TRILUX Luminaires - Proljus AB

Calculations
The necessary object luminance depends
on the ambient brightness (Table 1.26).
Most illuminated objects have matt surfaces
so the illuminance E (in Ix) can be calculated
from the luminance L (in cd/m 2 ) and the reflectance
value ◊ of the surface based on the
following formula:
L = ◊ · E / π
If the reflectance value of the surface is
known or determined by comparing with
surfaces of known reflectance values, the
maintenance value of the mean illuminance
on the surface to be illuminated can be calculated
according to the following formula:
E = L · π / ◊
Reflectance values of typical building
materials of illuminated objects are listed
in Table 1.27.
Optical systems and their effect
(taking Lumena as an example)
In case of facades with prominent projections,
e.g. balconies, bays, balustrades, etc.,
the spotlights should be positioned with
large intervals in order to prevent significant
cast shadows. Otherwise additional spotlights
are to be provided for illuminating and
accentuating the shady areas – if need be
with a different light colour.
In case of reflective facades, e.g. glazed surfaces,
the spotlights must be installed below
eye level in order to eliminate any reflections
(reflex glare). In case of aluminium facades
with significantly aligned reflection behaviour,
this arrangement would result in a dark
surface, because the light of the spotlights
is reflected upwards. Here, the spotlights
should be installed at a greater height so
C90
CO
C18O
C270
Reflector RE
rotationally symmetrical narrowangle
light distribution.
C90
Brightness
Luminance on the
of environment
illuminated surface
Less, in free environment 3 up to 6.5 cd/m2 Less, in developed dark environment 6.5 up to 10 cd/m2 Medium, in developed medium-bright environment 10 up to 13 cd/m2 High, in bright environment 13 up to 16 cd/m2 1.26 Guideline values for luminance on illuminated surfaces.
that there is no glare reflection at the main
viewing position.
Trees are illuminated either from far away
or from the treetop in order to be able to
perceive the foliage and the entire plant.
Alternatively, ground-level spotlights close to
the tree trunk are common for illuminating
the crown of the tree from below. In this
case, light sources with a significant green
component in spectrum are recommended,
e.g. metal halide lamps, possibly with green
filters as well.
The light colours of the implemented lamps
also have a particular impact on the results of
the lighting system. Yellow and red surfaces
are illuminated with high-pressure sodium
vapor lamps and thus offer a good colour
contrast to illuminated buildings with grey
CO
C18O
C270
Reflector SE
symmetrical narrow-angle light
distribution.
C90
CO
C18O
Building
Reflectance
material
value
Plaster, light 0.35 – 0.55
Plaster, dark 0.2 – 0.3
Sandstone, bright 0.3 – 0.4
Sandstone, dark 0.15 – 0.25
Tile, bright 0.3 – 0.4
Tile, dark 0.15 – 0.25
Wood, bright 0.3 – 0.5
Concrete, light 0.4 – 0.65
Concrete, dark 0.2 – 0.3
Granite 0.1 – 0.2
Facade, dirty 0.05 – 0.1
1.27 Reflectance values of building
materials.
C270
Reflector SM
symmetrical medium wide-angle
light distribution.
surfaces that are illuminated using metal
halide lamps. Even the combination of multiple
light colours at the same building may
have special effects. When selecting metal
halide lamps, which are available in the light
colours neutral-white and daylight white
depending on the lamp rating, particular
attention should also be given to their colour
rendering.
With regard to the use of spotlights with
colour filters and accent lighting with very
noticeable colours, it is necessary to carefully
differentiate between a rather inconspicuous,
historical mise-en-scene of the building
and spectacular conspicuousness and with
regard to the lighting concept.
C90
CO
C18O
C270
Reflector SB
symmetrical wide-angle light
distribution.
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Technical information