New lighting systems minimize energy, cost, maintenance By Bob Catone click the image to enlarge Fig. 1. The incredible shrinking linear fluorescent, saving energy, space, and money. Diagram: Osram. Lighting is a field where technological improvement in the past decade has been very rapid. It can be tough for design teams to keep up with the latest information—yet such knowledge can significantly lower a facility's initial costs, as well as ongoing operational and maintenance costs. Here are some tips about advances in lamp, ballast, and fixture design that can minimize fixture and lamp expenditures on your next project. Fluorescent technology remains the cornerstone of many lighting designs, but today's lamp and ballast choices have added many new options. Linear T8 lamps have become the standard for new construction, replacing the once-ubiquitous T12s (Fig. 1). Even smaller T5 lamps, just 5/8-in. in diameter, are entering the scene in indirect fixtures. click the image to enlarge Table 1. Comparison of four 4-ft linear fluorescents shows the great diversity of characteristics now available. Comparisons assume use of standard electronic ballasts. Reduced size is only the most obvious beneficial feature of these high-tech lamps. New phosphor coatings provide 17% to 28% higher lamp output and almost perfect natural color. Better lamp design has allowed life ratings up to 30,000 hr. New low-mercury lamps do not require special disposal. Table 1 summarizes differences in linear fluorescents that can impact operational costs, by comparing four available 4-ft T8 models. Fluorescent electronic ballasts optimize lamp performance and minimize energy usage. Their high frequency (20,000 hertz) eliminates lamp flicker and extends lamp life. Newer designs are smaller, and are intelligent and universal. Many operate different-wattage lamps and accept 120 or 277 volts. Some can operate four lamps at a time. Instant start versions operate lamps in parallel; if one fails, the others still operate. click the image to enlarge Table 2. The optimal combination of lamp and ballast choices can provide longer life and lower operating costs. As shown above, a high-output instant start ballast gets 38 W of power from a 32-W T8 lamp, allowing a reduction in the number of lamps per fixture compared with the standard configuration. Electronic ballasts are sensitive to heat. The fine print states that they need to operate at 70ºC or below for full life. Combining a high-efficiency lamp with an advanced electronic ballast can yield impressive savings in efficiency and lamp life, as shown in Table 2 (above). The standard instant start ballast has a ballast factor (BF) of 0.88 and drives a 32-W T8 at just 28 W. The "high light output" instant start ballast has a BF of 1.19 and drives the same lamp at 38 W. This gain in wattage allows you to remove one lamp from a four-lamp troffer. As a bonus, the fixture efficiency increases 5% to 7%. This ballast does not reduce lamp life or warranty. (Ballasts for T5 and compact fluorescent lamps are only available with a ballast factor of 1, which drives lamps at the rated wattage.) click the image to enlarge Fig. 2. Compact fluorescent lights (shown with an appropriate ballast) are dimmable and cool, and offer alternatives to metal halide, linear fluorescent, and incandescent lamps. Photo: Philips. Ballast controls, dimming systems, and software have the potential to reduce energy use through daylight harvesting, sensors, and optimizing illumination to task requirements. An open Digital Addressable Lighting Interface (DALI) is progressing toward becoming the lighting communications standard. Each ballast can be individually controlled and belong to any or all of 16 different groups. The open standard allows interchangeability from different manufacturers. Appropriate ballasts and control systems are just entering the marketplace. Subcategories of fixtures Though standard linear fluorescents dominate, the lighting "universe" includes a number of specialized lamp types that can be useful in tailoring the design to a particular lab's needs. click the image to enlarge Fig. 3. Anatomy of an HID (high-intensity discharge) lamp. Diagram: Philips. • Compact fluorescent lamps (Fig. 2 and Table 3) have become popular in the past two years. They offer high lumens and 83% color accuracy. Most are dimmable, and their output is almost unaffected by ambient temperature. They are the standard for down-lights and offer alternatives to metal halide, linear fluorescent, and incandescent lamps. • Special color spectrum systems and UV systems normally use tinted fixture lenses, lamp sleeves, or coated lamps. Our firm recommends sleeves or coated lamps, which are readily available from many sources. Tinted lenses may be less desirable because lens extruders require minimum runs of tinted plastic. Replacements that are an exact match may be impossible to obtain. If using a tinted lens system, always stock spare tinted lenses from the initial run. • Break-proof lamps are available from coating companies and some manufacturers. They generally use clear Teflon to contain broken glass from a fluorescent, incandescent, or HID lamp. • The "induction fluorescent," with an incredible 100,000 hr of rated life, is now offered by two manufacturers. The induction fluorescent uses microwave energy to excite the lamp. Lamps are available in three sizes up to 165 W. Lamps are shaped either like a coated HID or rectangular circle-line. The system is expensive but might be ideal for labs where maintenance is costly and sensitive. click the image to enlarge Fig. 4. Electronic metal halide ballast systems now offer performance equal to that of fluorescent systems. Photo: Advance. • LEDs—light emitting diodes rated at 100,000 hr of life—are increasingly being used for signage, exit lights, traffic signals, and in automobiles. White LEDs are only 30% as efficient