Nr Noise Rating
Reference data and engineering information about nr noise rating for acoustics applications.
noiserating
Overview
Engineering reference data for Nr Noise Rating in acoustics.
Key Formulas
Speed of Sound
Speed of sound in an ideal gas.
Sound Level
Decibel level.
Wavelength
Wavelength = speed / frequency.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Speed of sound | m/s | |
| Sound level | dB | |
| Wavelength | m | |
| Frequency | Hz |
Recommended NR Levels
8 rows
NR Rating | Recommended Application |
|---|---|
| NR 25 | Concert halls, broadcasting & recording studios, churches |
| NR 30 | Private dwellings, hospitals, theaters, cinemas, conference rooms |
| NR 35 | Libraries, museums, court rooms, schools, hospitals operating theaters & wards, flats, hotels, executive offices |
| NR 40 | Halls, corridors, cloakrooms, restaurants, night clubs, offices, shops |
| NR 45 | Department stores, supermarkets, canteens, general offices |
| NR 50 | Typing pools, offices with business machines |
| NR 60 | Light engineering works |
| NR 70 | Foundries, heavy engineering works |
Source: engineeringtoolbox.com
Noise Rating Curves
The NR curves define the maximum allowable sound pressure levels across nine octave-band center frequencies for each Noise Rating level.