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Coach, can you check my rationale?

PostPosted: Mon Apr 29, 2013 10:44 am
by salmonx
Hi Coach,

I am taking CDS on this saturday and would like to have my rationale on determining the duct space depth with you.

I usually choose the deepest duct size on the same ceiling surface. Then add 8" for lighting..
Please see the images and let me know. Thank you!

http://u.cubeupload.com/salmonx/3rd.png

http://u.cubeupload.com/salmonx/DUCTSPACE2.jpg ---> this is how I drew to determine the total depth for 1st floor ceiling
http://u.cubeupload.com/salmonx/Rationale01copy.png ----> this is the number I found "the deepest"
http://u.cubeupload.com/salmonx/Rationale02copy.png ---> this is the number I found "the deeepest" for 2nd floor

Re: Coach, can you check my rationale?

PostPosted: Mon Apr 29, 2013 3:02 pm
by Coach
You don't necessarily use the deepest duct.
You must use the largest joist/duct combination within each space having the same ceiling height.

Example

Within the first floor area that has a 9' ceiling, the following exist:

1) A 18" duct under a 24" joist
2) A 10" duct under a 30" joist
3) A 16" duct under a 28" joist

The governing combination is #3 and neither the largest duct nor the largest joist is used.

Re: Coach, can you check my rationale?

PostPosted: Mon Apr 29, 2013 10:14 pm
by salmonx
thank you