ISO 91:2017是指温度体积修正系数，允许用户将在环境条件下测得的体积转换为参考条件下的体积，以用于交易目的。本文件还提到了将压力下测得的碳氢化合物体积修正为测量温度下平衡压力下相应体积所需的压缩系数。

ISO 91:2017 refers to temperature volume correction factors, which allow users to convert volumes, measured at ambient conditions, to those at reference conditions for transactional purposes. This document also refers to compressibility factors required to correct hydrocarbon volumes measured under pressure to the corresponding volumes at the equilibrium pressure for the measured temperature.