David - I dont inspect them either, but it is good to know the requirements.
Here is a history of smoke detecor requirments.
SMOKE DETECTORS
1973 The National Fire Protection Association recommends that smoke detectors be placed in each bedroom and home hallway. They also recommend that smoke detectors over 10 years of age be replaced as smoke detectors lose their sensitive and at 15 years 50% will have failed in place. The test button merely ensures that the battery and horn are functioning."
, Detectors must be installed in hallways serving a sleeping room. Also, must be located a top of stairways where sleeping rooms are on an upper level. Must sound an alarm. (Section 1413)
1976, Added guest room of a lodging house, no other changes
1979, Requires a smoke detector when alterations, repairs or additions having a valuation of $1000.00 or more are made to an existing dwelling. Required that smoke detectors in new construction must be served by commercial power. In existing buildings the detector may be battery operated. (section 1413)
1982, Required that a smoke detector be placed in a basement with a stairway into the dwelling unit. The detector must sound an alarm audible in the sleeping areas. (Section 1210)
1982, No changes. (Section 1210)
1988, Specifically required smoke detectors on each level having a sleeping room. Where the ceiling height from the hall to sleeping room differs by 24 inches or more, then the detector must also be installed in the sleeping room. The alarm must be audible in all sleeping rooms. (Section 1210)
1991, Smoke detectors must be installed in the sleeping room as well as the hallway or area serving the sleeping room. Required battery backup when detectors are served by commercial power and low-battery signal must be included. (Section 1210)
1994, No changes, except exterior changes DO NOT require additional smoke detectors. (Section 310.9.1.4)
P21. Section 316.1 Smoke detecto****rs required.
Smoke detectors shall be installed in each sleeping room, outside of each separate sleeping area in the immediate vicinity of the bedrooms and on each additional story of the dwelling, including basements and cellars but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels, a smoke detector need be installed only on the upper level, provided the lower level is less than one full story below the upper level, except that if there is a door between levels, then a detector is required on each level. All detectors shall be interconnected such that the actuation of one alarm will actuate all the alarms in the individual unit and shall provide an alarm which will be audible in all sleeping areas. All detectors shall be approved and listed and shall be installed in accordance with the manufacturer’s instructions.
1994
B905.2 AUTOMATIC FIRE DETECTION
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B905.2.1 Single-station or multiple-station smoke detectors shall be installed within every dwelling and every dwelling unit within an apartment house, condominium or townhouse, and every guest or sleeping room in a motel, hotel or dormitory shall be provided with an approved listed smoke detector, installed in accordance with NFiPA 74. Where more than one detector is required to be installed within an individual dwelling unit, the detectors shall be wired in such a manner that the actuation of one alarm will actuate all of the alarms in the individual unit.
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B905.2.2 In dwellings and dwelling units, a smoke detector shall be mounted on the ceiling or wall at a point centrally located in the corridor or area giving access to each group of rooms used for sleeping purposes. Where the dwelling or dwelling unit contains more than one story, detectors are required on each story including basements, but not including uninhabitable attics, and shall be located in close proximity to the stairway leading to the floor above.
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B905.2.3 In dwelling units with split levels and without an intervening door between the adjacent levels, a smoke detector 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.
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B905.2.4 Smoke detectors connected to a fire protective signaling alarm system shall be installed in accordance with NFiPA 72 and 72E.
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B905.2.5 In dwelling and dwelling units, smoke detectors shall be hardwired into an AC electrical power source and shall be equipped with a monitored battery backup in all new construction. A monitored battery power source shall be permitted in existing construction.
2006 IRC
SECTION R313
SMOKE ALARMS
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:
- In each sleeping room.
- Outside 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.
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.