Smoke detector location ?

[goaliedad]

R Clark’s post prompted this. I need to install smoke detectors in our house. I have avoided it as it has been an ongoing remodel and I was afraid that dust would cause issues. It is now time….
Single story, two bedrooms and bath on a hallway. Mechanical room is off the hall near the center of the house. Kitchen and living room are on the end of the hoff ur de opposite bedrooms. They are separated by a 12 inch beam.

Where do put the smoke detectors? These will be battery operated as I am not interested in wiring them due to a very low roofline and poor attic space

[MKepke]

Strictly speaking, you should follow the residential building code for your area.

Hardwiring is often required if you've done a significant remodel.

For example, here's the IRC - your AHJ may or may not follow this. In any case, this provides some general guidance.

R313.1 Smoke detection and notification.
All smoke alarms shall be listed in accordance with UL 217 and installed in accordance with the provisions of this code and the household fire warning equipment provisions of NFPA 72.
Household fire alarm systems installed in accordance with NFPA 72 that include smoke alarms, or a combination of smoke detector and audible notification device installed as required by this section for smoke alarms, shall be permitted. The household fire alarm system shall provide the same level of smoke detection and alarm as required by this section for smoke alarms in the event the fire alarm panel is removed or the system is not connected to a central station.
R313.2 Location.
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 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.
When more than one smoke alarm is required to be installed within an individual dwelling unit the alarm devices shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms in the individual unit.
R313.2.1 Alterations, repairs and additions.
When alterations, repairs or additions requiring a permit occur, or when one or more sleeping rooms are added or created in existing dwellings, the individual dwelling unit shall be equipped with smoke alarms located as required for new dwellings; the smoke alarms shall be interconnected and hard wired.
Exceptions:
1. Inter connection and hard-wiring of smoke alarms in existing areas shall not be required where the alterations or repairs do not result in the removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available which could provide access for hard wiring and interconnection without the removal of interior finishes.
2. Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck, are exempt from the requirements of this section.
R313.3 Power source.
In new construction, the required smoke alarms shall receive their primary power from the building wiring when such wiring is served from a commercial source, and when primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection. Smoke alarms shall be permitted to be battery operated when installed in buildings without commercial power or in buildings that undergo alterations, repairs or additions regulated by Section R313.2.1.

-Mark

[msweig]

I'll add one other suggestion. Don't get only ionization smoke detectors. They are terrible are detecting smouldering fires. My company did a demo once where we built a room, filled it with a ton of smoke detectors (both ionization and photoelectric), and then a firefighter (full gear) went into the "room" and we saran wrapped the doorway shut while he started a smoldering fire. Once a detector went off he pulled it from the wall and handed it outside through a hole. The photoelectric ones were the first ones out. And many (almost all) of the ionization ones didn't go off. There was enough smoke in that small room where it was hard to see the outline of the firefighter.

Not all of them need to be photoelectric. Just make sure some of them are.

[Snipe Hunter]

One smoke and carbon monoxide detector on every level. The bedroom level, it should be near the bedroom doors. If bedrooms are separated like some on one end of the house and another on the other end, put in a 2nd "smoke" detector. But you don't need an extra carbon monoxide detector. Then one smoke detector in every bedroom near the door. Most states have adopted this configuration.

As a home inspector here in MD, I'm supposed to recommend 10 year maintenance free batteries and hard wiring but I know that's pretty cost prohibitive for some but I still recommend it. But hard wiring isn't required unless remolding work involves removing wall and ceiling finishes.

Any smoke or carbon monoxide detector over 10 years old should be discarded. If it doesn't have a manufacturer's date on the back, it's well over 10 years old. If the plastic has turned yellow, it's more than 10 year old.

The ones with the sealed maintenance free batteries start chirping at 10 years and you can't shut it off. The longer you wait, the more it chirps. Again, as a home inspector, I have to recommend "installed per manufacturer's recommendations"... they all recommend tossing them in 10 years.

We aren't code inspectors, we should be inspecting to "accepted standards", "safety standards" and "best practices". All of which meet or exceed code. The state says if a room is altered, it has to be brought up to current code. Otherwise, it has to meet the code when it was built. So real old homes don't "require" any detectors of any kind. But I wouldn't be doing my job if I didn't recommend detectors per current fire safety codes.