Smoke Detectors
One of the most requested items received in our Fire Prevention Division is information on smoke detectors. The following information has been provided by the New Hampshire State Fire Marshal’s Office to outline the requirements for smoke detectors. It is important to note that smoke detectors have a lifespan of ten years and need to be replaced when they reach this age.
Where are Smoke Detectors Required?
Smoke detectors are required in both single-family dwellings as well as multi-unit dwellings and rental units. The requirements for each are outlined below.
Single-Family Dwelling Units
Smoke alarms are required to be installed in all single-dwelling units.
Locations of Installation
Smoke alarms shall be installed in the following locations:
- In each sleeping room;
- Outside of each separate sleeping area in the immediate vicinity of the bedrooms;
- 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.
Powering the Detectors
The following information explains the requirements for powering smoke detectors in single-dwelling units.
New Construction: Smoke alarms shall receive their primary power from the building’s wiring (hardwired) and when the primary power is interrupted shall receive power from a battery (battery backup).
Existing Dwellings with Alterations, Repairs, and Additions: When there are alterations, repairs and additions requiring a permit or when one or more sleeping rooms are added, the individual dwelling unit shall be equipped with new smoke alarms located as required for new dwellings.
Exceptions to Existing with Alterations, Repairs, and Additions
- Hardwiring 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 without the removal of interior finishes.
- Work involving the exterior surface of the dwellings, such as the replacement of roofing or siding, the addition or replacement of windows or doors, or the addition of a porch or deck.
Existing Dwellings: In existing single-family dwellings, approved smoke alarms powered by batteries shall be permitted. Please check with the local Authority Having Jurisdiction in reference to which smoke alarms and batteries are approved.
Multi-Unit Dwellings and Rental Units
All multi-unit dwellings and rental units are required to be equipped with automatic fire warning devices.
Locations of Installation
Smoke alarms shall be installed in the following locations of all multi-unit dwellings and rental units.
- On the ceiling or wall outside of each separate sleeping area in the immediate vicinity of the bedrooms.
- In each room that is used for sleeping purposes.
- 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.
Powering the Detectors
The following information explains the requirements for powering smoke detectors in multi-unit dwellings and rental units.
New and Existing Construction: All automatic fire warning devices in multi-unit dwellings and all rental units shall be powered by the house electrical service (hardwired).
Required Interconnection of the Detectors
The following information explains the interconnection requirements for smoke alarms in new and existing construction.
When more than one smoke alarm is required to be installed within an individual dwelling unit or sleeping unit the smoke alarms shall be interconnected in such a manner that the activation of one alarm will activate all the alarms in the individual unit. The alarm shall be clearly audible in all bedrooms with all intervening doors closed and considering any ambient noise. Interconnection within the unit is required, not within the building. Wireless interconnection systems are permitted.
Additional Information and Resources
If you have questions or need more information, please contact the Lebanon Fire Department Fire Prevention Division at 603-448-8810.