Light Pollution Reduction: Sustainable Site Credit for LEED Existing building (O+M)

The LEED EBOM Sustainable Site Credit: Light Pollution Reduction is an important credit for building owners and operators to consider in their sustainability efforts. This credit applies to existing buildings seeking to improve their sustainability performance and can earn one point towards LEED EBOM certification. The intent of this credit is to increase night sky access, improve night-time visibility, and reduce the consequences of development for wildlife and people. To meet the requirements of this credit, building owners and operators must comply with one of the following options:

Option 1: Fixture Shielding – Shield all exterior fixtures (where the sum of the mean lamp lumens for that fixture exceeds 2,500) such that the installed fixtures do not directly emit any light at a vertical angle more than 90 degrees from straight down.

Option 2: Perimeter Measurements – Measure the night illumination levels at regularly spaced points on the project boundary, taking the measurements with the building’s exterior and site lights both on and off. At least eight measurements are required, at a maximum spacing of 100 feet (30 meters) apart. The illumination level measured with the lights on must not be more than 20% above the level measured with the lights off.

To comply with the credit, building owners and operators should perform a light pollution survey, replace inefficient lighting fixtures with energy-efficient fixtures that minimize light pollution, use dark-sky compliant lighting fixtures, use interior lighting that reduces light pollution, and use lighting controls such as timers, motion sensors, and photocells to automatically turn off lights when they are not needed.

Documentation is required for both options, including confirmation that exterior fixtures are shielded or site lighting measurements and a site plan showing the project boundary, location of all measurement points, distance between measurement points, existing and proposed light fixtures, and any related site features.

Light Pollution Reduction is an important credit for building owners and operators to consider in their sustainability efforts. Compliance can be achieved through either fixture shielding or perimeter measurements, and proper documentation is required. By taking steps to reduce light pollution, building owners and operators can improve night-time visibility, reduce the impact on wildlife and people.