Noise Criteria Curves: NC
NC-20#2000 to NC-25#250
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-20#2000 | 30 | 19 | 2,000 | NC-20 | recording studio |
| NC | NC-20#250 | 30 | 33 | 250 | NC-20 | recording studio |
| NC | NC-20#4000 | 30 | 17 | 4,000 | NC-20 | recording studio |
| NC | NC-20#500 | 30 | 26 | 500 | NC-20 | recording studio |
| NC | NC-20#63 | 30 | 51 | 63 | NC-20 | recording studio |
| NC | NC-20#8000 | 30 | 16 | 8,000 | NC-20 | recording studio |
| NC | NC-25#1000 | 35 | 27 | 1,000 | NC-25 | hospital |
| NC | NC-25#125 | 35 | 44 | 125 | NC-25 | hospital |
| NC | NC-25#2000 | 35 | 24 | 2,000 | NC-25 | hospital |
| NC | NC-25#250 | 35 | 37 | 250 | NC-25 | hospital |
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