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 a...
PROBLEMS
 Light

Trespass

Also known as “obstructive light”, defined as
unwanted light that falls beyond the property li...
PROBLEMS


Who does light trespass having the largest negative
impact on?
Neighborhood residents
 Unwanted light shining...
PROBLEMS


Biggest Offenders
Street lights with inadequate optical control
 Sports field lighting
 Commercial lighting
...
PROBLEMS
 Light

Pollution

Also known as “sky glow”, defined as light that is
directed upward to the sky or reflected fr...
PROBLEMS


Even light from well-designed lighting systems will
reflect from objects being illuminated and light will
ente...
ENVIRONMENTAL AFFECTS
 Environmental


Sea Turtles




Affects

Illuminated beaches

Birds
Nighttime illuminance confu...
SOLUTIONS


Luminaires that allow for control of light above the
horizontal plane.
Semi-cut-off
 Cut-off
 Full cut-off
...
LEED


Light Pollution Reduction Credit




Must provide cut sheets of all luminaires along with a
plan showing horizon...
EXAMPLES
EXAMPLES
EXAMPLES
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Light trespass and_pollution[1]

  1. 1. Electrical Breakfast Club 03/14/08 Light Trespass & Light Pollution
  2. 2. 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 
  3. 3. 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 
  4. 4. 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. 
  5. 5. 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 
  6. 6. 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
  7. 7. 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.
  8. 8. ENVIRONMENTAL AFFECTS  Environmental  Sea Turtles   Affects Illuminated beaches Birds Nighttime illuminance confusion  Death spiral 
  9. 9. 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 
  10. 10. 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.
  11. 11. EXAMPLES
  12. 12. EXAMPLES
  13. 13. EXAMPLES

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