Technical information

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Energy eciency in lighting installations
A lighting installation needs to confirm to the various requirements
stipulated for its specific area, without compromising on energy ef-
ficiency or visual comfort. This necessitates that care consideration
is paid towards the selection of the appropriate lighting system,
equipment, control systems and the use of daylight. A measure-
ment of eciency in a lighting installation is the installed output, in
W/m², that is required to meet defined demands.
Example of installed lighting outputs
Installation type Installed lighting
output
Required illuminance
while operational (lx)
Notes.
Corridors 5–10 W/m² 100 lx
Corridors 10 W/m² 200 lx
General public areas 10–12 W/m² 300 lx
Workplaces 10–12 W/m² 300 lx *)
Workplaces 10–15 W/m² 500 lx *)
Workplaces 15–30 W/m² 1000 lx *)
*) Required illuminance within the working zone according to EN 12464-1. The lower
value normally presupposes a localised lighting system adapted to the working area in the
workplace.
In addition to a low installed output, energy usage should be lim-
ited in an installation with the help of dierent control systems.
A better method of assessing the energy eciency of a lighting
system is to evaluate the annual energy consumption. This method
is described in the EN 15193 standard, which is linked to the Energy
Directive, see pages 511–514.
The maintenance factor aects energy
consumption
The new standards give light planners greater responsibility for the
system, as the installation’s maintenance factor has a direct eect
on the energy consumption. To select a high maintenance factor a
great deal of care must be exercised when choosing light sources,
luminaires and the lighting system. The choice of T5 luminaires
gives the best conditions for achieving a high maintenance factor.
For further information on calculating the maintenance factor,
refer to the SLL Code for Lighting.
Light planning
Planning and calculation tips
General advice
The following points should be considered in order to create low
energy usage in a lighting installation:
Selection of light sources with optimal luminous ecacy for the •
required colour reproduction.
Energy ecient lighting system with installed lighting output suit-•
able for the required task.
Ecient luminaires with the correct light distribution and good •
cut-o properties.
Ecient utilisation of daylight.•
Ecient utilisation of artificial and natural light through the selec-•
tion of a light interior colour scheme.
Control of lighting through presence detection.•
Possibility of localised control by the individual.•
High frequency operation with dimming.•
Well planned maintenance of the lighting installation to obtain a •
high maintenance factor.
120
100
80
60
40
20
0
1,00 0,90 0,80 0,70 0,60 0,50
43%
18%
Increase in relative power output(%)
Maintenance factor
Evaluation of a lighting system
Visual ergonomic aspects of the workplace’s design are impor-
tant for a stimulating working environment. There is an excellent
method called “visual evaluation” available to review and assess a
room with an installed lighting system, which is simply based on
describing what you see in the room.
Evaluate the room visually through its lighting system, colours
and design. These factors aect each other and are dicult to
assess individually. The room colours should not be distorted, and
visual work should be possible without the discomfort of glare or
reflections.
The room’s visual quality governs, to a large extent, your health
and your performance capacity. It is therefore important that you
do not completely rely on computer calculated results. Try to make a
visual evaluation of your own workplace using the adjacent table.
Rank the opposite pairs on a scale of 1–5.
Concept Description Evaluation
Light level – is it dark or light in the room? dark – light
Light distribution
– how is the light distributed in the
room?
varied – equally
Light colour
– is the light colour experienced as
warm or cold?
warm – cold
Colour
– how are the colours and objects
viewed?
distorted – natural
Glare – does unpleasant glare occur? troublesome – not noticeable
Shadows – whether they are hard or soft? hard – soft
Reflections – whether they are intense or diuse? intense – diuse
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