Technical information

www.fagerhult.com • www.fagerhult.co.uk492
140
120
100
80
60
40
20
φ %
0 m/s
0,5 m/s
-20 -15 -10 -5 10 15 20 25 °C
05
0 m/s
0,5 m/s
140
120
100
80
60
40
20
φ %
-20 -15 -10 -5 10 15 20 25 °C
05
140
120
100
80
60
40
20
φ %
0 m/s
0,5 m/s
-20 -15-10 -5 10 15 20 25 °C
05
140
120
100
80
60
40
20
φ %
0 m/s
0,5 m/s
0 m/s
0,5 m/s
-20 -15 -10 -5 10 15 20 25 °C
05
Cold spaces
Most luminaires are designed to give the best performance at
normal room temperature. In a cold area, for example, certain store
spaces or freezer rooms, the ambient environment for the luminaire
is very dierent. Many industrial luminaires are suitable for use in
this situation, but there are a number of parameters to bear in mind
in order to choose the right luminaires.
The selection of the luminaire and its placement in the room are
governed by:
What is the room temperature?•
What IP-class is required? •
Where are the chilled beams or conditioning units placed? Is the •
luminaire exposed to air currents?
Is there a risk of the luminaire being subjected to mechanical •
eects?
Should the luminaires be on continuously or are they switched on/•
o at specific intervals/days?
General
Open reflector luminaires are designed so that the maximum lumi-
nous flux is obtained at a normal room temperature of 25 °C. When
this kind of luminaire is placed in a cold space the luminous ux
and the ignition ability are aected. The lower luminous flux must
be taken into consideration during light planning.
On the other hand, luminaires with a degree of protection equal
to IP 44 and upwards can operate, from a luminous flux standpoint,
better when placed in a colder environment as the light source’s
ambient temperature is usually a little too high when the luminaire
is at normal room temperature. In this situation, the luminous flux
increases, up to a certain point, as the ambient temperature drops.
Ballasts
It is important to use the right ballast to ensure the luminaire also
ignites at low temperatures. The temperature specifications vary for
dierent manufacturers and ballast.
Light sources
The T5 light source emits its maximum luminous flux at an ambient
temperature (around the lamp) of 35 °C. The temperature around
the light source is controlled by the design of the luminaire. For
luminaires with a degree of protection equal to IP 44 and upwards
the light source can heat the space around itself even when the am-
bient temperature around the actual luminaire is low. This is why T5
luminaires can work very well even in cold surroundings.
The T8 light source is slightly dierent compared to the T5. It has
its maximum luminous flux at a lower temperature, 25 °C. Conse-
quently, the T8 light source emits a higher luminous flux than T5 at
certain, lower, ambient temperatures.
Thermo-lamps
In some locations the use of thermo-lamps maybe required.
Thermo-lamps have an extra outer glass that insulates (thermal
principle). The disadvantage of these lamps is that they have a
larger diameter, which can cause problems in some luminaires.
Thermo-lamps are available in both T5 and T8 designs, though not
34209 Densus 2x35 W – 81508 T5 Thermo
35183 Scatola Medium 2x28 W – 81507 T5 Thermo
32858 Inducon Medium 2x35 W – 81508 T5 Thermo
32733 Induline Wide 2x54 W – 81374 T5
32713 Induline Narrow 2x54 W – 81374 T5
in all outputs. Please refer to the light sources chapter for more
information.
Placement
Luminaires should not, if possible, be placed too close to chilled
beams or air conditioning units. The cold air currents can have a very
negative eect on the luminous flux. This also applies to enclosed
luminaires or when using thermo-lamps.
Actual luminous flux
The graphs below show how the luminous flux is aected by ambi-
ent temperature for a number of typical industrial luminaires. The
red curve indicates the luminous flux with no air movement and
the blue indicates the flux with an air flow of 0.5 m/s. As a reference
value the luminous flux at +25 °C with no air movement is used.
Text and order numbers in italics denote the light source.
The stated values are intended as a guide only and not an absolute
value. Please factor in a good margin when designing.
For more information go to www.barbourproductsearch.info