1.1This specification establishes requirements for dimensions and gaging of taper pipe threads used on threaded plastic pipe and fittings.

1.2Threads meeting this specification shall only be used on those plastic materials deemed suitable by the manufacturer.

1.3Specialty threads or threads not requiring a leak-tight joint are not covered in this specification.

1.4Thread 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.

1.5The values stated in inch-pound units are to be regarded as the standard. No other units of measurement are included in this standard.

1.6This 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.

1.7This 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.