Sound level, which is measured in decibels, is usually abbreviated as “dB”. Another important factor about sound level measurement is that it is made at a fixed distance since sound level decreases the further a sound wave travels. Mallory measures panel mount alarm sound level at two feet which means that if a person was standing two feet away from the alarm, that is how loud it would sound. Mallory’s 22 mm panel alarms are available in three different sound level categories. Soft sound level equals 65 to 75 dB at two feet, medium sound level equals 75 to 85 dB at two feet, and loud sound level equals 85 to 95 dB at two feet. While two feet is a common measurement distance for panel alarms, Mallory has developed a chart to show designers the equivalent sound levels at other distances. For example, a Mallory 22 mm alarm that is in the loud sound category is rated 85 to 95 dB at two feet. If the operator was standing only ten centimeters from the alarm, it would measure an ear piercing 100 to 110 dB. On the other hand, if an operator was standing ten feet away from the alarm, the sound level would be softer and would measure 71 to 81 dB.