National Pipe Thread (NPT)
- American National Standard Pipe Thread standards, often called national pipe thread standards for short, are U.S. national technical standards for screw threads used on threaded pipes and pipe fittings. They include both tapered and straight thread series for various purposes including rigidity, pressure-tight sealing, or both.
History
In 1864, William Sellers, the president of Franklin Institute, presented a standard for nuts, bolts, and screws. Out of this effort came the first United States Standard threads, including pipe threads.