Light Pollution Reduction - 1 Point

Existing Buildings - Sustainable Sites

Intent - To minimize light trespass from the building and site, reduce sky-glow to increase night sky access, improve nighttime visibility through glare reduction and reduce development impact from lighting on nocturnal environments.

Requirements

Project teams must comply with the interior lighting requirement

AND

1 of the 3 options for exterior lighting.

INTERIOR LIGHTING

All nonemergency built-in luminaires with a direct line of sight to any openings in the envelope (translucent or transparent, wall or ceiling) must be automatically controlled to turn off during all after-hours periods during the performance period. The total duration of all programmed after-hours periods annually must equal or exceed 2,190 hours per year (50% of annual nighttime hours). Manual override capability may be provided for occasional after-hours use.

Implement a program to ensure that the lighting control system is being properly used to adjust lighting levels during all after-hours periods.

EXTERIOR LIGHTING

OPTION 1

If the project is certified under LEED for Schools or New Construction, show that SS Credit 8: Light Pollution Reduction was earned. If the project is certified under LEED for Core & Shell Development and 75% of the floor area is LEED for Commercial Interiors, show that SS Credit 8: Light Pollution Reduction was earned for both systems.

OR

OPTION 2

Partially or fully shield all exterior fixtures 50 watts and over so that they do not directly emit light to the night sky.

OR

OPTION 3

Measure the night illumination levels at regularly spaced points around the perimeter of the property, taking the measurements with the building’s exterior and site lights both on and off. The building’s interior lights must be in the same state during both measurements. At least 8 measurements are required at a maximum spacing of 100 feet apart, so as to be representative of the illumination levels at the perimeter of the property. The illumination level measured with the lights on must not be more than 20% above the level measured with the lights off. This requirement must be met for each measurement point; averaging of all points is prohibited.

Referenced Standards

None

Design Strategies

• Projects should consider the use of low intensity, shielded luminaires and curfew controllers turning the lights off at 10p or at closing (whichever is later).
• Projects should minimize the lighting of architectural or landscaping features.
• Where lighting is required, utilize down-lighting instead of uplighting.

General Strategy for Designing Exterior Lighting:

1. Employ a lighting professional.
2. Review all applicable lighting ordinances and by-laws.
3. Document which environmental zone the site in in.
4. Use the least amount of lighting equipment while remembering it is sometimes better to use two luminaires with lower light output and good glare control instead of a single high output luminaire.
5. Select all lighting equipment carefully watching for glare, unneeded uplight and light trespass possibilities.
6. Design the exterior lighting so as to minimize reflected light going upward.
7. Light only areas that require lighting, using the least light possible. Design and develop a control scheme to minimize or turn-off lighting after hours.
8. Use a computer modeling tool to provide point-by-point illuminances throughout the space and off-site.
9. Commission and maintain the lighting system.