Figure 6-26.Isofootcandle diagrams.
The isofootcandle diagrams show what the light
level will be at any given point. The dimensions for the
diagram are based on the mounting height (MH) of the
floodlight. The aiming point (p) is also based on the
mounting height. Figure 6-27 provides a diagram for
mounting heights of MH x 0.5, MH x 1, and MH x 2.
The grid pattern is also based on the mounting
height. The grid line values left and right give the
distance to either side of the floodlight. The values up
the side show the distance in line with the aiming
direction of the floodlight. The number 3, for instance,
represents 3 x 40, or 120, feet from a 40-foot mounting
Each isofootcandle line shows where the
footcandle level is the same. These lines are identified
by a letter, which is used with the initial footcandle (fc)
table. The footcandle values between isofootcandle
lines do not change more than 2 to 1. That makes it
possible to approximate the level between lines.