Metrics for acoustical measurements in North America

Abstract

The primary source of standards for acoustical measurements in buildings and community noise for North America is ASTM E33 on Building and Environmental Acoustics. This paper focuses on the ASTM E33 standards and the metrics generated. There are six major categories of standards, Sound Absorption, Speech Privacy, Sound Transmission, Application of Materials and Systems, Mechanical and Electrical Noise, and Community Noise. The most familiar metrics include NRC, STC, and IIC, but there is an alphabet soup of metrics including AC, AI, AOITC(θ), ANISPL, ATL, CNEL, FSTC, NIC, and OINIC. Many of these are variations of the basic measurements targeting a specific measurement environment. This paper focuses on the basic measurements and how the metrics are calculated and then gives a broad overview of the range of variations and specialized test methods available through ASTM Committee E33 standards.