National Pipe Thread

Tube with NPT thread

The National Pipe Thread ( NPT thread , NPT pipe thread ) according to ASME / ANSI B1.20.1 is a US thread standard for self-sealing pipe fittings .

The seal is achieved in that the threads are tapered. When conventional pipe threads are screwed together, a sealant (e.g. Teflon tape , hemp ) is also placed between the threads. In contrast, the National Pipe Thread - Dryseal Form ( NPTF thread , NPTF pipe thread ) according to ASME / ANSI B1.20.3 does not require any sealant. Occasionally, NPT threads are also referred to as MPT (Male Pipe Thread) or FPT (Female Pipe Thread) and also as MIP (Male iron pipe) and FIP (Female iron pipe).

Compared to the Whitworth thread , also called British Standard Pipe (BSP or BSPT), the diameter, number of threads (pitch in threads per inch) and taper angle are slightly different, so that the two threads cannot be screwed together. For example, the number of threads for the 1/4 "NPT is 18 G, for the 1/4" Whitworth 19 G, and for the 1/4 "tripod thread 20 G.