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Residential smoke detector placement

VAC

SAWHORSE
Joined
Jul 10, 2022
Messages
96
Location
Florida's Treasure Coast
Hi all!
I'm preparing a short class for design students about Residential placement of smoke detectors -the basics
It includes both R-2 & R-3 groups.
R-2 specific to multi-units in a building (condos)

In my practice, I have always placed them inside/outside bedrooms and if the dwelling is one story, that is typically sufficient to satisfy the one per story requirement, and this has never been an issue with the AHJ.
However, now that I need to reference chapter and verse for the class, I noticed the very slight difference between IBC and IRC, particularly # 3.

IBC 907.2.10.2 (2018)
Single or multiple-station smoke alarms shall be installed and maintained in Groups R-2, R-3, R-4 and I-1 regardless of occupant load at all of the following locations:
  1. On the ceiling or wall outside of each separate sleeping area in the immediate vicinity of bedrooms.
  2. In each room used for sleeping purposes.
  3. In each story within a dwelling unit, including basements but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.

IRC 314.3
Smoke alarms shall be installed in the following locations:
  1. In each sleeping room.
  2. Outside each separate sleeping area in the immediate vicinity of the bedrooms.
  3. On each additional story of the dwelling, including basements and habitable attics and not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.
Does that mean that in an apartment/condo in addition to the ones outside of the bedroom, I would need another one in a living space? (and no one said anything until now? :))

Basically, I've been following the IRC for everything.
For reference: most of my work is new commercial or tenant fit ups & single family homes, but not a lot of residential renovations in the R2 category that fall under the IBC.

Thank you!
 
In the 2021 IBC the section is 907.2.11.2. The commentary offers this:

Because the occupants of a dwelling unit may be
asleep and unaware of a fire developing in the room or
in an area within the dwelling unit that will affect their
ability to escape, single- or multiple-station smoke
alarms must be installed in every bedroom, in the
vicinity of all bedrooms (e.g., hallways leading to the
bedrooms) and on each story of the dwelling unit (see
Commentary Figure 907.2.11.2 and the commentary
to “Dwelling unit” in Section 202).
If a sprinkler system is installed throughout the building
in accordance with NFPA 13, 13R or 13D, if applicable,
smoke alarms would still be required in the
bedrooms even if residential sprinklers are used.
Smoke alarms are required in split-level arrangements.
As required by Section 907.2.10.5, all smoke
alarms within a dwelling unit must be interconnected
so that actuation of one alarm will actuate the alarms
in all detectors within the dwelling unit.
These provisions do not apply to one- and two-family
dwellings and multiple single-family dwellings
(townhouses) not more than three stories in height
with a separate means of egress that are regulated by
the IRC. The IRC is intended to be a stand-alone document,
but if the residential units do not fall within the
scope of the IRC or for other reasons are intended to
be subject to this code, then the requirements of this
section would apply. IFC Committee Interpretation No.
42-03 addresses this condition and contains additional
explanatory information about the IRC and its relationship
to the other International Codes.
Although the occupants of a sleeping unit in a Group
I-1 occupancy may be asleep, they are still considered
capable of self-preservation. Regardless, smoke
alarms are required in sleeping units. The exception
allows single- or multiple-station smoke alarms to be
eliminated in the room if an automatic fire detection
system that includes in-room system smoke detectors
is installed as required by Section 907.2.6

Your question: "Does that mean that in an apartment/condo in addition to the ones outside of the bedroom, I would need another one in a living space?"

Answer: Yes. The code section lists three locations where smoke alarms must be placed. The code says "at all of the following locations."
 
Answer: Yes. The code section lists three locations where smoke alarms must be placed. The code says "at all of the following locations."
Assuming a single story dwelling: Are you saying that if there is an alarm in the bedrooms and an alarm outside but in the vicinity of the bedrooms, an additional alarm is required elsewhere in the dwelling?
 
Assuming a single story dwelling: Are you saying that if there is an alarm in the bedrooms and an alarm outside but in the vicinity of the bedrooms, an additional alarm is required elsewhere in the dwelling?

I'm saying that the IBC requires that.

IBC 907.2.10.2 (2018)
Single or multiple-station smoke alarms shall be installed and maintained in Groups R-2, R-3, R-4 and I-1 regardless of occupant load at all of the following locations:

  1. On the ceiling or wall outside of each separate sleeping area in the immediate vicinity of bedrooms.
  2. In each room used for sleeping purposes.
  3. In each story within a dwelling unit, including basements but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.

And then the commentary (from 2021 IBC, but the language is the same):

Because the occupants of a dwelling unit may be
asleep and unaware of a fire developing in the room or
in an area within the dwelling unit that will affect their
ability to escape, single- or multiple-station smoke
alarms must be installed in every bedroom, in the
vicinity of all bedrooms (e.g., hallways leading to the

bedrooms) and on each story of the dwelling unit (see
Commentary Figure 907.2.11.2 and the commentary
to “Dwelling unit” in Section 202).
 
If you are in the 2021 IRC or newer, you also need a smoke alarm for some vaulted ceiling areas in addition to the ones inside and outside of each bedroom.

R314.3​

Smoke alarms shall be installed in the following locations:

5.In the hallway and in the room open to the hallway in dwelling units where the ceiling height of a room open to a hallway serving bedrooms exceeds that of the hallway by 24 inches (610 mm) or more.
 
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