the natural agent that stimulates sight
and makes things visible.
Natural
-Sun
2. Artificial
-lasers
- Electric weldings
- -tungsten filament lamps
- Fluroscent lamps
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



Direct :-99-100%
Semi direct :- 10-40 %
Indirect :- 90-100%projected directly to walls
Semi indirect :- 60-90% projected upward
Direct –indirect :- equally distributed
 Protection
of eyes against
fatigue, stress and defect of
vision
 Enhances the working
capacity
 Protection against accidents
 Along
with the clean
and pure air , food,
water, ventilation etc
appropriate light is also
essential for health
Protection against headache and
psychological fear of darkness
 Proper lighting helps in the
proper functioning
 Plant life ( including
photosynthesis) and
conservation of environment

 I.



Natural sources
Sun and its reflected light
II. Artificial sources
1. Electric source
Hydro electricity
 Solar electricity
 Thermal electricity
 Nuclear electricity
 Wind electricity

 2.
Petroleum source:
 Light
through kerosene, LPG,
Candle , generators running on
diesel etc
Luminous intensity of light is
measured in terms of foot-candle
 In living rooms the intensity of
light should be 7 foot candle
 In bed room, 4-6 foot candle
 Reading room 10-15 foot candle
 OT 75 foot candle

 Presently
the unit of the
intensity of light has
been changed to “lux”
Sufficiency: Intensity of light
must be sufficient, so that it does
not strain the eyes while reading
or doing desired work
 Absence of glare: Glaring or
very bright light is not good as it
harms the eyes and reduces the
power of vision

 Shadow:
Shadow obstructs
the light. There should not
bee any shadow on the
book while reading
 Steadiness: Light should
be steady. Flickering of
light is not the sign of
adequate light
 Colour
: Coloured light is not
good for reading. White light
is good for doing any work.
 Distribution of light: the
distribution the light should
be uniform, having the same
intensity over the whole field
of work.
Satisfactory vision ----- 15 -20 foot
candles
Without eye strain
stairs ------ 5 foot candles
Corridors -------- 100 foot candles



Proper location, design, & orientation of
building
Removal of obstructions





Eye strain
Discomfort
Accidents
Injury to eye
Retinal burn







Proper illumination
Appropriate training
Proper design of buildings
Proper design of equipments
Protective eye shields
Avoid looking directly to sources of light
Proper planning of house – distance between
the building & windows