This guide will help break down noise levels (dBA) and give descriptions of the ranges of dBA.


      Sound Level Change      
 Human Perception
 2 to 3 dBA Barely Perceptible
 5 dBA  Readily Noticeable
10 dBA Doubling or Halving of Noise
 20 dBA Dramatic Change


     Sound Rating   
 Common Sounds
 0 dBA Threshold of Hearing
 10 dBA Breathing
 20 dBA  Rustling Leaves
 30 dBA  Whispering
 40 dBA Quiet Library
 50 dBA Refrigerator
 60 dBA  Air Conditioner