Are fire dampers required at 1-hr shaft walls?

[LeeEng]

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]

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]

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]

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]

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.