This document gives detailed information regarding the evaluation of uncertainty for the photometric reference measurement procedure specified in ISO 8655‑8 and the photometric procedure specified in ISO 8655‑7:2022, Annex B according to ISO/IEC Guide 98‑3.

This document also describes the determination of other uncertainty components related to the liquid delivery process of a piston-operated volumetric apparatus (POVA), e.g. repeatability and handling. Furthermore, it provides examples for the calculation and application of the uncertainty of the mean delivered volume and the uncertainty in use of a single delivered volume.