Hi all,
We have a project where the floor plate is 120'x120' with 12' high windows on 3 sides of floor plate. open offices as fully glazed private offices line the perimeter windows up to 45' into the floor plate. The center of the floor plate are support spaces like copy rooms/storage/etc. The client would like to know whether this type of space is qualified for LEED daylighting. We've never dealt with this depth and proportion of floor plate before for an office. We would suggest putting skylights in to add more daylighting into the deep offices at the back but otherwise it seems okay. I read the reference guide a couple of times though it doesn't mention anything about building depth it's quite intuitive that it should matter and that alternative daylight strategies need to come into play.
Can anyone point me in a direction where I can find information on building depth and daylight in the LEED CI 2009. Also, because this is the very beginnings of the project is there a quick and dirty way of measuring daylighting to ensure that we get the daylight points? I really don't want to go to a daylight simulation route as that can get tedious (unless someone knows how to do this quickly) I've looked into both software Radiance and Daysim and it makes my head spin.
Thanks,
D
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
January 3, 2012 - 4:19 pm
I believe the prescriptive path would be what you want to follow to help you determine compliance if you don;t want to go with simulation.You would be using the daylight zone, which would be the depth from the window wall, twice the window height, or at a 63 degree angle.
From what you are saying, I'm assuming perimeter offices about 10 feet in depth, then a corridor with more interior offices. The prescriptive path will not work in shared daylighting scenarios, so only the offices along the perimeter can be looked at. If thats the case, you would probably need a bilateral daylighting scenario, which would be toplighting and sidelighting. Areas under skylights can be analyzed using the prescriptive path.
There are simulation programs which do not have such a large learning curve as those you have mentioned. SPOT is one which can do simply geometries. Not sure what other programs you are using or have. If you have AutoCadd, there is 3D Studio Max or Ecotect. The learning curve is not as large (my opinon) as others.
Since this project is in the earliest stage of design, i would use this opportunity to look at the daylight, not to earn a LEED credit, but to provide the best daylighting scenarios to the occupants and for energy savings. This requires more work in the design phase, and to be done correctly you really need to use simulation.
Denise Santini
PrincipalRed Studio Inc. Architects
45 thumbs up
January 4, 2012 - 9:49 am
Hi Todd,
Thanks for the reply. In actuality we have 25' of open offices around the perimeter, 5' corridor, then 12' deep offices (glazed towards the open office to allow for "borrowed" light to come through) With this layout, between the perimeter glass to the back wall of the offices is 45' or so. the core itself contains a meeting room and there are a lot of offices which do not have daylight from perimeter windows because they are located in the core. I think your opinion is dead on, having skylighting would definitely benefit in terms of health and well being standpoint.
I'll take a look at SPOT for quick analysis. We've been getting a lot of assessment related issues early on in the process to decide on what space is viable for LEED and daylighting. I guess this will be worth the investment in time to learn something quick.
If there are any other suggestions I'd be pleased to hear it.
Cheers,
D
Denise Santini
PrincipalRed Studio Inc. Architects
45 thumbs up
January 4, 2012 - 11:29 am
Just an update. I tried sketchup and Daysim and it seems to be working out except intuitively I should be getting light into the offices (fully glazed wall oriented towards where the daylight is coming through) and the readings in the offices are 0. has anyone got a method to deal with this? i made a wall in sketchup and added a default single pane glass on it but no reading of light coming through, it's acting as though it's a solid wall.
any ideas would be greatly appreciated.
Thanks,
D.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
January 4, 2012 - 11:36 am
Not knowing the location or climate of the project, clerestories are something you may also consider. Depending on the ceiling height and the size of the skylight, it may cause glare issues (over daylit) in individual offices because of the skylights orientation to the sky dome and climate. Clerestories can help reduce this issue because of the geometry. Roof monitors can also be implemented and orientation needs to be considered to reduce the effects of direct solar penetration. Another option may be solar tubes. they are smaller than skylights and can provide a effective level of illuminance in individual offices or small conference rooms. But simulation or measurements would be needed to demonstrate LEED requirements.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
January 4, 2012 - 12:00 pm
Are you using the Daysim materials file for sketchup?
Denise Santini
PrincipalRed Studio Inc. Architects
45 thumbs up
January 4, 2012 - 1:09 pm
Yes, i'm using the Daysim materials provided by the Daysim skethcup plugin. i tried a basic model, it was okay, now im implementing rooms and with full height glass and it's not working.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
January 4, 2012 - 1:56 pm
Denise, i cannot accurately say what is wrong with your model without looking at it. I don;t typically use Sketchup to Daysim and have only really just used Daysim that way a few times. I usually go from Ecotect to Daysim. Here is the link to the Daysim forum that may help answer your specific question.
http://groups.google.com/group/daysim
Denise Santini
PrincipalRed Studio Inc. Architects
45 thumbs up
January 4, 2012 - 2:31 pm
Thanks Todd. I'll look into it. I should probably try Ecotect since we have it in the office. :)
Cheers.
D.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
January 4, 2012 - 2:56 pm
One piece of advice with using Ecotect and Daysim, keep your file names short and your paths to those files as short as possible to reduce any errors. I highly recommend reading the Daysim Tutorial on how to export from Ecotect to Daysim.
Jill Perry, PE
ConsultantJill Perry, LLC
LEEDuser Expert
440 thumbs up
January 5, 2012 - 6:11 pm
Hi Denise,
A good rule of thumb for daylighting and the LEED daylighting credit is that usable daylighting reaches back into a space about 1.5 - 2 times the head height of the window. In your case about 1.5 x 12' or 18' around the glazed perimeter. As you can see with your very wide floorplate, reaching the LEED credit is not really attainable with just the windows. (120' + 120' + (120'-(18'x2))) x 18' = 5832 sf or 41% of your total space of 14,400. Even subtracting out the non-regularly occupied space isn't likely to get you to the 75% required.
To address what you asked about the depth in the LEED 2009 CI reference guide on pages 58 and 59 they allude to a recommended depth as Todd and I are saying of 2 x the window head height. I agree, it does not address the issue very well.