English
The intensity of lighting (also illuminance in accordance with ČSN EN 12665) is a photometric value defined as the luminous flux incident on a particular surface. It is the quotient of the luminous flux (in lumens) and the area (in square meters). It is denoted as E. Its unit is a lux (lx), which is illumination caused by luminous flux 1lm incident on an area of 1 m².
A normal value of indoor light ranges from 100 ÷ 2,000 lx, on a sunny summer day outdoors it can reach up to 70,000 lx (at the latitude of the Czech Republic).
A clear moonlit night with the full moon represents the illumination of up to 0.5 lx.
Human sight is so adaptable that a person is able to read a clear text at approx. 10-8 lx.
Requirements for artificial lighting
|
Illuminance [lx] |
The place and the activity |
|
75 |
Communication in a flat |
|
100 |
Living kitchens, bathrooms, toilets |
|
150 |
Halls, reading in bed |
|
50 ÷ 100 |
Total or graded illumination of the living room with local lighting |
|
200 ÷ 500 |
Total or graded illumination of work areas without local lighting |
|
200 ÷ 300 |
A common meal |
|
300 |
Studying, writing, drawing, kitchen work, etc. |
|
500 |
Delicate manual work, homework, blackboard in the classroom, office |
The recommended ranges of illumination defined by the International Commission on Illumination (CIE):
|
Illuminance [lx] |
|
|
20 ÷ 50 |
Basic orientation in the environment |
|
50 ÷ 100 |
Simple orientation, short simple activities |
|
100 ÷ 200 |
Social spaces, short-term work |
|
200 ÷ 500 |
Routine work-related tasks (offices, schools) |
The main requirements and criteria for the lighting of the interior of flats are: good orientation in space, visual comfort and colour rendering fidelity. This is what the parameters of lighting intensity are based on, as well as the type of lighting fixtures (incandescent bulbs, fluorescent lamps, discharge lamps, LEDs). The recommended maximum ratio of illuminance of adjacent spaces in the flat is 1:5.
The level of outdoor lighting and indoor illumination is measured by the C-RI-0401S module, or its variants, e.g. the C-RI-0401R-design, or the C-RI-0401I.