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OBTRUSIVE LIGHTING. Upward reflected light. Upward direct light. Obtrusive light. Direct glare. R-TECH 1. Definitions. SKY GLOW. SPILL LIGHT. Area to be lit. Three phenomena are related to light control of luminaires and their installation. Glare. Obtrusive light.
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Upward reflected light Upward direct light Obtrusive light Direct glare R-TECH 1 Definitions SKY GLOW SPILL LIGHT Area to be lit
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
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
Lv E K and 10% or 15% TI = 65 Lv = LR0.8 2 Disability glare - TI (CIE 140) E 1°
Glare Rating - GR (CIE 112) GR = 27 + 24 lg (Lvl / Lve0.9) With Lvl = veiling luminance produced by luminaires Lve = veiling luminance produced by environment and Lve = 0.0355 Lav with Lav = EH.
Glare control Calculation of TI or GR At design stage : Cannot be measured On site :
Obtrusive light Light falling out of the area of interest , causing disturbances or reducing confort By – over lighting – stray light – bad wave length
CIE zoning system Maximum values of EV on properties - CIE 150
CIE zoning system Maximum values of I (cd) in specific directions - CIE 150
CIE zoning system Limitation of effects on transport system - CIE 150
CIE zoning system EAV x EAV x Limitation of effects on over lit building and signs CIE 150 or LAV
SKY GLOW Definition : Brightening of night sky resulting from reflection of radiations scattered from the constituents of the atmosphere in direction of observation
Sky glow Sky glow SKY GLOW
SKY GLOW 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
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
SKY GLOW First approach : CIE 126 (1997)
SKY GLOW CIE Zoning system - CIE 126
SKY GLOW Minimum distance (in km) between zone borderlines and ref. point
ULOR = % of flux of the lamp(s) of a luminaire above horizontal DLOR = % of flux of the lamp(s) of a luminaire below horizontal Definitions = DLOR + ULOR
ULR = % of flux of a luminaire above horizontal UWLR ULOR inst ULOR ULR = DLOR + ULOR Definitions
Sky glow limitation Second (our) approach : Limitation of UPF ( UPward Flux )
ULOR DLOR (DLOR-K) K r2 r2 r1 Where h = ULOR + DLOR, i.e. h = ULOR + K + (DLOR-K)
Then, Fupwards (potential)= Flamp x % of rays going upwards REFLECTION ON THE ROAD REFLECTION ON SURROUNDINGS FLUX OF THE LAMP DIRECT FLUX UPWARDS
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
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’)
USE OF FLAT GLASS IS WIDELY ACCEPTED BY ASTRONOMERS Road lighting applications In many occasions, low depth glasses (Onyx, Saphir and MC low deeps, Image,…) are the best photometrical compromiseBut flat glasses are good enough a lot of times too and... 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!!!
Curved glass protector is often the best solution Reducing ULOR Flat glass at 0°?
<70° 70° Recommendations for other installation Do not “over” light Direct light downwards Keep beam below 70° Take care with location and height of poles
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
Use asymetric light distribution Floodlighting
Louvers and shades to be used adequately Focal Neos 3 Citea
Recommendations for all lighting installations Use high IP luminaires Realise the most efficient lighting solution in long term condition