Equipment: Luminaires - Road Lighting: Fundamentals, Technology and Application - page 146

Chapter 11
Equipment: Luminaires

Abstract Luminaire characteristics are widely different for the different lamp types
and for the different areas of application. The luminaires employed in road lighting
are of three basic types: those that throw the main part of their light along the road,
which is the case for most of the luminaires used for motorway lighting; those
that have a more rotation symmetrically light distribution, as sometimes used for the
lighting of non-linear areas such as squares and some residential areas; those used for
high-mast lighting, which may have a rotationally-symmetrical light distribution, but
more often have an asymmetrical distribution that permits the lighting of complicated
multi-level junctions.
The light distribution itself and the efficiency with which it is created by its optical
system are key quality aspects of a luminaire. However, the mechanical, electrical
and thermal aspects of the luminaire are also important. These aspects determine
both the lifetime of the luminaire itself and of the components it houses, like the
lamp and gear. They are also important in view of safety and of ease of maintenance.
Finally, since road lighting luminaires are part of the daytime scene of an area, also
their aesthetical aspect has a role to play. All these aspects will be discussed in this
chapter.

A luminaire is a device that controls the light distribution of the lamp contained within
it and which includes all the items necessary for fixing and protecting the lamp (and
sometimes the control gear as well) and for connecting them to the electrical supply
circuit. In American English, the term fixture is usually used instead of luminaire,
while in Anglo-Saxon countries the term fitting is also sometimes used.
The principal characteristics of luminaires can be listed under the following
headings:

• photometrical

• optical

• mechanical

• electrical

• thermal

• aesthetical