SS Credit 8: Light Pollution Reduction
LEED-NC Credit: YES | UNSURE | NO
Credit Intent
Limit light pollution and increase night sky views by focusing lights towards the ground
rather than towards the sky. Improve visibility for campus users and visitors at night,
both indoors and outdoors.
Feasibility
This credit is primarily a matter of using the right light fixtures. Some outdoor lighting
currently at Stanford would fulfill this credit, while other lighting used on campus would
not. The other requirement for this credit concerns how interior lighting exits the
building. In general the lighting should not exit directly out of windows, or should be
automatically controlled to turn off during non-business hours. For this credit, the
Stanford campus likely qualifies as zone LZ3 -- Commercial/Industrial, High-Density
Residential.
Analysis
Interior Lighting -- Based on ARUP’s pre-SD electrical narrative, it appears that steps
have been taken to adequately address the interior lighting requirements of LEED-NC,
which state that “all non-emergency interior lighting shall be automatically controlled to
turn off during non-business hours,” with capabilities for manual override for after hours.
In particular, ARUP notes the following relevant automatic control features:1
 “Light fixtures in offices, corridors and public toilets shall be controlled by
occupancy sensing devices.”
 “Dimming ballasts shall be used in all areas receiving enough natural daylight to
meet the work lighting levels (below) without supplemental artificial lighting.”
 “Light control panels shall be able to turn relay controlled groups ON/OFF per
scheduled time function via astronomical time clock or EMCS input.”
 “Closed loop photo controls not controlled through the LCP’s will be acceptable in
private offices.”
In general, if these features are carried through to completion, then the LEED
requirements for interior lighting should be met. After construction, steps should also be
taken to ensure that the automatic control systems operate as required.
Exterior Lighting -- ARUP’s plans are a little fuzzier when it comes to exterior lighting,
which unfortunately has the potential to produce the largest amount of light pollution.
Given the zoning of the GSB campus, steps should be taken to ensure that exterior
lighting does not exceed the following parameters:
1. Initial illuminance value no greater than 0.02 horizontal and vertical
footcandles at the site boundary.
2. Initial illuminance no greater than 0.01 horizontal footcandles 15 feet beyond
the site.
3. Prove that no more than 5% of the total fixtures lumens are emitted at an angle
more than 90 degrees from straight down.
1
Arup: Stanford GSB Pre-SD Electrical Narrative, 30 April 2007, pg. 3 & 4.
Billings, Millea, Victorsson | LEED-NC Analysis: New GSB Campus | SS Page 1
SS Credit 8: Light Pollution Reduction
LEED-NC Credit: YES | UNSURE | NO
Arup also states that maintained exterior footcandle levels shall not be below 1, which
may present some problems is these fixtures are placed close to the GSB site boundaries.
Therefore, it is important that responsible light fixtures already used on campus, similar
to Figures 27 and 28 below are utilized. These fixtures focus light onto the ground,
minimizing light pollution. Bulb style lights used at the current GSB campus do not
appear to be acceptable (see Figure 29), and should not be used in the new campus. In
addition, care should be taken to avoid upward spotlighting onto buildings, trees, or
sculptures, which often occurs at Stanford (i.e., on the façade of Memorial Church, as
shown in Figure 30).
Many resources exist to choose lighting that limits light pollution, the LEED-NC
Sustainable Sites overview recommends many sites, including the International Dark Sky
Association: http://www.darksky.org/index.php.
Figure 27: Downward directed lighting on
east campus.
Photo by John Millea 5/14/07
Figure 28: Downward directed light near Campus
Drive east.
Photo by John Millea 5/14/07
Figure 30: Stanford’s Memorial Church illuminated
at night2
Figure 29: Unfocused light near
current GSB. Photo by John Millea 5/14/07
2
Tonynet Explorer, Hail Stanford, Hail; http://www.tonychor.com/archive/000292.html
Billings, Millea, Victorsson | LEED-NC Analysis: New GSB Campus | SS Page 2