illumination

1. ILLUMINATION
Prepared by
Vima Mali

2. INTRODUCTION
As we know that almost all human activities depends
on light.
Sun is a prime natural source of light but artificial
lighting plays almost main role in our daily life.
The electrical lighting are mainly used for domestic
purpose, decorative purpose, advertising, traffic control,
medical field and street lighting etc.

3. ILLUMINATION
When light falls on a surface, it becomes visible,
the phenomenon is called as illumination.
Illumination is also defined as luminous
flux falling on a surface per unit area.
It is denoted by E and measured in lumen
per square meter or meter - candle.
E = Ф / A

4. DESIGN OF INDOOR LIGHT SCHEME
While designing a good lighting schemes, the
following points must be kept in mind
1.It should provide adequate illumination.
2.It should provides uniformly distributed light
all over working plane.
3.It should avoid glare(a very harsh light) and
shadows as far as possible.
4.It should provide light of suitable colors.

5. LIGHTING SCHEMES
Lighting schemes are classified according to
the location, requirement and purpose etc.
are as under
1.Direct lighting
2.Indirect lighting
3.Semi direct lighting
4.Semi indirect lighting
5.General lighting

7. DIRECT LIGHTING
 As is clear from the name, in this system almost 90 to
95 % light falls directly on the object or on the surface.
The light is made to fall upon the surface with the help
of deep reflectors.
Such type of lighting scheme is most used in industries
and commercial lighting.
Although this scheme is most efficient but it is liable to
cause glare and shadows.

9. INDIRECT LIGHTING
The lamp fitting is hidden and the light rays reach the
working plane indirectly by reflection from the walls,
ceiling or any other surface.
90 % of light is directed upwards by using diffusing
reflectors (a polished surface for reflecting light).
Here the ceiling (i.e. polished surface) acts as a source
of light and this light is uniformly distributed over the
surface and glare is reduced to minimum.
It provides shadow less illumination which is useful
for drawing offices and composing rooms. It is also used
for decoration purposes in cinema halls, hotels etc.

11. SEMI DIRECT LIGHTING
This is also an efficient system of lighting and
chances of glare are also reduced.
Here transparent type shades are used through
which about 60 % light is directed downward and
40 % is directed upward.
This also provides a uniform distribution of
light and is best suited for room with high
ceilings.

13. SEMI INDIRECT LIGHTING
In this system about 60 to 90 % of total light is
thrown upward to the ceiling for diffused
reflection and the rest reaches the working plane
directly.
A very small amount of light is absorbed by the
bowl. It is mainly used for interior decoration.

15. GENERAL LIGHTING
This system employs such type of luminaries,
shades and reflectors which give equal
illumination in all the directions.

16. ILLUMINATION LEVEL
Type of work recommended illumination level
Offices 100-400 lumens/ meter square
Schools 250-400 lumens/ meter square
Industry 1000 lumens/ meter square
Shops 250-500 lumens/ meter square
Hotels 80-100 lumens/ meter square
Hospitals 250-3500 lumens/ meter square

17. ARTIFICIAL ILLUMINATION:
What do we understand by Artificial Illumination ?
Illumination provided by Electrical Light Fixtures or
other means, other than Natural Sun Light.

18. What was the earliest form of electric light which
was invented ?.
 The earliest invention was the electric arc which was
followed by carbon filament lamp which was
developed by Thomas Alva Edison in 1879.
 On the other hand Arc lamps are widely used even
today for film projection, in television studios etc.,

19. TYPES OF ARTIFICAL LAMPS
1.Arc lamp (Carbon Arc lamp)
2.Incandescent lamp
3. Compact fluorescent lamp
4. Neon lighting
5. Flood lighting
6. LED lighting

20. ARC LAMP
The principle of an arc lamp is that when two
electrodes carrying current are separated through
a small distance, an arc is struck between them.

21. The arc lamps were used in the past for street
lighting purposes but now a day these are used
when extreme brightness is required.
Most commonly use arc lamp is
Carbon Arc
Lamp
For maintaining the arc, a minimum voltage required
is given by : V = (39 + 28 L ), where L is length of
arc in centimeter.

