N.Y.C. Admin. Code § 28-312.2: § 28-312.2 Periodic replacement of carbon monoxide alarms.

Carbon monoxide alarms required pursuant to section 915.1 of the New York city building code or sections 27-981.1, 27-981.2 and 27-981.3 of the 1968 building code shall be replaced when the time elapsed since the installation of such alarm exceeds the manufacturer's suggested useful life of the alarm.

Exception: A carbon monoxide alarm installed before April 25, 2012 shall be replaced when the time elapsed since the installation of such alarm exceeds the manufacturer's suggested useful life of the alarm.