Civil Engineering Reference
In-Depth Information
Table 25 Illuminance per activity [
19
]
Illuminance (lux)
E
m
Activity
Area
100
Casual seeing
Corridors, changing rooms, stores
150
Some perception of detail
Loading bays, switch rooms, plant rooms
200
Continuously occupied
Foyers, entrance halls, dining rooms
300
Visual tasks moderately
easy
Libraries, sports halls, lecture theaters
500
Visual tasks moderately
dif
cult
General of
ces, kitchens, laboratories, retail
shops
k
L
is the correction factor taking into account the type of lamp (for lamps other
than tubular
fluorescent lamps from Table
26
);
k
R
is the correction factor taking into account the type of space, given in the
Table
27
.
cacy of a light source is the ratio of the light output to the power
consumed. It is given in lumens per Watt. Luminaire ef
The ef
cacy is the light output of
the entire luminaire (light
fitting) divided by the total power consumed by the lamps
and ballasts. It is equal to the lamp ef
cacy multiplied by the light output ratio of
the luminaire and is measured in lumens per watt (lm/W). The higher the ef
cacy
value is, the more the energy-ef
cient lamps or lighting systems will be. For
example, the ef
cacy of an incandescent light bulb of 60 W is 12 lm/W and of a
compact
fluorescent tube it
is 91 lm/W. The role of lighting systems is to provide adequate visual conditions for
human activities to be carried out ef
fluorescent lamp (CFL) of 11 W is 55 lm/W. For a 36 W
ciently and comfortably.
Table 26 Correction factor k
L
[
18
]
Type of lamp
Factor k
L
Ballast
-
EB
a
LLB
b
CB
c
Incandescent
-
-
-
6
-
-
-
Tungsten halogen
5
Tubular
uorescent
-
1.0
1.14
1.24
Compact fluorescent, with external EB
-
1.2
1.4
1.5
Compact fluorescent, with integrated EB
-
-
-
1.6
Metal halide high-intensity discharge
-
-
0.86
1
High-pressure sodium vapor
-
-
-
0.8
High-pressure mercury vapor
-
-
-
1.7
a
b
c
EB Electronic ballast;
LLB Low loss ballast;
CB Conventional ballast
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