Fire wall or Fire Barrier Group R-2 Type V construction

[Wooly]

Is the fire rated wall separating two multi level town houses (in a 6 plex) considered a fire wall or fire barrier? What I am really trying to find out is how to address the floor/ceiling / wall intersection. Three floor units, 6-8 units per building. All typical wood construction.

 

[Joe.B]

Your code may be different. This reference is from the 2022 California Building Code, based off of the 2021 IBC:

420. 1 General. Occupancies in Groups R-1, R-2, R-2.1, R-
2.2, R-3, R-3. l and R-4 shall comply with the provisions of
Sections 420.1 through 420.11 and other applicable provisions
of this code.

420.2 Separation walls. Walls separating dwelling units in
the same building, walls separating sleeping units in the same
building and walls separating dwelling or sleeping units from
other occupancies contiguous to them in the same building
shall be constructed as fire partitions in accordance with
Section 708.

420.3 Horizontal separation. Floor assemblies separating
dwelling units in the same buildings, floor assemblies separating
sleeping units in the same building and floor
assemblies separating dwelling or sleeping units from other
occupancies contiguous to them in the same building shall be
constructed as horizontal assemblies in accordance with
Section 711.

SECTION 708
FIRE PARTITIONS
708.1 General. The following wall assemblies shall comply
with this section:
l. Separation walls as required by Section 420.2 for
Group R occupancies.

SECTION 711
FLOOR AND ROOF ASSEMBLIES
711.1 General. Horizontal assemblies shall comply with
Section 711.2. Nonfire-resistance-rated floor and roof assemblies
shall comply with Section 711.3.
711.2 Horizontal assemblies. Horizontal assemblies shall
comply with Sections 711.2. l through 711.2.6.

 

[RLGA]

Townhouses of three stories or less are regulated under the IRC, not the IBC, unless your jurisdiction modified the reference in Chapter 1 of the IBC.

In the IRC, walls between townhouses are called "common walls" and are either 1-hour rated if sprinklered and 2-hour rated if not sprinklered.

 

[Wooly]

Your code may be different. This reference is from the 2022 California Building Code, based off of the 2021 IBC:

420. 1 General. Occupancies in Groups R-1, R-2, R-2.1, R-
2.2, R-3, R-3. l and R-4 shall comply with the provisions of
Sections 420.1 through 420.11 and other applicable provisions
of this code.

420.2 Separation walls. Walls separating dwelling units in
the same building, walls separating sleeping units in the same
building and walls separating dwelling or sleeping units from
other occupancies contiguous to them in the same building
shall be constructed as fire partitions in accordance with
Section 708.

420.3 Horizontal separation. Floor assemblies separating
dwelling units in the same buildings, floor assemblies separating
sleeping units in the same building and floor
assemblies separating dwelling or sleeping units from other
occupancies contiguous to them in the same building shall be
constructed as horizontal assemblies in accordance with
Section 711.

SECTION 708
FIRE PARTITIONS
708.1 General. The following wall assemblies shall comply
with this section:
l. Separation walls as required by Section 420.2 for
Group R occupancies.

SECTION 711
FLOOR AND ROOF ASSEMBLIES
711.1 General. Horizontal assemblies shall comply with
Section 711.2. Nonfire-resistance-rated floor and roof assemblies
shall comply with Section 711.3.
711.2 Horizontal assemblies. Horizontal assemblies shall
comply with Sections 711.2. l through 711.2.6.

This is a wealth of information. I'm not sure why I can read it in the IBC and not understand it but your laying it out like this is excellent! Thank you.

 

[steveray]

Yeah.....could go either way from your description, but IRC Townhouses are separated by something firewall esque.....

 

[Joe.B]

Townhouses of three stories or less are regulated under the IRC, not the IBC, unless your jurisdiction modified the reference in Chapter 1 of the IBC.

I always forget that other states handle this differently. In CA there was no Residential Code until 2010, so our code has this statement:

1.1.7.3.1 Detached one- and two-family dwellings.
Detached one- and two-family dwellings, lodging
houses, live/work units, townhouses not more than
three stories above grade plane in height with a separate
means of egress, and their accessory structures
may be designed and constructed in accordance with
this code, or the California Building Code, but not
both, unless the proposed structure(s) or element(s)
exceed the design limitations established in this code,
and the code user is specifically directed by this code
to use the California Building Code.

Most designers, drafters, architects, engineers, etc... in our area don't even know there is a residential code. We see stuff all the time submitted that could be (should be) designed to the residential code, but they call out the building code. We review as submitted.