Page 109 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

90 Cha pte r T w o

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.
The requirements for SS credit 8 in LEED 2.2 and LEED 2009 include both Interior
Lighting and Exterior Lighting restrictions. The interior lighting requirements are
substantially changed from the 2.2 version to the 2009 version and some of the exterior
requirements related to lighting power densities are not as stringent in the 2009 version as
they were in the 2.2 version. For clarity, the requirements in both versions are presented,
first for version 2.2 and then for version 2009.
Requirements
FOR INTERIOR LIGHT
LEED 2.2: 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
LEED 2.2: All non-emergency interior light shall be automatically controlled to turn off
during non-business hours. Provide manual override capability for after hours use.
LEED 2009 INTERIOR LIGHTING OPTION 1: This option requires that all non-emergency
interior luminaires with a direct line of sight to any openings in the building envelope have
automatically reduced input power between 11 p.m. and 5 a.m. and that any manual overrides
do not last more than 30 minutes. The openings can be transparent or translucent.
OR
LEED 2009 INTERIOR LIGHTING OPTION 2: This option requires that all non-emergency
interior luminaires with a direct line of sight to any openings in the building envelope have
automatic shielding that reduces the transmittance by at least 50% between 11 p.m. and
5 a.m. The openings can be transparent or translucent.
AND
FOR EXTERIOR LIGHTING
LEED 2.2 EXTERIOR LIGHTING (first requirement): 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.
LEED 2009 EXTERIOR LIGHTING (first requirement): Do not exceed the lighting power
densities in ASHRAE 90.1-2007 (with errata but without addenda, although addenda may
be used if consistently used across LEED).
(And)
LEED 2.2 and LEED 2009 EXTERIOR LIGHTING (second requirement): All projects shall
be classified under one of the following zones, as defined in IESNA RP-33, and shall follow
all of the requirements as listed 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