SS Credit 8: Light Pollution Reduction
1 Point
Intent
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 on
nocturnal environments.
Requirements
FOR INTERIOR LIGHTING
The angle of maximum candela from each interior luminaire as located
in the building shall intersect opaque
building interior surfaces and not exit out through the windows.
OR
All non-emergency interior lighting shall be automatically
controlled to turn off during non-business hours.
Provide manual override capability for after hours use.
AND
FOR EXTERIOR LIGHTING
Only light areas as required for safety and comfort. Do not exceed
80% of the lighting power densities for exterior
areas and 50% for building facades and landscape features as defined
in ASHRAE/IESNA Standard 90.1-2004,
Exterior Lighting Section, without amendments.
All projects shall be classified under one of the following zones,
as defined in IESNA RP-33, and shall follow all
of the requirements for that specific zone:
LZ1 — Dark (Park and Rural Settings)
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 footcandles at
the site boundary and beyond. Document
that 0% of the total initial designed fixture lumens are emitted at
an angle of 90 degrees or higher from nadir
(straight down).
LZ2 — Low (Residential areas)
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 footcandles at
the site boundary and no greater than
0.01 horizontal footcandles 10 feet beyond the site boundary.
Document that no more than 2% of the total
initial designed fixture lumens are emitted at an angle of 90
degrees or higher from nadir (straight down). 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.
LZ3 — Medium (Commercial/Industrial, High-Density Residential)
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 footcandles at
the site boundary and no greater than 0.01
horizontal footcandles 15 feet beyond the site. Document that no
more than 5% of the total initial designed
fixture lumens are emitted at an angle of 90 degrees or higher from
nadir (straight down). 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.
LZ4 — High (Major City Centers, Entertainment Districts)
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 footcandles at
the site boundary and no greater than 0.01
horizontal footcandles 15 feet beyond the site. Document that no
more than 10% of the total initial designed
site lumens are emitted at an angle of 90 degrees or higher from
nadir (straight down). 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.
Potential Technologies & Strategies
Adopt site lighting criteria to maintain safe light levels while
avoiding off-site lighting and night sky pollution.
Minimize site lighting where possible and model the site lighting
using a computer model. Technologies to reduce
light pollution include full cutoff luminaires, low-reflectance
surfaces and low-angle spotlights.
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