SR EN ISO 14912:2025

This document defines the following quantities commonly used to express the composition of gas mixtures: —     amount fraction and concentration; —     mass fraction and concentration; —     volume fraction and concentration. For these quantities of composition, this document specifies methods for: —     conversion between different quantities; —     conversion between different state conditions. Conversion between different quantities means calculating the value of the content of a specified component in terms of one of the quantities listed above from the value of the same content, at the same pressure and temperature of the gas mixture, given in terms of another of these quantities. Conversion between different state conditions means calculating the value of the content of a specified component, in terms of one of the quantities listed above, under one set of state conditions from the value of the same quantity under another set of state conditions, i.e., pressure and temperature, of the gas mixture. Gas mixture composition can be converted simultaneously between different quanti