Noise concrete* nc·vs guilty connector* gxcx·/ mod ros / f*p - untitled - Noise control -

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Room Noise (NC, RC, NCB)
Noise in buildings is more stable (over time) than outside community noise. The maximum acceptable background noise level generated by the mechanical systems in buildings is usually specified in terms of average A-weighted sound levels, NC, RC, or NCB.
The noise criteria (NC) values are determined from the measurements of the octave-band sound levels in an occupied room when the air-conditioning system is on. The measured values are then compared to standard NC curves.
The room criterion (RC) is mostly used for acoustical design of HVAC systems. The RC criteria take into account the noise components at the lowest and the highest frequencies. The measurement values should be taken in an unoccupied room.
Another criterion called balanced noise criterion (NCB) has been recently standardized and has concepts similar to NC and RC. The sound level measurements for NCB should be taken in an occupied room. The RC and NCB ratings include procedures for checking different factors such as the rumble compliance (excessive noise at frequencies below 500 Hz) and the hiss compliance (excessive noise at frequencies above 1000 Hz). Main Page - General Concepts - Room Acoustics - Lighting Definition - Interior Lighting - Sound Systems - Multichannel Audio