Room noise criteria—Time for common sense

Abstract

The acoustical environments of the many types of rooms designed for occupancy are supposed to be established in the design phase of a new project or during a project retro-fit so that the intended use of a room is not compromised by intrusive noise sources. A major tool in accomplishing the desired environment is the application of room noise criteria. However, given the many types of noise sources with a wide range in sound quality, frequency content, and temporal features, it seems impossible to achieve a desired, yet cost effective, acoustical room environment by using venerable noise criteria (NC) curves alone. ANSI S12.2-1995 is an attempt to include the means to account for different characteristics in noise sources by introducing the balanced noise criteria (NCB) and room criteria (RC) methods for evaluating noise. As a result of the introduction of ANSI S12.2-1995, a controversy has arisen over the practicality and even the viability of the new standard(s). The people who must live or work in the designed space will ultimately determine whether an adequate acoustical room environment has been achieved. The economics of the acoustical design often dictates whether a working solution is ever implemented at all. A practical basic criteria with just a handful of adjustment factors and guidelines to account for quality, frequency, and temporal anomalies, would be better suited to standardizing the design methodology in room acoustics. This paper provides examples of applications of standards in the everyday world of environmental acoustics. [See NOISE-CON Proceedings for full paper.]