as fluorescent lamps; a 5-W system can cost $150. They presently have no practical mainstream applications, though research to make them more feasible is underway (see page 22). • High-intensity discharge technology (Fig. 3 and Table 4) combines mercury and metal halide atoms under high pressure. In the arc stream, the atoms generate both UV radiation and visible light. A specially formulated glass bulb filters the UV radiation without affecting visible light. • Electronic metal halide ballast systems (Fig. 4) integral to HID technology now equal fluorescent performance; 320-, 350- and 400-W lamps provide 87 maintained lumens/W, have 0 to 10 volt continuous dimming to 50% power, integral occupancy sensors, and no noise. Lamp life is expected to increase to 30,000 hr.   click the image to enlarge Fig. 5. This “BioSeal” fixture offers special sealed characteristics to promote contamination control in sensitive environments. Photo: Guth Lighting. Laboratory fixtures can be recessed, surface-mounted, or suspended. They are available in painted steel, aluminum, or stainless steel with plastic or tempered glass optics. They are generally sealed to minimize contamination and facilitate cleaning. The design may include task and ambient lighting fixtures. Suspended direct/ indirect fixtures provide both types of illumination. Lighting levels range from 50 to 200 footcandles depending on the work being performed. Low-light-level ambient systems with individual task lights, where suitable, can reduce energy usage. Lamps used in today's labs are generally T8 fluorescent. They provide the highest efficiency, up to 30,000 hr of rated life, and moderate cost. They are available in Kelvin temperatures of 3000, 3500, 4000, 5000, and 6500. The area can be designed to provide a warm white to very cool white environment. T8 lamps have a color accuracy (CRI) between 78% and 86%. click the image to enlarge Fig. 6. A sealed tubular fixture with integral parabolic reflector is suitable for environments where hose-down is part of the sanitation protocol. Photo: Guth Lighting. Other available lamps include compact fluorescent (CFL) and linear T5 fluorescent. CFL's are available from 26 to 120 W and provide a lot of light in a small package, as discussed above. Life is up to 20,000 hours. Color accuracy is 85%. T5 lamps are designed for metric fixtures. They are slightly smaller than T8 lamps, have 20,000 hr rated life, and cost a premium. Fixture construction always involves a trade off in cost between material, sealing method, and performance. It is important to understand the trade-offs to provide the best value for the facility. click the image to enlarge Table 3. A variety of compact fluorescents are now available, offering an alternative to standard linear, high-intensity discharge, and incandescent lamps. Selection factors The following five characteristics usually govern the design team's choice of fixtures for a lab: • Design. Fixtures should clean easily and be gasketed to resist the entry of dirt and bacteria. They can be surface-mounted or recessed, with either top or bottom access for maintenance. • Materials. Bodies and doors are available in steel, stainless steel, and aluminum. Painted steel is cheapest but is susceptible to chemical attack. 300 Series stainless steel is the most expensive and can corrode from some chemicals. It also acts as an insulator, so ballasts operate warmer and life is shortened. Aluminum entails a moderate cost and is corrosion-resistant. Ballasts operate cooler, so life is extended. Aluminum fixtures weigh only a third as much as equivalent stainless steel versions and thus are easier to install. They also tend to provide a better seal to the ceiling (with a flange fixture). click the image to enlarge Fig. 7. Downlights with prismatic lenses can create an attractive aesthetic feature, and are available in a variety of configurations, including incandescent, compact fluorescent, induction, and HID lamps. Photo: Guth Lighting. • Recessed fixture optics. The lens should have the prisms reversed for easy wipe-down. Louvered units should have an underlay of clear acrylic to prevent baked-on dirt inside the fixture. • Surface fixture optics. Output can be direct or direct/indirect. Indirect illumination may reduce shadowing and provide an open atmosphere. Sealed fixture types include troffers (Fig. 5), prismatic acrylic tubes (Fig. 6), compact fluorescent acrylic lowbays (Fig. 7), and wrap-arounds. • Ingress protection. IP is a graduated European standard gaining in popularity with specifiers. This two-digit rating measures a fixture's ability to keep out various levels of dust (the first number) and water (the second number). The level of IP classification recommended depends on the installation. An IP 65 rating indicates that the fixture is dust-tight and can withstand a moderate hose-down over the entire body without leakage. These fixtures have welded housings because caulk normally fails. (The silicone sealing the lens can pass because it has a metal back frame.) click the image to enlarge Table 4. HID lamps and electronic metal halide ballasts (top 3 options) provide powerful light, are dimmable, have integral occupancy sensors, and produce no noise. (For comparison, fluorescent T8 and T5 systems are shown on the bottom two lines.) Advances in technology, when properly applied, can provide a low-cost, reduced maintenance, and more energy-efficient installation. Today you can provide 100 footcandles at less than 1.5 W/ft2. Robert Catone is the general manger of Guth Lighting and VP of JJI Lighting Group. He has been named a Certified Lighting Professional by the National Council of Qualifications for the Lighting Professions and a member of the Illuminating Engineering Society Progress Committee. Guth (www.guth.com) was founded in 1902 and specializes in food processing, cleanroom, laboratory, and school lighting.