An area in the public mode has an ambient sound level of 35 dBA and a maximum sound level of 40 dBA. During an acceptance test, at the desk of the area supervisor, you measure 48 dBA. Does this meet NFPA 72 requirements?

An area in the public mode has an ambient sound level of 35 dBA and a maximum sound level of 40 dBA. During an acceptance test, at the desk of the area supervisor, you measure 48 dBA. Does this meet NFPA 72 requirements?

• A. No
• B. Yes
• C. Only if average ambient is used
• D. Only if maximum is used

Answer: (A)

The key idea is that acceptance testing for public mode signals is judged against the area's maximum allowable sound level. In this scenario, the area’s maximum is 40 dBA. The desk measurement of 48 dBA is 8 dB higher than that maximum, so the level exceeds what NFPA 72 permits. Therefore, it does not meet the requirements. Ambient noise (35 dBA) is background information, but the controlling criterion is the maximum allowance, not an average ambient. The options suggesting rules about averaging or using the average/maximum conditional criteria don’t apply here.

The key idea is that acceptance testing for public mode signals is judged against the area's maximum allowable sound level. In this scenario, the area’s maximum is 40 dBA. The desk measurement of 48 dBA is 8 dB higher than that maximum, so the level exceeds what NFPA 72 permits. Therefore, it does not meet the requirements.

Ambient noise (35 dBA) is background information, but the controlling criterion is the maximum allowance, not an average ambient. The options suggesting rules about averaging or using the average/maximum conditional criteria don’t apply here.