Exterior Lighting 2012/2013 - Fergin AB

Planning aids
Luminous intensity distribution curve
Photometrically, a luminaire's characteristic is
described by its luminous intensity distribution
curve.
These luminous intensity distribution curves are
described in detail in DIN 5040. Typical luminous
distribution curves:
The light distribution of a lamp or light fixture can
be shown on a chosen plane by the luminous intensity
distribution curve.
A luminous intensity distribution curve is created if
one imagines a point source of light in the centre of
a polar diagram, luminous intensity radiating from
this source is represented as true to scale vectors
originating from the centre of the graph.
If all these vector points are connected together,
the result is the luminous intensity distribution curve
(see graph below).
Unless otherwise stated, the luminous intensity
values in this curve relate to a luminous flux of 1000
Lumen. If the lamp or lamps in a light fixture have
differing luminous flux values, the luminous intensity
values stated in the luminous intensity distribution
curve have to be multiplied by the appropriate
factors. The display of one plane is usually sufficient
in case of circular symmetrical reflectors.
3000
4500
6000
30 30
I I (cd/klm)
90 90
60 60
368 Planning aids
In case of axially symmetrical and asymmetrical
reflectors the radiation characteristics can only be
represented by the various planes.
500
750
1000
I (cd/klm)
90
60
Technical documentation therefore mostly shows
light intensity distribution on the longitudinal and
transverse planes.
As you can see from the following diagrams, the
curves on the transverse plane (A0-plane) show the
luminous intensity distribution curve vertical to the
light fixture's longitudinal axis. These luminous intensity
distribution curves are called the transverse
curves.
A plane = C0 – 180
0
The curves on the longitudinal plane (B-plane),
so-called longitudinal curves, are shown parallel
to the lighting fixture's longitudinal axis on the
luminous intensity distribution curve.
B plane = C90 – 270
0