3.
PERSONNEL LIGHTING REQUIREMENTS. The desired illumination level per
unit floor area at various locations %n a hyperbaric complex, and resulting
power consumption, will be determined primarily by personnel requirements.
The detailed design of interior lighting installations is quite complex and
depends on many variables. The entire process is treated in the Lighting
Handbook. In this subsection, a small amount of basic material will be given
to acquaint the designer with the terms and general approach taken.
a.
Illumination.
Surface illumination is commonly measured in
footcandles, where
1 footcandle = 1 lumen / square foot
b.
Illumination Requirements. Table 9-1 gives recommended
illumination in footcandles for various grades of tasks.
c.
Illumination Realization. To obtain the desired illumination
level at the work area, the characteristics of both the lamp and the fixture,
or luminaire, must be considered. Generally, light levels inside the chamber
should be between 30 and 50 footcandles for personnel comfort. Consideration
should be given to providing a means of varying the light intensity.
TABLE 9-1
Recommended Illumination Levels for
Various Task Grades
Illumination,
Task Description
footcandles
Performance of visual tasks of extremely
100 or more
fine detail under poor contrast conditions
for long periods of time
Performance of visual task of fine detail
50-100
under medium contrast conditions
Performance of visual tasks of moder-
25-50
ately fine detail under better than
average contrast for intermittent time
periods
Performance of visual task of simple
5-10
orientation for short temporary
durations
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