NFPA 72 categorizes an air-aspirating system as which type of detector?

• A. Heat detector
• B. Smoke detector
• C. Air sampling-type detector
• D. Photoelectric detector

Answer: (C)

NFPA 72 classifies air-aspirating systems as air-sampling-type detectors. These systems actively pull air from the protected space through a network of tubes to a central sensing unit, where smoke particles are detected—often with optical or laser-based sensing. This approach provides very early warning and is used in environments where rapid detection is critical or where space is large and dissemination of smoke is slow.

This differs from heat detectors, which respond to temperature rises, and from conventional smoke detectors that sense smoke right at a local spot rather than sampling air from multiple locations. So the best fit is the air-sampling-type detector, reflecting the centralized, air-sampling detection method core to an air-aspirating system.