This second edition of IEC 61672-3 describes procedures for periodic testing of time-weighted sound level meters, integrating-averaging sound level meters and integrating sound level meters designed to meet IEC Class 1 or Class 2 specifications 61672-1. The purpose of this standard is to ensure that periodic testing is performed consis ently by all laboratories.
NF S31-009-3*NF EN 61672-3:2014 Referenced Document
ISO/IEC GUIDE 98-3 Uncertainty of measurement - Guide to the expression of uncertainty in measurement (GUM:1995). Extension to any number of output quantities