Interior Lighting question.
Option 2. Lighting Quality (1 point)
A. For all regularly occupied spaces, use light fixtures with a luminance of less than 2,500 cd/m2 between 45 and 90 degrees from nadir.
Exceptions include wallwash fixtures properly aimed at walls, as specified by manufacturer’s data, indirect uplighting fixtures, provided there is no view down into these uplights from a regularly occupied space
above, and any other specific applications (i.e. adjustable fixtures).
What is the actual meaning of "provided there is no view down into these uplights from a regularly occupied space above", can not imagine the Scenario, why is " no view down into" not " no view up into"?
Thanks!
Tristan Roberts
RepresentativeVermont House of Representatives
LEEDuser Expert
11474 thumbs up
June 20, 2014 - 11:16 am
Qiang, let's say you have a mezzanine, with fixtures on the first floor using uplighting, with the uplights being visible from the mezzanine. This would create a lot of glare. I think that is the kind of situation this requirement is speaking to—so it is "down" into, not "up" into.
April Wang
May 6, 2016 - 5:10 am
Hello. I'm new to assessing the interior lighting part of LEED. For strategy A, I am wondering what specific documentation to use to calculate that the luminance for each fixture is indeed less than 2,500 cd/m2 between 45 and 90 degrees from nadir. The specs sheet for the fixtures give photometric data that show candela values for the angles. I'm a little unsure what area to use to obtain cd/m2.
Melissa Kelly
Sustainability SpecialistGensler
85 thumbs up
May 10, 2016 - 1:36 pm
Hi April,
It sounds like your spec sheet has candlepower distribution but not luminance, is that correct? If so, the easiest approach is to request a luminance data summary from the manufacturer, since most manufacturers will have this on hand from testing results.
If they don't have a luminance table, they may also be able to provide a photometric (IES) file, and you can use an online viewer to generate the table yourself. I've used this one before but there are a few others out there: https://www.visual-3d.com/software/photometrictool.aspx
Hope this helps!
April Wang
May 10, 2016 - 9:27 pm
Hi Melissa,
Thanks for your reply. Yes our project is here in Taiwan and not all of the manufacturers will have/can provide photometric (IES) files. They can give us spec sheet, samples I have included in the following link. (I would really appreciate any feedback).
https://www.dropbox.com/sh/s1sptyha3wrof8i/AACqxQSASIMI1huia2T81SENa?dl=0
I'm unsure if this document is sufficient to satisfy strategy A. It does show candlepower distribution and a max cd value (which appears to be at 0°). So would it be correct to translate that cd value at 45 to 90° and hense the illuminance at these angles are less than what is experience at its max at 0°.