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Note 55. Fluorescent Lighting

The Energy Efficiency Manual includes a large group of energy conservation measures related to fluorescent lighting. This Note explains the construction, design, and operation of fluorescent lamps and ballasts. With this background, you will be able to select fluorescent lighting equipment with assurance, and to understand the changes that are occurring in fluorescent lighting technology.

The Note starts by explaining how a fluorescent lamp is made and how it works. It explains the roles of mercury, argon, and “buffer gas.” It explains phosphors and the improvements in phosphors that are responsible for improved efficiency and efficacy (lumens per watt) and color rendering (CRI). And, it explains different types of filaments and electrodes in fluorescent lamps affect lamp operation and starting.

The Note explains the factors that affect lamp performance. The operating temperature of the lamp affects efficiency and light output, and it limits applications. The lamp shape affects efficiency and cost. The number of starting cycles affects service life. Lumen output declines as the lamp ages.

An enormous variety of fluorescent lighting types are available. The common types are described, including conventional straight tubes, compact fluorescent types, and screw-in fluorescent fixtures intended for replacement of incandescent lamps. The naming system for fluorescent lamps is explained.

The Note explains why fluorescent lamps need ballasts. You will learn about the three main types of ballasts, magnetic, electronic, and hybrid. The methods of starting fluorescent lamps are explained, including instant-start, rapid start, preheat, and trigger-start systems of ballasts and filaments, and fluorescent starter.

The environmental problem posed by the need for mercury in fluorescent lamps is cited.

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Note 55. Fluorescent Lighting