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Guideline S.5: Light Pollution Reduction

Intent

To eliminate light trespass from the site, improve night sky access, and reduce development impact on nocturnal environments.

Required Performance Criteria

Guidelines apply to all projects designated New Buildings and for all new exterior lighting scope within Major Renovations.

  1. Do not exceed the following nighttime (sunset to sunrise) vertical illuminance values for each of the four exterior lighting zone types defined below. The illuminance measurement must be at 5 feet above ground level, along the site property line and facing into the site, perpendicular to the site property line. Vertical illuminance solely from site lighting fixtures may be used; light reflectance off of site surfaces may be ignored in meeting this criteria.
Environmental Lighting ZoneDescriptionMaximum Vertical Illuminance Levels [fc] at Property Line
E1: Intrinsically DarkParks and residential areas where controlling light pollution is a high priority 0.1
E2: Low Ambient Brightness Outer urban and rural residential areas 0.1
E3: Medium Ambient Brightness Urban residential areas 0.2
E4: High Ambient Brightness Urban areas having both residential and commercial use and experiencing high levels of nighttime activity0.6

Note: This table was adapted from Illuminating Engineering Society of North America (IESNA) RP-33-99, using “post curfew” recommendations for all values to ensure that light trespass is minimized for each environmental zone. In situations where the property line is very close to the area of development (commonly referred to as “zero property line”), and where lighting is required for emergency egress purposes, it may not be possible to meet these recommendations, and an exception may be made for lighting within 10 feet of these areas. Carefully explain and document these conditions.

Recommended Performance Criteria

  1. Reduce upward emissions to reduce light pollution or sky glow.
    1. For the environmental lighting zones as defined above for light trespass, achieve the following light distribution characteristics:For parking lot and security lighting areas:
        1. Zone E1: Use luminaires with light distribution that meets IESNA’s Full Cutoff Fixtures.
        2. Zone E2: Use luminaires with light distribution that meets IESNA’s Cutoff Fixtures.
        3. Zone E3: Use luminaires with light distribution that meets IESNA’s Semi-Cutoff Fixtures.
        4. Zone E4: Use luminaires with light distribution that meets IESNA’s Cutoff Fixtures.

      For facade, display, sculptural, and sign lighting:

      1. For luminaires of 3500 or more lumens, light objects from above.
      2. For luminaires of less than 3500 lumens, objects may be lit from below. Make an effort to minimize non-target light (maximize the percentage of uplight that falls on the target).
  2. Create lighting control zones and provide lighting control devices for parking lot, security, and decorative and façade lighting so that each type of lighting can be controlled independently and can be turned off or reduced in response to reduced lighting needs during low use or non-use periods.Note: The principles for sky glow criteria S.5 B-C are adapted from principles outlined in IESNA RP33-99, Lighting for Exterior Environments.
  3. Use lamps with a minimum CRI of 65 in areas of safety/security (i.e., main walking routes through large parking lots, isolated areas), at building entrances, and locations where identification of objects or individuals is essential.

Implementation in the Design Process:

During the design process, define zones that require high, medium, and low levels of lighting based on safety, security, and environmental concerns. Take into consideration existing nighttime ambient lighting levels. Develop coverage patterns of lighting and design of light fixtures in relation to the scale of the development and the need for light or safety. Focus on enhancing way-finding, increasing safety, and minimizing glare and light trespass. At site periphery, increase wayfinding and minimize light trespass.

In the construction documents and construction administration and buyout of the project, develop site lighting that adds and directs light only where it is required, is efficient in its use of energy, maximizes safety, and minimizes light trespass.

During construction, monitor submittals for compliance with plans and details and make bidders aware that plans are diagrammatic and that adjustments will need to be made when installing lighting. When installed, ensure that lighting is installed upright and plumb with correct luminaires, bulbs, and attachments. Remedy pattern and color rendition if needed.

During occupancy, monitor and maintain vegetation around lighting to keep it from obscuring light coverage pattern, and clean or replace light lenses at regular intervals.

Design:

  • S.5A: Vertical illuminance allowed at property line.
  • S.5B: Verification of use of cutoff fixtures.
  • S.5C: Verification of creation of outdoor lighting control zone, use of control devices.
  • S.5D: Verification of use of lamps with CRI within guideline limits.

Final Design:

  • S.5A: Vertical illuminance allowed at property line, vertical illuminance as designed.
  • S.5B: Verification of use of cutoff fixtures.
  • S.5C: Verification of creation of outdoor lighting control zone, use of control devices.
  • S.5D: Verification of use of lamps with CRI within guideline limits.

Closeout:

  • S.5A: Vertical illuminance as installed and verification that the site contractor understands the requirements and intent of this guideline.
  • S.5B: Verification of use of cutoff fixtures and verification that the site contractor understands the requirements and intent of this guideline.
  • S.5C: Verification of outdoor lighting control zone, use of control devices and verification that the site contractor understands the requirements and intent of this guideline.
  • S.5D: Verification of use of lamps with a CRI above 65 and verification that the site contractor understands the requirements and intent of this guideline.

Illuminating Engineering Society of North America (IES) Recommended Practice (RP-33-14) Lighting for Exterior Environments: http://www.techstreet.com/standards/ies-rp-33-14?product_id=1888389

American National Standard Practice for Design and Maintenance of Roadway and Parking Facility Lighting: https://store.ies.org/product-category/roadway-lighting/

Illuminating Engineering Society of North America (IES) Technical Memorandum TM-11-00, Light Trespass: Research, Results and Recommendations: https://www.amazon.com/IES-TM-11-00-Light-Trespass-Recommendations/dp/B008SVFSOQ

International Dark-Sky Association: www.darksky.org

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