NR Calculator








  What are NR values?

The use of the NR values is a method for rating the quality of indoor environemnts for the purposes of speech communication, hearing preservation and annoyance. Add a noise pressure level in the following form for rate it.

  Ranting the noise spectrum

The NR curve that applies is the highest numerical value that is not exceeded in the band. The overall NR is the highest of all the NR values obtained.

31.5 Hz62.5 Hz125 Hz250 Hz500 Hz1 KHz2 KHz4 KHz8 KHz
Noise Spectrum
NR Upper Limit
NR Upper Number

  Applications of the NR curve obtained

The acceptable applications of the NR curve number obtained are showed in green in the next table.

Noise rating curveApplication
NR 25
Concert halls, broadcasting and recording studios, churches
NR 30
Private dwellings, hospitals, theatres, cinemas, conference rooms
NR 35
Libraries, museums, court rooms, schools, hospitals operating theatres and 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