Which standard ensures audible public warning signals are clearly heard?

• A. NFPA 72 says they shall have a sound level of at least 15db above the average ambient sound level
• B. OSHA noise exposure limits
• C. NFPA 70 electrical code
• D. ADA accessibility guidelines

Answer: (A)

Audible warnings must cut through background noise so people can hear them in an emergency. NFPA 72, the standard for fire alarm and life safety systems, requires occupant notification signals to be audible at a level that stands out from the environment—specifically, at least 15 dB above the average ambient sound level. This ensures the alarm is detectable in typical spaces, improving safety during evacuations.

The other options don’t establish this general audibility requirement: OSHA focuses on worker noise exposure limits, not building-wide warning levels; NFPA 70 governs electrical wiring and equipment; ADA guidelines address accessibility and may require accessible alerting methods, but they don’t set the specific loudness standard for audible alarms.