The standard that contains requirements for duct detection in HVAC systems is which NFPA standard?

• A. NFPA 70
• B. NFPA 90A
• C. NFPA 101
• D. NFPA 13

Answer: (B)

Duct detection in HVAC systems is governed by how HVAC installations are planned and integrated with fire protection. Detectors in air ducts are used to sense smoke and trigger automatic actions—like shutting down fans or isolating portions of the system—to prevent smoke from spreading.

NFPA 90A, the Standard for the Installation of Air-Conditioning and Ventilating Systems, covers these installation details for HVAC equipment, including where to place duct detectors and how they should operate with other controls. That’s why this standard is the best fit for duct detection requirements.

The other standards focus on different areas: NFPA 70 is about electrical wiring, NFPA 101 sets broad life-safety requirements, and NFPA 13 covers sprinkler systems, none of which address the specific installation rules for duct detectors in HVAC systems.