Smart questions
Smart answers
Smart people
Join Eng-Tips Forums

Member Login

Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

Are fire dampers required at 1-hr shaft walls?

LeeEng (Civil/Environmental) (OP)
21 Oct 06 21:21
I could use a bit of help trying to understand the code requirement for fire dampers at shaft walls.  I was reviewing a building air system design that includes a duct riser that extends from the roof down three floors.  The shaft wall is noted as 1-hour rating (as expected).  I understand in a fully sprinklered building, ducts that penetrate 1-hour walls do not require smoke dampers.  Is the same true for shaft walls?  I looked through NFPA 90A, but I could not seem to get a clear answer (the diagram does not provide any insight).  Perhaps I am overlooking the obvious.  Any assistance you can provide is greatly appreciated.  Thank you.  
DrRTU (Mechanical)
21 Oct 06 22:50
A fire damper would not be required. The dwg. at the back of 90A shows plain metal duct going thru a 1hr. rated wall without a damper. Shafts, floors & walls if 1hr. are the same.
GMcD (Mechanical)
21 Oct 06 23:28
In my area of the world- you MUST have a fire damper at any duct that penetrates a fire rated separation, period.  Welcome to Canada, eh.
stanlsimon (Mechanical)
22 Oct 06 0:01
Don't know what your codes are, type of building occupancy, type of construction, ?

Under the International building Code, a sprinkler system may eliminate many dampers.  However your local Authority having jurisdiction may not agree.  
LeeEng (Civil/Environmental) (OP)
22 Oct 06 11:13
Thank you for the responses.  I do see the 1-hr wall on diagram.  My original thought was that it does not need a fire damper, but I was having trouble proving it to myself.  However, I think my confusion stemmed from the same figure and some of the language in 90A.  The figure shows a 3-story shaft that should only be 1-hr rated (but is not specified) with fire dampers.  

I read the following two items in 90A that appear to conflict with each other:
"Approved fire dampers shall be provided where air ducts penetrate...rating of 2 hours or more"

"Fire dampers shall be installed at each direct or ducted opening into or out of enclosures required by 3-3.4.1."  The referenced section includes 1-hr construction.

Thanks again.  I think I better understand it now.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Back To Forum

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close