"For all regularly occupied spaces, meet one of the following requirements:
- Use light fixtures with a luminance of less than 7,000 candela per square meter (cd/m)2 between 45 and 90 degrees from nadir. OR
- Achieve a Unified Glare Rating (UGR) rating of <19 using software modelling calculations of the designed lighting."
My questions regarding this, if #1 is chosen, does this have to be applied throughout the entire project? Or either 1 or 2 can be applied on each fixtures to satisfy the requirement?
Thank you.
Lauren Kottis
4 thumbs up
February 7, 2022 - 11:09 am
Also, if UGR option is chosen, it is required to submit the lighting calculation for every regularly occupied space?
Glenn Heinmiller
PrincipalLam Partners
100 thumbs up
February 7, 2022 - 5:00 pm
Lauren,
I'm not sure I understand your first question. Option 1 the luminance limit is a fixture-based metric, but option 2 UGR using modeling of actual lighting designs is based on the results of the models, not the fixtures themselves. I suppose you could do some spaces using one method and some using the other, but I'm not sure why you would want to.
On your second question:
So far we've used the luminance limit option to meet this requirement, so I don't know the answer. But here's some thoughts
The requirement says you have to use "software modeling calculations" (which intends to say that you can't use the tabular method -- i.e. UGR numbers from the fixture manufacturers) So I think you'd need to show your UGR modeling results from AGI at least for one typical instance of each regularly occupied space type. But this is a ton of work by a lighting designer who understands how to do UGR modeling (and is why we've never pursued this option!)
Ellis John Mandia
Senior Lighting Designerdpa Lighting Consultants
August 12, 2022 - 8:28 am
Hi,
We have received this luminance table from a manufacturer. I don't know if I am interpreting the LEED requirement correctly.
https://www.dropbox.com/s/jdsaqlrdee54gb3/Luminance%20table.jpg?dl=0
In Column CO° and rows 45° to 80°, values are less than 7000. However in row 85°, the value is 9894, which means that the fixture does not comply. Can someone please confirm if I am reading the chart right?
Karen Joslin
Sustainability LeadPAE Consulting Engineers
5 thumbs up
August 12, 2022 - 3:42 pm
You are reading that - the goal is tp prevent direct light into people's eyes as they might look up to the source from below. This product would not comply.
Sara BENLOUBA
Green building managerConfidential
13 thumbs up
October 13, 2023 - 11:14 am
Hello Lauren,
yes, you can combine. For each fixture, you choose either Option 1 or option 2.
We have asked our LEED coach, see his answer below:
""Dear Sara,
Thank you for contacting us to get clarification regarding the requirements of EQc Interior Lighting, Option 1. Glare Control.
Yes, it would be acceptable to document compliance with UGR requirements in some spaces and fixture luminance requirements in other spaces. ""