1. OBTRUSIVE LIGHTING

2. Definitions Area to be lit Upward reflected light SKY GLOW
Upward direct light
Obtrusive light
Direct glare
SPILL LIGHT
R-TECH 1
Area to be lit

3.  Glare  Obtrusive light  Sky glow
Three phenomena are related to light control of luminaires and their installation
 Glare
 Obtrusive light
 Sky glow
All are the result of waste of energy

4. the most critical problem
Glare
the most critical problem
As it has to do with safety of drivers and pedestrians
 Threshold Increment TI limitation for road lighting
 Glare Rating GR limitation for large area

5. Disability glare - TI  K E 2 and Lv = TI = 65 Lv LR0.8  10% or 15%
(CIE 140) E  1° K E 2
and
Lv =
TI = 65 Lv
LR0.8
 10% or 15%

6. Glare Rating - GR GR = 27 + 24 lg (Lvl / Lve 0.9)  
(CIE 112)
GR = lg (Lvl / Lve 0.9)
With Lvl = veiling luminance produced by luminaires
Lve = veiling luminance produced by environment
and Lve = Lav
with Lav = EH.  

7. Glare Rating limitation
Glare Ratio GR
Unbearable
Disturbing 90 80 70 60
Just admissible 50
Noticeable
Unnoticeable 40 30 20 10

8. Glare control At design stage : Calculation of TI or GR On site :
Cannot be measured
On site :

9. Obtrusive light Light falling out of the area of interest ,
causing disturbances or reducing confort
By – over lighting
– stray light
– bad wave length

10. CIE zoning system (CIE Nr. 126)
Zone rating
Description E1
Areas with intrinsically dark lanscapes E2
Areas of ’’low district brightness ’’ E3
Areas of ’’middle district brightness ’’ E4
Areas of ’’high district brightness ’’

11. CIE zoning system Application of CIE Nr. 150
Zone rating
Surrounding
Examples E1
Natural
National parks or protected sites E2
Rural
Industrial or residential rural areas E3
Suburban
Industrial or residential suburbs E4
Urban
Town centres and commercial areas

12. Application conditions
CIE zoning system
Maximum values of EV on properties - CIE 150
Light
Technical parameter
Application conditions
Environmental Zones E1 E2 E3 E4
Illuminance
In vertical
Plane (Ev)
Pre-curfew :
2 lux
5 lux
10 lux
25 lux
Post-curfew :
0* lux
1 lux

13. Application conditions
CIE zoning system
Maximum values of I (cd) in specific directions - CIE 150
Light
Technical parameter
Application conditions
Environmental Zones E1 E2 E3 E4
Luminous
Intensity
Emitted by
Luminaires (I)
Pre-curfew :
2500 cd
7500 cd
10000 cd
25000 cd
Post-curfew
Hours :
0 cd*
500 cd
1000 cd

14. Light Technical Parameter Threshold Increment TI
CIE zoning system
Limitation of effects on transport system - CIE 150
Light Technical Parameter
Road Classification
No road lighting M5
M4 / M3
M2 / M1
Threshold Increment TI
15% based on adaptation luminance of 0.1 cd/m²
15% based on adaptation luminance of 1 cd/m²
15% based on adaptation luminance of 2 cd/m²
15% based on adaptation luminance of 5 cd/m²

15. Limitation of effects on over lit building and signs CIE 150
CIE zoning system
Limitation of effects on over lit building and signs CIE 150
Parameter
Application
Conditions
Environmental Zones E1 E2 E3 E4
Building
Facade
Luminance
(Lb )
0 cd/m²
5 cd/m²
10 cd/m²
25 cd/m²
Sign
(Ls )
50 cd/m²
400 cd/m²
500 cd/m²
1000 cd/m²
EAV x  
EAV x  
or LAV

16. SKY GLOW Definition : Brightening of night sky
resulting from reflection of radiations
scattered from the constituents of the
atmosphere in direction of observation

18. SKY GLOW
Sky glow
Sky glow

19. Many factors contribute to sky glow
- Artificial lighting installations
 direct upward light
 upward reflected light
- Headlights of vehicules
- Atmosphere pollution
- Atmosphere humidity
- Clouds
- Radiation from celestian sources

