At which interval do duct smoke detectors utilized for HVAC shutdown need to be tested?

Duct detectors are used to shut down air handling systems to prevent smoke from circulating. NFPA 72 requires that these detectors and their shutdown functions be testedannually.

NFPA 72 (2022), Table 14.4.3.2 – Testing Frequencies:

"Duct-type smoke detectors with HVAC shutdown" → Frequency: Annually.

The test must verifydetector functionandHVAC control activation.

Correct answer: D. Annually