Foreword

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This document was prepared by Technical Committee ISO/TC 158, Analysis of gases, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 238, Test gases, test pressures, appliance categories and gas appliance types, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This third edition cancels and replaces the second edition (ISO 6143:2001), which has been technically revised.

The main changes are as follows:

— update of definitions, in particular those taken from the VIM;
— update of the bibliography and the corresponding references in the text;
— update of the information in Annex C on the computer programme B_LEAST; information on alternative software (Annex D);
— amendment of 6.2 (now 7.2) “Comparison of several calibration gas mixtures” and related statements in other parts of the document
— amendment of the recommendations concerning the number of replicate measurements per sample;
— revision of the requirements for the report of results (“Test report”);
— new Annex D (informative) “Additional information on data evaluation”;
— deletion of A.1 “Uncertainty specifications for reference gas mixtures”;
— additional references to relevant ISO standards (ISO 12963, ISO 14912, ISO 15796);
— correction of Formula (4) for the power functions.
— recommendation added to Annexes B and C not to use B_LEAST for evaluations using the exponential function (due to recently demonstrated errors) or to calculate the parameter uncertainties (standard uncertainties and covariances) separately.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

ISO 6143:2025

Gas analysis. Comparison methods for determining and checking the composition of calibration gas mixtures

Current

Published:

12 Jun 2025