Illuminance
Illuminance Ev (English illuminance, SI unit: lux or lux, unit symbol: lx ) is the photometric equivalent of the radiometric irradiance E (Unit: lumens / square meter or lm / m²).
Theoretical derivation
Ev is the quotient of the luminous flux incident per unit area Ae of the receiver, so the light output per area:
Thus, the illuminance is a pure receiver size. The analog quantity for light sources is called radiance Mv:
The luminous flux is the total radiated from a light source in all directions, light output. Illuminance, which produces a point-shaped light source of constant light intensity on a surface that will decrease as a consequence of conservation of energy with the square of the distance:
It represents the solid angle steradian dar.
By the definition of the illumination, this may be different measured or calculated, since the surface of any object need not be perfect square.
Normatively required illuminance
Target illuminance:
- Escape routes: minimum illumination of at least one lux
- Workplaces Inside: minimum average illuminance of 100 lux
- General lighting in work areas: at least 100 Lux, the necessary task lighting on the particular visual task depends on: constantly occupied workplace: at least 300 lux
- VDU workstation in Table Height: minimum 500 lux
For comparison, cloudy winter day: 2,000 to 4,000 Lux
- Workplaces outside: at least 5 lux
- Roads: at least 7.5 Lux