How loud does noise have to be to damage the ears?
• The amount of damage that noise can do to ears seems to be related to the amount of energy in the noise. • The amount of energy in a noise depends on: • the intensity of the noise, ie., how loud it is • its duration, ie. how long it lasts, or how long the listener is exposed to the noise. • Obviously a noise that lasts twice as long has twice as much energy, but the amount of energy in the sound grows very quickly as the sound gets louder (it doubles every time the sounds gets louder by 3dB). • Thus there is not a fixed level below which noise is entirely safe, but noise that is not so loud can be endured much longer than noise that is very loud before it will damage the ears. • In practice, a noise is probably quite safe if it is not too difficult to hold a conversation when people are about a metre apart during the noise. • If a very loud voice is required to talk over the noise, (or the noise is over 90dBA), it is likely that the noise is harmful if endured frequently or for long
