Alliance for Lighting Information
Circadian Stimulus and S/P Ratios discusses the directly proportional relationship between a light source's S/P ratio - used widely now in marketing - and its corresponding stimulus to the human circadian system.
Some Inconvenient Truths About CFLs include the lack of energy savings from "normal power factor" CFLs, the difference in life and savings from frequent switching, and disposal issues.
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- is a complex and important issue in outdoor lighting, and some topics are discussed here along with links to more information.
- are involved in outdoor lighting design and maintenance decisions. This page introduces the issues and provides links to more information within the ALI website.
- Environmental Effects
- from outdoor lighting are evident and hidden. This page presents some of the signfiicant issues and links to more information in the ALI website.
- Health Effects
- from lighting are varied - from sunburn to neurotoxin pollution - and in particular, recent research is showing that light can have a very significant health effect on melatonin and our diurnal cycle.
- Legislation and Ordinances
- are being proposed and adopted in many areas, from local jurisdictions up to states (so far). This page cites some of the issues and provides links to information with the ALI website that may be relevant to lighting legislation and ordinances.
- Light Pollution or Skyglow
- is a growing concern and to some extent depends on choices made when lighting systems are designed. This page introduces the issues and provides links to more information within the ALI website.
- Older Eyes
- work differently under outdoor lighting levels and conditions, particularly driving at night. This page provides brief information about the most important effects of aging on vision, and includes links to more information within the ALI website.
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- Efficacy of Metal Halide and High Pressure Sodium Sources
- End-of-Life Lamp Lumen Data
- Foveal, Para-foveal and Peripheral Vision
- Initial and Maintained Conditions
- Lamp Lumen Depreciation (LLD)
- Light Loss Factor (LLF)
- Luminaire Cutoff Classification by the IESNA Roadway Lighting Committee
- "Mean" for Metal Halide and High Pressure Sodium Sources
- Photopic Sensitivity Functions
- Rated Life of Metal Halide and High Pressure Sodium Sources
- Rated Lumens and Initial Efficacy
- Rated Lumens for Various Outdoor Sources
- Rayleigh Scatter Index (RSI)
- Relating Intensity and Flux using Solid Angle and Zonal Multipliers
- RSI Data for Sources
- Retinal Ganglion Cells and Melanopsin
- Scotopic Sensitivity Function
- Uniformity Ratio
- Unit Power Density (UPD)
- Unit Uplight Density (UUD)
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- Color Contrast
- discusses how contrast has both luminous and chromatic aspects, and what that means about contrast calculation methods and results.
- Color Rendering Index Values for MH
- discusses the "chromatic difference" metric DC in the CIE's Colour Rendering Index calculation (CIE 13.3-1995) and why CRI values for MH sources are at best "less accurate".
- Errors in the Eley Outdoor Lighting Research Report
- includes information about problems in the document used as the sole technical basis for the outdoor lighting portion of the CEC's proposed legislation.
- A Misleading Example of Outdoor Lighting
- discusses the use of the Ferrari of Denver auto dealership as an example of quality outdoor retail lighting - even though it fails to meet the IESNA requirements (in RP-20-98) for parking lot lighting!
- Melanopsin, Melatonin and Human Health
- presents recently developed information on the relationship between retinal ganglion cells and melanopsin, melatonin and effects on human health.
- Mesopic Vision and Outdoor Lighting Criteria
- discusses the mesopic range and the luminances that correspond to outdoor lighting design criteria.
- PIER Review
- by Jefferey Knox discusses his findings in a review of the Public Interest Energy Research (PIER) program's Outdoor Lighting Baseline Assessment Final Report on behalf of the California Energy Commission. Additional discussions on specific issues include:
- Recurring Errors in Ordinances: Site Uniformity and Property Line Limitations
- discusses the problems that misunderstood and misapplied elements in ordinances can produce.
- Roadway Lighting Research
- discusses the findings from research into Unit Power Density (UPD) and Unit Uplight Density (UUD), published in four papers by David Keith in the Journal of the IESNA from 2000 through 2003.
- Some Inconvenient Truths About CFLs
- include the lack of energy savings from "normal power factor" CFLs, the difference in life and savings from frequent switching, and disposal issues.
- There is More to Lighting Quality Than What Meets the Eye
- presents the issues involved in outdoor lighting quality, recognizing that the visual appearance and performance of a lighting system are only part of the complete story.
- Uniformity Ratios in Ordinances
- discusses the way such ratios are defined and implemented in lighting ordiances, along with problems that occur when the implications of uniformity ratios are not undestood.
- What Blue Skies Tell Us About Light Pollution
- is a introduction to the issues of skyglow and particularly evaluation of relative contributions by different light sources.
- Why MH Systems Cost More Than HPS Systems
- discusses the relative costs - in monetary and environmental terms - of choosing Metal Halide or High Pressure Sodium sources for outdoor lighting.
- Xenon Headlights
- are a nuisance (or worse!) for many drivers and this discussion includes review of the relevant standards and reasons why these headlights are such a pain in the eye.
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- Legislation, Ordinances and Energy Codes: the Future for Outdoor Lighting
- - an outline of the the presentation made to the IEEE 2003 Regional Conference in Denver, CO in March. The Powerpoint presentation (255 kB) is available here.
- IESNA Street and Area Lighting Committee 2001
- conference included this Powerpoint presentation about research into Unit Power Density (UPD), with special emphasis on the potential reduction of uplight.
- Sources, Surfaces and Eyes:
Calculational Procedures Incorporating Spectral Distribution Information
- is the Powerpoint presentation (pdf format, 1.6 MB) made in August 2003 at the IESNA Annual Conference.
- Sources and Surfaces: Evaluating Spectral Distribution Interactions Using Roadway Signage
- is a 2004 presentation to the IES Roadway Lighting Committee on the results of using spectrally informed calculation procedures to evaluate the contrast of roadway signage surfaces under diffferent sources (pdf format, 0.3 MB). The corresponding paper is available here (in .pdf format, 59 kB).
- Sources, Surfaces and Scatter
- is the Powerpoint presentation made to the International Dark-sky Association 2003 Annual Conference in Tuscon, AZ in March The abstract is available here.
- The Spectra of Choices in the Choice of Spectrum
- is the Powerpoint presentation (pdf format, 2.7 MB) made to the 2004 IESNA Street and Area Lighting Conference. Links to additional information about the topics discussed in the presentation are here.
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- Roadway Unit Uplight Density (UUD) Calculation Examples
- includes information about calculating UUD with references and examples.
- Scientific Method in Research
- is the topic of this paper by Professor Gifford, part of a discussion on Full Spectrum Lighting.
- Sources' Spectra, Roadway Surfaces and the Potential for Uplight Scattering
- is the paper submitted to the International Dark-sky Association 2003 Annual Conference in Tuscon, AZ in March. The abstract is here.
- Technical Summary of Research into UPD and UUD
- is (the browser version of) a discussion of the work, results and conclusions published in four papers by David Keith in the Journal of the IESNA since 2000 (and the document in pdf format is here.)
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- 2005 Update Residential & Nonresidential Energy Efficiency Building Standards
- has been developed by the California Energy Commission, based on the Eley Outdoor Lighting Report and the PIER Outdoor Lighting Baseline Assessment. Proposed measures are outlined in this presentation.
- Colorado Jurisdictions
- which have been posting lighting standards or ordinances on the web are linked to the IESNA's Rocky Mountain Section's website.
- Full Spectrum Lighting
- is discussed in this website, including Professor Gifford's paper on scientific method.
- Lance Hahn's Retina Reference
- is an excellent discussion about the retina and eye - detailed, technical and comprehensive - based in part on the highly recommended book "Color Science" by Wyszecki & Stiles.
- Links about Color
- are available on the ALI Color page.
- Additional ALI links can be found here
- and corrections or contributions are welcome, please send to David Keith
For more information, or to send along comments, suggestions or contributions, please contact David Keith by email at firstname.lastname@example.org
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