OBTRUSIVE LIGHTING

Direct glare

SPILL LIGHT

SKY GLOW

Obtrusive light

Area to be lit

R-TECH 1

Upward direct light

Upwa

rd re

flecte

d ligh

t

Definitions

Three phenomena are related to light control of luminaires and their installation

Glare

All are the result of waste of energy

Obtrusive light Sky glow

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

1°E

Disability glare - TI

(CIE 140)

K E2

andLv = TI = 65Lv

LR0.8

10% or 15%

Glare Rating - GR

(CIE 112)

GR = 27 + 24 lg (Lvl / Lve 0.9)

With Lvl = veiling luminance produced by luminaires

Lve = veiling luminance produced by environment

and Lve = 0.0355 Lav

with Lav = EH.

Glare Ratio GR

Unbearable

Disturbing

90

80

70

60

Just admissible 50

Noticeable

Unnoticeable

40302010

Glare Rating limitation

Glare control

At design stage :

On site :

Calculation of TI or GR

Cannot be measured

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 (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 ’’

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

CIE zoning system

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 2 lux 5 lux

Maximum values of EV on properties - CIE 150

CIE zoning system

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 2500 cd

Maximum values of I (cd) in specific directions - CIE 150

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

CIE zoning system

Limitation of effects on over lit building and signs CIE 150

CIE zoning system

Parameter

Application

Conditions

Environmental Zones

E1 E2 E3 E4

BuildingFacadeLuminance(Lb )

0 cd/m² 5 cd/m² 10 cd/m² 25 cd/m²

SignLuminance

(Ls )50 cd/m²

400 cd/m²

500 cd/m²

1000 cd/m²

EAV x

EAV x

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 glowSky glow

SKY GLOW

SKY GLOW

- Artificial lighting installations

direct upward light

upward reflected light

- Headlights of vehicules

- Atmosphere pollution

- Atmosphere humidity

- Clouds

- Radiation from celestian sources

Many factors contribute to sky glow

SKY GLOW

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

Stray light due to artificial lighting

SKY GLOW

First approach : CIE 126 (1997)

SKY GLOW

CIE Zoning system - CIE 126

Zone rating ULOR inst (%) Astronomical acivities

E1 0Observatories of (inter)national

standing

E2 0 – 5 Postgraduate and academic studies

E3 0 - 15Undergraduate studies, amateur

observation

E4 0 - 25 Casual sky viewing

SKY GLOWMinimum 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 1 100

E3 1

E4 No limits

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

Definitions

ULR = % of flux of a luminaireabove horizontal

UWLRULOR inst

ULR = DLOR + ULOR

ULOR

CIE recommandation for thelimitation of sky glow

Zone rating ULORinst (%)

E1 0

E2 0 – 5

E3 0 – 15

E4 0 - 25

Sky glow limitation

Second (our) approach :

Limitation of UPF ( UPward Flux )

DLOR

ULOR

(DLOR-K)1

2 2

Where = ULOR + DLOR, i.e. = ULOR + K + (DLOR-K)

K

).(. 21)(_ KDLORKULORLpotentialtotalupwards

FLUX OF THE LAMP DIRECT FLUX

UPWARDS

REFLECTION ON THE ROAD

REFLECTION ON SURROUNDINGS

Then, upwards (potential)= lamp x % of rays going upwards

).(. 21)(_ KDLORKULORLpotentialtotalupwards

Depends on :

E resquested by

standards

S surface to be lit :

political

decision The nature of the surfaces to be lit and the surroundings: we have very little influence on this choice

These are the luminaire features,

where we can have a say

How can we influence the upwards (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’)

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 , deep

protectors (that have higher ULOR) and even refractors

are a less “polluting” solution than the others!!!

Road lighting applications

High pollution

Reducing ULOR

Flat glass at 0°?

Curved glass protector isoften the best solution

Recommendations for other installation

Do not “over” light

Direct light downwards

Keep beam below 70°

Take care with location and height of poles

70° <70°

Lower aiming

possible

Use of narrow beam floodlight possible

Higher aiming

necessary

Use of wider beam floodlight

may be necessary

(a) Higher mounting heights – less spill and glare

(b) Lower mounting heights – more spill light and glare

Floodlighting

Use asymetric light distribution

Focal

Neos 3

Citea

Louvers and shades to be used adequately

Recommendations for all lighting installations

Use high IP luminaires

Realise the most efficient lighting solution

in long term condition

Thank you for your attention