3. • Light occurs in nature, and sunlight, moonlight, and starlight are the most important sources of light
to life. But because of their need for additional light, humans have learned to create light as well.
Understanding the fundamental difference between natural and man-made light is the beginning of
understanding light sources.
• Natural light sources occur within nature and are beyond the control of people. These include
sunlight, moonlight, starlight, various plant and animal sources, radioluminescence, and, of course,
fire.
• Man-made light sources can be controlled by people, more or less when and in the amount wanted.
These include wood flame, oil flame, gas flame, electric lamps, photochemical reactions, and
various reactions, such as explosives.
MODULE 1 :- SOURCES OF LIGHT
4. Electrical lighting: - An electric light is a device that produces visible light from electrical current.
It is the most common form of artificial and is essential to modern society providing interior lighting
for buildings and exterior light for evening and night time activities.
In technical usage, a replaceable component that produces light from electricity is called a lamp.
Lamps are commonly called light bulbs; for example, the incandescent light bulb Lamps usually
have a base made of ceramic, metal, glass or plastic, which secures the lamp in the socket of a light
fixture.
6. I n d o o r L i g h t i n g
Some of the most common indoor light bulbs are incandescent bulbs, which look like a traditional light
bulb. Generally, the input for these bulbs is either 40W or 60W. But there are other kinds of indoor light
bulbs as well, such as CFLs and LEDs.
Keep in mind that the wattages listed for the CFLs and LEDs correspond to the 40W and 60W
incandescent bulbs. This means that for a lamp that takes a 40W incandescent, you could also use a 9W
CFL or a 6W LED. This will allow you to easily compare the bulbs to one another.
Incandescent Bulbs:
• Has same design for over 100 years since Thomas Edison invented it! It produces
light when a thin wire called a tungsten filament.
• This releases a lot of heat and the bulbs get hot to the touch, thus is very inefficient.
• Standard incandescent lamps generate between 5 and 20 lumens per watt incandescent
light sources are the latest infrared-reflecting halogen lamps, which generate
between 20 and 35 lumens per watt.
Wattage 40 60
Lumens 290 840
7. Compact Fluorescent Light Bulbs (CFL):
• These spiralled light bulbs are far more efficient than the standard incandescent bulb.
• Compact Fluorescent Light bulbs (CFLs) work by running electricity through gas inside the coils,
exciting that gas, and producing light.
• There is a coating on the spirals, which makes this light white. These bulbs do not get nearly as hot as
the incandescent bulbs.
• Fluorescent and compact fluorescent lamps provide good energy efficiency, good to
excellent color, dimming, and many other features expected of modern light sources.
• There are two major types of compact fluorescent lamps: those with screw bases,
designed to directly replace incandescent lamps in incandescent lamp sockets, and
those with plug-in bases designed to fit into sockets in luminaires designed specifically
for compact fluorescent lamps.
Wattage 9 13
Lumens 550 810
CRI: 50-80
8. Light Emitting Diode (LED):
• Unlike incandescent and CFL bulbs, LED bulbs have moved into the technological age.
• LEDs that produce white light work in a rather complicated way, and their invention won a Nobel Prize
in Physics in 2014! While these are the most efficient bulbs to date, they are not without problems
• Although the light they produce looks white, remember that white light contains all the colours of the
rainbow. LEDs contain a lot of blue light, too much of which can have negative effects on
human health and wildlife.
• LED lamps can be used in specialty applications, including signs and display
lighting. Systems employing red, green, and blue LED lamps can be used to create
changing color washes.
Automotive and sign lighting applications, including traffic signals, are
multiplying rapidly.
Wattage 6 13
Lumens 550 800
9. O u t d o o r L i g h t i n g : -
Outdoor lights are usually different from those bulbs used indoors because they need to be much brighter
and last longer. There are many different kinds of light bulbs used outdoors, and they each have pros and
cons.
Halogen Bulbs:
• Also known as tungsten halogen, quartz halogen or quartz iodine lamp, is an
incandescent lamp consisting of a tungsten filament sealed into a compact transparent
envelope that is filled with a mixture of an inert gas and a small amount of a halogen
such as iodine or bromine.
• The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical
reaction which redeposit evaporated tungsten to the filament, increasing its life and maintaining the
clarity of the envelope. This allows the filament to operate at a higher temperature than a standard
incandescent lamp of similar power and operating life; this also produces light with higher luminous
efficacy and colour temperature. Wattage 53 72 75
Lumens 940 1350 1500
10. Metal Halide: -
• Metal halide lamp is special type of arc discharge lamp that works on the arc stream
via some iodide salts along with argon gas and mercury vapour pressure at several
millimetres with the arc tube temperature of 1000 K.
