This 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 Standard and are considered to be special cases of the single component gravimetric preparation method.
This Standard also describes the procedure for verifying the composition of gravimetrically prepared calibration gases. Calibration gases of the highest accuracy can be obtained for a wide range of gas mixtures, in comparison with other methods of preparing such gases.
Foreword I
1 Scope
2 Normative References
3 Principle
4 Preparation of the Mixture
5 Calculation of Uncertainty
6 Verification of Calibration Gas Mixture Composition
7 Test Report
Appendix A (Informative) Practical Example
Appendix B (Informative) Guidelines for Estimating Filling Pressures so as to Avoid Condensation of Condensable Components in Gas Mixtures
Appendix C (Informative) Precautions to be Taken When Weighing, Handling and Filling Cylinders
Appendix D (Informative) Derivation of the Equation for Calculating the Calibration Gas Mixture Composition
Appendix E (Informative) Sources of Error
Appendix F (Informative) Estimation of Corrections and Correction Uncertainty
Appendix G (Informative) Computer Implementation of Recommended Methods
Bibliography
