9.10.19.4.Power Supply

(1) Except as provided in Sentences (2) and (3), smoke alarms described in Sentence 9.10.19.1.(1) and 9.10.19.3.(1.1) shall (a) be installed with permanent connections to an electrical circuit, (See Note A-3.2.4.20.(9)(a)) (b) have no disconnect switch between the overcurrent device and the smoke alarm, and (c) in case the regular power supply to the smoke alarm is interrupted, be provided with a battery as an alternative power source that can continue to provide power to the smoke alarm for a period of not less than 7 days in the normal condition, followed by 4 minutes of alarm. (2) Where the building is not supplied with electrical power, smoke alarms are permitted to be battery-operated. (3) Suites of residential occupancy are permitted to be equipped with smoke detectors in lieu of smoke alarms, provided the smoke detectors (a) are capable of independently sounding audible signals with a sound pressure level between 75 dBA and 110 dBA within the individual suites, (See also Note A-3.2.4.18.(4)) (b) except as permitted in Sentence (4), are installed in conformance with CAN/ULC-S524, “Standard for Installation of Fire Alarm Systems,” and (c) form part of the fire alarm system. (See Note A-3.2.4.20.(10)) (4) Smoke detectors permitted to be installed in lieu of smoke alarms as stated in Sentence (3) are permitted to sound localized alarms within individual suites, and need not sound an alarm throughout the rest of the building.