This document discusses lighting definitions, types of lamps, and lighting design principles. It begins by defining key lighting terms like luminous flux, illuminance, luminous intensity, and color temperature. It then describes various lamp types including incandescent, fluorescent, high intensity discharge lamps, and LEDs. Their characteristics like efficacy, color rendering, and lifetime are compared. The document also covers lighting design considerations like recommended light levels for different tasks and the laws of illumination. Overall it provides a comprehensive overview of lighting fundamentals and design concepts.

1. By Dr. Kok Boon Ching
2012@JEK/FKEE
1

2. Outlines
 Introduction
 Important Definitions
in Lighting
 Laws of Illumination
 Types of lamps and
their characteristics
 Electrical Lighting
Design
 Requirements of
Proper Lighting
2

3. Introduction
 Light is just one portion of the various
electromagnetic waves flying through
space which have both frequency and
length.
3

4. Introduction
4

5. Introduction
 Light is emitted through:
a) Incandescence: Solids and liquids emit visible
radiation when they are heated to temperatures
about 1000K. (e.g. metal heated)
b) Electric Discharge: When an electric current is
passed through a gas, the atoms and
molecules emit radiation whose spectrum is
characteristic of the elements present. (e.g.
corona)
c) Electro luminescence: Light is generated
when electric current is passed through certain
solids such as semiconductor or phosphor
materials. (e.g. LED)
d) Photoluminescence: Radiation at one
wavelength is absorbed, usually by a solid, and
re-emitted at a different wavelength. (e.g 5

6. Introduction
 Energy consumption via lighting systems is
significant.
 The global electricity consumption for
lighting in 2005 is estimated at 3418 TWh
(terawatthours), i.e. 19% of total global
electricity consumption.
6

7. Introduction
 Today the global light
production (in lumen) can
be divided as follows on
the different sectors:
◦ 44 % for lighting of
commercial and public
building,
◦ 29 % for industrial
lighting,
◦ 15 % for residential
lighting,
◦ 12 % outdoor lighting
(streets, security, road
signs and car parks).
7

8. Introduction
Energy consumption in different
sectors:
8

9. Important Definitions in Lighting
2 objectives of lighting designer:
1. to provide the right quantity of light.
2. to provide the right quality of light.
9

10. Important Definitions in Lighting
 Luminous flux, F (lumen, lm)
Total amount of visible light power emitted by a
light source. (concentrated on source)
1 lumen = the photometric equivalent of the watt.
1 lumen = luminous flux per m2 of a sphere with
1 m radius and a 1 candela isotropic light source
at the centre
1 watt = 683 lumens at 555 nm wavelength
10

11. Important Definitions in Lighting
 Illuminance, I (Lux, lx)
The amount of light arriving on a working plane.
(concentrate on object to illuminate)
1lux = 1lm/m2 . This value is used in light
calculations and design plans. (classroom =
300lux min)
Or unit in foot-candles (1 Lux = 0.0929 fc) –
USA.
11

12. Important Definitions in Lighting
For example, 1000
lumens, concentrated
into an area of one
square meter, lights up
that square meter with
an illuminance of 1000
lux. The same 1000
lumens, spread out over
ten square meters,
produce a dimmer
illuminance of only 100
lux.
12

13. Important Definitions in Lighting
 Luminous intensity, P
(candela, cd = lm/sr)
Measure of the luminous flux emitted by a light
source in a particular direction, measured in
lumens per steradian. (take light emitted from
candle as example)
13

14. Important Definitions in Lighting
14

15. Important Definitions in Lighting
 Luminance (cd/m2)
Measure of the
density of luminous
intensity in a given
direction. It describes
the amount of light
that passes through
or is emitted from a
particular area, and
falls within a given
solid angle. 15

16. Important Definitions in Lighting
16

17. Important Definitions in Lighting
 Uniformity
The uniformity of illuminance describes how evenly light
spreads over an area (HD). Non-uniform illuminance
creates bright and dark spots (blurred black and white
pictures), which can distract and discomfort some
occupants.
17

18. Important Definitions in Lighting
 Glare
Glare is a sensation caused by relatively bright objects
in an occupant’s field of view. The key word is relative,
because glare is most probable when bright objects are
located in front of dark environments (car spot light at
night).
18

19. Important Definitions in Lighting
 Colour Rendering (contrast)
The colour rendering of a light source is an indicator for
its ability of realistically reproducing the colour of an
object. Colour rendering is given as an index between 0
and 100, where lower values indicate poor colour
rendering and higher ones good colour rendering.
Other index used is 1A (extremely good), 1B (Very
good), 2 (Moderate), 3 (Low), and 4 (Little or almost
none).
19

