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FIRE WALL effect on Sprinkler System Throughout Building containing R Occupancy

R

ryan81

Member
Joined
Jan 7, 2015
Messages
29
Location
Cedar Rapids, Iowa
Good Afternoon,

I think I know the answer to this, but was hoping to bounce it off you all for verification. 2018 IBC is the adopted Code by the way...

I am working on a mixed-use building containing several occupancy classifications including one residential dwelling unit (R3). Section 903.2.8 reads that "An automatic sprinkler system installed in accordance with Section 903.3 shall be provided Throughout all BUILDINGS with a Group R Fire area." Based on this language, it is my understanding that the entire building needs to be needs to be sprinkled. This requirement is further confirmed in the commentary.

Regarding Fire Walls, my understanding is that they serve to create separate "buildings". My question is this: If one were to construct a fire wall to separate the R3 occupancy from the others, thereby creating "separate" "buildings", would that allow me to eliminate the sprinkler from the other occupancies and only include for the residential occupancy?

The commentary for section 706 seems to indicate that a Fire Wall creates "separate buildings", but only in terms of "allowable area, allowable height and type of construction requirements" and that "Using these provisions to control other building features or elements such as means of egress, building systems or building utilities is not intended or implied by the provisions".

Based on the commentary, it would seem that a Fire Wall would NOT eliminate the requirement for a sprinkler system throughout, or on both sides of the Fire Wall.

Do you agree?

Thanks in advance for your help!

-Ryan
 
Hold up... you cannot just construct a fire wall in an existing building. A fire wall requires structural independence on either side of the wall. Basically, if it is an existing building, it has to be cut in half, and each half has to remain structurally sound. Now, I am not sure of the specifics of your building in question, but I am willing to bet a coffee that this building was not designed with this in mind. Bracing/shear most likely prevents this from happening. Keep in mind that the fire wall, in most circumstances, cannot be a structural bearing wall either.
 

706.2 Structural Stability​

Fire walls shall be designed and constructed to allow collapse of the structure on either side without collapse of the wall under fire conditions. Fire walls designed and constructed in accordance with NFPA 221 shall be deemed to comply with this section.
Exception: In Seismic Design Categories D through F, where double fire walls are used in accordance with NFPA 221, floor and roof sheathing not exceeding 3/4 inch (19.05 mm) thickness shall be permitted to be continuous through the wall assemblies of light frame construction.​
 
classicT said:
Hold up... you cannot just construct a fire wall in an existing building. A fire wall requires structural independence on either side of the wall. Basically, if it is an existing building, it has to be cut in half, and each half has to remain structurally sound. Now, I am not sure of the specifics of your building in question, but I am willing to bet a coffee that this building was not designed with this in mind. Bracing/shear most likely prevents this from happening. Keep in mind that the fire wall, in most circumstances, cannot be a structural bearing wall either.
Click to expand...
ClassicT: I should have been more clear on project specifics. This is not an existing building. We are in the schematic design stages of a new-build project.

Would you agree with my interpretation that even though it creates a "separate" "building", the inclusion of a fire wall does not eliminate the requirement for a sprinkler system to be installed for the adjacent (non-residential) occupancies?
 
I believe the OP is on the right track. A fire wall is used to create separate buildings for the "purposes of determining area limitations, height limitations and type of construction" (Section 503.1). Other than that, it is a single building. Since there is some ambiguity in the code, some building officials may interpret the use of a fire wall to create separate buildings in all aspects, but I would not count on it.

From a non-code perspective, if I were the caretaker of a facility full of who-knows-what, I would sleep better at night knowing a system was there to extinguish the fire before it reached my residence.
 
ryan81 said:
ClassicT: I should have been more clear on project specifics. This is not an existing building. We are in the schematic design stages of a new-build project.

Would you agree with my interpretation that even though it creates a "separate" "building", the inclusion of a fire wall does not eliminate the requirement for a sprinkler system to be installed for the adjacent (non-residential) occupancies?
Click to expand...
My apologies. I had read the description as it was an existing building you were working on.

As you are in design, be sure to speak with the engineer to see if a structurally independent fire wall, and by relation each building on opposing sides of the fire wall, can be done with the current design.

That said, I agree with Ron and others... the code is a bit ambiguous in this circumstance. Fire walls create separate buildings for purposes of determining area limitations, height limitations and type of construction. Sprinklers are not included in that list. Would each building separated by the fire wall be allowed to have an area up to the Ch. 5 area limit for a non-sprinkled building, yes. For that purpose they are separate.

I will add a caveat to that statement, a fire wall exceeds a fire barrier. So, if the requirement was for a fire area to be sprinkled, a fire wall would be suitable. However, in this case the requirement for sprinklers stipulates "the building" and not fire area.
 
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