Single-Station and Multiple-Station Alarms Defined
Chapter 29 of NFPA 72 covers single-station and multiple-station alarms and household fire alarm systems. A single-station alarm is a self-contained device that includes a detector and an audible alarm in one unit. A multiple-station alarm consists of two or more single-station alarms that are interconnected so that when one alarm activates, all interconnected alarms sound. These devices are the primary fire detection and notification systems in residential occupancies such as single-family homes, apartments, and dormitories.
Required Locations
Smoke alarms must be installed in every sleeping room, outside each separate sleeping area in the immediate vicinity of the bedrooms, and on every level of the dwelling unit, including the basement. When installed on a ceiling, smoke alarms must be located at least 4 inches from any wall. Wall-mounted units must be installed between 4 and 12 inches from the ceiling. Smoke alarms must not be installed near kitchens, bathrooms, or forced-air supply registers where nuisance alarms are likely.
Power and Interconnection
Smoke alarms in new construction must receive their primary power from the building’s electrical system and must not be connected to a circuit that can be switched off separately from the building’s main power. Battery backup is required so that alarms continue to function during power outages. All smoke alarms within a dwelling unit must be interconnected so that activation of any one alarm causes all alarms to sound, which can be achieved through hardwiring or listed wireless interconnection technology.
Replacement and Maintenance
Smoke alarms must be replaced when they fail to respond to testing or no later than 10 years from the date of manufacture, unless a different replacement schedule is specified by the manufacturer. Alarms must be tested at least monthly by the occupant using the test button. Batteries in battery-powered or battery-backup alarms must be replaced according to the manufacturer’s instructions, typically annually, unless the alarm uses a sealed, long-life battery.
