ISO 6145-6:20 17规定了一种使用临界流量孔系统从纯气体或气体预混合物动态制备包含至少两种气体（通常其中一种是补充气体）的校准气体混合物的方法。 该方法主要适用于制备非反应性气体混合物，所述非反应性气体混合物不与在临界流孔系统或辅助设备内形成气体回路的任何材料反应。其优点是，如果使用适当数量的临界流动孔，则允许像二元混合物一样容易地制备多组分混合物。 通过选择适当的临界流孔组合，可实现1 × 104的稀释比。 尽管它更特别地适用于在大气压下制备气体混合物，但该方法也提供了在大于大气压的压力下制备校准气体混合物的可能性。上游压力将需要比下游压力高至少两倍。 本文件涵盖的流速范围从1mL/min延伸至10L/min。

ISO 6145-6:2017 specifies a method for the dynamic preparation of calibration gas mixtures containing at least two gases (usually one of them is a complementary gas) from pure gases or gas pre-mixtures using critical flow orifices systems. The method applies principally to the preparation of mixtures of non-reactive gases that do not react with any of the materials forming the gas circuit inside the critical flow orifices system or auxiliary equipment. It has the merit of allowing multi-component mixtures to be prepared as readily as binary mixtures if an appropriate number of critical flow orifices are used. By selecting appropriate combinations of critical flow orifices, a dilution ratio of 1 × 10⁴ is achievable. Although it is more particularly applicable to the preparation of gas mixtures at atmospheric pressure, the method also offers the possibility of preparing calibration gas mixtures at pressures greater than atmospheric. The upstream pressure will need to be at least two times higher than downstream pressure. The range of flow rates covered by this document extends from 1 ml/min to 10 l/min.