The difference between NPT vs. BSP threads has more to do with where you live than their applications. NPT and BSP are pipe thread standards for screw threads used on pipes and pipe fittings to seal pipes.
BSP – UK, Europe, Asia, Australia, New Zealand, and South Africa (most countries worldwide)
NPT – United States, Canada
Both threads have the same pitch and familiar-shaped peaks and valleys. However, the designs of the threads differ in two fundamental ways. With NPT, the peaks and valleys of the threads are flat. In BSP, they are rounded. Secondly, the NPT angle of the thread is 60 degrees, and the BSP angle is 55 degrees. (more…)