• Metal halide lamps are commonly used in streetlights, parking lot lights, and stadium
lights. They are very bright and contribute to a lot of light pollution.
• They are fairly efficient.
• They produce very white light and have good colour rendition, meaning that objects under these lights
look their true colour.
Wattage 250 400 1000
Lumens 22,000 36,000 1,10,000
11. High Pressure Sodium (HPS):-
• The high-pressure sodium lamp (HPS) is the most commonly used street light throughout the world. It
produces light by running electricity through a mixture of gases, which produces light. The lamp itself is
preferred because it requires little maintenance.
• These lamps are fairly efficient. They take a while to turn on completely and exhibits a golden-pinkish
light that tends to create spaces with a distinctly brown or dirty quality.
• A big driver behind their use is their high efficiency –
around 100 lumens per Watt (when measured for photopic lighting conditions).
Some higher-power lamps (>600 Watt) can achieve efficacies of around
150 lumens per watt.
Although HPS lamps offer very high lumens per watt, their color deficiencies limit use to
lighting roads, parking lots, heavy industrial workspaces, warehousing, security lighting,
and other applications where light color is not important.
Wattage 150 250 400
Lumens 16,000 24,000 50,000
12. Low Pressure Sodium (LPS):-
• The low-pressure sodium (LPS) lamp works similarly to the HPS light. Instead of producing white light
(all the colours of the rainbow), LPS lamps produce almost exclusively yellow light.
• While this light is fairly efficient, it takes several minutes for the bulb to turn on.
• Low-pressure sodium emits monochromatic yellow light, creating stark
scenes devoid of color altogether.
• LPS lamps are even higher in lumens per watt, but their color is so poor
that their use is limited to security lighting.
`
Wattage 18 35 55
Lumens 18,00 4550 7800
13. LED Street Lamps:-
• LED technologies have developed rapidly in recent years and these bulbs are
now being integrated into outdoor lighting solutions.
• While the energy savings are significant, LEDs produce a lot of blue light, too
much of which can have negative effects on human health and wildlife
Phosphor-Converted Amber (PCA) LED Street Lamps:-
• (PCA) LEDs have only been on the market for the past few years.
• They use very little energy and have good colour rendition, but are still rather expensive.
Some cities have already installed these lights on their streets.
Wattage 25 42 202
Lumens 2772 3648 13620
Wattage 0.9 1.8
Lumens 140 77
14. S P E C T R U M O F L I G H T
• The spectrum of light is seen in a rainbow or from a prism, and it includes all of the visible colors.
• We tend to organize color into three primaries (red, green, and blue) and three secondaries (yellow, cyan,
and magenta). When primaries of light are combined, the human eye sees white light.
•
• Historically, filter was used to remove colors from white light generated colored light. Blue light, for
instance, is white light with green, and red removed. Filtered light is still common in theatrical and
architectural lighting.
• Most of the non-incandescent light sources tend to create specific colors of light. Modern fluorescent
lamps, for example, create prime colors of light (red, green, and blue) that appear to the human eye as
white light. Other lamps, such as low-pressure sodium lamps, create monochromatic yellow light.
• While most lamps are intended to appear as white as possible, in some cases lamps are designed to
create specific colors, such as green or blue.
15. Intent of most light sources is to produce white light, of whose appearance there are two measures:
Color temperature: which describes the light appearance i.e. Whether the light appears warm (reddish),
neutral, or cool (bluish).
• The term temperature relates to the light emitted from a metal object heated to the point of
incandescence. For instance, the color temperature of an incandescent lamp is about 2700K, appearing
like a metal object heated to 2700° Kelvin (2427° Celsius or 4400° Fahrenheit).
• It is measured in degrees of Kelvin (K) on a scale from 1,000 to 10,000.
• The three primary types of color temperature for light bulbs are: Soft White (2700K –3000K), Bright
White/Cool White (3500K – 4100K), and Daylight (5000K – 6500K).
16. • Typically, commercial and residential lighting
application Kelvin temperatures fall
somewhere on a scale from 2000K to 6500K.
• The color temperature of a light bulb (lamp) is
assigned using the basis of correlated colour
temperature (CCT).
17. • Color rendering index (CRI):- which describes the quality of the light on a scale of 0 (horrible) to 100
(perfect).
• A color rendering index (CRI) is a quantitative measure of the ability of a light source to reveal the
colors of various objects faithfully in comparison with an ideal or natural light source.
