Smoke alarms in one- and two-family dwellings shall be replaced when they fail to operate...

NFPA 72 requires smoke alarms in residential settings to be replaced every10 years, even if they have not shown any signs of failure.

NFPA 72 (2022), Section 29.8.1.4:

“Unless otherwise recommended by the manufacturer, smoke alarms shall be replaced when they fail to respond to operability tests or have been in service for 10 years.”

Correct answer: C. 10

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