PatrickGSR94
Member
2-hour fire wall (structurall independent) adjacent to an existing building: I'm guessing CMU or other masonry or concrete design is probably the only viable solution?
We have a church facility that has been added on several times over the years. It's a mixture of A-3 and E, with a small area of B. 2-story building, fully sprinklered, with voice evac. Using Mixed Use Nonseparated, with A-3 as most restrictive, we're allowed 35,625 SF (Type II-B multistory with full open space all around the building). Current building gross floor area is 30,567. So we could add up to 5,058 SF per floor to remain Mixed Use Nonseparated. As a side note, I did run the numbers with the weighted averages for Mixed Use Separated, and there's no help there.
So if they need more than 5,000 SF, it seems that a fire wall is the only option, to create separate buildings. A structurally independent fire wall along the outside face of (not not actually attached to) the existing building. I don't know of any other way to achieve this other than CMU block or other masonry or concrete construction. We discussed the double-stud shaft wall liner with burn clips wall design for area separation walls, but as far as I know that's only for wood construction, and also can't really be properly constructed from only one side, against existing construction.
Code calls for a 3-hour fire wall for A and E uses, which can be reduced to 2-hour for fully sprinkled buildings. So 2-hour CMU with all its associated reinforcing and footings, and 90-minute doors in that wall for access through it.
Am I missing anything important?
We have a church facility that has been added on several times over the years. It's a mixture of A-3 and E, with a small area of B. 2-story building, fully sprinklered, with voice evac. Using Mixed Use Nonseparated, with A-3 as most restrictive, we're allowed 35,625 SF (Type II-B multistory with full open space all around the building). Current building gross floor area is 30,567. So we could add up to 5,058 SF per floor to remain Mixed Use Nonseparated. As a side note, I did run the numbers with the weighted averages for Mixed Use Separated, and there's no help there.
So if they need more than 5,000 SF, it seems that a fire wall is the only option, to create separate buildings. A structurally independent fire wall along the outside face of (not not actually attached to) the existing building. I don't know of any other way to achieve this other than CMU block or other masonry or concrete construction. We discussed the double-stud shaft wall liner with burn clips wall design for area separation walls, but as far as I know that's only for wood construction, and also can't really be properly constructed from only one side, against existing construction.
Code calls for a 3-hour fire wall for A and E uses, which can be reduced to 2-hour for fully sprinkled buildings. So 2-hour CMU with all its associated reinforcing and footings, and 90-minute doors in that wall for access through it.
Am I missing anything important?