The loudness of sounds is measured in decibels (dB). Laughter is 60 to 65 dB compared to a lawnmower, which is 85 to 90 dB.
The National Fire Protection Association (NFPA) regulates fire codes and mandates that a smoke alarm emit a sound that is a minimum of 75 decibels. The average smoke alarm in North America exceeds that by emitting an 85-decibel alarm.
A smoke alarm cannot save lives if the batteries are dead or the unit is disconnected or broken. It is important to test the alarm regularly and replace the batteries at regular intervals.
Fire protection specialists recommend testing alarms monthly and changing batteries once a year. If the alarm chirps, indicating a low battery, replace it right away.
The NFPA recommends installing smoke alarms in every sleeping area, outside each bedroom and on every level of the home, including the basement. It is best to interconnect all smoke alarms throughout the home. That way, when one sounds, they all sound, at 85 decibels.