本文件规定了用于在压力下输送原水、饮用水和污水的球墨铸铁管长度的计算方法。 该计算方法考虑了所有常见的管道路线变化，包括管道本身直径和管道末端死端的变化、管道外径、系统测试压力（用于估算推力）、覆盖深度、管道周围土壤的特性以及全球使用的管沟回填方法。本文件未涵盖受约束接头的特性，但也可以考虑使用任何适当的方法确定约束长度。 本文件中定义的计算方法适用于所有类型的约束接头系统，其球墨铸铁管道的工作压力额定值符合ISO 2531、ISO 7186和ISO 16631。 注？1？ISO 10804涉及管道各种工作压力下接头的实际设计。 注？2？可以使用国家标准或既定的计算方法代替本ISO标准。

This document specifies a computation method used to determine the length of the ductile iron pipes to be restrained, when used for conveying raw water, drinking water, sewerage under pressure. This computation method takes into account all common pipeline route changes, including changes in the diameter of the pipeline itself and dead ends at the extremity of the pipeline, the outside diameter of the pipe, the system test pressure (to estimate the thrust), depth of cover, the characteristics of the soil surrounding the pipe and trench backfilling methods for a worldwide usage. The characteristics of the restrained joint are not covered by this document but can also be considered to determine the restraining length using any appropriate method. The computation method defined in this document is applicable to all types of restrained joint systems, with their operating pressure ratings of ductile iron pipelines complying with ISO 2531, ISO 7186 and ISO 16631. NOTE？1？ISO 10804 deals with actual design of the joint for various operating pressures of the pipeline. NOTE？2？National standards or established calculation methods can be used instead of this ISO standard.