ILP CPD webinar: How to eliminate light pollution - How we can mitigate light pollution
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No one likes light pollution, obtrusive light, or nuisance light. It affects people, animals and plants, it wastes energy, and it is completely avoidable. The ILP’s world-renowned guidance on the reduction of obtrusive light was updated in 2020. In this presentation, it talks about how to discover practical information on what type of products to apply in what situations, available from many manufacturers. By Emily Bolt BEng (Hons), at Signify
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ILP CPD webinar: How to eliminate light pollution - How we can mitigate light pollution
- 1. Philips Outdoor Lighting Application How to Eliminate Light Pollution Emily Bolt – Technical Services Manager, UK 8th July 2020
- 2. The world is becoming brighter As the world continues to develop, it needs more light. Urban populations are growing particularly rapidly, increasing the need for light. We are becoming a 24/7 society, so basic infrastructures need to be available all the time. Lighting has a fundamental role in providing greater visibility, increased safety, and ensuring smooth mobility. Due to its obvious advantages like high efficiency and low maintenance, LED is becoming the preferred light source. But...Source: https://www.space.com/38872-light-pollution-increasing-globally.html
- 3. Poor quality lighting can have negative consequences It can be a nuisance for residents. Glare can cause discomfort for people relaxing in their homes or walking on the streets at night. It can turn areas of cities into unwelcoming spaces, negatively impacting tourism. It can increase light pollution and sky glow, preventing people from enjoying the stars and a clear sky. It can have a negative impact on biodiversity by disturbing various species of birds, bats and other animals.
- 4. Light pollution is a broad term covering various aspects associated with the wrong direction of light and its negative impact. Sky glow: Brightening of the night sky over inhabited areas Light Spill: Light appearing where it is not intended or needed Glare: Excessive brightness that causes visual discomfort What is light pollution?
- 5. 1. Preserve a clear night sky
- 6. The most significant of the three elements of light pollution is sky glow, which is increasing throughout the world as the amount of lighting increases Sky glow is increasing Source: Fabio Falchi et al. Sci Adv 2016;2:e1600377 Published by AAAS
- 7. 7 More than 80% of the population of the world and over 99% of the population of the U.S. and Europe live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Light-polluted nights are experienced in 23% of the world’s land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States. The size of the sky glow problem Source: The new world atlas of artificial night sky brightness, Science Advances, 10 June 2016 (http://advances.sciencemag.org/content/2/6/e1600377.full)
- 8. 8 It makes it more difficult for professional astronomers to perform observations. It prevents people all over the world from enjoying the night sky and the stars. It wastes energy and money. Why is sky glow an issue?
- 9. 9 Current practices include: Reducing light levels Turning off unnecessary lights Limiting lighted hours of outdoor areas (which may lead to safety issues) Limiting lighting installations Using full cut-off luminaires to minimize the amount of light emitted directly upwards How can sky glow be reduced?
- 10. Using full cut-off luminaires to minimize the amount of light emitted directly upwards 10 Full cut off luminaires Full Cut Off Luminaires
- 11. 11 Standard optical plate Philips optical plate A lighting solution- approved by astronomy institutes Ensuring the clear view of the stars
- 12. Case study - Los Realejos Los Realejos is located in the north of Tenerife, one of the Canary Islands. The nearby island of La Palma is a world-class site for astrophysics studies. The Instituto de Astrofísica de Canarias has established strict regulations whereby municipalities in Tenerife North and La Palma need to mitigate light pollution. Los Realejos has become the first municipality to change to PC Amber LED light to preserve the view on the night sky. 12
- 13. 2. Light Spill
- 16. Examples of optical distributions Narrow optics Medium optics Wide optics Extra-wide optics DW50 DM50 DN50 DX50 DX51 DW52 Sport & Area Square , Park Railwa y DS50 DX60 OFA52 S DRN1 DRN2 DRM1 DRM2
- 17. Case study Parking DX50 is the wide optic dedicated to parkings illumination, according to EN13201 (Ehave ≥ 20 lux, Uo ≥ 0.40). Additionally, DX51 allows to prevent residents and neighbourhood from spill light thanks to the sharp cut off behind the luminaire and in front, opposite to the luminaire. DX50 Source flux = 17000 lm Ehave = 20 lux Uniformity Uo = 0.45 DX51 Source flux = 23500 lm Ehave = 20 lux Uniformity Uo = 0.42 Spill light control to prevent obtrusive light towards residents appartments. Illuminance scale:
- 18. Back spill light is controlled and cut thanks to optional louvers, added to the optical system Obtrusive light prevention Focus on • Greatly reduced light spill: 60% to 90% light reduction on façades • Available as internal louver • Preserve aesthetic of the luminaire • Retrofit solutions • Photometric data available for calculation Luminaire located at a certain distance from the façade BL1 has limited cut off to keep some light on the ground in front of the housing Luminaire located close or on the façade BL2 has a sharp cut off cutting back-light 0 to 1m h ½ h
- 19. Internal Louvers Light trespass prevention Backlight 60%-90% of light reduction on façade With Without Obtrusive light prevention DM32 BL2 DM32 DM32 BL1 distance from facade=2m DM32 distance from facade=2m Illuminance scale: Comfort for residents. Maximum vertical illuminance on façade reduced by 80%.
