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.