20. Important Definitions in Lighting
 Colour Temperature (K)
Color appearance of a lamp and the light it
produces.
It’s expressed in degrees Kelvin (K).
Below 3300K, the source is considered as
“warm light” (normal fire yellow). Above 5300K,
the source is considered as “cold light” (gas fire
blue).
Incandescent lamps: “true value” color
temperature.
Fluorescent and high intensity discharge (HID)
lamps: correlated color temperature.
20

21. Colour Temperature in
Degrees Kelvin
21

22. Laws of Illumination
 Inverse Square Law
Defines the relationship between the
illuminance from a point source and
distance.
 Lambert’s Cosine Law
States that the illuminance falling on
any surface varies as the cosine of the
incident angle, .
22

23.  The illuminance from a point source can be
put in the form
2
2
4
)
_
(
_
)
( 
S
area
sphere
strength
Sources
d
P
I 


23

24. Example 1:
2
2
2
1
2
2
1
2
1
2
2
2
2
1
1
2
1
/
40
/
10
5
.
0
1
)
(
)
(
m
lm
m
lm
m
m
I
I
d
d
I
d
I
d
I
P
P





















24

25.  The illuminance or the intensity of
illumination is written as:

Normal
Luminous
Flux

cos
' 2
2
D
F
I 
2
1
D
F
I 
25
D1
D2

26. Laws of Illumination –
Lambert’s Cosine Law
 Example:
26

27. Example 2:
Two lamps with 3000 lumens and 5000 lumens are
placed at A and B, respectively. The arrangement is
shown as follows:
C is the midway between the lamps. Calculate the
27
Laws of Illumination –
Lambert’s Cosine Law
Normal
10 m 7 m
A
B
C
D
θ1
θ2
15 m
2.5 m

28. Solution:
Illumination at C,
28
Lux
COS
BC
COS
AC
FC 77
.
47
41
.
32
36
.
15
5000
3000
2
2
1
2






 

m
AC 5
.
12
5
.
7
10 2
2



m
BC 26
.
10
5
.
7
7 2
2



5
.
12
10
cos 1 

26
.
10
7
cos 2 

Nor
mal
10 m 7 m
A
B
C
D
θ1
θ2
15 m
2.5 m

29. Types of lamps
• Incandescent lamps
• Tungsten Halogen Lamps
• Fluorescent lamps
• High pressure sodium lamps
• Low pressure sodium lamps
• Mercury vapour
• Metal halide
• Blended lamps
• LED lamps
HID lamps
29

30. Incandescent Lamps
• Efficiency: 70 – 90 % of
energy converted into heat.
• Bulb contains vacuum or
gas filling
• Efficacy: 12 lumen / Watt
• Color rendering index: 1A
• Color temperature: 2500 –
2700 K
• Lamp life <2000 hrs
30

31. Tungsten-Halogen Lamps
• Tungsten filament and a halogen gas filled bulb
• Tungsten atoms evaporate from the hot filament
and move to cooler wall of bulb
• Efficacy: 18 lumens/Watt
• Color rendering index: 1A
• Color temperature: warm
• Lamp life < 4000 hrs
Advantages:
• More compact
• Longer life
• More and whiter light
Disadvantages:
• Cost more
• Increased IR and UV
• Handling problems
31

32. Fluorescent Lamps
32
STEP 1 Electron emitted by
electrode at one end of fluorescent lamp
travels at high speed through the tube
until it collides with one of the electrons
of the mercury atom.
STEP 2 The impact diverts the electron of the
mercury atom out of its orbit. When it snaps back
into place, ultra-violet radiations are produced.
STEP 3 When the ultra-violet
radiations reach the phosphor crystal, the
impulse travels to one of the active centers in
the crystal and here an action similar to that
described in Step 2 takes place. This time,
however, visible light is produced.
PHOSPHOR
CRYSTALS
VISIBLE
LIGHT
ELECTRODE
ATOM OF VAPORISED MERCURY

33. Compact Fluorescent Lamps
• Different types (T12,
T10, T8 and T5) differing
in diameter and
efficiency
• Most efficient at ambient
temperature of 20-30 oC,
• Compact fluorescent
lamps (CFL) have much
smaller luminaries
Features:
Halo-phosphate
• Efficacy – 80 lumens/Watt (HF
gear increases this by 10%)
• Color Rendering Index –2-3
• Color Temperature – Any
• Lamp Life – 7-15,000 hours
Tri-phosphor
• Efficacy – 90 lumens/Watt
• Color Rendering Index –1A-1B
• Color Temperature – Any
• Lamp Life – 7-15,000 hours
Compact fluorescent lamp (CFL)
33

