Thread Type

Understanding Plumbing Thread Types:

BSP – British Standard NPT – American Standard

The American standard for tapered or parallel threads have a thread flank angle of 60 degrees.

The British standard for tapered or parallel threads have a threaf flank angle of 55 degrees.

Identification can also be made by inspecting the root and crest of the threads. the truncation of the root and crest of American threads are flat. The truncation of root and crest of British standard threads are round