5.0 Measurements in compliance with DIN 5035, section 6
Please observe the following before performing any measurements:
• In installations comprising discharge lamps (tubular fluorescent lamps), they should have
been already operated for minimum 100 hours, glow lamps minimum 10 hours.
• In order to ensure a stationary lighting, the lamps should be switched on
approx. 10-15 minutes prior to measurement.
• For all measurements, the influence of an external light source on the measurement result
must be taken into consideration. In order to obtain maximum precision two measurement
procedures are available:
a) The room in which the measurement is to take place has to be completely blacked out (e.g.
measurement in the evening or at night). The windows or indirect lights are blacked out,
whereby the degree of reflection of the black-out shield has to be the same as for the gla-
zing (approximately).
b) The first measurement is carried out while the lighting or the external light source are swit-
ched on. The second measurement is carried out at the same spot whereby all lights are
switched off.
The exact measurement result is determined by means of the difference of measurement 1
minus measurement 2.
Example:
Measurement value 1
1235lx with lighting and external light source
Measurement value 2
355lx without lighting, only external light source
Measurement result 1235lx - 355lx = 880lx
For this type of measurement, both measurements have to be carried out immediately one after
the other, as the daylight or external source share are subject to considerable natural fluctua-
tion.
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Measurements in compliance with DIN 5035, section 6
