Figure 6-15.Luminaire utilization.
Normally, each luminaire manufacturer can
supply you with the maintenance factor for your lamp
model; however, when the manufacturers information
is not available, a 0.70 maintenance factor is widely
used in the industry.
LIGHTING INTENSITY CALCULATIONS
Achieving the most satisfactory solution for any
given lighting problem requires sound judgment in
making necessary compromises of all factors
Selection of the luminaire can be influenced by
budget constraints, present stock levels in the Federal
Supply System, and availability. Once the luminaire is
selected, it is important that you use the manufacturers
literature to determine the number of luminaries,
mounting height, and spacing required to produce the
desired illumination intensity.
Using the manufacturers literature supplied in
figure 6-14, let us solve this sample problem:
One-sided spacing required to provide specified
Uniformity of illumination
Given: (fig. 6-16)
Street width, 50 feet
Mounting height, 40 feet
Pole setback from curb, 2 feet
Figure 6-16.Streetlight sample problem.