Noise Criteria Curves: NC
NC-50#4000 to NC-55#500
Noise Criteria (NC) and Room Criteria (RC) curves for HVAC acoustics design. NC curves per ANSI S12.2-2008 from NC-15 through NC-70 (12 curves), and RC Mark II curves per ASHRAE from RC-25 through RC-50 (6 curves). Each curve has 8 octave band center frequencies (63-8000 Hz) with maximum allowable sound pressure levels in dB. Includes recommended occupancy type and equivalent dBA background noise level. 144 records total.
| criterion type | curve point | background noise dBA equivalent (dBA) | max sound pressure level dB (dB) | octave band center Hz (Hz) | rating | recommended occupancy |
|---|---|---|---|---|---|---|
| NC | NC-50#4000 | 60 | 48 | 4,000 | NC-50 | retail |
| NC | NC-50#500 | 60 | 54 | 500 | NC-50 | retail |
| NC | NC-50#63 | 60 | 71 | 63 | NC-50 | retail |
| NC | NC-50#8000 | 60 | 47 | 8,000 | NC-50 | retail |
| NC | NC-55#1000 | 65 | 56 | 1,000 | NC-55 | factory |
| NC | NC-55#125 | 65 | 67 | 125 | NC-55 | factory |
| NC | NC-55#2000 | 65 | 54 | 2,000 | NC-55 | factory |
| NC | NC-55#250 | 65 | 62 | 250 | NC-55 | factory |
| NC | NC-55#4000 | 65 | 53 | 4,000 | NC-55 | factory |
| NC | NC-55#500 | 65 | 58 | 500 | NC-55 | factory |
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