Light pollution reduction | U.S. Green Building Council
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LEED BD+C: New Construction | v4 - LEED v4

Light pollution reduction

Possible 1 point

Submittal Tips (click to expand)

SS Credit: Light Pollution Reduction

All Projects
  • Make sure the site lighting plan clearly highlights the lighting boundary. If the lighting boundary does not align with the LEED Project Boundary, make sure to explain any differences. See the credit requirements for an explanation of when the boundary can extend beyond the project boundary.
  • The lighting plan must also include locations of fixtures, applicable measurements, and any other key features.
  • Make sure to classify the project under the proper MLO lighting zone and to reference that lighting zone consistently throughout all documentation.
  • Remember to check that all internally illuminated exterior signage does not exceed a luminance of 200 cd/m2 during nighttime hours and 2,000 cd/m2 during daytime hours. Provide the maximum luminance data of the sign(s).
  • Remember to note any exterior lighting that is exempt from the requirements. Note that existing light fixtures used in the final project design are not exempt.
Uplight - BUG
  • Ensure the site lighting plan clearly notes the location and orientation of each exterior lighting fixture.
  • Ensure that the lumens calculator shows each exterior lighting fixture and the corresponding BUG rating.
  • Make sure the allowed uplight rating for the specified MLO lighting zone has not been exceeded.
  • Note that if a light is under an overhang, the U rating is not automatically 0. It depends on where the light is located in relation to the overhang, and if there are any angles at which light can escape from the sides of the overhang.
  • Uplight - BUG
    • Make sure to include the total lumens per luminaire above horizontal for each exterior lighting fixture.
    Light Trespass - BUG
    • Make sure to orient all luminaires less than two mounting heights away from the lighting boundary such that the backlight points toward the nearest lighting boundary line.
    • Building-mounted luminaires with the backlight oriented toward the building are exempt from the backlight rating requirement.
    • Be sure that the allowed backlight or glare ratings for the specified MLO lighting zone have not been exceeded.
    • Make sure to include the mounting height and distance from the lighting boundary, especially for any fixture where it may be difficult to visually determine if the distance from the lighting boundary is between 0.5 and 2 mounting heights from the lighting boundary.
    Light Trespass - Calculation
  • Ensure the photometric plan shows a point-by-point calculation illustrating the worst-case scenario of vertical illuminance for each luminaire as it crosses the lighting boundary.
Vertical Illuminance Visualized