Here are some interesting figures, that can help you to understand the volume levels of various sources and how they can affect our hearing.

Loudest Sound Possible194 dB
Death of Hearing Tissue180 dB
Jet Take-Off140 dB
Pneumatic Hammer130 dB
Pain Level120 dB
Klaxon100 dB
Machine Workshop90 dB
Noisy Pub80 dB
Noisy Office70 dB
Human Conversation60 dB
Standard Home Ambient50 dB
Silent Bedroom30 dB

Perceptions of Increases in Decibel Level

Imperceptible Change1 dB
Barely Perceptible Change3 dB
Clearly Noticeable Change5 dB
About Twice as Loud10 dB
About Four Times as Loud20 dB