To begin, you must know that the lighting power in Lux is a subjective enough size: Some people will be happy with 80 lux in their living room while others will want 300!
Also the type of light (lighting spectrum) plays a lot: economic and LED bulbs a bulb in natural sunlight will give a much greater light impression while the lumens of the source are the same.
Recommended lighting powers (high scale):
Stairs, basements, attics: 30 lux
Garages, hallway, utility room: lux 60
Kitchen, games room, lounge, dining room, local
domestic work, waiting room: 250 lux
Eating, cooking and leisure work, works
secretarial and laboratory: 500 lux
Entrance hall, shower room, bathroom, bedroom
for children, cellar: 720 lux
Reading, writing, handicrafts, homework, DIY,
drawings, make-up: 750 lux
Architecture, precise works, exact control,
differentiate colors 7000 lux
Regulatory powers according to wiki
streets, roads and highways: 15 to 50 lux
intermittent activity or simple task: 125 lux
average mechanics, office work: 200 lux
fine mechanics, drawings: 400 lux
precision mechanics, electronics: 600 lux
difficult tasks, laboratories: 800 lux
Examples of other common lighting powers (to compare):
sensitivity of a low level camera: 0,001 lux
full moon night: 0,5 lux
well lit night street: 20 - 70 lux
living room: 100 - 200 lux
well-lit apartment: 200 - 400 lux
work area: 200 - 3 000 lux
night stage: 1 500 lux
outside by overcast sky: 25 000 lux
outside in full sun: 50 000 to 100 000 lux
The disparity of these values confirms my 1ere remark on the subjectivity of lighting.
Calculation method of lighting design
It's pretty simple.
- 1 Lux = 1 Lumens / m²
- With the area of the room to be illuminated and the number of lux desired, you get a number of Lumens.
- By knowing the Lumens per bulb, you have the number of bulbs needed to install and thus light points / sconces / fixtures to install.
Example of dimensioning with 3 choice of types of bulbs.
120 Lux requested in 36 m² room will require a source of 120 * 36 = 4320 lumens
A good fluorescent bulb has a yield of 50 65lm / W so it will require a compact fluorescent power of 4320 / 50 = 86 W.
It should be known that the higher the power of the bulb, the better its performance.
Conclusion
Here is for the method, it is necessary to keep in mind the strong subjectivity of the concept of lighting (in the same kind as "the tastes and the colors ..."), that one is not near Lux and that it is always possible to add a free-standing ambient lighting in addition ... the color of the walls or the furniture, for example, has a strong influence on the ambient light!
