Poznámky redaktora
Note B10 and B50:
By values are statistical values: they mean
that percent the product-based criteria
are not fulfilled.
B50 identifies approximate man value
for the reduction luminous flux.74
The Lighting Handbook
A service life 50,000 corresponds to
continuous operation for around 5. B10 names
10% off luminaires that not satisfy one
criterion. This lead the false assumption
that B10 luminaires last longer than B50 lumi-
naires.7 years. However, method exists
that allows such statistics safely calcu-
lated advance for longer operating time.
A maintenance factor can determined for
different presence times for various types of
LED luminaires with service life specification
(see chapter 8).
Example: Service life “L80
50,000 means that the light
output has dropped 80% of
the initial value after 50,000 h
operating time.
When quoting longer service lives, has to
be considered which operating times would
be necessary for these. For this reason, those service life
figures not further specified Zumtobel
data sheet relate B50.
What correct that service lives as
long these cannot measured but only
calculated.
LED technology
Service life hours
10000 20000 30000 40000 50000 60000
100
90
80
70
60
50
40
0
/
/
60000h L90
50000h L80
50000h L70
The service life describes the time
until the mean light output an
LED luminaire has dropped a
specified percentage the initial
light output. B10 has only be-
come established for street lighting.
Apart from the mean service life, the total
failure rate AFV (Abrupt Failure Value) can
also quoted. This refers the total failure
of the modules the luminaire and nor-
mally less than 3%.
It common quote the
“mean rated service life”.
Service life data for LEDs
Relative
light output.
A failure the control gear excluded
here. This has quoted separately and is
normally covered the warranty terms for
the control gear. Whereas B50 can derived from
known forecasting methods, there no
method for B10 that described technical
instructions. With the normal
operating times office use 2,500 per
year, service life 50,000 corresponds
to presence time years
