Treatment of Joint Between Shear Wall and Exterior Wall

[jmc4]

Hello All, this is my first post on this site, though I’ve found a lot of useful information here. I appreciate any guidance.

I’m on a high-rise condo project where a 12” thick concrete shear wall makes up part of a demising wall between dwelling units (2009 IBC, Type IA construction). The shear wall is contained between two non-rated GWB furring walls—the shear wall is the wall intended to carry the rating. The exterior wall (0 hr rated) is precast slenderwall-type panel, and the shear wall ends at the slab edge at the back of the panel metal framing. The joint between the floor and ceiling slabs and the precast panel are protected in accordance with 2009 IBC 714.4. However, the joint between the end of the shearwall and the exterior wall is filled in (to some extent) with the same spray foam insulation that is on the back of the precast panels. My question is:

Does the joint between the end of the shearwall and the non-rated exterior wall require any special treatment for fire resistance?

2009 IBC section 714 on joints only discusses joint “in and between” rated walls. 2009 IBC section on continuity of fire partitions (709.4) only discusses the continuity of such partitions to floors/ceilings. Am I missing something?

Any guidance is appreciated.

 

[cda]

Welcome

Great first post!!

Give it a day or two for fantastic replies

 

[Builder Bob]

The code does not indicate as such, the termination of the walls that are rated should be fire blocked. The fire rating of partitions is for interior fire exposure from dwelling unit to dwelling unit. The fire protection of the exterior wall is by fire separation distance or other aspect involved.

The question comes with concealed spacing and fire blocking, that may be where you find your answer in combustible framing/ if non-combustible, I believe there may be a loop hole that may need to be visited.

Also look at curtain wall spaces, this may be applicable at the transfer or passing of the dwelling unit fire partition lines. The highrise provisions often talk about floor to floor so the curtain wall is fire blocked or fire stopped at the floor levels -

 

[RLGA]

This is a gap (pardon the pun) in the IBC that was partially addressed in the 2015 IBC. The 2015 IBC addition only mentions the gap between a fire barrier and a curtain wall, and since the walls between dwelling units in a condo are required to be fire partitions, then this added requirement still does not address the issue. This type of condition exists in any multifamily high-rise construction, so it's not a new problem. I think that as long as the gap is sealed to prevent the passage of smoke, then it should be acceptable. However, it will boil down to what is acceptable to the local building official.

 

[ICE]

The architect or engineer must specify how the gaps are filled.

 

[sergoodo]

check the specifics on requirements for the foam plastics being used, basically required to be 'incased'/protected for commercial costruction.

UK just had a condo with foam on backside of exterior panels dramatically ignite.