UFC 3 -520-01
June 10, 2002
can be glaring and often creates dark ceilings and upper walls, which, although
dramatic, are uncomfortable due to high contrast.
F-8.1.1.2 Indirect luminaires emit light upward, in turn bouncing light from the ceiling into
the space. These include many styles of suspended luminaires, sconces, and some
portable lamps, generally suited for offices and other clean interior spaces. Indirect
luminaires tend to create comfortable low-contrast soft light that psychologically
enlarges space. Indirect lighting is less efficient for general and task lighting. Indirect
lighting can be used but it must be applied carefully as an ambient light source.
F-8.1.1.3 Diffuse luminaires emit light in all directions uniformly, and include most types
of bare lamps, strips, globes, chandeliers, and some table and floor lamps. Diffuse
luminaires tend to create broad gene ral light that often is considered glaring due to lack
of side shielding. They are usually chosen for ornamental reasons or for utilitarian
applications.
F-8.1.1.4 Direct/indirect luminaires emit light upward and downward but not to the side.
These include many types of suspended luminaires, as well as some table and floor
lamps. Note that direct/indirect luminaires can be mostly direct or mostly indirect
according to the proportions of up and down light. Direct/indirect luminaires are often a
compromise between the efficiency of direct lighting and the comfort of indirect lighting.
F-8.1.1.5 Asymmetric and adjustable luminaires are designed for special applications.
Wallwashers are a form of asymmetric direct luminaire with stronger distribution to one
side to illuminate a wall. Adjustable luminaires, including track lights, floodlights, and
accent lights are generally direct luminaires that can be adjusted to throw light in
directions other than down.
F-8.1.2 Standard Lighting Systems. Insofar as possible, select standard
commercial or industrial type luminaires intended for use in the application. For most
lighting applications, there are specific types of luminaires that have been developed for
the application.
F-8.2
Fluorescent Lighting Systems.
F-8.2.1 Strip Lights. Strip lights or "channels" are the most basic of fluorescent
luminaires, but have a surprising number of uses. Like bare incandescent lamps, a strip
light can be used to produce cheap general illumination, so long as efficiency and glare
control are not important. But often, the strip light is used in unique situations, such as
inside cabinets or cases, in coves or valances, behind Plexiglas sign panels, or other
applications where a "line of light" is needed.
F-8.2.2 Troffers. Troffers are simple steel-trough fluorescent fixtures with a lensed
face (in the case of lensed troffers) or louver face (in the case of parabolic troffers).
Most troffers are designed to fit in an opening in an acoustic tile ceiling, and are usually
0.6 meters by 1.2 meters (2 feet by 4 feet) in nominal dimensions. Troffers are placed
in a pattern to create general lighting throughout the room. Typically, a two -lamp
F-13
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