ANSI S12.9 (Quantities and Procedures for Acoustical Measurement)

ANSI S12.9 is a standard that defines how to accurately measure and report sound levels in various environments. It provides guidelines for setting up equipment, selecting measurement methods, and calculating noise quantities so that results are consistent, reliable, and comparable. This ensures that acoustical data—such as noise levels from communities, workplaces, or products—is collected systematically, enabling engineers, regulators, and designers to assess and manage noise effectively. The standard helps maintain quality and accuracy in sound assessments across different studies and applications.