ANSI B1.20.3 — DRYSEAL PIPE THREADS

The American National Standard officially provides all applicable requirements to the dry seal pipe threads. Subject threads are based on the American pipe thread but they significantly differ from USA pipe thread because they are commonly designed to seal the pressure tight joints without having top use additional sealing components. In order to accomplish this purpose, some modification shall be made to the form of the thread and greater manufacturing accuracy shall be reached.

The roots of the internal and external threads truncate more than crests so their flats are slightly wider than crests. This results in the metal to metal contact occurring at the roots and crests either at the time of flank contact or prior to that... This document addresses different types of threads, notations and designations, applications, assembly limitations, tolerances and forms, basic dimensions of the threads and many other information and data.

Three appendices deal with the symbols and formulas, suggested tap drill sizes, specific pipe threads such as special and special-extra short and others. Data tables at the end of the standard provide additional information on basic dimensions, recommended assembly limitations etc.