22. 75 hrs average-----------------(1890s)
175 hrs--------------------------- (1911)

23. INCANDESCENT LAMPS
•These are the most inefficient form of
artificial
lighting.
•They work by heating an electric element to
white heat, and produce much more heat than
light.
• Standard filament bulbs are more common in
homes than in offices.
• They are cheap to buy but short lived, with a
typical life of only about 700- 1,000 hours.
• They should only be used in places that are lit
for short periods and not very often, such as
storage cupboards.
• Very sensitive to the voltage fluctuations.

24. INCANDESCENT LAMP (TUNGSTEN LAMP)
These are the standard bulbs that most people are
familiar with.
Incandescent bulbs work by using electricity to heat a
tungsten filament in the bulb until it glows.
The filament is either in a vacuum or in a mixture of
argon / nitrogen gas.
Most of the energy consumed by the bulb is given off
as heat, causing its Lumens per Watt performance to be
low.

25. COMPACT FLUORESCENT LAMPS (CFLS)
• Compact fluorescent lamps (CFLs) now
come in a wide range of shapes and can be
used to replace almost any incandescent
lamp.
•They are four to five times more efficient
than incandescent lamps.
•They have a lifetime of 10,000 to 15,000
hours.

26. COMPACT FLUORESCENT LAMPS
Approximate Equivalents to Incandescent Bulbs.
CFL. INCANDESCENT.
7–10 Watts. 40 Watts.
15-18 Watts. 60 Watts.
20 Watts. 75 Watts.
20-25 Watts. 100 Watts.
32 Watts. 150 Watts.

27. NEON LIGHTING / LAMPS

Neon lighting is created by brightly glowing, electrified
glass tubes or bulbs that contain rarefied NEON or
other gases.
Georges Claude, a French engineer and inventor,
presented neon tube lighting in essentially its modern form.

28. NEON LIGHTING / LAMPS
While neon tube lights are typically
meters long, the lamps can be less than
one centimeter in length.
Through the 1970s, neon glow lamps
were widely used for displays in
electronics, for small decorative lamps,
and as electronic devices in of themselves.
Since the mid 20th Century, in recent
decades neon lighting has been used
consciously in art, both in individual
objects and integrated into architecture.

29. FLOOD LIGHTING
Floodlights are broad-beamed, high-intensity artificial
lights often used to illuminate outdoor playing fields
while an outdoor sports event is being held during low-
light conditions.
A floodlight used on a A floodlight in a cricket
football field. field.

30. FLOOD LIGHTING:
The most common type of floodlight is the Metal Halide
which emits a bright white light colour.
However most commonly used for sporting
events are high pressure Sodium floodlights which emit a
soft orange light, similar to that of street lights.

31. LED – LIGHT EMITTING DIODES
Light Emitting Diodes (LED) are bulbs without a
filament, that are low in power consumption and have a
long life span.

32. LED
Light emitting diodes are a relatively new lighting
technology although they have been used for a
long time for other uses.
•They are also commonly used in traffic lights,
street lights etc.
•One big advantage is that provided they are well
designed, they can have a very long life of 50,000
or even up to100,000 hours.
•Withstand high voltage fluctuation in the power
supply

33. Power consumption of LED light bulbs
• Most modern LED operate in a range of 2 to 4 volts
and consume anywhere between 350mA and
1500mA.
• The power consumption varies from manufacturer to
manufacturer and also because of the purpose for
which the LED was designed.
• Now a days using latest of the LED manufacturing
technology, manufacturers are able to produce LEDs
that are not only super bright but also consume less
power while producing light of higher intensity.

34. Benefits of using LED light bulbs over standard
light bulbs
• Power consumption of LED light bulb is only 10% of
the standard light bulb.
• LED light bulbs withstand great amount of
vibration, shock and temperature variations.
• LED light bulbs are 10-60 times more energy
efficient than incandescent light bulbs.
• Incandescent light bulbs produce light that flickers
where as LED light bulbs produce flicker free light.
• LED bulbs can produce many rich and vibrant
colors when compared to incandescent light bulbs.

35. Disadvantage of a LED light bulb

36. Disadvantage of a LED light bulb
• Some LED light bulbs show sign of age after a couple
of years of use and may produce only 50% of the
light output when compared to what it used to
produce when it was new.
However new technologies are in process to
enhance its performance over its life span.