### Strutt Help

NRC Rating
**Strutt|Criteria|Ratings|Absorption|NRC** calculates the Noise Reduction Coefficient (NRC) of the current row of the worksheet

NRC is calculated as:

`NRC=(alpha_(250)+alpha_(500)+alpha_(1k)+alpha_(2k))/4`

where:

`alpha_(250,500,1k,2k)` is the absorption coefficient in the 250 Hz, 500 Hz, 1 kHz and 2kHz octave bands, respectively.

Comments or suggestions to
strutt@arup.com