Fire barrier with story above

[chris macko]

Per 707.5, fire barriers need to extend from a rated assembly below to a roof/floor assembly above. The diagram in the commentary shows that assembly above rated on 1 side of the wall, but not the other, and there is no clear mention of that assembly above having a required rating. I have office and mechanical space on the floor above in a type II-B building, with F-1 below. We are looking at adding a 3-hour fire barrier to provide a horizontal exit and I'm trying to figure out if that barrier can just stop at the unrated floor above, or if I need to rate that floor to 3 hours on at least 1 side.

 

[RLGA]

(1) A horizontal exit is only required to be 2-hour rated (IBC Section 1026.2).

(2) A horizontal exit must extend vertically through all floors unless the floor assembly has an equal or greater fire-resistance rating (IBC Section 1026.2).

 

[chris macko]

1026.2 says the minimum rating is 2 hours. Since it also says the separation using a fire barrier must comply with 707, and 707 lists 3 hours for a fire barrier in an F-1 space, I was assuming a 3 hour barrier was needed. Sorry if it wasn't clear this was for exiting in the F-1 space below.

 

[Jay Smith]

1026.2 says the minimum rating is 2 hours. Since it also says the separation using a fire barrier must comply with 707, and 707 lists 3 hours for a fire barrier in an F-1 space, I was assuming a 3 hour barrier was needed. Sorry if it wasn't clear this was for exiting in the F-1 space below.

You’re looking at the paragraph for the fire ratings between fire areas. Go up a few paragraphs to the one for horizontal exits and it sends you back to 1026.