Light trespass and_pollution[1]
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Light trespass and_pollution[1]






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Light trespass and_pollution[1] Light trespass and_pollution[1] Presentation Transcript

  • Electrical Breakfast Club 03/14/08 Light Trespass & Light Pollution
  • INTRODUCTION  There is an increasing concern for the problems created by unwanted light at night.  Lighting designers are faced with conflicting challenges Meeting Local ordinances controlling the light  Meeting the needs of having the light 
  • PROBLEMS  Light Trespass Also known as “obstructive light”, defined as unwanted light that falls beyond the property line or area intended to be illuminated.  Results of light trespass  Spill Light. Lighting areas beyond the area intended to be lit. Producing illuminance outside of the property lines.  Brightness. Bright sources within the observer’s field of view, such as direct viewing of luminaires.  Discomfort glare  Disability glare – Reduction in the visibility of significant visual tasks 
  • PROBLEMS  Who does light trespass having the largest negative impact on? Neighborhood residents  Unwanted light shining into homes at night  Desire to have a low level of ambient light  Drivers  Disability glare can seriously affect a driver’s visibility and ability to locate and recognize signal lights. 
  • PROBLEMS  Biggest Offenders Street lights with inadequate optical control  Sports field lighting  Commercial lighting   Biggest Reasons Excessive and unnecessary use of lamps with light lumen output  Incandescent floodlights improperly aimed  Luminaires left on all dusk to dawn for no real purpose 
  • PROBLEMS  Light Pollution Also known as “sky glow”, defined as light that is directed upward to the sky or reflected from surfaces that is interference.  Results of light pollution   Natural and manmade particles in the air scatter light rays from outdoor lighting and create an artificial fog in the sky.  General Public  Astronomy
  • PROBLEMS  Even light from well-designed lighting systems will reflect from objects being illuminated and light will enter the atmosphere. Almost impossible to eliminate all light from entering the atmosphere.
  • ENVIRONMENTAL AFFECTS  Environmental  Sea Turtles   Affects Illuminated beaches Birds Nighttime illuminance confusion  Death spiral 
  • SOLUTIONS  Luminaires that allow for control of light above the horizontal plane. Semi-cut-off  Cut-off  Full cut-off  Luminaire shields  Reduce amount of light on highly reflective surfaces.  Review lighting systems 
  • LEED  Light Pollution Reduction Credit   Must provide cut sheets of all luminaires along with a plan showing horizontal and vertical footcandles. Projects attaining this credit saw an average of 30% electricity savings due to elimination of luminaires and reduction in lumens.