12
The Lighting Handbook
The right light traditional and new quality criteria
Illuminance definition terminology
Traditional quality criteria
– Sufficient illumination level
– Harmonious brightness distribution
– Glare limitation
– Avoidance reflections
– Good modelling
– Correct light colour
– Appropriate colour rendering
Illuminance maintenance value Ēm
Value below which the illuminance level must
not fall the visual task area.
The visual task area may horizontal,
vertical inclined plane.
See also Section Checklists.
If the exact location unknown, the room
as whole defined area the work
station used for specification.g.
The maintenance factor can determined
individually, and takes the installation’s
reduction luminous flux caused soiling
and ageing lamps, luminaires and room
surfaces into account.
New quality criteria
– Changing lighting situations
– Personal control
– Energy efficiency
– Daylight integration
– Light interior design element
Maintenance factor
The initial value multiplied the mainte-
nance factor gives the illuminance
maintenance value.
Visual task area
Illuminance levels are specified for specific
visual tasks and are designed for the area in
which these may take place. 300 500 lx).
Area immediately surrounding the visual
task area
Here illuminance may one level lower than
in the visual task area (e.
Uniformity UO
In order perform visual tasks illuminated
areas, there should not any great differ-
ences brightness that uniformity should
not fall below Emin/Ē.
The maintenance schedule (the cleaning
and maintenance intervals for the lamps and
installation) must documented.
Quality characteristics lighting
