury at the source is probably the best way to deal with disposal problems,” Goldmacher pointed out. Lighting controls For energy conservation with fluorescent lighting, as well as with other types of lighting, commercial applications can take advantage of any of the various types and levels of lighting control. Automated as well as user-regulated lighting control are becoming more visible and popular, at least partly due to new energy codes (such as recently passed in Wisconsin and California). If you are in a position to sell lighting controls to an owner, you might also point out that, in addition to saving energy, some studies have indicated lighting controls often afford employees a more user-friendly workplace, which, in turn, increases productivity among the workers. Siemens Energy & Automation recently introduced the Lighting Control System (LCP 2000) series of lighting control systems—including low-voltage lighting control panels, low-voltage relay panels with 32 programmable switch inputs, and 32 control relays, power wiring, and switch inputs—which can be controlled locally from a keypad and local switch or by telephone or pager from anywhere in the world. Factory preassembled to simplify installation; the new panels feature self-prompting menus for easy programming. The panels feature the ability to mask inputs so switches can be bypassed during certain hours of the day. The system includes 64 time-of-day/holiday schedules for 365 days, 32 holiday dates, a warn-off system, and timed overrides that can provide an extra one to 999 minutes of illumination. An option for networking between lighting control panels, so that one network may support a maximum of 127 control panels, permits data sharing for global control. Leviton Manufacturing offers two new options for sophisticated lighting control option for indoor commercial applications. Suitable for architectural applications, Leviton’s Commercial Grade Modular Dimming Cabinets—capable of controlling incandescent, fluorescent, low-voltage, neon, and cold cathode loads—can hold up to 18 2.4 kw plug-in electronic dimmers. The cabinets are stackable to accommodate 36 2.4 kw dimmers that can be factory prewired, and will fit between two stud widths for a flush installation, the company points out. Flush- or surface-mounted, the cabinets can be integrated with preset control systems, manual controls, building automation systems, time clocks, hand-held preset infrared controllers, photocell energy conservation systems, and any other type of required control system. For a scalable, networkable lighting control system, Leviton’s Dimensions Architectural Lighting controllers and control consoles integrate with customized, high-density remote dimmer panels and lightweight rolling dimmer racks. Any number of controllers can reside on a computer network accessible over the Internet or a corporate Intranet. The Dimensions 4200 Controller, for example, features eight programmable scene switches and controls up to 16 zones with an LED bar graph that displays the status of each zone. Capable of accommodating up to 128 stations in a system subnetwork, the D4200 also features an astronomical time clock, event scheduler for automatic date and time operation, and a Macro Sequencer for fast chase and special effects applications. Lutron Viseo Display lighting control is a lucite crystal display (LCD)-based control that offers direct access to Lutron lighting control systems. Working in conjunction with Lutron’s GRAFIK 5000 and GRAFIK 6000 systems, Viseo allows users to monitor and operate the lighting in any room of a facility from one or more locations. In addition to recalling and modifying preset light levels, the device, which is well-suited for ballrooms, lobbies, houses of worship, and public spaces, as well as total building control systems, affords precise control of every lighting zone, with graphic and numeric intensities in one percent increments. 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