This document discusses lighting, including units of measurement for brightness, flux, illumination, and luminance. It outlines requirements for good lighting such as sufficiency, distribution, and absence of glare or shadows. Lighting standards provide recommended illumination levels for different visual tasks. Natural lighting comes from the sun and is impacted by design, location, weather, and pollution. Artificial lighting includes filament, fluorescent, and LED lamps, with LEDs being long-lasting, efficient, and mercury-free compared to other options.

1. LIGHTING
LIGHTING

2. LIGHT
 What ?
 How ?
 Why ?

3. Units of measurement
No description Quantity
measured
Name
recommend
ed unit
Other units
1 Brightness of point
source
Luminous
intensity
Candela Candle power
2 Flow of light Luminous flux Lumen Foot candle
3 Amount of light
reaching surface
Illumination or
illuminance
Lux Lumen/cm2
(Phot)
4 Amount of light re-emitted
by surface
Brightness or
luminance
lambert Foot Lambert
Candles/cm2

4. Requirements for good lighting
 Sufficiency
 Distribution
 Absence of glare
Absence of sharp shadows
 Steadiness
Colour of light
 Surroundings

5. Lighting standards
 Illumination range – 0.1 lux to 100,000 lux
 Vision against illumination follows a curve
 30 times higher than the minimum required
 Illuminating engineer society
Visual task Illumination (lux)
Casual reading 100
General office work 400
Fine assembly 900
Very severe tasks 1,300 - 2,000
Watch-making 2,000 - 3,000

6. sources

7. Production of light
 Thermo luminance
 Chemo luminance
 Phosphorescence
 Cathodoluminescence

8. Natural
 Direct or reflected
 Design, Orientation,
location, surroundings.
 Time, season, weather &
pollution

9. Measuring Daylight
 Daylight factor (D F)
 D F = instantaneous illumination indoor x 100
simultaneously occurring illumination outdoor
 Daylight factor meter
 Living room 8 %
 Kitchen 10%

10. Improving daylight illumination
 Orientation
 Removal of obstacles
 Windows
 Interior

11. Artificial
Types
 Direct
 Semi-direct
 Indirect
 Semi-indirect
 Direct - indirect

12. Filament lamps
 Tungsten filament
 Light depends on temperature
 5 % light
 Dust – illumination by 30 to 40 %

13. Florescent lamps
 Similar to natural light
 21 % light
 Glass tube, mercury vapour, & electrode
 fluorescent chemical coating – absorbs all UV

14. LED lamps
 Long-lasting -up to 10 times
Durable -do not have a filament, they are solid
 Cool- LEDs produce 3.4 btu's/hour, compared to
85 for incandescent bulbs
 Mercury-free
 More efficient - 2-17 watts
 Cost-effective
 Light for remote areas and portable generators