Abstract:

There has been much controversy in recent years regarding the various room noise criteria that have been proposed and are in use today. Included in these criteria are the NC curves, the PNC curves, the RC curves, and most recently, the NCB curves. The NR curves, which are commonly used in Europe, must also be mentioned. The recent adoption of ANSI S12.2 has not resolved the controversy---in fact, it has actually heightened the debate because it acknowledges two room noise criteria (RC and NCB) that are clearly at odds with each other in the low-frequency region. This paper examines the limitations of each method (RC and NCB) and provides possible suggestions for modifications that might create a path for eventual resolution of this controversy. This paper also emphasizes the important characteristics of any room criteria method: it must be as simple as possible without sacrificing effectiveness, relatively easy to measure, and credible from the standpoint of human perception. In any event, it is the opinion of the author that any resolution will have to await the completion of the ASHRAE research project which is currently in progress in Australia. [See NOISE-CON Proceedings for full paper.]