Post on 25-Jun-2022
Key Lighting Principles for Facilities Managers
FMANZ Webinar15 June 2021
Susan Manders.mander@massey.ac.nz
(09) 213 6328
All images by Susan Mander unless noted otherwise
Today’s Themes
• Units and instruments What is light, and how is it measured?
• Colour Concepts What is CCT, and how does it affect productivity? Why do some colours appear different in artificial light?
• Light SourcesHow do LED sources compare to older technologies?
• FlickerWhat is flicker, and is it harmful?
A little terminology…
Lamp Luminaire
Part 1 – Units and Instruments
What is light?
Electromagnetic Spectrum
https://commons.wikimedia.org/wiki/File:Electromagnetic-Spectrum.svg Downloaded 21 May 2021
Electromagnetic Spectrum
https://commons.wikimedia.org/wiki/File:Electromagnetic-Spectrum.svg Downloaded 21 May 2021
Spectral Power Distribution (SPD)
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Wavelength (nm)
Wavelength (nm)
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0.2
0.4
0.6
0.8
1
1.2
380 430 480 530 580 630 680 730 780
Wavelengths
Photopic
Wavelength (nm)
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380 430 480 530 580 630 680 730 780
Wavelengths
555nm
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How is light measured?
Summary of Units
Luminous Flux (Φ)[lumen (lm)]
Illuminance (E)[lux (lx)]
Luminance (L)[candela per square metre (cd/m2)]
Luminous Flux
Luminous Flux (Φ)[lumen (lm)]
Illuminance (E)[lux (lx)]
Luminance (L)[candela per square metre (cd/m2)]
The amount of light emitted in all directions
Luminous Flux
Luminous Flux
Integrating Sphere
Luminous Efficacy
• Efficacy is the luminous flux produced per watt of electricity.
• LEDs can have efficacies over 100 lm/W.
Luminous Efficacy
Efficacy =lumens
watts
=500 lm
5.5 W
= 91 lm/W
Luminous Intensity
Luminous Flux (Φ)[lumen (lm)]
Illuminance (E)[lux (lx)]
Luminance (L)[candela per square metre (cd/m2)]
The amount of luminous flux in a certain direction.
Luminous Intensity
800 cd
0 cd
Polar curve of intensity
Luminous Intensity
800 cd
0 cd
Polar curve of intensity
800 cd
0 cd
Luminous Intensity
• Luminous intensity can give us an indication of how much glare there will be in an area.
Luminous Intensity
800 cd
0 cd
800 cd
0 cd
More potential for glare at higher angles
Luminous Intensity
• Glare is calculated using lighting software. Higher number = more probability of glare.
• From AS/NZS 1680 series:
- Office = 19
- Lecture Theatre = 19
- Kitchen = 22
- Plant room = 25 Higher number = more glare is allowed
Luminous Intensity
http://www.everfine.net/en/productsinfo.php?cid=8&id=21 Downloaded 9 February 2019
Goniophotometer
Luminous Intensity
http://www.everfine.net/en/productsinfo.php?cid=8&id=21 Downloaded 9 February 2019
Goniophotometer
Test Luminaire
Illuminance
Luminous Flux (Φ)[lumen (lm)]
Illuminance (E)[lux (lx)]
Luminance (L)[candela per square metre (cd/m2)]
The amount of light (per square metre) that falls on a surface.
Illuminance• Building Code Clauses D1 (access routes), F6
(visibility in escape routes), G8 (artificial light)
• From AS/NZS 1680 series:
- Office 320 lux (working plane – desk height)
- Lobby 160 lux (floor level)
- Corridors 40 lux (floor level)
• See AS/NZS 1680 series for further information
Illuminance
• Note that all illuminance values in the AS/NZS 1680 series are maintained illuminance values (the minimum values that the average illuminance should fall to).
• All light sources lose output over time. Higher initial light levels are needed if it is known that there will be large gaps between maintenance cycles.
Illuminance
• The colour of room surfaces has a major impact on the amount of illuminance in a room.
• Dark colours absorb light, light colours reflect light.
Quarter Pavlova 70 Pavlova 51 Triple Pavlova 35
Illuminance
Illuminance Meter
Luminance
Luminous Flux (Φ)[lumen (lm)]
Illuminance (E)[lux (lx)]
Luminance (L)[candela per square metre (cd/m2)]
The intensity of a source or surface (in the direction of the observer) divided by the area of the source (or surface) seen by the observer.
Luminance
• Note: luminance is not the same as brightness. Brightness depends on the viewer’s perception and the state of adaptation of their eyes.
• Example: car headlights have the same luminanceduring the day or night, but they will appear to be brighter at night.
Luminance
Luminance
Luminance Meter
Question
A contractor has suggested a 1-for-1 replacement of fluorescent troffers with new LED sources. Both luminaire types produce the same number of lumens. Is this acceptable?
