Julia XA wrote:I have been advised that I would be designing under the IBC (not the IRC) because of the total number of units on the site and the fact that they will be rentals and not individually owned. So we would fall under the 2015 IBC.
Apparently some local requirement wording, that is not uncommon.
However, it is also strange as the IBC specifically states this: (underlining is mine)
- From the 2015 IBC:
- - 101.2 Scope.
- - - The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.
- - - -
Exceptions: Detached one- and two-family dwellings and multiple single-family dwellings (
townhouses)
not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height,
shall comply with the International Residential Code.
Nonetheless, you have been told that all will be under the IBC, so we will go with that code.
Interesting then about town houses being defined as 3 units or more.
Obviously my 8 gang units would be considered townhouses, but those are only 3 story.
So my question about the 4 story "duplexes" is still in question w/r/t fire sprinkler requirements. I assume they will be required because they are 4 story, but have not been able to get a definitive answer. The code mentions 12,000 sf total for Type 5A and 7,000 sf total for Type 5B but it is not clear to me whether this is an exception to the sprinkler requirement if we are under those totals in each building.
From the IBC: (underlining is mine)
- 504.3 Height i feet.
- - The maximum height, in feet, of a building shall not exceed the limits specified in Table 504.3.
- - - Exception: (exception does not apply to your project, so I am not including it)
- Table 504.3a Allowable Building Height In Feet Above Grade Plane
- - (Under 'Occupancy Classification' column - go down to 'R')
- - (Under 'See Footnotes' column - go down to 'NS'd,h, 'S13R', and 'S')
- - (read footnote 'a' which applies to the entire table)
- - (read footnotes 'd' and 'h' as they apply to 'NS' - 'NS' is 'not sprinklered')
- - - (footnotes)
- - - - a. See Chapters 4 and 5 for specific exceptions to allowable height in this chapter.
- - - - d. The NS value is only for use in evaluation of existing building height in accordance with the International Existing Building Code.
- - - - h.
New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8Footnote 'a' comment - Nothing in Chapters 4 or 5 removes the requirement for sprinklers.
Footnote 'd' comment - Not applicable to new construction.
Footnote 'h' comment - Requires Group R occupancies to be sprinklered in accordance with 903.2.8, and under 'See Footnotes' it says 'S13R' - this refers to it being 'Sprinklered' with an NFPA '13R' compliant system for a height of up to 60 feet. A height of greater than 60 feet requires an NFPA 13 compliant system.
The townhouses need to have fire-resistance rated separation between units as required - from foundation to the roof, from front to back, including soffit overhangs, attics, etc.
Anything in those fire-resistance rated walls requires the proper listing and rating to be used in those walls.