EN ISO 6142-1:2015

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Principle
6 Planning the preparation of the mixture
7 Purity analysis
8 Determination of masses and calculation of
   preparation uncertainty
9 Homogeneity and stability of the calibration
   gas mixture
10 Verification of calibration gas mixture composition
11 Uncertainty of the calibration gas mixture and
   preparation of certificate
Annex A (informative) - Precautions to be taken when
        weighing, handling and filling cylinders
Annex B (informative) - Practical examples
Annex C (informative) - Guidelines for estimating filling
        pressures so as to avoid condensation of
        condensable components in gas mixtures
Annex D (normative) - Liquid introduction
Annex E (informative) - Atomic weights and molar masses
Annex F (informative) - Derivation of the equation for
        calculating the calibration gas mixture composition
Annex G (informative) - Sensitivity coefficients for the
        calculation of the uncertainty of the amount fraction
        of a component
Annex H (informative) - Derivation of the equation for the
        final measurement uncertainty on the calibration
        gas mixture
Bibliography

ISO 6142-1:2015 specifies a gravimetric method for the preparation of calibration gas mixtures in cylinders with traceable values for the amount-of-substance fraction (amount fraction) of one or more components. This part of ISO 6142 describes a method for calculating the uncertainty associated with the amount fraction of each component. This uncertainty calculation requires the evaluation of the contributions to the uncertainty due to factors including the weighing process, the purity of the components, the stability of the mixture, and the verification of the final mixture.ISO 6142-1:2015 is only applicable to mixtures of gaseous or totally vaporized components, which may be introduced into the cylinder in the gaseous or liquid state. Both binary and multi-component gas mixtures (including natural-gas type mixtures) are covered by this part of ISO 6142. Methods for the batch production of more than one mixture in a single process are not included in this part of ISO 6142.ISO 6142-1:2015 requires estimation of the stability of the mixture for its intended life time (maximum storage life), but it is not for use with components that react with each other unintentionally. This part of ISO 6142 also requires the impurities in each parent gas or liquid used in the preparation of the mixture to be assessed and quantified.