How To Distiguish BSP, BSPP, BSPT, NPT

What’s the difference between BSP, BSPP & BSPT and NPT?

And Which Seal Do You Need?

Some people are confused about BSP, BSPP & BSPT, NPT.

There are two sets of standards that govern pipe threads: National Pipe Thread (NPT) and British Standard Pipe (BSP). These standards stipulate the types of screw threads used to connect and seal pipe fittings together.

BSP thread is the most popular in the UK, Europe, Australia, New Zealand, Asia, Middle East and South Africa (most countries worldwide)

NPT thread is common in the United States, Canada

BSP includes BSPP & BSPT thread, which has a 55 degree angle.

BSPP Thread

BSPP is also called G thread, which is the straight(parallel) thread. To form a seal or connection by washer or O-ring on the boss.

BSPT Thread

BSPT is a taper thread, it creates a seal by thread.

Both Threads have the same pitch and angle of 55 degrees.

Tapered males can fit parallel or tapered females, according to the golden rule.

That is, a BSPT (tapered) male thread can fit both a BSPT (tapered) and a BSPP (parallel) female since the taper of the male will fit equally into a cylindrical thread. In the case of using a tapered tap on a parallel female, sealing material is recommended to ensure the   tightness of the joint.

However, a BSPP (parallel) male thread will only fit into a cylindrical (BSPP) female thread, as it will be impossible to fit into a tapered recess.

NPT thread

NPT is National Pipe Tapered threads, which has a 60 degree angle, also known as ANSI/ASME B1.20.1 pipe threads. It is a U.S. standard for measuring tapered threads on threaded pipes and fittings. NPT threads are tapered in both female and male.

Welcome to contact us to choose which seal you need.