scope:

This International Standard specifies a gravimetric method for the preparation of calibration gas mixtures in cylinders of which the target accuracy of the composition has been pre-defined. It is applicable only to mixtures of gaseous or totally vaporized components which do not react with each other or with the cylinder walls. A procedure is given for a method of preparation based on requirements for the final gas mixture composition to be within preset levels of uncertainty. Multi-component gas mixtures (including natural gas) and multiple dilution mixtures are included in this International Standard and are considered to be special cases of the single component gravimetric preparation method. This International Standard also describes the procedure for verifying the composition of gravimetrically prepared calibration gases. Provided rigorous and comprehensive quality assurance and quality control procedures are adopted during the preparation and validation of these gravimetric gas mixtures, calibration gases of the highest accuracy can be obtained for wide range of gas mixtures, in comparison with other methods of preparing such gases.