Can we get a clarification on Kathleen's comment above regarding the difference between "bays" and "daylight zones"? The credit form and reference guide seems to be inconsistent. Is the "Daylight Zone Depth" on the credit form "2H" (H=head height) per figure 2 in the reference guide? The credit form says the "size of the daylight zone must be adjusted to satisfy this formula: 0.150
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David Posada
Integrated Design & LEED SpecialistSERA Architects
LEEDuser Expert
1980 thumbs up
June 10, 2010 - 8:34 pm
Here, they use "bay" to describe the regular areas of a floor plan that are often created by the structural column grid, the exterior building skin, and the central core. You won't see bays mentioned in the spreadsheet or credit form, and the reference guide lacks a clear example. The Documentation Toolkit here at LEEDUser has a sample prescriptive plan showing a west bay, corner bay and south bay in step 3.
For a conventional commercial office building that has regular column grid spacing and a fairly rectangular shape, the structural bays can provide an easier way of dividing and naming the spaces. Many of these bays will have the same dimensions and glazing area, so can simplify calculating the area totals. You can also use individual rooms instead of bays to define each space, if you prefer.
The "Supplemental Daylight and Views Calculation Spreadsheet" in the Credit Resources found under Quick Links on the right side of the EQc8.1 credit page in LEED Online can help calculate the daylit area.
The "daylight zone" is usually the perimeter area of the building side lit by windows to a depth of two times the window head height (2H). Here's an approach I've seen work in the past:
Once you define and identify all the spaces in your plan, draw a line in plan to show the daylight zone. Start with it set at 2H. Perform the calculations to see if you have a good ratio of window area for this day lit floor area. If you're lucky, the areas in this daylit zone will add up to be 75% of the Regularly Occupied Space. If the day light area is not enough to be 75%, you can try moving the line defining the daylight zone further than 2H from the exterior wall and re-do the calculations to see if it works. If your window area is big enough, it may to work, but if you have smaller windows it may not.
You may need to adjust the boundary of the daylight zone several times or in different places to get it to work. It sounds odd, but you're just finding what amount of floor area gets an appropriate amount of daylight given your window area and the Visible Light Transmittance of the glass.
This credit can take a lot of time to document with plans, sections/ elevations, and the spreadsheet. 30 to 40 hours for a large building is not uncommon. It's kinda like fun, only different.
Sustainability CoordinatorDES Architects + Engineers
5 thumbs up
July 28, 2010 - 6:48 pm
We have another project that has a non-regularly occupied space separating a regularly occupied space from the window. If there are no partitions in this non-regularly occupied space, how are you supposed to calculate the daylight zone for the regularly occupied space beyond? The credit form only gives you the option of entering the daylight width and depth, which automatically adds the non-regularly occupied space square footage to the total area of daylit regularly occupied space.
Eddy Santosa
Director of SustainabilityDBR Engineering Consultants
376 thumbs up
August 5, 2010 - 9:30 pm
Christina,
If there is no physical separation between the spaces, you may need to develop your own spreadsheet for your case. I would suggest to include the non regularly and after you know how much the area compliance, you can deduct with the non-regularly one.
If there is a physical separation such as a glass wall, I would suggest to use measurement or simulation.