FCI 84-1-2019定义了阀门流量系数Cv，该系数通常用于以公制术语计算阀门流量或泄漏（见FCI标准FCI 70-2），以满足人们对公制尤其是国际单位制（SI）日益增长的关注，制定未来的标准，并帮助国际社会接受现有的美国标准。

FCI 84-1-2019 defines the valve flow coefficient Cvcommonly used for the purpose of calculating valve flow capacity or leakage (see FCI Standard FCI 70-2) in metric terminology to meet the growing need for attention to the metric system and the international system of units (SI) in particular, in the preparation of future standards and as an aid to the international acceptance of existing US standards.