•
An alarm should be centrally located outside of each separate sleeping area in the immediate
vicinity of the bedrooms. Where bedrooms are separated and audibility of the alarm to occupants
within the bedroom area could be seriously impaired, more than one alarm could be needed.
• Locate the first combination alarm in the immediate area of the bedrooms. Try to protect the
escape route as the bedrooms are usually farthest from an exit. If more than one sleeping area
exists, locate additional combination alarms in each sleeping area. If a hall is more than 40 feet
(12 meters) long, install a combination alarm at each end.
• Locate additional alarms to protect any stairway as stairways act like chimneys for smoke and heat.
• Locate at least one combination Smoke, CO and Gas alarm on every floor level.
• Locate an alarm in any area where a smoker sleeps or where electrical appliances are operated
in sleeping areas.
• Smoke, heat and other combustion products rise to the ceiling and spread horizontally. Mounting
the alarm on the ceiling in the center of the room places it closest to all points in the room. Ceiling
mounting is preferred in ordinary residential construction. However, in mobile homes, wall mount-
ing on an inside partition is preferred to avoid the thermal barrier that may form at the ceiling.
• When mounting the alarm on the ceiling, locate it a minimum of 4" (10cm) from a side wall or
corner (see Diagram A).
• When mounting the alarm on a wall, if local codes allow, use an inside wall with the top edge of the
smoke alarm a minimum of 4" (10cm) and a maximum of 12" (30.5cm) below the ceiling/wall
intersections (See Diagram A).
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Sloped Ceilings (Peaked Ceilings):
Smoke alarms or combination alarms mounted on a peaked ceiling shall be located within 36 in. (914 mm)
horizontally of the peak, but not closer than 4 in. (102 mm) vertically to the peak.
Sloped Ceilings (Shed Ceilings):
Smoke alarms or combination alarms mounted on a sloped ceiling having a rise greater than 1 ft. in 8 ft. (1
m in 8 m) horizontally shall be located within 36 in. (914 mm) of the high side of the ceiling, but not closer
than 4 in. (102 mm) from the adjoining wall surface.
Tray-Shaped Ceilings:
Smoke Alarms or combination alarms shall be installed on the highest portion of the ceiling or on the
sloped portion of the ceiling within 12 in. (305 mm) vertically down from the highest point.
Mobile Home Installation:
For minimum protection, smoke alarms should be installed in compliance with H.U.D. Manufactured Home
Construction Safety Standards, Title 24 CFR, Section 3280.208 and Section 3282. For additional protection,
see Single Story Residence smoke alarm requirements/recommendations for Existing Homes and New
Construction Homes.
Note: For mobile homes built before 1978, install smoke alarms or combination alarms on inside walls
between 4” and 12” from the ceiling (older mobile homes have little or no insulation in the ceiling). This is
especially important if the ceiling is unusually hot or cold.
Install smoke alarms or combination alarms inside each bedroom and in the hallway outside each separate
sleeping area.
Existing Homes:
The NFPA requires smoke alarms or combination alarms on every level and outside each sleeping area in
existing construction. An existing household with one level and one sleeping area is required to have one
smoke alarm.
New Construction Homes and Manufactured Homes:
The NFPA requires AC-powered, interconnected smoke alarms to be installed inside each bedroom, outside
each bedroom area, and on every level of the home. They also require a minimum of two AC-powered,
interconnected smoke alarms or combination alarms in any new construction home.
