This credit requires that all internally illuminated exterior signage must not exceed a luminance of 200 cd/m2 (nits) during nighttime hours and 2000 cd/m2 (nits) during daytime hours.
Our team received a manufacturer spec sheet for the exterior signage for our project showing a chart that includes (nits) results that indicates translucency of 30% that is based on white acrylic face with no vinyl applied to the face, and beside it is shows results of (nits) after calculation (which includes the vinyl applied to the white plexi which will further reduce the translucency).
The chart clearly shows the requirements are met; however, does the requirement need to be met at face-value for this exterior signage? Does the requirement need to be met without the added vinyl applied to the white plexi?
Looking forward to a response that can help further clarify.
Thank you
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
731 thumbs up
March 12, 2020 - 1:38 pm
For documentation, I'm sure the reviewer would be fine with either value.
The value is based on worst case for the signage. Different colors can have different values.
Is the value WITH the vinyl applied
- an average for the whole surface?
- only a single measurement at one random location? or
- the value at the brightest point on the surface? Likely, this point would be white in color.
Ideally it would be the 3rd value. If it is unknown what exactly this value WITH vinyl is measuring, some might just use the value with NO vinyl as the worst case.
There are no hard rules defining this. The above is my description. And I'm impressed that the signage company was able to provide values.
Estra Marku
PM - Sustainable Building SolutionsEllisDon
3 thumbs up
March 17, 2020 - 3:01 pm
Thank you, Bill. Your response was extremely helpful.
I will have to reach out to the signage company for the answers to the questions above but those are great questions.