U-Bend Fluorescent Tubes
U-bend fluorescent tubes are linear fluorescent bulbs bent into a U-shape at the factory, allowing for more compact fixtures that provide the light output of a full-length tube in roughly half the fixture length. This space-efficient design makes U-bend tubes popular in troffer fixtures (the recessed grid ceiling fixtures common in commercial spaces), wrap-around fixtures, and various industrial and commercial lighting applications where you want the efficiency and output of fluorescent technology in a more compact package.
The U-bend configuration typically follows the standard fluorescent tube diameters: T8 (1-inch diameter) and T12 (1.5-inch diameter), with T8 being far more common in modern installations due to better efficiency and smaller size. The overall dimensions are usually described by the length of each leg – for example, a 22-inch U-bend has legs that are each 22 inches long before the bend. Common sizes include 17-inch and 22.5-inch U-bends, though other sizes exist for specific fixture types.
Most U-bend fluorescent tubes use a single bi-pin base at one end where both electrical connections are made, making installation straightforward. The bulb slides into sockets on one side of the fixture, with the U-bend supported by a clip or holder on the opposite side. Some older U-bend designs used separate pins at each end, but the single-base configuration has become standard because it simplifies fixture design and bulb replacement.
Color temperature and light output specifications mirror standard linear fluorescent tubes. Common options include warm white (3000K) for spaces where comfortable ambiance matters, cool white (3500K-4100K) for offices and commercial spaces, and daylight (5000K-6500K) for industrial applications or anywhere maximum brightness and visibility are priorities. Wattages typically range from 28W to 40W depending on tube size, providing substantial light output while consuming far less energy than equivalent incandescent lighting.
Ballast compatibility is important with U-bend fluorescents just as with straight tubes. Older magnetic ballasts are less efficient and can cause humming and flickering. Electronic ballasts provide instant-on operation, eliminate flicker and hum, and improve overall system efficiency. If you're replacing bulbs in fixtures with older magnetic ballasts and experiencing performance issues, upgrading to electronic ballasts along with new U-bend tubes can significantly improve lighting quality.
LED retrofitting of U-bend fluorescent fixtures has become increasingly popular as LED technology has matured and prices have dropped. LED U-bend replacements offer dramatic energy savings (typically 50-60% versus fluorescent) and 50,000+ hour lifespans that virtually eliminate maintenance. However, most LED U-bend retrofits require ballast bypass – removing or disconnecting the fluorescent ballast and rewiring the fixture for direct connection. This adds installation complexity and cost compared to simply replacing fluorescent tubes.
Common Applications: Commercial office lighting (troffer fixtures), industrial facilities, retail stores, schools and universities, parking garages, warehouses, anywhere compact fluorescent fixtures are needed
Standard Sizes: T8 (1" diameter) and T12 (1.5" diameter) in various lengths. Common leg lengths: 17", 22.5". Wattages typically 28W-40W. Single bi-pin base configuration most common.
