Noise Criterion vs. Noise Rating and dB(A)
Noise Criterion - NC - were established in U.S. for rating indoor noise, noise from air-conditioning equipment etc.
In Europe it is common to use Noise Rating Curves - NR.
dB(A) - LA - is a weighted method compensating for the human hearing of sound pressure at different frequencies.
Choosing appropriate noise criteria is important when specifying acceptable levels of noise. Most organizations use a particular index based upon practical experience. Recommended maximum noise levels for different types of rooms and standards are indicated in the table below
| Type of Room - Occupancy | Maximum Level (dB) | ||||
|---|---|---|---|---|---|
| Noise Criterion - NC, NCB, RNC - | Noise Rating - NR - | dB(A) | RC | ||
| Very quiet | Concert and opera halls, recording studios, theaters, etc. | 10 - 20 | 20 | 25 - 30 | 20 |
| Private bedrooms, live theaters, television and radio studios, conference and lecture rooms, cathedrals and large churches, libraries, etc. | 20 - 25 | 25 | 25 - 30 | 25 | |
| Private living rooms, board rooms, conference and lecture rooms, hotel bedrooms | 30 - 40 | 30 | 30 - 35 | 30 | |
| Quiet | Public rooms in hotels, small offices classrooms, courtrooms | 30 - 40 | 35 | 40 - 45 | 35 |
| Moderate noisy | Drawing offices, toilets, bathrooms, reception areas, lobbies, corridors, department stores, etc. | 35 - 45 | 40 | 45 - 55 | 40 |
| Noisy | Kitchens in hospitals and hotels, laundry rooms, computer rooms, canteens, supermarkets, office landscape, etc. | 40 - 50 | 45 | 45 - 55 | 45 |
Related Topics
• Acoustics
Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.
Related Documents
Decibel A, B and C
Sound pressure filters that compensates for the hearing sensed by the human ear.
Human Effects when Exposed to Low-Frequency Noise or Vibration
Physiological effects from low-frequency noise or vibrations.
NC - the Noise Criterion
Noise Criterion - NC - level is a standard uesd to describe the relative loudness of a space within a range of frequencies.
Noise Criterion (NC) - Free Online Calculator
Calculate Noise Criterion (NC) from octave band pressure levels.
Noise Rating (NR) - Free Online Calculator
An online Noise Rating (NR) calculator.
NR - the Noise Rating Curve
The Noise Rating (NR) Curve used to determine acceptable indoor environments for hearing preservation, speech communication and annoyance.
SIL - the Speech Interference Levels
Background noise frequencies that interferes with speech.
Sound - Hearing Threshold vs. Age
Shift in hearing threshold for men and women vs. age.
Use of Telephones in Noisy Areas
Satisfactory, difficult and impossible noise levels for telephone use in noisy areas.