Key Lighting Principles for Facilities Managers

Key Lighting Principles for Facilities Managers

FMANZ Webinar15 June 2021

Susan [email protected]

(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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380 430 480 530 580 630 680 730 780

Wavelengths

Photopic

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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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• 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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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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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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3000 K

LED

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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.