Pipe Thread Standards in Industry

 

Mainly there are two thread standards used in most of the manufacturing sector. They are:

1.       NPT (National Pipe Thread) – US standard

2.       BSPT (British Standard Pipe Taper)

The NPT are most used in US and Canada while the BSPT is most popular in Europe, China, and Japan. NPT has taper and straight thread types also called as NPT (tapered) and NPS (Straight). Similarly, BSP also has BSPT (tapered) and BSPP (parallel/straight). The main difference between these two thread standards is the thread pitch angle. NPT has thread angle of 60^o while BSPT has thread angle of 55^o.  And due to this variance in pitch angle these two threads have different pitch (TPI: thread per inch).

The other notations used for thread are:

G - BSP parallel threads, BSPP

R – BSP tapered threads, BSPT (external) * R mates with R_c and R_p and also with G

R_c – BSP tapered threads (internal) *R_c mates with R

R_p – Internal parallel threads, * R_p mates R

R_s – external parallel threads

*G series mates with G series as they are parallel

Note: BSPP is also known as SS, whitworth, G or R_p