20. Stray light due to artificial lighting
SKY GLOW
Stray light due to artificial lighting
 advertising signs ;
 area lighting of sales areas, parking lots, etc..
floodlighting of buildings, discos and monuments
lighting of billoards ;
lighting of greenhouses ;
lighting of industrial site, airports and buiding sites
lighting of sports facilites
road and street lighting

21. SKY GLOW
First approach : CIE 126 (1997)

22. SKY GLOW CIE Zoning system - CIE 126 Zone rating ULOR inst (%)
Astronomical acivities E1
Observatories of (inter)national standing E2
0 – 5
Postgraduate and academic studies E3
0 - 15
Undergraduate studies, amateur observation E4
0 - 25
Casual sky viewing

23. Zone rating of reference point
SKY GLOW
Minimum distance (in km) between zone borderlines and ref. point
Zone rating of reference point
Zone rating surrounding zones distance (km) tobordeline of surrounding zones
E1 – E2
E2 – E3
E3 – E4 E1 1 10
100 E2 E3 E4
No limits

24.  = DLOR + ULOR Definitions ULOR = % of flux of the lamp(s)
of a luminaire above horizontal
DLOR
= % of flux of the lamp(s)
of a luminaire below horizontal
 = DLOR + ULOR

25. ULOR ULR = DLOR + ULOR Definitions ULR = % of flux of a luminaire
above horizontal
UWLR
ULOR inst
ULR =
DLOR + ULOR
ULOR

26. CIE recommandation for the limitation of sky glow
Zone rating
ULORinst (%) E1 E2
0 – 5 E3
0 – 15 E4
0 - 25

27. Second (our) approach : Limitation of UPF ( UPward Flux )
Sky glow limitation
Second (our) approach :
Limitation of UPF ( UPward Flux )

28. ULOR DLOR r2 r2 r1 K (DLOR-K)
Where h = ULOR + DLOR, i.e.  h = ULOR + K + (DLOR-K)

29. Then, Fupwards (potential)= Flamp x % of rays going upwards
REFLECTION ON THE ROAD
REFLECTION ON SURROUNDINGS
FLUX OF THE LAMP
DIRECT FLUX UPWARDS

30. Depends on :
E resquested by standards
S surface to be lit : political decision
These are the luminaire features, where we can have a say
The nature of the surfaces to be lit and the surroundings: we have very little influence on this choice

31. How can we influence the Fupwards (potential) ?
Finding the good compromise between:
 Reducing ULOR
 Increasing K (as close as possible to DLOR)
 Optimizing the E/L ratio for road lighting installations
Getting the best possible photometry
But being aware that there is no magic recipe (due to the uncertainty on the surfaces reflection properties, especially on the surroundings’)

32. Road lighting applications
In many occasions, low depth glasses (Onyx, Saphir and MC low deeps, Image,…) are the best photometrical compromise But flat glasses are good enough a lot of times too and...
USE OF FLAT GLASS IS WIDELY ACCEPTED BY ASTRONOMERS
But we must not forget that for some r, deep protectors (that have higher ULOR) and even refractors are a less “polluting” solution than the others!!!

33.  High pollution

34. Reducing ULOR
Flat glass at 0°?
Curved glass protector is
often the best solution

35. Recommendations for other installation
 Do not “over” light
 Direct light downwards  
 Keep beam below 70°  
70°
<70°
 Take care with location and height of poles

36. (a) Higher mounting heights – less spill and glare
Use of narrow beam floodlight possible
Lower aiming
possible
(a) Higher mounting heights – less spill and glare
Use of wider beam floodlight
may be necessary
Higher aiming
necessary
(b) Lower mounting heights – more spill light and glare

37. Use asymetric light distribution
Floodlighting

38. Louvers and shades to be used adequately
Focal
Neos 3
Citea

39. Recommendations for all lighting installations
Use high IP luminaires
Realise the most efficient lighting solution
in long term condition

40. Thank you for your attention