Threads per inch, pitch and diameter for the two thread standards used on TUPY Brazil pipe fittings: BSP (British Standard Pipe, 55° Whitworth form to ISO 228 / ISO 7) and NPT (American, 60° form to ASME B1.20.1). To tell a taper thread from a parallel one and identify a size with a caliper, see the BSP thread identification guide.
Nominal reference values. BSP to ISO 228-1; NPT to ASME B1.20.1. Confirm critical dimensions against the current standard.
BSP and NPT look similar but are not interchangeable: the thread angle (55° vs 60°) and the threads per inch differ at most sizes, so forcing one into the other damages the thread and leaks. TUPY supplies fittings in both BSP and NPT - state which you need when you request a quote. For weights and carton quantities use the fitting weight calculator; for the full figure and size range see all fittings.
11 threads per inch, a pitch of 2.309 mm, in the 55° Whitworth form to ISO 228.
BSP is a 55° Whitworth form (ISO 228 / ISO 7); NPT is a 60° form (ASME B1.20.1). The TPI differs at most sizes, so they are not interchangeable.
14 TPI, pitch 1.814 mm, on a pipe outside diameter of 21.34 mm.
