Fluorescent Lamps

Linear, U-bend and Circular Fluorescent Tubes
Linear Fluorescents T5 Linear Fluorescents T8 Linear Fluorescents T8 /T8 HO Linear Fluorescents T12
Fluorescents T12 HO & VHO Fluorescents T10 VHO Circular Fluorescents U-Bend Fluorescents

Fluorescent Tubes


        Fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent tube converts electrical power into useful light more efficiently than an incandescent lamp. Lower energy cost typically offsets the higher initial cost of the lamp. The fluorescent tube is more costly because it requires a ballast to regulate the flow of current through the lamp.

While larger fluorescent tubes have been mostly used in commercial or institutional buildings, the compact fluorescent tube is now available in the same popular sizes as incandescent and is used as an energy-saving alternative in homes.



·         Luminous efficacy

Fluorescent tubes convert more of the input power to visible light than incandescent lamps. A typical 100 watt tungsten filament incandescent lamp may convert only 2% of its power input to visible white light, whereas typical fluorescent tubes convert about 22% of the power input to visible white light. The efficacy of fluorescent tubes ranges from about 16 lumens per watt for a 4 watt tube with an ordinary ballast to as high as about 100 lumens per watt for a 32 watt tube with modern electronic ballast, commonly averaging 50 to 67 lm/W overall. Most compact fluorescents above 13 watts with integral electronic ballasts achieve about 60 lm/W. Lamps are rated by lumens after 100 hours of operation. For a given fluorescent tube, a high-frequency electronic ballast gives about 10% efficacy improvement over an inductive ballast. It is necessary to include the ballast loss when evaluating the efficacy of a fluorescent lamp system; this can be about 25% of the lamp power with magnetic ballasts, and around 10% with electronic ballasts. Fluorescent lamp efficacy is dependent on lamp temperature at the coldest part of the lamp. In T8 lamps this is in the center of the tube. In T5 lamps this is at the end of the tube with the text stamped on it. The ideal temperature for a T8 lamp is 25 °C (77 °F) while the T5 lamp is ideally at 35 °C (95 °F).


·         Life

Typically a fluorescent tube will last between 10 to 20 times as long as an equivalent incandescent lamp when operated several hours at a time. The higher initial cost of a fluorescent lamp is usually more than compensated for by lower energy consumption over its life. The longer life may also reduce lamp replacement costs, providing additional saving especially where labour is costly. Therefore they are widely used by businesses and institutions, but not as much by households.


·         Lower heat

About two-thirds to three-quarters less heat is given off by fluorescent tubes compared to an equivalent installation of incandescent lamps. This greatly reduces the size, cost, and energy consumption of air-conditioning equipment.

·         Long Maintenance Cost

Fluorescent tubes and fixtures are definitely more expensive to install than incandescent lighting, but they are considerably cheaper to operate and the fluorescent tubes last far longer than incandescent lamps, making the long term cost-of-operation for fluorescent lighting far less than incandescent lighting.


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