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Light Pollution Research and Education Light Pollution Research and Education at the LRCat the LRC
Michele McColgan Ph. D.
Lighting Research CenterRensselaer Polytechnic Institute
Scope of PresentationScope of Presentation
� Introduction to the Lighting Research Center
� Developing a Light Pollution Program at the LRC
� Research and Education Projects
– Street lighting design tools for municipalities (CL&P)– Outdoor fixture testing (NLPIP)– Questions and answers (NLPIP) – Luminaire design and development (NYSERDA)– Luminaire cutoff classification and skyglow– Illuminated signs
The Lighting Research CenterThe Lighting Research Center
� Founded 1988
� Largest university research and educational center devoted solely to lighting
� Only M.S. program in lighting
� 11 partners - manufacturers, government, and utilities
� Independent objective 3rd party status
MissionMission
To advance the effective use of light and create a positive legacy for society and the environment
The Lighting Research CenterThe Lighting Research Center
Staff – Over 40 full time faculty and staff– Over 15 full time students
Funding– ~5.2 million per year
Projects– 40 - 60 funded projects being performed
PartnersPartners
U.S. Dept. of Energy
Current SponsorsCurrent SponsorsAARP
LRC’s Outdoor Lighting GoalsLRC’s Outdoor Lighting GoalsAct as an independent facilitator for all stakeholders in outdoor lighting
– Bridge the lighting, astronomical, and environmental communities
– Provide a voice for outdoor lighting end-users
Perform objective research to assist in design, specification, and regulation of efficient outdoor lighting
Develop an outdoor lighting information resource
New LRC ProgramNew LRC ProgramInformation Resource on Light Pollution and Information Resource on Light Pollution and
Energy Efficient Outdoor LightingEnergy Efficient Outdoor Lighting
No one resource available to obtain accurate, unbiased and timely information on the issues of light pollution and outdoor lighting
Decisions are being made about outdoor lighting based on few or incorrect facts
– often resulting in unintended consequences with negative impacts on design performance, light pollution or energy use
The LRC is creating a collection of information on the topic of light pollution and energy efficient outdoor lighting
– The ultimate goal being to provide decision makers, specifiers, and designers with up to date and reviewed information that is based on sound scientific study
Information Resource on Light Information Resource on Light Pollution and Energy Efficient Outdoor Pollution and Energy Efficient Outdoor
LightingLightingDevelopment of this resource will have two benefits:
• Access to data will help decision makers make the correct choices to ensure that light pollution concerns are met without compromising safety or energy efficiency
• Additionally, gaps in the collective knowledge will become evident
Possible topics include: • proposed and current lighting legislation• design guides• demonstrations and evaluations• system design and energy use• research results • new specifications, standards, and classifications• testing reports• education, seminars, and conference presentations
Connecticut Light & PowerConnecticut Light & Power
� White paper� Checklist� Street Lighting Design
Patterns� Seminar
www.lrc.rpi.edu/programs/transportation/index.asp
White PaperWhite PaperEFFICIENT STREET LIGHTING AND EFFICIENT STREET LIGHTING AND
LIGHT POLLUTIONLIGHT POLLUTIONScope of this document
– Provide information to lighting decision makers in the state of Connecticut about street lighting and light pollution
– This document:• Outlines current Connecticut legislation • Defines light pollution • Discusses lighting considerations that should be considered before
embarking on a lighting project, • Summarizes good lighting practice
– Is intended to be used with companion documents• Checklist and design guide
How to Use the ChecklistHow to Use the Checklist
Design GuideDesign GuideEfficient Street Lighting Design Efficient Street Lighting Design
GuideGuideScope of document
– This guide is designed to aid Connecticut municipalities in designing and specifying energy efficient street lighting to meet their illumination goals
• The intent of this guide is to provide illustrative examples of typical street lighting designs and present alternative options
• Although all possible outdoor lighting scenarios cannot be illustrated in this document, it is presented as a tool to identify practical approaches that consider light pollution issues
Example I: a cul de sac with a diameter of about 53’-0”in a residential setting has been usedGoal: To illustrate how uniformity and light distribution change for various wattages for two different full cutoff luminaires mounted at different heights.
A
B
A. Lighting Scheme
GE SL_C_70WHPS_6300_14_2.40_7.30_24.00
B. Lighting Scheme
GEM250_FC_70WHPS_6300_27_1.50_4.10_15.00
Product TestingProduct Testing
� NLPIP (National Lighting Product Information Program)
� http://www.lrc.rpi.edu/nlpip/index.cfm
Update Specifier ReportUpdate Specifier Report� Original published in 1993� Has become outdated
– No full cutoff classification– Not much consideration of
light pollution concerns– More products currently
available
Specifier ReportSpecifier Report Update GoalsUpdate Goals
� Expand scope of the earlier report
� Provide manufacturer’s data
� Include product testing– Full 360o intensity characterization– Finer angular increments above
the luminaire and in the glare zone– Spot check manufacturers info
� Explore light pollution issues – Uplight (reflected and direct), trespass, and glare
� Include further calculation and analysis– Glare– Uplight– Energy usage
NLPIP Lighting Answers Light PollutionNLPIP Lighting Answers Light PollutionQuestions and Answers
– What is light pollution?– What is sky glow? – What is light trespass? – What is glare? – How is the issue of light pollution currently
being addressed?– What are lighting environmental zones?– How are luminaires evaluated for their
potential to contribute to light pollution or light trespass?
– What are the IESNA cutoff classifications?– Are the IESNA cutoff classifications a good
indicator of direct uplight?– What is the difference between full cutoff
and fully shielded?
