Does 1-Hour Exit Stair Require a 1-Hour Floor?

I am designing a two-story dormitory Type II-B (under 2018 IBC) with CMU walls throughout.

The floor deck consists of 5-inch composite metal deck. The corridor walls and walls between suites must be 1/2-hour (due to sprinkler exception - NFPA 13 fully sprinklered).

There is also a horizontal separation between the two floors of 1/2-hour minimum.

There are two stair towers which are required to be 1-hour fire rated.

With the walls of the stair tower requiring a higher rating than is required between the two floors, is the floor then required to also be 1 hour?

In other words, can the floor penetrating a shaft enclosure (the walls of the stair shaft will sit on the metal deck) be of a lesser rating than the actual stair enclosure walls?

From what I've read regarding continuity, I'd say the floor rating would have to be 1 hour; but, I'm not clear. Please help.

​​​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe