ISO 13347-4:2025

This document specifies a method to measure sound power by using sound intensity measurements on a measurement surface which encloses the sound source. This document provides guidelines on the acoustical environment, ambient noise, measurement surface, and number of measurements. The installation categories are generally designed to represent the physical orientation of a fan installed in accordance with ISO 5801, ISO 13350 and also defined in ISO 13349-1. This document is applicable to fans defined in ISO 5801 and ISO 13349-1. This document is limited to the determination of airborne sound emission for the specified installation categories. Vibration is not measured, nor is the sensitivity of airborne sound emission to vibration effects determined. The sizes of the fan, which can be tested in accordance with this document are limited only by the practical aspects of the test installations.