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The luminous flux describes the photometrically evaluated luminous efficiency, hence the light quantity delivered by a light source. The luminous flux is related to the entire room, or to only a part of it (partial luminous flux in a room-angle element). All further photometric variables can be derived from the luminous flux: Unit: Lumen (lm) Customary technical light sources emit the following luminous-flux values (selection): |
| Lamp types |
Nominal Luminous Flux
|
| Compact fluorescent
lamp TC-D/-DEL 10 W |
600 lm
|
| Energy-saving lamp TC-TSE
20 W |
1.200 lm
|
| Fluorescent lamp T26 18 W |
1,350 lm
|
| Incandescent lamp A60
100 W |
1,380 lm
|
| Compact fluorescent
lamp TC-T/-TEL 26 W |
1,800 lm
|
| Low-voltage halogen
incandescent lamp QT12 90 W |
1.800 lm
|
| Fluorescent lamp T16 28 W |
2,600 lm
|
| Fluorescent lamp T16
35 W |
3,300 lm
|
| Fluorescent lamp T26
36 W |
3,350 lm
|
| Fluorescent lamp T16
54 W |
4,450 lm
|
| Sodium-vapour high-pressure
lamp Philips SDW-T 100 W |
4,800 lm
|
| Compact fluorescent
lamp TC- L 55 W |
4,800 lm
|
| Fluorescent lamp T26
58 W |
5,200 lm
|
| Metal halide lamp HIT-CRI 70 W/840 |
5,800 lm
|
| Fluorescent lamp T16 80 W |
6,150 lm
|
| Mercury-vapour high-pressure lamp HME 125 W |
6,300 lm
|
| Metal halide lamp HIE 250 W |
19,000 lm
|
| Metal halide lamp HIE 400 W |
34,000-36,000 lm
|
| The data are basically manufacturer-dependent, although they have been partly brought into line with one another. The ratio between luminous flux and the power consumed is known as Not all the luminous flux emitted by the lamp reaches the work plane. There are losses in the luminaire (absorption, transmission, reflection losses) and at the room perimeters (reflectance). In the normal case about 60-70% of luminous flux will reach the work plane (Light Output Ratio). |
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