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.