• Light sources with a high CRI are desirable in color-critical applications such as neonatal care and art
restoration. Natural light is generally defined as having a CRI of 100 (perfect).
• All white light sources can be evaluated by color temperature and CRI. Color temperature is the more
obvious measure; two light sources of the same color temperature but different CRI appears much more
alike than do two light sources of similar CRI but different color temperature.
18. When choosing electric light sources, it is
generally best to select source color
temperature and CRI according to the table on
right.
Note that even if daylight enters the space, it
is usually not a good idea to try to match
daylight with electric light, as daylight varies
considerably.
19. • It is equal to one lumen per square metre.
• Sunlight on an average day ranges from 32
000 to 100 000 lux
• TV studios are lit at about 1 000 lux [i.e. 1000
lumens per square metre]
• A bright office has about 400 lux of
illumination
• At sunset and sunrise, ambient outdoor light is
also about 400 lux (if the sky is clear).
• Moonlight represents about 1 lux
• starlight measures a mere 0.00005 lux
Wha t is Lumino us f lux ?
Quantity of light emitted by the light source for a specific period of time. It can also be defined as the rate at
which light is emitted from the luminous body.
The lux (symbol: lx) is the SI derived unit of illuminance or illumination.
20. • Lumens measure "luminous flux". This is a measure of the total number of packets (or quanta) of light
produced by a light source (e.g. a globe or fluorescent tube). This is the “quantity” of light emitted by
the light source. The purpose of lux is intended to tell you how many lumens you need given the area
you are trying to illuminate.
• The difference between the lux and the lumen is that the lux takes into account the area over which the
luminous flux is spread. 1000 lumens, concentrated into an area of one square metre, lights up that
square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square
metres, produces a dimmer illuminance of only 100 lux.
To understand better let us take an example:-
• Achieving an illuminance of 500 lux might be possible in a home kitchen with a single fluorescent light
fixture with an output of 1200 lumens. To light a factory floor with dozens of times the area of the
kitchen would require dozens of such fixtures. Thus, lighting a larger area with the same number of Lux
requires a larger number of lumens.
21. Now to the issue of watts vs lumens produced.
When evaluating LEDs, we are often asked for the wattage of LED lamps when what is really meant is:
“How bright are they?”.
One can only compare the brightness of the various light sources on the market by knowing the number of
lumens they produce. We have all developed expectations about the how bright a 20-, 40-, 60- or 100-watt
bulb should be and we tend to apply that frame of reference to LED lamp. To clarify the relationship of
watts to light output and LED bulbs, we talk about the number of ‘lumens per watt’ (lm/w) that the device
produces.
• Incandescent bulbs are very inefficient and only generate around 12 lm/w, whereas LEDs and halogen
sources now have almost equivalent efficiencies of 40 lm/w. Some fluorescent tubes generate 60 lm/w
(which is where LEDs are predicted to be next year!)
• It is always better to talk about lumens (and lux required) than watts when it comes to lighting decisions.
22. Points to bear in mind:-
Unlike incandescent light bulbs that illuminate in a 360-degree spherical pattern regardless of the shape of
the bulb, LEDs depend on the shape and composition of their lenses and package structure to direct the light
where it is needed.
When we illuminate an area with a ‘spherical bulb’ source, even with a reflector, only a small proportion
(perhaps 50% at best) of the lumens are delivered as lux to the surface we are lighting – the rest is lost With
LEDs, properly applied, over 80% of the lumens can be directed to provide lux at the surface. That is why
LEDs can seem such bright pinpoints when you look at them.
So, LEDs are as bright per watt as halogen and nearly as bright as fluorescent – and when properly applied
they can deliver more lux per watt than either of these onto a surface such as a display case floor.
23. LU M IN A IR ES
A luminaire is any device that includes a lamp holder and the means of electrification and support for that
device. Lighting fixtures are luminaires that are permanently attached to a building. In other words, a table
lamp is a luminaire but not a fixture.
Luminaires are characterized by the manner in which light is distributed:
• Direct luminaires emit light downward. These include most types of recessed lighting, including
downlights and troffers.
• Indirect luminaires emit light upward, bouncing light from the ceiling into a space. These include many
styles of suspended luminaires, sconces, and some portable lamps.
• Diffuse luminaires emit light in all directions uniformly. These include most types of bare lamps, globes,
chandeliers, and some table and floor lamps.
24. • Direct/indirect luminaires emit light upward and downward but not to the side. These include many
types of suspended luminaires as well as some table and floor lamps. Note that direct/indirect luminaires
can be semi-direct or semi-indirect according to the proportions of up and down light.
