NPT - National Pipe Taper
American National Pipe Taper (NPT), Like British Standard Pipe (BSP), is designated by trade size, rather than actual diameter, as shown in the NPT/NPS Table.
NPT threads are also sometimes referred to as
- MIP (Male Iron Pipe)
- FIP (Female Iron Pipe)
- IPT (Iron Pipe Thread)
- FPT (Female Pipe Thread)
- MPT (Male Pipe Thread)
Note that these are casual references.
NPT threads have a 60° included angle and have flat peaks and valleys (this is a Sellers thread form).