Note 50. Measuring Light Intensity
The Energy Efficiency Manual provides an important group of energy conservation measures that improve the efficiency of lighting layout and light distribution. You need to understand the concepts of light intensity and lighting measurement for selecting lamps, for designing efficient lighting layouts, and for lighting retrofit programs.
Confused about the terminology of lighting units? This Note will eliminate the confusion. It concisely explains the terms that the lighting trade uses to communicate about light intensity. The important terms to understand are lumens, footcandles and lux, and candlepower.
You will also learn the terms used to express the brightness or luminance of objects, using units of candelas. An understanding of brightness is important for avoiding glare.