• Asymmetric luminaires are usually designed for special applications.
• Asymmetric uplights, for instance, are indirect luminaires with a stronger distribution in one direction,
such as away from a wall. Wallwashers are a form of direct luminaire with stronger distribution to one
side so as to illuminate a wall.
• Adjustable luminaires are generally direct luminaires that can be adjusted to throw light in directions
other than down. These include track lights, floodlights, and accent lights.
25. HOW TO CHOOSE BASIC LUMINAIRE TYPES
The choice of luminaire type is fundamental to the overall appearance and psychology of a room and its
ambience. Here are reasons for choosing particular luminaires:
Direct lighting:-
• luminaires tend to be more efficient by distributing light directly onto the task area.
• Light falls from the luminaires on the ceiling directly onto the workplace, in part highly directional.
• The ceiling can appear dark (cave effect).
• The workplace layout should not allow any shadows.
• Direct lighting is typically used in building lobbies, executive offices,
restaurants, and other spaces where the designer wishes to convey a
sense of drama.
• Glare suppression is important under flat angles
26. Indirect luminaire
• luminaires tend to create comfortable, low-contrast soft light that psychologically enlarges space
• Light is directed to the ceiling and walls so that it illuminates the workplaces indirectly.
• The lighting effect may appear diffuse through the absence of shadows.
• Most types of indirect lighting illuminate the ceiling, but without additional direct light, many
people experience totally indirect lighting as bland and feeling like a cloudy day.
• Indirect lighting is generally preferred for spaces in which people spend a lot of time working,
although some task light or other directional light is generally recommended to eliminate the bland
character.
• The room increases in height
• The light is glare-free
• Workplaces can be arranged at random
• Lower energy efficiency
27. Direct/indirect luminaires :-
• Often a good compromise between the efficiency of direct lighting
and the comfort of indirect lighting.
• The indirect component creates a comfortable, balancing light,
while the direct component creates a dramatic light, resulting in
comfortable, interesting space.
• Light is directed to the workplace directly and indirectly via the
ceiling from suspended luminaires or free-standing luminaires.
• Pleasant room visuals.
• High user acceptance.
• Good contrast ratios
• Flexible workplace layout with an indirect share of > 60%
• Good combination of energy efficiency and lighting quality.
28. Asymmetric luminaires:- are chosen when accent lighting of objects or surfaces is desired.
For example, choose a wall washer to illuminate a wall, an accent light to illuminate a painting or sculpture.
Mellow Light:-
• The advantages of direct-indirect lighting are combined in a ceiling-mounted luminaire.
• Possibility of a free workplace layout.
• Glare-free lighting that looks good make for a high acceptance.
• Gives impression of daylight in a room.
• Good combination of energy efficiency and lighting quality.
29. IP RATING SYSTEM
• A two-digit number established by the International Electro Technical Commission, is used to provide an
Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.
• The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP
and a code numeral for the amount of the protection.
• Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:
a) The first digit represents protection against ingress of solid objects.
b) The second digit represents protection against ingress of liquids.
• The larger the value of each digit, the greater the protection. eg, a product rated IP54 would be better
protected against environmental factors than another similar product rated as IP42.
• IP protection of the PIP: A PIP in the standard PIP housing is generally IP51 protected. Higher IP
protection level with the standard PIP housing (up to IP54) can be reached with good positioning /
orientation of the PIP. In other special PIP-housings, like a MIL-housing up to IP67 protection is
possible.
• IP protection of the PANEL-PIP: The PANEL-PIP is available in various housings. Those allow a
protection level of up to all around IP65
30.
31.
32. Zone 0: - is inside the bath or shower itself. Any fitting used in this zone must be low voltage, (max
12v) and be rated at least IP67 which is total immersion proof.
Zone 1: - is the area above the bath or shower to a height of 2.25m from the floor. In this zone a
minimum rating of IP45 is required but it is generally accepted that IP65 is to be used. It's also worth
noting that most shower lights are rated at IP65 in any case.
Zone 2: - is an area stretching 0.6m outside the perimeter of the bath and to a height of 2.25m from
the floor. In this zone an IP rating of at least IP44 is required. In addition, it is good practice to
consider the area around a wash basin, within a 60cm radius of any tap to be considered as zone 2.
Outside Zones: - are anywhere outside zones 0, 1 and 2 (subject to specific limits) and where no
water jet is likely to be used. There are no special IP requirements in this zone, however we suggest that
you consider a light with an IP rating of at least IP20+