ISO 12999-2:2020

This document specifies how to calculate:
- the uncertainty of sound absorption coefficients and equivalent sound absorption areas measured according to ISO 354;
- the uncertainty of the practical and weighted sound absorption coefficients determined according to ISO 11654;
- the uncertainty of the object sound absorption coefficient according to ISO 20189; and
- the uncertainty of the single number rating determined according to EN 1793-1.
Furthermore, the use of uncertainties in reporting measured or weighted sound absorption coefficients is explained.