Interior Lighting for Designers

ft × 4 ft, 2 ft × 4 ft, and 2 ft × 2 ft; the last
of these is used when a nondirectional
(square) ceiling element is desired. Because
these luminaires take up such a large por-
tion of the ceiling surface (as compared to a
round-aperture downlight), they are signifi-
cant factors in the design and appearance of
the ceiling plane (figure 12.17).
Suspended ceiling systems frequently
use2ft×4ftfluorescent downlights
because they integrate easily. Square 1 ft ×
1 ft and 1.5 ft × 1.5 ft luminaires with com-

pact fluorescent sources take up a smaller

portion of the ceiling surface, providing

energy-effective luminaires in compact sizes.

Shielding.With all fluorescent down-

lights, the shielding material is the critical

component, because this element is most

prominent in the direct field of view. The pur-

pose of diffusers, lenses, louvers, reflectors,

and other shielding materials used influores-

cent downlight luminaires is to redirect light

from the glare zone down toward work surfaces.

LUMINAIRES

Figure 12.17Fluorescent 1 ft ×4 ft eight-cell parabolic downlight.