1.1 本规程涵盖了根据规范制造的地下垂直钢筋圆形预制混凝土人孔和部件的规划、现场准备、安装、测试和回填过程中应遵循的程序 C478/C478M 用于下水道、排水和供水工程。 1.2 本规程不包括混凝土管涵和箱涵。此外，规范中涵盖的预制混凝土公用设施结构 C858 被排除在本惯例之外。 1.3 单位- 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。 每个系统中规定的值不一定是精确的等价物；因此，为确保符合本标准，每个系统应独立使用，且两个系统的值不得组合。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本规程可供业主和/或工程师在编制项目规范时参考。 4.2 本规程可供业主、工程师或安装承包商参考，以正确安装预制混凝土圆形人孔。

1.1 This practice covers the procedures to be followed in the planning, site preparation, installation, testing and backfilling of underground vertical reinforced circular precast concrete manholes and components manufactured in accordance with Specification C478/C478M and used in sewer, drainage, and water works. 1.2 Concrete pipe and box culverts are not covered under this practice. Also, precast concrete utility structures covered in Specification C858 are excluded from this practice. 1.3 Units— The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This practice is useful as a reference by an owner and/or the engineer in preparing project specifications. 4.2 The practice is useful as a reference by an owner, engineer, or installing contractor to properly install precast concrete circular manholes.