Page 292 - Mechanical Engineers' Handbook (Volume 4)

2 Performing an Energy Audit—Analyzing Energy Use 281

Figure 1 Reduction in light output from fluorescent fixtures as a function of fixture cleaning frequency
and the cleanliness of the fixture’s surroundings. 3

illumination for a variety of activities. A level much in excess of these guidelines usually
indicates an opportunity for saving energy. However, the auditor should recognize that good
seeing also depends on other factors such as glare and contrast and that the esthetic aspects
of lighting systems (i.e., their appearance and the effect they create) can also be important.
More information about the design of lighting systems can be found in Ref. 1.