ISO 6145包括一系列国际标准，涉及用于制备校准气体混合物的各种动态方法。ISO 6145-2:2014描述了使用活塞泵的方法和制备系统。混合物成分及其相关不确定度基于通过尺寸测量对活塞泵进行校准。 使用该方法制备的标定气体混合物由两种或两种以上的组分组成，这些组分由纯气体或使用气体混合泵的其他气体混合物制备而成。此类气体混合泵包含至少两个活塞泵，每个活塞泵以规定的冲程比驱动，以及用于气体供给和混合物均匀化的适当附件。 ISO 6145-2:2014仅适用于包括腐蚀性气体在内的气体或完全蒸发成分的混合物，只要这些成分既不相互反应，也不与混合泵的湿润表面反应。 还包括气体混合物作为母体气体的使用。本国际标准包括多组分气体混合物和多步稀释程序，因为它们被视为双组分混合物制备的特例。 ISO 6145-2:2014描述了一种制备校准气体混合物的方法，其成分以体积分数表示。必要的方程式和相关的不确定度评估，以表示气体成分的数量？属于物质组分见附录A。 使用该方法，如果采取了充分的质量保证和控制措施，则可以制备体积分数相对扩展不确定度为0.5%（覆盖系数k=2）的标定气体混合物。 附录B至D中给出了表明在规定条件下可获得较小不确定性的数值示例。 使用这种方法，可以以离散增量实现1:10000的稀释比。低馏分（低至1×10？8）可通过多级稀释或使用气体混合物作为输入气体来实现。根据所用设备的不同，可实现5 l/h至500 l/h的最终混合流量。

ISO 6145 comprises a series of International Standards dealing with various dynamic methods used for the preparation of calibration gas mixtures. ISO 6145-2:2014 describes a method and preparation system using piston pumps. The mixture composition and its associated uncertainty are based on calibration of the piston pumps by dimensional measurements. The calibration gas mixtures prepared using this method consist of two or more components, prepared from pure gases or other gas mixtures using gas-mixing pumps. Such gas-mixing pumps contain at least two piston pumps, each driven with a defined ratio of strokes, and appropriate accessories for gas feeding and mixture homogenization. ISO 6145-2:2014 is applicable only to mixtures of gaseous or totally vaporized components including corrosive gases, as long as these components neither react with each other nor with the wetted surfaces of the mixing pump. The use of gas mixtures as parent gases is covered as well. Multi-component gas mixtures and multi-step dilution procedures are included in this International Standard as they are considered to be special cases of the preparation of two-component mixtures. ISO 6145-2:2014 describes a method of preparing calibration gas mixtures whose composition is expressed in volume fractions. The necessary equations and associated uncertainty evaluation to express the gas composition in amount?of?substance fractions are given in Annex A. With this method, provided that sufficient quality assurance and control measures are taken, calibration gas mixtures can be prepared with a relative expanded uncertainty of 0,5 % (coverage factor k = 2) in the volume fraction. Numerical examples showing that under specified conditions smaller uncertainties are attainable are given in Annexes B through D. Using this method, dilution ratios of 1:10 000 can be achieved in discrete increments. Lower fractions (down to 1 × 10？8) can be achieved by multi-stage dilution or by the use of gas mixtures as input gases. Final mixture flow rates of 5 l/h to 500 l/h can be realized depending on the equipment used.