Fire Barrier Perpendicular to Trusses 2

[medeek]

This one is a real head scratcher. I've got a single story commercial building (160'x 58', big rectangle) where the owner wants to take the last 50' feet of the building and turn it into a residence. Based on the occupancy group A-2 and R-3 I would need to call out a 2 hour rated fire barrier between the two occupancies. Instead of making thing easy and separating the last 50' of the building with the fire barrier parallel to the trusses the owner wants to leave an approximate 15' sliver of the building attached to the rest of the commercial space for storage. This would require a fire barrier constructed perpendicular to the trusses extending up to the roof diaphragm.

This seems like a bad idea just from the shear effort it would take to frame up and around all of these trusses to the roof sheathing and apply the two layers of gypsum to both sides. Furthermore the truss bottom chords penetrate the fire barrier so how does that work?

Has anyone every seen something like this?

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[medeek]

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[medeek]

There is really nothing on this anywhere.

The only reference or related item was a building review in Florida in 2005 that addresses this issue:

http://bocc.citrus.fl.us/permitting/AddInfo?APNO=200410934

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[jayrod12]

Why don't you run the attic separation full building width, then rate the storage room ceiling. I could see that working, but I'm not architect, and if you call me one I may have to kill you.

 

[medeek]

Here is an interesting case that went to court over this exact problem:

http://www.mah.gov.on.ca/Page8075.aspx

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[medeek]

I could see that would work Jayrod but I'm trying to minimize the amount of firewall actually needed. I just told the client that he would be better served running the fire barrier across the full width and then if he needs access into the "storage space" from the non-residential side he can frame in a fire rated door (1-1/2 hour) through the barrier. I think this is the most common sense solution to the problem. The storage space would then be grouped with the residence as far as occupancy classification.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[jayrod12]

Agreed that is the easiest solution. Which once the owner has input from a framer, that will likely be confirmed. Considering how much time would be spent going around each truss it should more than pay for a fire rated door.