We are being challenged by the modification to IEQc8.1 Option 1 Simulation from May 9th, 2011, which replaced the entire section. The question is regarding how to determine the 75% that is compliant with new credit requirements. I will demonstarte below. Say we have a building of four quadrants: [1][2][3][4] where each number in brackets represents one quadrant (25% of building area). Also, say [D] represents a quadrant that is between 10 FC and less than 500 FC. [X] represents a non-compliant space. Consider this example: at 9am the building looks like this: [D][D][D][X] and at 3pm the building looks like this: [X][D][D][D]. Does the wording in IEQc8.1 Addenda ("spaces that do not meet the daylight illumination levels at both times do not qualify") indicate this design is not compliant - because when looked at in union, the result = [X][D][D][X] = 50%, which is not compliant?
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Jill Perry, PE
ConsultantJill Perry, LLC
LEEDuser Expert
440 thumbs up
April 18, 2012 - 6:17 pm
Rebekah, thank you for bringing this issue to LEEDuser. It has been a topic of much debate for a while now. I can tell you that if your reviewer is asking you to use the method that results in the 50% compliance, it is the first time I have heard of it directly from a reviewer. It seems that there is no real agreement among reviewers or practitioners. I have pushed hard on the USGBC to please make this unarguably clear in the 2012 version, but they have ignored my request. I would love to hear more details from your case (and anyone's case who might be reading this) if you or they are willing to share. For now, it seem like it is the luck of the draw on which reviewer you get. (Gulp!) You can see a comment from a technical representative of the USGBC (not a reviewer, just an answer to a question) I received earlier in this forum if you're interested.
Tiffany Moore
Built Environment ProfessionalBuilt Kansas City LLC
35 thumbs up
April 18, 2012 - 6:27 pm
Jil,
Could you be more specific about the earlier comment from the USGBC tech rep? I looked a bit, but didn't find that posting.
Thanks!
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
April 19, 2012 - 8:27 am
It is as how it is defined. Lets use a sensor point instead of square footage. So that sensor meets the illuminance requirements at one time and not the other. As stated in the credit language, it must meet it at both times. Since it does not, then that point is not compliant.
Averaging the the different illuminance levels at that sensor is also not acceptable. So lets say at 9am its 700fc and at 3pm its 150fc, the average is 425fc, The reason it is not acceptable is because of the upper limit of 500fc was established so that issue of direct sun penetration would be addressed.
Jill, I believe that your argument is heard for 2012. It seems it is not because the only things being posted is the credit language, not the guts of the section in the reference guide.
Jill Perry, PE
ConsultantJill Perry, LLC
LEEDuser Expert
440 thumbs up
April 19, 2012 - 11:02 am
http://www.leeduser.com/credit/NC-2009/IEQc8.1?page=2#comments - starting with the post by George Abul Adal.
The reason I thought it was being ignored is because they made no comment on it either way in their response to comments. Do you have a copy of the 2012 reference guide?
Thanks
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
April 19, 2012 - 11:24 am
I plead the fifth on any information concerning 2012!!
Are you saying that they directly responded to your comments on your issue, or are you saying that based on your comments, the 3rd pulblic version did not address your comments at all.
Again, its only credit language that is posted and not what i call the meat of the credit which includes how to perform the calculations, referenced standards, etc. which is in the Reference Guide.
Rebekah Burke
Clark Nexsen31 thumbs up
April 19, 2012 - 4:31 pm
In our case we haven't submitted the credit, but are in a heated discussion at a 65% submittal about ensuring our project is in compliance with this credit. It is essentially required per our contract. We orginally required additional windows be incorporated from the bridging documents, using the prescriptive method as we were still learning our way around simulation software. However, now we go back with the simulation software and are encountering all kinds of issues, and are in turn analyzing every word of the credit.
Thank you all for your input.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
April 19, 2012 - 4:38 pm
What simulation program are you using?
Eddy Santosa
Director of SustainabilityDBR Engineering Consultants
376 thumbs up
April 19, 2012 - 5:08 pm
Rebekah, If I were you, I would try to submit by using the area of ([D][D][D][X] or [X][D][D][D] whichever lesser and put a narrative in there. Hopefully, the reviewer will understand the logic behind that.
As your backup plan, you can use the measurement method with an assumption that your daylight modeler has sufficient experience in modeling and validation. To ensure the compliance during the measurement, you may need to re-run the daylight simulation with the sky model that is suitable with your area. Therefore, your measurement numbers and your simulation results should be similar.
Jill Perry, PE
ConsultantJill Perry, LLC
LEEDuser Expert
440 thumbs up
April 25, 2012 - 4:20 pm
Todd, I received responses (via the Responses to Comments on the USGBC web site) to just about all of my review comments except for that one.
Rebekah, I agree with Eddy on how to move forward. When you stated "We are being challenged" this strongly suggested to me that you meant you were being challenged by a USGBC reviewer. Sorry for the misunderstanding.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
April 26, 2012 - 8:23 am
Rebekah,
Did this project have daylighting goals established from the beginning? What i mean by beginning is before the first line was drawn. Also, if the goals were established (and hopefully they were more than just to earn the LEED credit) when during the design did you look at the daylighting levels?
The reason I bring this is so that you guys don;t run into the situation you are having now. If you have performance goals prior to design, and you check during schematic that the design decisions are not hampering these goals, then by the time you get to the end of DD, there shouldn;t be any issues.
If you check to see what the daylight levels are well into DD, there are many more issues that come into play. So you need more glazing, well that effects the mechanical system, which by DD the engineers should have stuff almost figured out. Now they have to recalculate.