Smoke alarm
A smoke alarm is a device that detects smoke and sounds a local alarm. These are most commonly used in dwelling units.
Wiring
In new buildings, smoke alarms are required to be powered by both batteries and the building electrical supply. This ensures that if one of the power supplies fails, the smoke alarm will remain powered.
Some smoke alarms are exclusively battery-powered; these are meant for retrofits in locations that previously did not have smoke alarms and to replace existing battery-only smoke alarms. In some locations, battery-only smoke alarms are required to have sealed batteries that cannot be removed to minimize the risk of the battery being depleted or removed, as a battery-only smoke alarm with a dead battery cannot alert occupants of its battery status.
Applications
Dwelling units
The most common use of a smoke alarm is to protect a dwelling unit. Certain residential occupancies are now required by the model codes to be constructed with smoke alarms producing a 520 Hz tone; because most smoke alarms do not have this capability, this is typically accomplished using a smoke detector on a sounder base.[1]: 13.7.2.17.5.1 [2]: 28.3.4.6.1, 30.3.4.5.1 [3]: 24.3.4.5, 25.3.4.5.1 [4]: 907.5.2.1.3.2 [5]: 907.5.2.1.3.2
Day care homes
NFPA's codes require new and existing day care homes to be equipped with smoke alarms, regardless of whether they are used for sleeping.[1]: 13.7.2.5.6.1, 13.7.2.6.6.1 [2]: 16.6.3.4.1, 17.6.3.4.1 [3]: 18.7.3.4.1 Smoke alarms are also permitted to be used in corridors serving a day care home instead of a smoke detection system if they are hardwired and interconnected to the smoke alarms.[1]: 13.7.2.5.6.3, 13.7.2.6.6.3 [2]: 16.6.3.4.3, 17.6.3.4.3 [3]: 18.7.3.4.3(2)
Health care kitchens
NFPA's codes require kitchens in health care occupancies to be protected by two interconnected photoelectric smoke alarms that can be silenced.[2]: 18.3.2.5.3(11), 19.3.2.5.3(11) [3]: 19.3.2.4.3(11) The presence of two smoke alarms is for redundancy as the smoke alarms are not supervised by the fire alarm system; a single smoke detector arranged to produce a local audible signal can be used in place of these smoke alarms.[2]: 18.3.2.5.3(13), 19.3.2.5.3(13), A.18.3.2.5.3(11), A.19.3.2.5.3(11) [3]: 19.3.2.5.3(13)
References
- ↑ 1.0 1.1 1.2 Fire Code (NFPA 1, 2024)
- ↑ 2.0 2.1 2.2 2.3 2.4 Life Safety Code (NFPA 101, 2024)
- ↑ 3.0 3.1 3.2 3.3 3.4 Building Construction and Safety Code (NFPA 5000, 2024)
- ↑ International Building Code (2024)
- ↑ International Fire Code (2024)