Decibel Scale – Noise Overview

Decibel Scale – Noise Overview

Noise Overview- What’s a dB?  A decibel (dB) is simply a convenient measurement unit for sound level (volume) measured at a specific point.

As a reference, the following chart will give you an idea of the sound level (measured in dB’s) of various sources:


Typical noises rated in decibels (dB)

155 dB – A .30 Caliber Rifle Extreme Danger!

140 dB – A Shotgun Blast/Jet Engine (at 30 m)

130 dB – Riveting Hammer : Threshold of Feeling

120 dB – Propeller Aircraft : Threshold of Pain

110 dB – Rock Drill/Amplified Music

100 dB – Chain Saw/Subway Station

90 dB – Lawn Mower/Heavy vehicle. Limit of exposure for 8 hrs

80 dB – Computer Print Room

70 dB – Noisy Restaurant or Heavy Traffic

60 dB – Conversation – moderate

40 dB – Quiet Office

30 dB – Quiet Whisper

20 dB – Buzzing Insect

10 dB – Rustle of a Leaf

1 dB – The applause following a Rick Boyce lecture about noise

0 dB – No sound : Threshold of Hearing

Excessive Noise:

  • Auditory nerves can be permanently damaged from prolonged exposure at 90 dB
  • 120 dB can cause pain and ringing in the ear
  • Sharp pain and extensive destruction of the auditory nerves occurs at 140 dB

Noise Control – Why do we need it?

  • Government regulations mandate maximum acceptable noise levels in the workplace or in neighborhoods. These rules are enforced by OSHA, as well as state and local laws.
  • Productivity of employees: prolonged exposure to loud environment cuts down productivity, creates stress and can lead to accidents.
  • Too much echo and reverberation can garble speech intelligibility and make music sound dreadful.
  • Excessive noise in neighborhoods can be an annoyance and can negatively affect property values.
  • In recording studios and broadcast facilities a low-noise, echo-free environment is required to guarantee speech clarity.