- 20. Light trespass prevention ½ h BL1 Luminaire located close or on the façade Luminaire located at a certain distance from the façade BL2 Sharp cut off neededBL1 Limited cut off to keep light on the ground in front of housing 60% to 90% light reduction on façades BL2 h ½ h 0 to 1m
- 21. Light trespass prevention Excessive light trespass on the facades of houses / buildings to be prevented to enhance quality of living.
- 22. 22 Full cut off luminaires External Louvers
- 23. 3. Glare
- 24. Luminous intensity classes allow the definition of disability glare limitations. They are named : • G* classes in EN13201:2015 Annex A, based on lumen output of the luminaire • G classes in EN13201:2003 Annex A, based on lumen output of the source G*/G classes are calculated for the installation‘s tilt of the luminaire (typically 0/5/10°). The highest G*/G classes are the most comfortable. G*1, G*2 and G*3 correspond to "semi cut-off" and "cut-off" concepts. G*4, G*5 and G*6 correspond to “full cut-off”. G* /G Luminous intensity class definition Requirements for maximum luminous intensity in cd/klm defined in EN13201-2:2015(1): Class Maximum luminousa intensity in directions below the horizontal in cd/klm of the output flux of the luminaire. Other requirements at 70° and aboveb at 80° and aboveb at 90° and aboveb G*1 - 200 50 None G*2 - 150 30 None G*3 - 100 20 None G*4 500 100 10 Luminous intensities above 95° b to be zeroc G*5 350 100 10 Luminous intensities above 95° b to be zeroc G*6 350 100 0c Luminous intensities above 90° b to be zeroc a. Luminous intensities are given for any direction forming the specified angle from the downward vertical with the luminaire installed for use b. Any direction forming the specified angle from the downward vertical, with the luminaire installed for use. c. Luminous intensities up to 1 cd/klm can be regarded as being zero. (1) standard extract with the permission of NEN, Delft, www.nen.nl
- 25. Contact details Emily Bolt Technical Services Manager Emily.bolt@signify.com 25 Q&A
Editor's Notes
- Good afternoon I am Emily Bolt the Technical services manager for Signify today we are going to take a look at how we can mitigate light pollution.
- The world has become brighter, as the world continues to develop, it needs more light due to the fact that Urban populations are growing rapidly, increasing the need for light We are becoming a 24/7 society, so basic infrastructures need to be available all the time LED is becoming the preferred light source Lighting has a fundamental role in providing greater visibility and increased safety.
- Poor quality lighting can have negative consequences It can be a nuisance for residents. Glare can cause discomfort for people relaxing in their homes or walking on the streets at night It can turn areas of cities into unwelcoming spaces, negatively impacting tourism. It can increase light pollution and sky glow, preventing people from enjoying the stars and a clear sky. It can have a negative impact on biodiversity by disturbing various species of birds, bats and other animals.
- Light pollution is a broad term covering various aspects associated with the wrong direction of light and its negative impact. The three topics we are going to cover today are Sky glow: Brightening of the night sky over inhabited areas Light Spill: Light appearing where it is not intended or needed Glare: Excessive brightness that causes visual discomfort
- So how do we preserve a clear night sky?
- The most significant of the three elements of light pollution is sky glow, which is increasing throughout the world as the amount of lighting increases
- More than 80% of the population of the world and over 99% of the population of the U.S. and Europe live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Light-polluted nights are experienced in 23% of the world’s land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States.
- Why is sky glow and issue It makes it more difficult for professional astronomers to perform observations. It prevents people all over the world from enjoying the night sky and the stars. It wastes energy and money.
- How can sky glow be reduced Current practices include: Reducing light levels Turning off unnecessary lights Limiting lighted hours of outdoor areas (which may lead to safety issues) Limiting lighting installations Using full cut-off luminaires to minimize the amount of light emitted directly upwards
- The move to LED has naturally seen a move to flat glass luminaires, which therefore due to there design see reduction in sky glow as these become semi or full cut of luminaires, Limiting the amount of light emitted above the horizontal . This means manufactures need to design luminaries with optics so no light is emitted at imax 95 and very little if any at imax 90. It is important to note that the imax values change with the tilt of the luminaire, For floodlighting schemes, floodlights can now be mounted in a horizontal position with the peak beam being at a max of 60deg meaning there is little need to tilt the luminaires, to light the application again putting the light in the correct place at the correct time.
