8.5.5.7.1 Required smoke dampers in ducts penetrating smoke
barriers shall close upon detection of smoke by approved smoke
detectors in accordance with NFPA 72, National Fire Alarm and
Signaling Code, unless one of the following conditions exists:
(1) The ducts penetrate smoke barriers above the smoke barrier
doors, and the door release detector actuates the damper.
(2) Approved smoke detector installations are located within
the ducts in existing installations.