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

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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

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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

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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

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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