Illuminance ranges for Indoor Activities/Areas


The illuminance recommended for a specific type of activity will depend partly on the nature of that activity(principally its visual difficulty) and partly on the design of the interior concerned (particularly the lightness of the surroundings).
The table below gives recommended illuminance , based on the scale defined above, for different areas and activities. The values given are average maintained illuminance over the task area. There fore the illuminance may not fall below these values, no matter what the age of the installation.

The values are valid for normal visual conditions and take into account the following factors:
- requirements for visual tasks
-safety
-psycho-physiological aspects such as visual comfort and well being
-economy
-practical experience

The illuminance should be increased, when:
-unusually low reflectances and /or contrasts are present for the task
-visual work is critical
-errors are costly to rectify
-accuracy or higher productivity is of great importance
-the visual capacity of the worker is below normal

A lower value may be used, when:
-reflectances or contrasts are unusually high
-speed and /or accuracy are not critically important
-the task is executed only occassionaly

Recommended Illuminance for various areas and activities
Recommended Illuminance                                          Type of area or activity
(Lux)
30                                                           Outdoor circulation and work areas
100                                                         Circulation areas, simple orientation
150                                                         Rooms not used continuously for working purposes
300                                                         Visually simple tasks
500                                                         Average visual tasks
750                                                         Visually demanding tasks
1000                                                        Tasks with difficult visual requirements
1500                                                       Tasks with special visual requirements
2000                                                       Very exacting visual tasks


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