ISO 21238:2007给出了经验确定比例因子的通用基本方法指南，以评估中低水平放射性废物包装中难以测量的核素的放射性。 ISO 21238:2007给出了在使用水冷反应堆的核电厂中产生的污染废物的特性描述中使用的比例因子的通用指南。ISO 21238:2007也适用于其他类型的反应堆，如气冷反应堆。ISO 21238:2007未涵盖基于理论考虑（即不基于实验测量）确定比例因子的方法。

ISO 21238:2007 gives guidelines for the common basic methodology of empirically determining scaling factors to evaluate the radioactivity of difficult-to-measure nuclides in low- and intermediate-level radioactive waste packages. ISO 21238:2007 gives common guidelines for the scaling factors used in the characterization of contaminated wastes produced in nuclear power plants with water-cooled reactor. ISO 21238:2007 is also relevant to other reactor types, such as gas-cooled reactors. Methodologies for determining scaling factors based on theoretical considerations (i.e. not based on experimental measurement) are not covered by ISO 21238:2007.