� www.lrc.rpi.edu/nlpip/lightinganswers.cfm
Smart Roadway LightingSmart Roadway Lighting
� The LRC will develop two types of lighting elements:
1. Street lighting fixtures � Use less energy� Light roadways more effectively� Greatly reduce the amount of stray light
2. An integrated, “intelligent” roadway marking system � For hazardous areas such as SPUIs, highway exit and entrance
ramps, sharp curves, or pedestrian crossings� Using low-mounted solid-state lighting equipment LEDs� These devices may also give drivers information about road
conditions, upcoming accidents, hazards, or pedestrians entering the road
Luminaire Design ConsiderationsLuminaire Design Considerations
� What is the application?– Roadway
• What is the road surface?– Parking lot– Area/pathway
� What are the objectives?– Safety – driver/pedestrian– Security– Economic development– Esthetics
� What light levels are required?� Appropriate beam distribution?� How can energy use be minimized?
– Lower wattage– Fewer poles
� What are acceptable limits for glare?– Baseline offensive glare levels on full cutoff
� How to minimize trespass/sky glow?
Direct and reflected candela distributionDirect and reflected candela distribution
Luminaire Cutoff Classification and Luminaire Cutoff Classification and SkyglowSkyglow
Blue -measuredPink – Software
0
0.2
0.4
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0.8
1
1.2
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0 5 10 15 20 25 30 35 40
ObjectivesObjectives
� To study the effects of different types of cutoff luminaires on local skyglow
� Develop accurate simulation methods
� “Light pollution index” or LPI
– Ratio of the lumens on each plane by the lumens falling on the parking lot surface
Experimental Geometry Experimental Geometry
� Parking lot in Rensselaer Technology Park
� Rasphalt = 7%� Dimensions 135’ x 180’� Grass surrounding parking lot
extends 200’ in each direction� 18 pole-mounted luminaires
– 4 full cutoff, 7 cutoff, 7 semicutoff– different manufacturers
Analysis 1Analysis 1
� Constants– height (30’), wattage (250W), and throw (Type-III)
� Similar average ground illuminance (~ 25 lux)– In all cases the IESNA parking lot recommendations of
min illuminance > 2 lux and max/min ratio < 1:20 were met
� Variables– # luminaires– spacing
Analysis 1Analysis 1Average Illuminance ComparisonAverage Illuminance Comparison
8Semicutoff2
8Semicutoff1
7Cutoff2
7Cutoff1
Manufacturer A
No. of LuminairesCutoff Type
8Semicutoff2
7Semicutoff1
8Cutoff2
8Cutoff1
8Full Cutoff2
7Full Cutoff1
Manufacturer B
11Semicutoff2
10Semicutoff1
No. of LuminairesCutoff Type
8Semicutoff
8Cutoff
7Full Cutoff2
7Full Cutoff1
Manufacturer D
7Cutoff2
8Cutoff1
Manufacturer C
LPI LPI -- TopTop--down planedown plane
0
0.1
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0.7
Full Cutoff Cutoff Semi-CutoffCutoff Type
Ligh
t Pol
lutio
n In
dex
(Top
-Dow
n Pl
ane)
Average Illuminance
Analysis & Discussion of ResultsAnalysis & Discussion of Results
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
50.0% 55.0% 60.0% 65.0% 70.0% 75.0% 80.0% 85.0%
Luminaire Efficiency (%)
LPI
Full CutoffCutoffSemicutoff
Cutoff Classification and Skyglow Cutoff Classification and Skyglow ConclusionsConclusions
� Modeling methods can be used to predict and compare skyglow
� IESNA Cutoff classification is not:– A good predictor of # of lamps needed– A good predictor of total system uplight
� This work needs further exploration to determine why luminaires exhibit these features regardless of cutoff classification
Illuminated signsIlluminated signs
� Illuminated signs are very popular
� Cold cathode fluorescent and neon are the most commonly used light sources in illuminated signs
Super Vision Ato Haas ILE
ILE
LEDs for channel letter signsLEDs for channel letter signs
Normalized efficacy -Typical 60-cm Neon and LED RED signs
1.00
1.98 2.091.88
1.301.53
2.60
0.0
1.0
2.0
3.0
Neon A B C D E FSample
Rel
ativ
e E
ffica
cy (%
)
LRC Data 2002
Normalized efficacy -Typical 60-cm Neon and LED RED signs
1.00
1.98 2.091.88
1.301.53
2.60
0.0
1.0
2.0
3.0
Neon A B C D E FSample
Rel
ativ
e E
ffica
cy (%
)
LRC Data 2002
� LEDs may provide a better solution for illuminated signs
Need an Energy Efficiency StandardNeed an Energy Efficiency Standard� Presently, there are no visibility standards for illuminated
signs (how bright does a sign really need to be?)
� Energy waste and light pollution result from– over lit signs– light going upwards– 24 hour operation in many cases– older technologies based on craftsmanship (neon)– low transmittance acrylics
� Definition of these characteristics would result in a set of specifications for energy efficient signs
� Potential to achieve significant energy savings by using– more efficient technologies, such as LEDs– better optics that direct light only to where it is needed– automatic shut-off – For channel letter red signs, LEDs offer the potential of
50% energy savings
� An optimized red sign could achieve 80% energy savings
Potential Energy SavingsPotential Energy Savings
ConclusionsConclusionsDecisions are being made about outdoor lighting based on few or
incorrect facts– often resulting in unintended consequences with negative impacts
on design performance, light pollution or energy use
The LRC is creating a collection of information on the topic of light pollution and energy efficient outdoor lighting
– The ultimate goal being to provide decision makers, specifiers, and designers with up to date and reviewed information that is basedon sound scientific study
www.lrc.rpi.edu/programs/transportation/index.asp