I realized the answer for my second question. Heres another one. This is more for verification. I am unsure if it is the same for CI v3 but in the reference guide for CI v2 it states that "window areas above 7'6" are considered to be daylight glazing....windows areas from 2'6" to 7'6" are considered to be vision glazing." When they say "window area" they mean your window height correct? So if my windows are greater than 7'6" in height they are considered daylight glazings correct?
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David Posada
Integrated Design & LEED SpecialistSERA Architects
LEEDuser Expert
1976 thumbs up
July 30, 2010 - 3:10 pm
Kelvin,
The prescriptive formula has been simplified from v2.2; they no longer distinguish between Vision glazing and Daylight glazing, so use the head height to calculate your area (unless it's blocked by a soffet).
Re: your question above on re-lite glazing and interior offices: It's easy enough to calculate the 8.2 Views credit with this condition, since you can trace the lines of sight through all the planes of glass, but it usually doesn't work with the prescriptive glazing area formula for 8.1.
The formula is essentially a ratio of window to room area, and only works with simple office layouts. The two layers of glass and internal walls complicate the situation enough that the formula doesn't really give a useful assessment of your daylight levels beyond the perimeter office. You can either use software simulation or, better yet, actual measurements with a light meter.
Since the space is already built, that's probably the best method. But given the size of the punched windows, my intuition says you may not have enough daylight in the interior office to acheive the credit for those areas.
kelvin duen
68 thumbs up
July 30, 2010 - 3:18 pm
I see. As far as a calculations method goes, It states that window areas that fall above 7'6" from the ground are considered daylight glazing and those that fall under are vision glazing. For clarification sake, do i split up a window that fall in both zones? ie: do I take the area of the window above 7'6" and do the daylight glazing calculation then take the area below and do the vision glazing calculation and then add them to see if the total room DF is above 2%? OR does the entire window constitute as the daylight glazing and I just do that calculation?
kelvin duen
68 thumbs up
July 30, 2010 - 3:19 pm
I'm trying to achieve LEED cert. for CI v2. Not v3. That is why I am asking.
David Posada
Integrated Design & LEED SpecialistSERA Architects
LEEDuser Expert
1976 thumbs up
July 30, 2010 - 4:10 pm
Oh, didn't realize you were submitting under v2. In that case, yes, you split the window area into two different window areas: Daylight glazing is any window area above 7'-6" and Vision glazing is any window between 7'-6" and 2'-6".
The reason for spliting it out is the v2 formula gives different multipliers for those areas since the higher position of the daylight glazing is assumed to penetrate further into the space, and sometimes has different T-vis or shading conditions.
Jill Dalglish, PE
Lighting EngineerMKK Consulting Engineers
LEEDuser Expert
440 thumbs up
August 5, 2010 - 2:54 pm
Kevin,
I agree with David on this, you must split the window area. Also, you must separate window area that has a different T-vis value and glazing below 2'-6" does not apply. Design-wise it is best to use opaque insulated surfaces below 2'-6" to increase R-value and reduce solar gain.