A T5 lamp is a fluorescent lighting system introduced onto the U.S. lighting market in 1995. T5 lamps are 5/8-inch in diameter equipped with a miniature bi-pin base and vary in length.
In industrial applications, T5 lamps are used in bays of either four or six lamps to provide lighting in large areas, such as gymnasium. T5 lamps have, in 2011, largely been replaced for use by more energy-efficient light-emitting diode (LED) lighting.
A four-lamp bay using high output T5 lamps uses 220 watts of power including the power used for the ballast; a six-lamp T5 bay uses approximately 342 watts of electricity. Four-lamp T5 bays use about 6,840 kilowatts (kW) of electricity per hour, with six lamp bays consuming about 10,260 kW per hour.
The amount of light produced by a T5 four-lamp bay is about 51 foot candles, with six-lamp bays producing 75 foot candles of light.