Occupancy Separation Boundaries - Expansion Joint Fire Rating

[nealderidder]

I've got a two-story CA office building with two levels of mostly below-grade parking below. The building is type II-B and has no required fire ratings other than the one hour B-S2 separation. The garage is concrete and the office building is steel frame with composite metal deck floors. I've got a seismic joint at the grade level parking deck that runs along side (but outside of) one edge of the building in-line with the second floor above. See attached to make sense of this...

The question is - does the expansion joint need to be fire rated? There is no enclosed "B" space above this joint until you get to the 2FL above, some 14' overhead and even then it's right on the exterior boundary of that wall.

The seismic (I'm using seismic and expansion interchangeably) joint I want to use doesn't come with a fire rated listing. I can get around this by using a fire rated joint filler below the fancy pants seismic cover but I don't want to do that if I don't have to...

So after all that, question remains - does this expansion joint need to be fire rated?

 

[classicT]

My take is that the area above the joint is exterior to the building; therefore, a fire-resistive joint filler is not required so long as the horizontal assembly separating the S-2 and B is fully enclosed. The challenge that comes into play is that for ease of construction, the horizontal assembly may have been continued for the entire roof of the upper level of the S-2 parking garage.

The 1-hr horizontal assembly is only required for the separation of the S-2 and B uses; however, that is the minimum requirement. If the horizontal assembly was provided for the entire roof of the upper S-2 level, then you have a joint in the horizontal assembly, which in turn must be sealed per IBC Section 715. This may have been done for simplicity and ease of construction. Further review of the existing building is required.