What is the NPT Thread?
NPT (National Pipe Thread) is an American standard taper thread that features a specific taper angle, sealing achieved through extrusion between threads.
NPT thread belongs to the ANSI/ASME B1.20.1 standards.
The NPT thread is widely used in America, parts of the Middle East, water heat, fire sprinkler, petrochemical, and gas industries.
What is BSPT Thread?
BSPT (British Standard Pipe Taper Thread) is a British Standard taper pipe thread. The BSPT thread executive standard is ISO 7-1/BS 21.
The BSPT thread is a type of taper thread, similar to the NPT thread, but it differs in tooth profile angle, sealing method, and pitch. The BSPT thread is one of the widely used pipe threads globally, especially in Asia, Europe, the Middle East, and Australia.
Features of BSPT Thread VS. NPT
| NPT Thread | BSPT Thread | |
|---|---|---|
| Taper | 1:16 taper | 1:16 taper |
| Thread Angle | 60° V-thread angle (standardized with general American threads) | 55° rounded tooth peaks/roots (Whitworth threads) |
| TPI (Example) | 1/2" NPT：14 TPI | 1/2" BSPT → 11 TPI |
The 60° V-thread angle of the NPT thread and the 55° of the BSPT thread are key differences between BSPT and NPT.
NPT and BSPT pipes cannot be used interchangeably due to their differences in TPI (Threads Per Inch), tooth angles, and shapes.
NPT threads, whether female or male, are all taper threads; but, with BSPT threads, the male thread is tapered, and the female threads are parallel or tapered.
To ensure compatibility, the NPT female thread must be connected to NPT male thread fittings, while the BSPT female thread must be connected to BSPT male thread fittings. This guarantees that the pipeline system is properly connected, compatible, and sealed.
FAQ
How can you choose the most suitable one for your project?
NPT pipe and NPT fittings are commonly used in American petroleum projects, while BSPT pipe and BSPT fittings are prevalent in European hydraulic systems.
