Hello, I am in the process of working on collecting information for LEED certification on 3 different schools that all have large amounts of glass in the cafeteria, gym, and Library, as well as a few other classrooms. Has anyone had any experience in getting this situation to work with the daylighting credit? I have been working on getting a simulation going but still have to change the window square footage in order for the room to pass the credit.
Any help would be appreicated!
Thanks
Tyler
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TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
June 1, 2011 - 12:26 pm
Tyler,
Not sure as to exactly what you are asking. So you are saying that the rooms you are simulating will only meet the credit requirements if the amount of glazing is changed? What program are you using? Is your VLT correct? Are all your input parameters correct? Is it only meeting at one time and not the other?
Lots of unknowns to your question so if you could be more specific it would help in providing you an answer that will help.
Tyler Barter
ArchitectOak Point Associates
62 thumbs up
June 1, 2011 - 3:25 pm
Sorry for the lack of info.
I am using IES ve with a sketch up model.
I am working with a 5000 sf cafeteria that has just under 2000 sf of glazing..
the room is meeting the 9am simulation but not the 3pm.
I have my parameters in to the best of my knowledge with the IES ve Program.
It seems that we have a few rooms with large amounts of glass that go over the maximum threshold for this credit. Does anyone know how to work around this?
Thank you!
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
889 thumbs up
June 2, 2011 - 8:35 am
There is no work around for this. There have been complaints about the 500fc limit at these times in trying to meet the requirements. I think the next addenda may be addressing this issue.
If you have this submit this soon, this is what i would do. Run a simulation with binds half way down the window and all the way down. You can do this two ways to simulate blinds. Actually create a blind in the model and give it an opacity of 10%. Or you can take half the window area and make it translucent with a 10% VLT. Assuming then that you meet the requirement, make the argument that blinds will be in all those spaces and they will be used. People use blinds to reduce direct sun, especially in schools and an assumption that occupants would not lower the blinds is not accurate. DAYSIM, which is yearly daylight simulation program and calculates daylight autonomy uses blinds in the calculations. The reason that the blind option is there is that we know people use blinds. The trick is figuring out at what level of illuminance do people pull the blinds down. Anyway, state the argument that it is not possible for space with easterly or westerly facing spaces to meet the 500 limit. Automated shades are costly, and again, shades will be installed and used.
Have you modeled all exterior buildings and other natural features? There is no barren sight. So if you have buildings or terrain that would help use it. I would on a project that was located very close to the north side of a very large mountain. The sun never impacted the east elevation till late in the morning in the summer time. Without actually modelling the terrain, the project would have issues meeting the 500fc limit even with exterior shading.
Good luck
Tyler Barter
ArchitectOak Point Associates
62 thumbs up
June 15, 2011 - 3:30 pm
Do you know when the next addenda may be coming out?
This is a school in Falmouth, Maine. there are no other buildings around just lots of trees along the outside of the site.
Thank you!
Eddy Santosa
Director of SustainabilityDBR Engineering Consultants
376 thumbs up
June 20, 2011 - 1:37 pm
Tyler,
the new addenda may help you. It said "Identify the area of the room that has daylight illumination between 10 footcandles and 500 footcandles at both times (9:00 am and 3:00 pm).Spaces that do not meet the daylight illumination levels at both times do not qualify."