34. High Pressure Sodium (HPS) Lamps
• Used in outdoor and industrial applications
• Consist of: ballast, high- voltage electronic
starter, ceramic arc tube, xenon gas filling,
sodium, mercury
• No starting electrodes
• High efficacy: 60 – 80 lumen/Watt
• Color rendering index: 1 - 2
• Color temperature: warm
• Lamp life < 24,000 hrs
34

35. Low Pressure Sodium (LPS) Lamps
• Commonly included in the HID (High
Intensity Discharge Light) family
• Highest efficacy: 100 - 200 lumen/Watt
• Poorest quality light: colors appear
black, white or grey shades
• Limited to outdoor applications
• Color rendering index: 3
• Color temperature: yellow
• Lamp life < 16,000 hours 35

36. Mercury Vapor Lamps
• Oldest HID lamp
• Consists of: arc tube with mercury and argon
gas and quartz envelope, third electrode, outer
phosphor coated bulb, outer glass envelope
• Long life and low initial costs
• Very poor efficacy: 30 – 65 lumens/Watt
• Color rendering index: 3
• Color temperature: intermediate
• Lamp life: 16000 – 24000 hours
36

37. Metal Halide Lamps
• Works similar to tungsten halogen lamps
• Largest choice of color, size and rating
• Better efficacy than other HID lamps: 80 lumen/Watt
• Require high voltage ignition pulse but some have
third electrode for starting
• Color rendering index: 1A – 2
• Color temperature:
3000 – 6000 K
• Lamp life:
6000 – 20,000 hours
37

38. Blended Lamps
• “Two-in-one”: 2 light sources in 1 gas filled bulb
• Quartz mercury discharge tube
• Tungsten filament
• Suitable for flame proof areas
• Fit into incandescent lamps fixtures
• Efficacy: 20 – 30 lumen/Watt
• Lamp life < 8000 hours
• High power factor: 0.95
• Typical rating: 160 W
38

39. LED Lamps
• Newest type of energy efficient lamp
• Two types:
• red-blue-green array
• phosphor-coated blue lamp
• Emit visible light in a very narrow
spectrum and can produce “white
light”
• Used in exit signs, traffic signals, and
the technology is rapidly progressing
• Significant energy savings: 82 – 93%
• Longest lamp life: 40,000 – 100,000
hours
39

40. Reflectors
• Impact how much light reaches
area and distribution pattern
• Diffuse reflectors:
• 70-80% reflectance but declining in time
• Painted or powder coated white finish
• Specular reflectors:
• 85-96% reflectance and less decline in time
• Polished or mirror-like
• Not suitable for industrial open-type strip fixtures
40

41. Gear
 Ballast
• Current limiting device
• Helps voltage build-up in fluorescent lights
 Igniters
• Start metal halide and sodium vapor lamps
41

42. Comparing Lamps
Type of Lamp
Lumens /
Watt Color
Rendering
Index
Typical Application
Life
(Hours)
Range
Avg.
Incandescent 8-18 14 Excellent Homes, restaurants, general
lighting, emergency lighting
1000
Fluorescent Lamps 46-60 50 Good w.r.t.
coating
Offices, shops, hospitals, homes 5000
Compact fluorescent lamps (CFL) 40-70 60 Very good Hotels, shops, homes, offices 8000-10000
High pressure mercury (HPMV) 44-57 50 Fair General lighting in factories,
garages, car parking, flood
lighting
5000
Halogen lamps 18-24 20 Excellent Display, flood lighting, stadium
exhibition grounds, construction
areas
2000-4000
High pressure sodium (HPSV)
SON
67-121 90 Fair General lighting in factories, ware
houses, street lighting
6000-12000
Low pressure sodium (LPSV)
SOX
101-
175
150 Poor Roadways, tunnels, canals, street
lighting
6000-12000
42

43. Electrical Lighting Design
Better lighting
increased
productivity
Two main
questions for
designer:
• Choose correct
lighting level
• Choose quality of
light (color
rendering)
43

