1.1 本规范规定了螺纹塑料管和配件上使用的锥形管螺纹的尺寸和测量要求。 1.2 符合本规范的螺纹只能用于制造商认为合适的塑料材料。 1.3 本规范不包括特殊螺纹或不需要密封接头的螺纹。 注1: 术语“扳手装配”和“扳手拧紧”是紧密性的标准术语，并不意味着使用管道扳手或其他会损坏塑料管道和配件的工具。术语“手紧”和“手紧啮合”仅指螺纹测量（非管道和管件连接），是 L 1. 标距。 1.4 螺纹名称- 根据ANSI/ASME B 1.20.1，本规范中包括的管螺纹类型通过按顺序指定标称管道尺寸、每英寸螺纹数和螺纹系列符号来指定: 3. / 8. -18 NPT。对于左侧螺纹，将LH添加到名称的末尾，否则将理解右侧螺纹。例如: 3. / 8. -18 NPT-LH。 1.4.1 符号中的每个字母都有明确的意义，如下所示: N = 国家（美国标准） P = 管 T = 变尖 1.5 以英寸-磅为单位的数值应视为标准值。本标准不包括其他计量单位。 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。 有关具体预防说明，请参阅 7.2.1 和 8.3 . 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。

1.1 This specification establishes requirements for dimensions and gaging of taper pipe threads used on threaded plastic pipe and fittings. 1.2 Threads meeting this specification shall only be used on those plastic materials deemed suitable by the manufacturer. 1.3 Specialty threads or threads not requiring a leak-tight joint are not covered in this specification. Note 1: The terms “wrench makeup” and “wrench tight” are standard terminology for tightness and do not imply using a pipe wrench or other tools which would damage plastic pipe and fittings. The terms “hand-tight” and “hand-tight engagement” refer only to thread gaging (not pipe and fitting connections) and is the definition of the L 1 gage length. 1.4 Thread Designations— The type of pipe threads included in this specification are designated by specifying in sequence the nominal pipe size, number of threads per inch, and the thread series symbols as follows in accordance with ANSI/ASME B 1.20.1: 3 / 8 -18 NPT. For left-hand threads add LH to the end of the designation, otherwise right-hand threads will be understood. For example: 3 / 8 -18 NPT-LH. 1.4.1 Each of these letters in the symbol has a definite significance as follows: N = National (American Standard) P = Pipe T = Taper 1.5 The values stated in inch-pound units are to be regarded as the standard. No other units of measurement are included in this 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. For specific precautionary statements, see 7.2.1 and 8.3 . 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.