1.1 本规程提供了一种方法，用于确定拟安装在地下的聚酰胺-12（PA12）气管的允许拉伸载荷（ATL）值，该方法使用将管道拉入沟槽（切割或犁削）、钻孔、套管等的方法。ATL值考虑了管道尺寸、拉伸屈服强度、管道温度和拉伸载荷持续时间。 1.2 ATL用于设置“薄弱环节”装置的断裂强度，或作为控制用于将PA12气体管道拉入地下位置的设备施加的最大拉力的其他装置的极限设置，或确定牵引设备是否可以施加大于所安装气体管道ATL值的拉力。在拔管设备连接到PA12气管的位置安装了一个弱连接装置。如果牵引负荷超过ATL极限，则装置将管道与牵引设备断开连接。 还使用了限制管道上拉力的其他措施或设备。如果将ATL值与拉入安装设备产生的拉力进行比较，并且设备不能施加大于ATL值的拉力，则不需要使用薄弱环节或其他装置来限制拉力。 1.3 本规程不涉及薄弱环节装置的设计或要求，也不涉及用于限制引入安装期间施加在PA12气管上的拉力的其他设备或程序的设计或要求。 1.4 本规程不涉及PA12气管引入所采用的安装方法或程序。 1.5 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.6 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。 1.7 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 ATL值用于设置弱连接装置的断开强度，或设置用于限制PA12气管引入安装期间拉力的其他设备，或确定牵引设备是否可以施加大于所安装PA12气管ATL值的拉力。 4.2 ATL值在气体管道安装之前确定。

1.1 This practice provides a means to determine an allowable tensile load (ATL) value for a polyamide-12 (PA12) gas pipe that is to be installed underground using methods that pull the pipe into a trench (cut or plowed), bore hole, casing pipe, or the like. The ATL value takes into account pipe size, tensile yield strength, pipe temperature, and pulling load duration. 1.2 The ATL is used to set the break-away strength for a “weak-link” device, or as a limit setting for other devices that control the maximum pulling force exerted by equipment used to pull PA12 gas pipe into an underground location, or to determine if pulling equipment can exert pulling force greater than the ATL value for the gas pipe being installed. A weak-link device is installed where the pipe pulling equipment is connected to the PA12 gas pipe. If pulling load exceeds the ATL limit, the device de-couples the pipe from the pulling equipment. Other measures or equipment that limit the pulling force on the pipe are also used. When the ATL value is compared to the pulling force developed by the pull-in installation equipment, and the equipment cannot exert a pulling force greater than the ATL value, a weak-link or other device for limiting the pulling force is not necessary. 1.3 This practice does not address weak-link device design or requirements, nor does it address the design or requirements for other equipment or procedures used to limit the pulling force applied to PA12 gas pipe during pull-in installation. 1.4 This practice does not address installation methods or procedures employed for pull-in of PA12 gas pipe. 1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.6 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. 1.7 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 The ATL value is used to set the break-away strength of a weak-link device, or to set other equipment used to limit pulling force during pull-in installation of PA12 gas pipe, or to determine if pulling equipment can exert pulling force greater than the ATL value for the PA12 gas pipe being installed. 4.2 The ATL value is determined before gas pipe installation.