This issue of Lighting Answers helps specifiers better understand the advantages and disadvantages of T5FT lamps and ballasts so that they can specify and use the lamps in suitable applications. In some applications, T5FT lamps are an alternative to incandescent, other fluorescent, or metal halide lamps. T5FT fluorescent lamps (twin-tube lamps with 5/8-inch diameter tubes) produce maximum light output at higher ambient temperatures than linear or U-bend fluorescent lamps. Controlling light distribution is easier with T5FT lamps than with linear and U-bend lamps because the T5FT lamp has a narrower diameter. This narrow diameter also allows designers to improve luminaire efficiency. Ballast compatibility and potential glare are the greatest concerns for specifiers considering the use of T5FT lamps. |