Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Noise Criterion vs. Noise Rating and dB(A)

Comparing Noise Criterion (NC, NCB, RNC) to Noise Rating (NR) and dB(A).

Sponsored Links

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 - OccupancyMaximum Level (dB)
Noise Criterion
- NC, NCB, RNC -
Noise Rating
- NR -
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
Sponsored Links

Related Topics

Related Documents

Sponsored Links

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

About the Engineering ToolBox!


We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.


This page can be cited as

  • Engineering ToolBox, (2004). Noise Criterion vs. Noise Rating and dB(A). [online] Available at: [Accessed Day Mo. Year].

Modify access date.

. .


3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Scientific Online Calculator

Scientific Calculator

3 10

Sponsored Links