Home Up Nature of Light Basic Illumination Concept Relationship between Luminous Intensity and Illumination Lamps Luminaires


5.    Luminaires

The luminaire is the equipment which contains the lamp. Its purposes are:

(a) connecting the lamp to the electricity supply,

(b) controlling the light emitted by the lamp,

(c) protecting the lamp from a hostile environment, and

(d) providing a fixture of satisfactory appearance.

The intensity distribution of light from a luminaire usually indicated graphically called the 'Polar Curve' by plotting the intensity in a series of direction within one vertical plan through the luminaire.

Figure 8 Polar Curves

Different luminaire design gives different polar curve shapes. For easy reference, in U.K. the British Zonal system has been developed, which classifies ten standard forms of downward light distribution as shown in Figure 9.

Figure 9 BZ Curves