When talking about the quality of light in a working environment, the question 'How much light?' is the first one to ask. There are recommendation as to what the minimal illuminance should be. The table below shows some examples from the CIE Code for Interior Lighting:
| Category | Recommended illuminance (lux) | Example | ||
|---|---|---|---|---|
| General areas that are not in permanent use or that do not demand a high visibility of the task |
|
|
| public
areas |
|
|
|
| orientation
during short stop | |
|
|
|
| rooms
that are not in permanent use (storage rooms) | |
| General lighting for indoor work |
|
|
| details
easy to see (operation of machinery) |
|
|
|
| normal
visual tasks (offices) | |
|
|
|
| details
difficult to see (quality control) | |
| Tasklighting for highly demanding work |
|
|
| demanding
task undertaken for an extended time (watchmaking) |
|
|
|
| extremely
fine details (microelectronic assembly) | |
|
|
|
| special
tasks (surgery) | |
Recommended illuminances for work places
These recommendations are derived from visibility tests. They are applicable for mid-aged persons, medium reflectances in the visual environment and for normal priority tasks. Should the conditions differ, then the illuminances will have to be adjusted.