Ra the lower limit for the colour rendering
index.
height 0. The result is
a minimum level. The the selected lamp must be
equal greater than this value.
Uniformity the ratio between the
lowest (Emin) and the mean illuminance level
(Ē) the area evaluated.
EN 12464 specifies that the lighting
designer must document the maintenance
factor and maintenance schedule. the precise location not
known, the limit should applied the
whole room
specific working area.
UGRL the upper limit for direct glare.
“Lighting indoor workplaces”,
EN 12464-1
(June 2011)
“Lighting outdoor workplaces”,
EN 12464-2
(October 2007)
“Sports facility lighting”, 12193
(April 2008)
The following limits have been specified in
the tables:
Illuminance levels must not fall below
the maintenance
values the visual
task area.
Example for office task area:
The maintenance factors can deter‑
mined case-by-case basis, according
to the manufacturer’s specifications.75 m
task area
user floor-area
1. The
UGR value calculated the design process
must lie below this.00.67
clean atmosphere, and 0.The Lighting Handbook
30
Standard values for lighting indoor and outdoor workplaces
and sports facility lighting
Tables and figures were taken from the
European standards.50 in
very dirty environments.
Where individual maintenance data is
available, the following values are recom-
mended reference maintenance factors for
modern technology and three-yearly mainte-
nance: 0
