Tips for
Efficient Lighting Design
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- Natural light
should be used as far as possible. Especially artificial light
is not required in staircases during daytime. Use of blinders
to block the sunlight should be minimized. Use of curtains or
blinders made-up of cloth should be promoted. This will allow
maximum utilization of day light without causing glare. It was
also observed that by opening venetian blinders by just 10-20
degrees, the illumination level can be raised by 100-150 lux with
out causing any problems of glare.
- While designing
the illumination system, care should be taken so as the lights
in each area can be switched off partially when not in use. (e.g.,
The illumination level required for working on computers is 300
- 500 lux, but when the area is not used for work illumination
level of 150 lux is sufficient. (This can be achieved by switching
off some of the lights.) Also proper naming or numbering of the
switches will facilitate the use of them by occupants or security
staff.
- While designing
new offices, Task Lighting can be used for lighting system :-
Use new generation tri-phospher coated tubelights (with 3300 lumens
o/p) for providing general illumination level of 100-200 lux.
In addition, use the 11 watt or 18 watt Compact Fluorescent Lamps
near the working table, to increase the illumination level from
200 lux to 500 lux whenever required. This approach should be
kept in mind while making the interior design. As after finalizing
any design, making such changes will be difficult. Also this strategy
should be first used at a small office or in a part, so as to
analyze occupant satisfaction with this system.
- A bimonthly
cleaning schedule for lighting fittings (lamps & reflectors) should
be prepared, so that the lumen loss due to dirt accumulation &
environmental impact can be avoided. In addition, this information
should be provided to the illumination designer, to enable him
to consider a higher maintenance factor while designing the lighting
system. If the maintenance factor assumed is low, then there will
be wastage of electrical energy in the initial few years of operation
of lights. Also higher maintenance factor will directly reduce
the total number of tube lights required at the design stage itself.
- As a thumb
rule for fluorescent lamps, group replacement of lamps can be
used to keep the system operating near peak o/p & efficiency.
It is proved that the economic replacement can be done at 70%
- 80% of the lamps rated life. The replacement interval in years
can be calculated by dividing useful operating life in hours by
annual operating hours. This strategy should be used to reduce
the initial lumens & system power while resulting in same maintained
illumination level. (i.e. designer should use maintenance factor
of near unity.) Maintenance & operating staff should be trained/informed
about the energy management issues & procedures.
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