window area

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.

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.

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.