STEP SYSTEMS LUX Operating Instruction page 8

The following table you can use as a help while conversing the radiation (W/m²) in radiation sum
(J / cm²). For example, if you measure in one hour an average radiation of 25 W / m², so it
corresponds to the calculated total radiation of 9 J / cm². The table contains also a directive for
measurements with a lux meter. Light intensity of 4,500 lux corresponds to an average radiation of
about 100 W / m².
Measured total radiation (J / cm ²), when for the duration of one hour, a certain radiation (W / m²) is
measured, and the relation between lux and W / m².
At 100 W/m² about 4.500 lux is measured (1:45)
At 500 W/m² about 44,570 lux is measured (1:89,14)
At 1,000 W/m² about 104,000 lux is measured (1:104)
The lux values are classified as follows:
< 300 lux
300 lux – 1,000 lux
1,000 lux – 3,000 lux
3,000 lux – 10,000 lux
10,000 lux – 12,000 lux
> 12,000 lux
By shading the lux values should not be reduced below 8,000 lux.
Exception is propagation, here not less than 3000-5000 lux
Reference values in lux
Cloudy weather
Sunshine
W/m² J/cm² Lux-Meter
25 9
50 18
75 27
100 36
150 54
200 72
250 90
300 108
350 126
400 144
450 162
500 180
550 198
600 216
650 234
700 252
750 270
800 288
900 324
1.000 360
= growth stagnation, plants wither
= no growth of plants
= plants grow very slowly
= plants grow proportionally with increasing lux level
= optimum for the most plants
= the light intensity is no longer utilized by the plants, because in most
cases the heat interferes with the assimilation process.
Open land
5.000 - 15.000
40.000 -150.000 30.000 - 40.000
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Printed in Germany.
STEP Systems GmbH 2016
1.050
2.140
3.290
4.500
7.145
10.270
14.240
20.900
29.950
34.675
39.550
44.570
49.800
55.200
60.800
66.700
72.850
79.300
93.100
104.000
Greenhouse Under old plastics
3.000 - 10.000 2.000 - 8.000
10.000 - 30.000
Duisburger Str. 44
Tel: ++49 (0) 911 96 26 05-0
Fax: ++49 (0) 911 96 26 05-9
D-90451 Nürnberg
e-mail: info@stepsystems.de
www.stepsystems.de