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Kelly Kha
Attended California Polytechnic State University
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Hello, I have a general question about the CDS vignette. How do you know where/when the duct starts & end? It's hard for me to tell if for example, the 24" duct is with this set of joists or the other set of joists since there's no start/stop line.

I had the same question about the joists and where it stops/end. I assume that it would just go to the closest bearing wall.

I can't find any clarification on this anywhere online and this is important for the joist/duct combination calculation. 
Kitty Fornkahl's profile photoKelly Kha's profile photo
Thanks +Kitty Fornkahl! What about determining when the joists starts/stops?
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I've seen the NALSA guide to finding the largest joists & ducts combo, but I still have one question.
Say where the section cut is for the first floor, it's cutting through a 12" joist with largest 18" duct, but in another room on the same floor, the joist is 16" with largest 16" duct.

Do you accommodate for the larger joist in the background or just where the section is cut? I saw an example recently but I can't find it anymore. 
Terry NALSA's profile photoKelly Kha's profile photo
+Terry NALSA , thanks for the response! So with the scenario I described, does that mean I will lay out the section allowing for 16" joist/16" duct since that is the largest joist/duct combination (32")? 
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I haven't found a forum or a post asking this problem that I've been having. I would greatly appreciate if you can help me :)
So with some vignettes, it's not clear to me where the different joists stop and begin. For example:
- Floor 1: What type of joists does the Lobby, Security, and Corridor have? Is it the 24" or 28"? 
- Floor 2: What type of joists does the Corridor and Lobby have? 16" or 20"?

I took CDS and did really well on the multiple choice part but received a 2 on the vignette. This definitely contributed to my confusion on the calculation of the biggest joist/duct combination when it was unclear to me which type of joists made up a particular area where the duct would be. 

Thanks in advance!
Kelly Kha's profile photoDamion Spilman's profile photo
Looks like:

1st Floor - 28" Joist and 24" Tall Duct
2nd Floor - 20" Joist and 24" Tall Duct within the majority of the plan and 28" Joist with 12" Tall Duct over the meeting room.
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  • California Polytechnic State University
    Architecture, 2009 - 2014
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