Intent

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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.

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Requirements

 

Project teams must comply with 1 of the 2 options for interior lighting AND the requirement for exterior lighting.

 

For Interior Lighting

 

Option 1

Reduce the input power (by automatic device) of all nonemergency interior luminaires with a direct line of sight to any openings in the envelope (translucent or transparent) by at least 50% between 11 p.m. and 5 a.m.

After-hours override may be provided by a manual or occupant-sensing device provided the override lasts no more than 30 minutes.

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OR

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Option 2

All openings in the envelope (translucent or transparent) with a direct line of sight to any nonemergency luminaires must have shielding (controlled/closed by automatic device for a resultant transmittance of less than 10% between 11 p.m. and 5 a.m.).

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For Exterior Lighting

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Light areas only as required for safety and comfort. Lighting power densities must not exceed ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda 1) for the classified zone. Meet exterior lighting control requirements from ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda 1) Exterior Lighting Section, without amendments.

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Classify the project under 1 of the following zones, as defined in IESNA RP-33, and follow all the requirements for that zone:

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LZ1: Dark (developed areas within national parks, state parks, forest land and rural areas)

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Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.01 horizontal and vertical foot candles at the site boundary and beyond.

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Document that 0% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

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LZ2: Low (primarily residential zones, neighborhood business districts, light industrial areas with limited nighttime use and residential mixed-use areas)

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Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.10 horizontal and vertical foot candles at the site boundary and no greater than 0.01 horizontal foot candles 10 feet beyond the site boundary. Document that no more than 2% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

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LZ3: Medium (all other areas not included in LZ1, LZ2 or LZ4, such as commercial/ industrial, and high-density residential)

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Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.20 horizontal and vertical foot-candles at the site boundary and no greater than 0.01 horizontal foot-candles 15 feet beyond the site. Document that no more than 5% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

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LZ4: High 2 (high-activity commercial districts in major metropolitan areas)

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Design exterior lighting so that all site and building-mounted luminaires produce a maximum initial illuminance value no greater than 0.60 horizontal and vertical foot-candles at the site boundary and no greater than 0.01 horizontal foot-candles 15 feet beyond the site. Document that no more than 10% of the total initial designed fixture lumens (sum total of all fixtures on site) are emitted at an angle of 90 degrees or higher from nadir (straight down).

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LZ2, LZ3 and LZ4 - For site boundaries that abut public rights-of-way, light trespass requirements may be met relative to the curb line instead of the site boundary.

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For All Zones

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Illuminance generated from a single luminaire placed at the intersection of a private vehicular driveway and public roadway accessing the site is allowed to use the centerline of the public roadway as the site boundary for a length of 2 times the driveway width centered at the centerline of the driveway.

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Potential technologies & Strategies

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Adopt site lighting criteria to maintain safe light levels while avoiding off-site lighting and night sky pollution.

Minimize site lighting where possible, and use computer software to model the site lighting. Technologies to reduce light pollution include full cutoff luminaires, low-reflectance surfaces and low-angle spotlights.

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FBK Solutions

• Light using:

+ LED Street Light 60W – 5520lm ± 5% (AC)

+ LED Flood Light 20W – 1450 – 1550lm

• LEED requirement:

• At the boundary: no greater than 0.2 fc

• 15 feet beyond the site: 0.01 fc

• Performance:

• At the boundary: 0.19 fc

• 15 feet beyond the site: 0.01 fc

=> To reduce development impact from lighting on external environments.