Building Systems Vignette Rigid Duct Questions

Mechanical & Electrical Plan Vignette and Multiple Choice

Building Systems Vignette Rigid Duct Questions

Postby Cosninety » Thu Apr 13, 2017 3:28 pm

Building Systems Questions.pdf


Ignoring whether or not these design approaches are required to solve this particular vignette plan, I have a few questions about what can be done with the rigid ducts.

Refer to coded plan for each question (A,B,C,D)

A) Can the rigid duct fork immediately in two directions once it penetrates the bearing wall?
B) Can the supply duct pass by or in front of the return duct?
C) Can the duct turn inside the shaft?
D) Can the duct fork in two directions from the shaft?
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Re: Building Systems Vignette Rigid Duct Questions

Postby Coach » Thu Apr 13, 2017 4:11 pm

Cosninety wrote:A) Can the rigid duct fork immediately in two directions once it penetrates the bearing wall?

Yes.

B) Can the supply duct pass by or in front of the return duct?

Don't cross. Leave daylight.

C) Can the duct turn inside the shaft?

It shouldn't.

D) Can the duct fork in two directions from the shaft?

If you mean in the shaft, don't do that. And don't penetrate the riser twice unless absolutely necessary.
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Re: Building Systems Vignette Rigid Duct Questions

Postby Cosninety » Thu Apr 13, 2017 4:41 pm

Thanks for the quick reply coach.

A few things that are still unclear.

B) What do you mean by "leave daylight"? If the return duct is shorter so that it doesn't intersect with the supply, can the supply pass in front of it?

C) It shouldn't? Can it?

D) Yes, I mean, can the supply branch in two directions from the shaft and penetrate on two different sides of the bearing wall?

thanks!
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Re: Building Systems Vignette Rigid Duct Questions

Postby Coach » Thu Apr 13, 2017 4:45 pm

Cosninety wrote:B) What do you mean by "leave daylight"? If the return duct is shorter so that it doesn't intersect with the supply, can the supply pass in front of it?

The definition of daylight.

C) It shouldn't? Can it?

Well, of course it can. You drew it. I meant what I said.

D) Yes, I mean, can the supply branch in two directions from the shaft and penetrate on two different sides of the bearing wall?

Answered.
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Re: Building Systems Vignette Rigid Duct Questions

Postby Cosninety » Thu Apr 13, 2017 5:08 pm

I am not fully understanding. I've moved the return and supply riser to demonstrate a condition which would require one of the two scenarios I am talking about.

B) How can we leave daylight? There isn't daylight in the plenum space...right? Are you saying that a supply duct should not pass directly in front of the return duct? See pass in front pdf --- Is this allowed?

PASS IN FRONT.pdf


C) The condition might require the supply to bend inside the riser as shown -- is this allowed?

BEND IN RISER.pdf


thanks again!
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Re: Building Systems Vignette Rigid Duct Questions

Postby cjamal » Thu Apr 13, 2017 6:01 pm

In terms of B, I think its easily avoidable to have the return go in a completely separated direction than the supply thus avoiding any issue of crossing. For instance, in the first example you provided (building systems questions PDF), just have the return riser go straight up. Then it avoids the supply completely. You could also have the supply go straight up and then bend outside of the shaft which would avoid your problem C as well. But like coach said, you shouldnt have to have 2 supply runs going through the shaft. Look at other examples of postings to see how others are accomplishing this.
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Re: Building Systems Vignette Rigid Duct Questions

Postby Cosninety » Thu Apr 13, 2017 6:53 pm

cjamal wrote:In terms of B, I think its easily avoidable to have the return go in a completely separated direction than the supply thus avoiding any issue of crossing. For instance, in the first example you provided (building systems questions PDF), just have the return riser go straight up. Then it avoids the supply completely. You could also have the supply go straight up and then bend outside of the shaft which would avoid your problem C as well. But like coach said, you shouldnt have to have 2 supply runs going through the shaft. Look at other examples of postings to see how others are accomplishing this.



Hi cjamal. I understand that there are a number of ways to avoid having a supply crossing in front of a return, or a supply bending inside a riser---my question doesn't relate to solving the specific ncarb vignette. I am asking a hypothetical question to know if those this can be done in a vignette which might point point towards one of those solutions. I am asking if what is shown in BEND IN RISER.pdf and PASS IN FRONT.pdf is allowed.
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Re: Building Systems Vignette Rigid Duct Questions

Postby Coach » Fri Apr 14, 2017 2:13 am

"Daylight" is a figure of speech.
Those situations can be avoided.
DON'T BEND IN CHASE.
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Re: Building Systems Vignette Rigid Duct Questions

Postby nidagm » Tue May 02, 2017 8:27 pm

I think B is not a good idea but C is OK. I had seen similar scenarios at Google+ group.
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