ISO 6145-4:20 04规定了一种通过借助注射器将校准组分连续注射到互补气流中，从纯气体或其它气体混合物连续生产包含两种或更多种组分的校准气体混合物的方法。 如果使用预混合气体代替纯气体（见附录A），则可以获得低得多的体积分数。可以根据各个流速计算确定体积分数的体积流速，并且可以通过ISO 6145-1中给出的合适方法独立地测量。 该方法的优点在于，可以在连续的基础上制备大量的气体混合物，并且如果使用适当数量的注射器，或者如果注射器已经包含多组分混合物，则可以几乎与二元混合物一样容易地制备多组分混合物。已知组成的组分混合物。该方法还提供了以小步骤增加混合物中校准组分的体积分数的便利手段。因此，它是评估气体分析仪其他特性（例如最小检测限和死区以及准确性）的有用方法。二元混合物（覆盖率为2）可获得的体积分数的相对扩展不确定度为5%，适用范围为10-5至10-2。

ISO 6145-4:2004 specifies a method for continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by continuous injection of the calibration component(s) into a complementary gas stream by means of a syringe. If pre-mixed gases are used instead of pure gases (see Annex A), much lower volume fractions can be obtained. The volume flow rates, from which the volume fractions are determined, can be calculated from the individual flow rates and can be independently measured by a suitable method given in ISO 6145-1. The merits of the method are that a substantial quantity of the gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared almost as readily as binary mixtures if the appropriate number of syringes is utilized, or if the syringe already contains a multi-component mixture of known composition. This method also provides a convenient means for increasing the volume fraction of the calibration component in the mixture in small steps. It is therefore a useful method for evaluation of other characteristics of gas analysers, such as minimum detection limit and dead zone, as well as accuracy. The relative expanded uncertainty in the volume fraction obtainable for a binary mixture (at a coverage factor of 2) is 5 % and the range of applicability is 10^-5 to 10^-2.