Forum discussion
NC-v4 SSc6: Light pollution reduction
We have a project with a backlit perforated super-graphic mounted to the face of the exterior wall. Would this feature be exempt from Light Trespass as a façade treatment if we have an automatic shutoff between midnight and 6am?
Thanks,
Deb Favaretto
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Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
736 thumbs up
June 11, 2020 - 1:27 pm
What is this doing and who is viewing it? Are the perforated openings creating a pattern on the wall? Or is the pattern only visible to people inside of the building when looking directly at the super-graphic?
"backlit perforated super-graphic", sounds like an Internally illuminated exterior sign to me. That's why I'd like more details about what the intent is.
Glenn Heinmiller
PrincipalLam Partners
100 thumbs up
June 11, 2020 - 2:16 pm
Deb,
If this is "internally illumnated exterior signage" (this is what Bill is asking about) then you have to meet the internally illumnated exterior signage limits, but you would be exempt from the uplight and tresspass limits.
If you decide it is "facade lighting" AND you are in Lighting Zone 3 (LZ3) or higher, then you you would have the exmeption from the uplight and trespass limits if turned off at midnight
Deb Favaretto
Architect & Sustainability LeaderCannonDesign
4 thumbs up
June 11, 2020 - 3:33 pm
Bill and Glenn,
Thanks for your responses. The feature can only be seen from the exterior of the building. Our lighting designer had not previously considered it a sign, as the pattern of the perforations essentially form a large piece of artwork, not any branding or wayfinding purpose. However, if that's an inaccurate assumption, she can look at whether it meets signage luminance requirements. What are your thoughts?
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
736 thumbs up
June 12, 2020 - 1:42 pm
If this was intended as stand alone artwork then it does not sound like facade lighting. Facade lighting is generally used to turn the building itself into the artwork.
There is no definition for what a sign is used as in LEED. Signs are generally used to convey meaning. Is an artwork a sign? It might be. I say, give it a shot. But measuring peak light output may be difficult.