Fire partition vs. Fire barrier

[Sifu]

In a mixed use, separated R1 building with A3 areas, which applies: IBC 420.2 which requires that walls separating sleeping units from other occupancies in the building be fire partitions, or 508.4.4.1 which requires fire barriers for occupancy separations?

And, where an A area abuts a corridor in that R1 area, what occupancy is the corridor, and would 1020.1 only require fire partitions for the corridor walls.

Or does the most restrictive application of separated occupancies apply and require fire barriers instead of fire partitions?

 

[classicT]

Most restrictive (fire barrier) applies.

Apply each one as stipulated under the applicable section. Where a fire partition and fire barrier is required at the same location, build the fire barrier (most restrictive).

 

[RLGA]

As ClassicT stated, when one wall has two possible fire-resistive assembly requirements, the most restrictive applies--in your case, the fire barrier is the most restrictive.

As for your second question, if the corridor serves both the Group A-3 and Group R-1 occupancies, then I would consider only the area meeting the requirements for Group A occupancies as the Group A-3. The corridor would be excluded from the Group A-3 floor area but must be considered an egress component for the Group A. Therefore, the corridor requirements would be based on the most restrictive requirements per Table 1020.1. Since your building is required to be sprinklered (it has a Group R occupancy), Table 1020.1 does not require a rating for corridors serving a Group A occupancy but it does require either a 1/2- or 1-hour rating for the Group R occupancy. Thus, the requirements for the Group R occupancy must be applied.

However, the occupancies must still be separated (if using the separated occupancies method), so the best solution is to put the 1-hour occupancy separation fire barrier on the wall between the Group A-3 occupancy and the corridor, and the wall on the other side of the corridor can be the fire partition.

 

[Jay Smith]

Similar question: If a corridor in the R-1 occupancy goes through an occupancy separation into an A-3 occupancy, is the corridor wall in the A-3 allowed to have no fire rating? Let’s assume we comply with 1020.6 on the other end of the corridor in the R-1 occupancy.

 

[RLGA]

Similar question: If a corridor in the R-1 occupancy goes through an occupancy separation into an A-3 occupancy, is the corridor wall in the A-3 allowed to have no fire rating? Let’s assume we comply with 1020.6 on the other end of the corridor in the R-1 occupancy.

No. You have to provide the protection required for the occupancies the corridor serves. If a corridor serving a Group R-1 goes through a separated Group A-3 occupancy, the corridor must still have the fire partition separation, since the protection is required at the point of entry into the corridor to the exit per Section 1020.6.

 

[Jay Smith]

No. You have to provide the protection required for the occupancies the corridor serves. If a corridor serving a Group R-1 goes through a separated Group A-3 occupancy, the corridor must still have the fire partition separation, since the protection is required at the point of entry into the corridor to the exit per Section 1020.6.

I figured the designer of the project @Sifu describes would use separated occupancies to try to do what I described in my question. I see now in the other post they are indeed proposing that. The markup calls the occupancy separation a horizontal exit, but the plan under the markup seems to show a 1-hour graphic in the wall. As in my question, I assume the other end of the corridor is continuous to an exit.

 

[Sifu]

BEST FORUM/RESOURCE EVER!

 

[Sifu]

I figured the designer of the project @Sifu describes would use separated occupancies to try to do what I described in my question. I see now in the other post they are indeed proposing that. The markup calls the occupancy separation a horizontal exit, but the plan under the markup seems to show a 1-hour graphic in the wall. As in my question, I assume the other end of the corridor is continuous to an exit.

The page I marked is a floor plan and it is hard to tell, that's why I marked it (I used it because the code plans and fire safety plans are full of comments), this was the cleanest page I had. The fire safety plans do clearly label it as a 2-hr fire barrier, however I am assuming it is being used to create a horizontal exit...because they don't tell me via any notations, or exit paths. That wing of the building has two exits at the far end, but they don't provide the required exit separation, so it is my assumption it is being used to create a compliant exit. And the door swing is a comment.

 

[Jay Smith]

The page I marked is a floor plan and it is hard to tell, that's why I marked it (I used it because the code plans and fire safety plans are full of comments), this was the cleanest page I had. The fire safety plans do clearly label it as a 2-hr fire barrier, however I am assuming it is being used to create a horizontal exit...because they don't tell me via any notations, or exit paths. That wing of the building has two exits at the far end, but they don't provide the required exit separation, so it is my assumption it is being used to create a compliant exit. And the door swing is a comment.

Where is the top of the 2-hr fire barrier? This is type VA construction, so a 1-hr horizontal assembly is above?

 

[Sifu]

Where is the top of the 2-hr fire barrier? This is type VA construction, so a 1-hr horizontal assembly is above?

The 2-hr FB is required to extend through all floors since all floors are 1-hr assemblies. I have asked for the details of continuity because they don't show me that. The horizontal exit appears to be required due to a CPET and dead end issue on the first floor, separation of exits on the second floor, and because there is only one other exit on the third & fourth floor.

 

[steveray]

One of my biggest struggles....Getting the designers to specify "why" the assembly is rated instead of just calling out "1 hour wall" on the plans...

 

[Sifu]

One of my biggest struggles....Getting the designers to specify "why" the assembly is rated instead of just calling out "1 hour wall" on the plans...

Absolutely. It just leaves the door open for me to interpret what they are trying to accomplish, and I can certainly get it wrong.