Lighting
in High-Bay Manufacturing &
Color Critical Areas
Daylight
is unmatched for color rendering, and safety and productivity
of manual tasks. To supplement it efficiently, use electric
light with similar distribution. For even ambient light distribution,
introduce light high in a space with light-colored upper surfaces.
Locate fixtures just above work areas for task illumination.
Lighting
levels should respond to visual tasks. Efficient lighting
power densities (LPD) range from 0.75 to 1.5 W/sq.ft., though
select areas with task- and color-critical work may range
from 2.0 to 2.5 W/sq.ft.
High-bay,
metal halide (MH) lamps supplement natural light efficiently.
Newer 360-watt lamps provide the same output as standard 400-
watt MH lamps. High-output 400-watt lamps can provide 10%
more lumens. Both have a 20,000- hour life.
Newer
MH lamps eliminate the color shift problems of older lamps.
When color quality is important, choose lamps with improved
color stability, or use high color rendering index (CRI) T8
or T5 fluorescents.
Metal
halide and high-pressure sodium (HPS) lamp output can be dimmed
using photo-cell controls and high/low ballasts, to respond
to daylight. Occupancy sensors can also switch high/low ballasts
for areas with intermittent occupancy, such as aisles.
Cautions
- Consider
power quality and lamp/ballast compatibility when using
dimming ballasts.
- Control
glare from direct sunlight.
- Requires
careful luminaire and sensor selection, placement and commissioning.