44. Recommended Light Levels
Illuminance
level (lux)
Examples of Area of Activity
General Lighting for
rooms and areas
used either
infrequently
and/or casual or
simple visual tasks
20 Minimum service illuminance in exterior circulating areas,
outdoor stores , stockyards
50 Exterior walkways & platforms.
70 Boiler house.
100 Transformer yards, furnace rooms etc.
150 Circulation areas in industry, stores and stock rooms.
General lighting for
interiors
200 Minimum service illuminance on the task
300 Medium bench & machine work, general process in
chemical and food industries, casual reading and filing
activities.
450 Hangers, inspection, drawing offices, fine bench and
machine assembly, colour work, critical drawing tasks.
1500 Very fine bench and machine work, instrument & small
precision mechanism assembly; electronic components,
gauging & inspection of small intricate parts (may be
partly provided by local task lighting)
Additional localized
lighting for visually
exacting tasks
3000 Minutely detailed and precise work, e.g. Very small parts
of instruments, watch making, engraving.
44

45. Example 3
An industrial plant has an incandescent lighting
load of comprising 100 Nos. of 60 W and 140 Nos.
of 100 W. Calculate the energy savings if each
incandescent load is replaced by 1 X 40W
fluorescent load. Lighting is required for 4000
hours/year and the cost of electricity is RM 0.22 per
kWh. Replacement cost is RM 13.5 per unit
consider ballast consumption as 15 W.
Given data:
100 W incandescent lamp = 2200 lumens
60 W incandescent lamp = 1320 lumens
40 W Fluorescent lamp = 2400 lumens
45

46. Solution
 Power required by existing incandescent lamps
= 100 x 60 + 140 x 100 = 6000 +14000 =20.0 kW.
 One 40 W fluorescent lamp each will be required to
replace one 100 W incandescent and two of 60 W
lamps (as observed from given data).
  we require 140 nos. of 40W fluorescent lamps (to
replace 100 W incandescent lamps) and 50 Nos. of 40
watts fluorescent lamps (to replace 60W incandescent
lamps).
 Total number of Fluorescent lamps required
= 50 + 140 = 190 Nos.
 Power required for one of fluorescent lamp is 55 W
(including conventional ballast power)
46

47. Solution
 Power required for total fluorescent load
= 190 x 55 W = 10.45 kW
 Annual Energy Savings
= (20 – 10.45) x 4000 = 38,200 kWh
 Annual cost savings
= 38,200 x RM 0.22 = RM 8404.00
 Replacement cost
= 190 x RM13.5/unit = RM2565.00
 Simple payback period
= (RM 2565.00/ RM 8404.00) X 12 = 4 months
47

48. Methods of Lighting
Watts Per
Square Meter
Method Rough
calculations and
normally for checking
use only. According
to the watts/m2 of
area to be
illuminated.
Lumen or Light
Flux Method
Most commonly used
method in lighting
scheme design.
Point to Point
Method
Applicable to
illuminate a point
due to one or more
sources of light is
required. Normally
for flood lighting
calculation.
48

49. N = number of lamps
W = wattage of each lamp
 = efficacy of each lamp
(lumens/watt)
UF = utilisation factor
DF = depreciation factor
MF
UF
W
N
OR
DF
UF
W
N
plane
working
on the
received
Lumens








 

49
Lumen Method

50. Utilisation Factor
lamps
by the
out
given
lumens
Total
plane
working
the
reaching
Lumens
UF 
50

51. Depreciation Factor
conditions
working
normal
under
on
Illuminati
conditions
clean
ideally
under
on
Illuminati
DF 
Dust absorb some light
Wall
lamp
reflector
Typical value:
ranging from
1.2 to 1.4.
51

52. Maintenance Factor
 The ratio of illumination on a given area after a
period of time to the initial illumination on the same
area.
 Lighting efficiency is seriously impaired by
blackened lamps, by lamp life, and by dirt on the
lamp reflecting surfaces of the luminaire.
 The losses are due to the physical changes on
lamps, reflecting and transmitting surfaces, ceiling
and walls.
 Typical value is about 0.8.
52

53. Example 4
A lecture hall with dimension of 12 m
long and 10 m wide is to be
illuminated and the illuminance
required is 350 Lux. Assuming a
depreciation factor of 1.2 and
utilisation factor of 0.6 for the lighting
scheme design. If 36 W fluorescent
lamps (75 lumens/ watt) were to be
used, calculate the number of
fluorescent lamps required.
53

54. Solution
Area = 12 m x 10 m = 120 m2.
Total lumens required
= 350 lux x 120 m2 = 42,000 lumens.
1 x 36 W Fluorescent lamp
= 75 lumens/W x 36 W = 2700 lumens.
Gross lumens output by the lamps:
= 42,000 x (1.2/0.6) = 84,000 lumens.
Nos of lamps = 84,000/2700  32
lamps.
54