Aiming with Reflector Panels
Reflector panels are a way of improving the aiming of conventional fixtures. For example, if a reflecting panel is installed vertically alongside a fluorescent fixture that has a “batwing” distribution pattern, the distribution pattern becomes a single-lobed beam centered about an angle of 70 degrees from the ceiling, a geometry that is desirable for avoiding veiling reflections. The additional reflected light on the task may allow partial delamping of the fixture. In experiments with office task lighting, reflector panels increased the illumination of the task from 40 to 80 percent when installed with existing fluorescent ceiling fixtures.
This is primarily a retrofit technique. For example, it may be the most practical way to improve the light distribution of existing fluorescent fixtures. In new construction, consider other methods of controlling light distribution.
The surfaces of the reflector may be specular or diffuse, depending primarily on the existing fixtures. With fixtures that have broad light distribution, such as conventional fluorescent fixtures, use specular reflectors to avoid further scattering of the light.
Reflector panels can be fabricated easily from a wide variety of inexpensive materials, including paper, fabric, aluminized paper and plastic, and polished aluminum with an anti-oxidant coating. For example, specular reflectors can be made from various types of aluminum stock used to make the fluorescent fixture “reflectors” covered by Measure 9.2.7.
Panels may be flat, bent, or curved as needed to improve light distribution, to provide more effective glare shielding, and to provide rigidity. For example, a reflector may be installed around two of the four sides of a fluorescent ceiling fixture.
Coordinate reflectors with glare shielding, as described under “Glare Shielding,” below. With diffuse reflector panels, the illuminated side will appear excessively bright to persons outside the task area. On the other hand, a specular reflector will not allow a distant viewer to see an image of the bright fixture, provided that the reflector is tilted backward somewhat from the vertical. Any type of downward projecting reflector shields against glare from the rear of the panel. The rear sides of the panels can be decorated.