Have you come across similar scenarios in your job?
?
End of Part 1
Part 2 – Colour Concepts
What is CCT and how does it
affect productivity?
LED Source
Wavelength (nm)
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Correlated Colour Temperature (CCT)
https://commons.wikimedia.org/wiki/File:Color_temperature_of_a_black_body.svg https://commons.wikimedia.org/wiki/File:Color_temperature_comparison_of_5_CFLs.jpg
Low CCT“Warm” light“Yellowish”Example: 2700 K
High CCT“Cool” light“Bluish”Example: 6500 K
Unit = Kelvin (K)
Correlated Colour Temperature (CCT)
Correlated Colour Temperature (CCT)
• Lighting can affect our wake/sleep cycles (“circadian rhythms”)
https://commons.wikimedia.org/wiki/File:Little_Gasparilla_sunrise.jpghttps://upload.wikimedia.org/wikipedia/commons/6/6b/Lake_in_summer_scenics_landscape.jpg Downloaded 21 May 2021
Circadian System
https://commons.wikimedia.org/wiki/File:Figure_36_05_02.png Downloaded 21 May 2021
Circadian System
https://commons.wikimedia.org/wiki/File:Figure_36_05_02.png Downloaded 21 May 2021
Circadian System
https://commons.wikimedia.org/wiki/File:Figure_36_05_02.png Downloaded 21 May 2021
Circadian System
https://commons.wikimedia.org/wiki/File:Suprachiasmatic_Nucleus.jpg Downloaded 27 February 2019
“SCN”
Circadian System
https://commons.wikimedia.org/wiki/File:Suprachiasmatic_Nucleus.jpg Downloaded 27 February 2019
Circadian System
• The amount of melatonin:
– Builds in the evening
– Peaks in the middle of the night
– Declines in the morning
• Light suppresses the release of melatonin
Circadian System
https://www.flickr.com/photos/145362038@N02/41522888305 Downloaded 17 May 2021
Circadian System
• Lighting can affect our wake/sleep cycles (“circadian rhythms”)
• Some manufacturers produce tunable white sources. These are designed to change colour during the day, as the sun also changes colour during the day.
• The science behind this is in its infancy.
Designing with Circadian Stimulus
• The Lighting Research Centre (Rensselaer Polytechnic Institute) has developed a “Circadian Stimulus” metric.
Designing with Circadian Stimulus
• CS is between 0.1 and 0.7
• CS = 0.3 for at least an hour in the morning
• Consider horizontal and vertical illuminance
• At night, use less illuminance and/or a different spectrum (more yellow, less blue).
Designing with Circadian Stimulus
https://www.lrc.rpi.edu/resources/newsroom/LDA_CircadianStimulus_Oct2016.pdf Downloaded 11 April 2019
Designing with Circadian Stimulus
https://www.lrc.rpi.edu/resources/newsroom/LDA_CircadianStimulus_Oct2016.pdf Downloaded 11 April 2019
Why do certain colours appear different in artificial light?
• Green surface:
- absorbs red & blue
- reflects green
Selective Absorption
• Green surface:
- absorbs red
- Person sees black or grey
Selective Absorption
Selective Absorption
Selective Absorption
Selective Absorption
Selective Absorption
What is this colour?
Selective Absorption
Selective Absorption
Selective Absorption
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Wavelength (nm)
Wavelength (nm)
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• Colour rendering of a light source indicates how realistically the source can reproduce the colour of an object
Colour Rendering
• Colour Rendering Index (Ra) has a maximum of 100.
• Better performance = larger number
Colour Rendering
Colour Rendering
https://en.wikipedia.org/wiki/Color_rendering_index Downloaded 4 July 2018
“Ra” colour swatches
Colour Rendering
https://en.wikipedia.org/wiki/Color_rendering_index Downloaded 4 July 2018
Additional
“R9”
“Ra” colour swatches + optional extras
Colour Rendering
Created using TM-30 Calculation Tool
“TM30” colour swatches
Question
This spectrum is from a high-efficacy low pressure sodium lamp, which was used for road lighting. What problems do you think this lighting caused?
Have you come across colour rendering issues in your job? ?
https://upload.wikimedia.org/wikipedia/commons/3/3f/SOX.png Downloaded 11 June 2021
End of Part 2
Part 3 – Light Sources
How do LED sources compare to
older technologies?
