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| LIGHT TECHNICAL
INFORMATION |
Luminous flux. Luminous flux is a measurement of how much light a light source
emits. Luminous flux is measured in lumen (lm).
Luminous efficacy.The efficiency of a light source is expressed with the term
luminous effi cacy and is the relation between luminous flux and electrical power.
The luminous efficacy is measured in lumen per watt (lm/W).
Colour reproduction. Colour reproduction is a measurement of a light source's
ability to correctly reproduce the colours in the colour spectrum and is measured
in Ra. The Ra index for retail lighting ought to be greater than 80. The value for
maximum colour reproduction is stated as Ra-100.
Colour temperature. The colour temperature states the light source's colour tone
and is measured in Kelvin (K). 2700 K is described as environment/interior colour
temperature, 3000K is described as warm white and 4000 as cold-white colour
temperature. The higher the colour temperature the colder the light.
Colour code. The light source's colour code is denoted by three digits. The first
digit represents the colour reproduction (Ra) and the last two denote the colour
temperature in Kelvin divided by 100. A light source with the code 830 has a colour
reproduction value (Ra-index) above 80 and a colour temperature of 3000 K.
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| Colour temperature/colour reproduction |
| |
| Colour code |
Colour reproduction |
Colour temperature in K |
 |
| 827 |
Ra>80 |
2700 |
|
| 830 |
Ra>80 |
3000 |
|
| 840 |
Ra>80 |
4000 |
|
Life span. Here there are two different concepts: mean mortality rate and service
mortality rate.
Average mortality rate. States the number of burning hours when half of a large
number of controlled light sources have gone out.
80 % service mortality rate.When 80 % of the lighting installation’s original
luminous flux remains. Depreciation of the luminous flux depends on a
combination of reduced luminous flux and extinguished light sources.
Note that the luminous effi cacy (lm/W) applies to the light source
and ballast losses have not been taken into consideration. |