- Uncontrolled lights can create light pollution, producing too much brightening of the night sky that prevent people enjoying and observing the night sky and the stars, when wasting energy and money. Light spectrum composition with significant blue light part has a negative impact for astronomers activities. Some governmental regulations are limiting blue light spectrum in light sources. The use of efficient white LED boards with the dedicated colored optical plates for night preservation ensures the optimal solution for the safety and comfort of inhabitants, astronomers research and compliancy to regulations. In some cases manufactures where looking at using things like an Amber LED to reduce sky glow, however Two new solutions are proposed for the night preservation, based on colored optics, these ensure a higher efficiency than a standard optical plate with Amber LED. The colored optics can be combined with neutral white or warm-white LED boards, providing two different CCT and CRI. So a standard Amber LED has a colour temperature of 1700K with a CRI of 37. the new proposals provide either 2000K or 1800K with a CRI of 36 or 48 respectively In this case they allow the lighting distributions to remain unchanged thanks to standard transparent optical plate.
- Lest look at an application where this has been implemented The medium-sized municipality (40,000 people) of Los Realejos is located in the north of Tenerife, the largest of the Canary Islands. The nearby island of La Palma is a world-class site for astrophysics studies. Currently it’s the second choice of location for a Thirty Meter Telescope (TMT). The IAC (Instituto de Astrofísica de Canarias) has established very strict regulations whereby all municipalities surrounding Tenerife North and La Palma need to be extremely conscious about light pollution. Los Realejos has become the first municipality to change to Amber LED technology. In the picture you can see that the night sky is still very dark.
- Light Spill is Light appearing where it is not intended or needed, so how do we prevent this?
- Preventing Light spill, is about putting the right light in the right place, therefore connecting the correct optic to the application.
- When assessing the lighting application its important to consider the User lighting criteria level of comfort Geometry of the area to be lit beam width
- Nowadays there are many different lighting distributions its about choosing the correct distribution for the application not only meeting the required standards but also, managing the light so its in the right place not only will this limit light spill but it will also provide a better lighting solution. It is important to pick the correct lighting distribution and understand the pattern of light provided by that distribution. When optimising in lighting reality its important to understand what options are being selected for example it might throw out the DS50 optic as a solution but this is a symmetrical optic it provides a circular distribution to replace an old SOX post top it will give you the same amount of light to the front of the luminaire as to the back, therefore if you use this on a straight road application there will be a significant amount of spill light, outside of the target area.
- Lets look at an example Here we have too very similar optical distributions on the left we have a wide optic to light these parking areas to the correct standard, but a similar optic on the right could be used which has a sharp cut off behind and in front of the luminaire. Preventing the spill light towards the residents apartments, you may have noticed that to achieve this a higher lumen pack is required. So we can control as much light as possible using the correct optical distribution, but what if we still have an issue?
- Spill back light can be controlled and cut thanks to optional louvers added into the optical system Focus on Greatly reduced light spill: Available as internal louver Preserve aesthetic of the luminaire Retrofit solutions Photometric data available for calculation
- You can see here the internal louvers fitted to the optical board and the reduction to the spill light with these fitted, If you look at the example on the slide then we can see that the maximum vertical illuminance on the façade is reduced by 80%, providing comfort for the residents. The internal louvers preserve the aesthetics of the luminaire as the can not easily be seen from the ground. We have all seen in the past luminaires with blacked out bowls or some sort of cowl behind them.
- Here is an example of two different louver distributions BL1 has limited cut off keeping the light on the ground in front of the housing, where the distance from the property is approx. half the mounting height. BL2 has a much sharper cut off this is where the luminaire is upto 1m from the property. Photometric data can easily be provided for internal louvers which means you can model the reduction in light spill in your lighting design software.
- As seen here you can see the different cut of on the building for each of the internal louvers these can provide a 60% to 90% light reduction on façades
- External louvers can also be provided, normally a set of external louvers would consist of a front, rear and side louver, these in general are not normally photometered but can provide somewhere in the % of a reduction of light?
- Glare: Excessive brightness that causes visual discomfort What can we do to limit the glare?
- The realise if the new BS5489-1:2020 see’s us moving to measuring Ti for disability glare for our lighting classifications , however the Ti is a measure of the disability glare from an observer point on the roadway within the application area. It does not consider observers outside the application area so for example the residents therefore we still need to consider the direct glare from the luminaires. BS5489-1:2020 states Direct glare from luminaires in subsidiary roads and associated areas, footpaths and cycle tracks should be controlled. Where luminaires have clear bowls or refractors, these should conform to class G*1 as specified in BS EN 13201‑2:2015, Table A.1, or a higher class, to provide adequate control of glare. Table A1 is detailed here you can see that G*1-G*3 are semi cut off luminaires with G*4 and above being full cut off luminaires, again the g* rating of a luminaire will change with the tilt angle of the luminaire in your lighting design so for example at 0deg it may be G*4 but at 5deg tilt it may be G*3 It is important to note the higher the G class in general you get a reduction in spacing and a increase in energy consumption due to the level of comfort of the distribution, if you are comparing luminaires with no G rating to a luminaire with a G3 rating for example then although the comfort level for the user will be better the energy consumption may increase so its important to remember the driver here and specify if a glare classification is required.