Incandescent
• Heated Filament
https://commons.wikimedia.org/wiki/File:Halogen_lamp_macro_02.jpg https://commons.wikimedia.org/wiki/File:Wolfram-Halogengl%C3%BChlampe.pnghttps://commons.wikimedia.org/wiki/File:Tungsten_filament_in_an_incandescent_light.JPG Downloaded 6 May 2021
Incandescent
Filament (Light Source)
Inert Gases
Glass
Base
https://commons.wikimedia.org/wiki/File:Gluehlampe_01_KMJ.jpg Downloaded 6 May 2021
Incandescent
Incandescent
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Wavelength (nm)
Incandescent - Summary
• Very inefficient (∼ 8 - 25 lm/W)
• Short life (∼ 1000 - 2000 hours)
• Catastrophic failure
• Warm CCT (∼ 2700 - 3000 K)
Data from Van Bommel (2019), p. 266
Linear Fluorescent
• Gas discharge
• Mainly ultraviolet
• Phosphor coating is used
• Needs control gear (ballast)
https://commons.wikimedia.org/wiki/File:Leuchtstofflampen-chtaube050409.jpg Downloaded 6 May 2021
source: www.lamptech.co.uk
Linear Fluorescent
http://www.lamptech.co.uk/Documents/FL%20Operation.htm Downloaded 21 April 2013
Linear Fluorescent
Tubes
Louvres
Linear Fluorescent
Tubes
Prismatic Controller
Compact Fluorescent (CFL)
• Gas discharge
• Similar technology to linear fluorescent
• Available in a variety of shapes and sizes
• Needs control gear (ballast)
Compact Fluorescent Ballast
Source: http://en.wikipedia.org/wiki/Electrical_ballast Downloaded 5 March 2019.
Linear Fluorescent Ballast
https://commons.wikimedia.org/wiki/File:BEMKO_2x18W_T8.JPG Downloaded 5 March 2019.
Fluorescent
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Wavelength (nm)
Fluorescent - Summary
• Efficient (∼ 70 – 105 lm/W)
• Long life (∼ 12,000 – 20,000 hours)
• Parametric failure
• Full range of CCT values (∼ 2700 – 17,000 K)
• Contains mercury
• Needs control gear (ballast)
• Take time to reach full light output
Data from Van Bommel (2019), p. 266
Light Emitting Diode (LED)
• Uses electronics to make light
• Phosphor coating is used to convert blue light to white
• Can be part of a lamp or integral to a luminaire
• Needs control gear (driver)
LED Retrofit Lamp
Base
LEDs(Light Source))
Diffusing Plastic
Electronic Circuitry
LEDs and Heat
Heat Sink
LED
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Wavelength (nm)
3000 K
LED
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Wavelength (nm)
6500 K
LED
Compatibility issues
LED - Summary
• Efficient (∼ 70 - 160 lm/W)
• Long life (∼ 20,000 – 100,000 hours)
• Parametric failure
• Full range of CCT values (∼ 2700 K – 10,000 K)
• Needs a driver
• Sensitive to heat
• “Blue spike”
Data from Van Bommel (2019), p. 266
Question
This is an LED retrofit lamp, which is designed to replace a fluorescent tube. What problems can this type of retrofit source have?
Have you come across issues with these in your job? ?
End of Part 3
Part 4 - Flicker
What is flicker and is it harmful?
Incandescent
Incandescent
https://commons.wikimedia.org/wiki/File:Tungsten_filament_in_an_incandescent_light.JPG Downloaded 6 May 2021
Incandescent
Incandescent
Full Brightness
No Light
Incandescent
Incandescent
100 Hz
Linear Fluorescent
Linear Fluorescent - Magnetic
Linear Fluorescent - Electronic
LED
LED
LED Type 1
LED
LED Type 2
LED
LED Type 4
The Effects of Flicker
The Effects of Flicker
Minimal Flicker High Level of Flicker
The Effects of Flicker
Minimal Flicker High Level of Flicker
The Effects of Flicker
The Effects of Flicker
Minimal Flicker High Level of Flicker
Case Studies
https://commons.wikimedia.org/wiki/File:RNZAF_A109_helicopter_at_the_2012_Wanaka_Airshow.jpg Downloaded 11 June 2021
Case Study – Food Mixer
https://commons.wikimedia.org/wiki/File:Mixer,_cake_(AM_2002.50.1-1).jpg Downloaded 11 June 2021
Case Study – Toy Shop
https://upload.wikimedia.org/wikipedia/commons/c/c2/Interior_of_Streets_Toy_Shop%2C_Ringwood_-_geograph.org.uk_-_174283.jpg Downloaded 11 June 2021
Case Study – Internal Stairwell
Case Study – Internal Stairwell
Detecting Flicker
• Simple flicker detection:
– Put your phone camera onto “slow mo” mode
– If the image is turning on and off, that’s flicker
Warning: Don’t do this is you are sensitive to strobing light
Question
If you are not sensitive to strobing light have a go at detecting flicker in your present location. What is it like?
Have you come across issues with flicker in your job?
?
End of Part 4
References
Van Bommel, W. (2019). Interior lighting: Fundamentals, technology and application. Springer.