Introduction

It is necessary to know the sealing types which used in thread joint, when we working in pipe industry. There are two common types, NTP( National Pipe Thread) and BSP(BS Standard pipe ). both of the two types are widely used in pipeline, oil industry, gas industry, manufacturing industry and many other industries. But the main different decide the way and scope of their use. So, for fresher of industrial pipe fittings, it’s very important to know the differences, to make sure the safety of pipeline.

In this introduction, we will show the sealing types of NPT and BSP. You can learn about the differences between them, and when to use any of them.

What is an NPT Seal?

NPT seals are made from National Pipe Thread and widely used in American and Canada pipe line system. The shape of NPT thread id tapered, that means, when the threads are screwed together, they can form a tight seal. The NPT thread is 60 degrees, and the peaks and troughs are flat. This has the advantage of inserting a thread into another thread to create a leak-proof connection.

How NPT Seals Work

NPT seals rely on the mechanical interaction between the tapered threads, which create a seal by pressing tightly together as the components are screwed in. To further improve the seal, a thread sealant (such as PTFE tape or pipe dope) is often used.

What is a BSP Seal?

BSP is according to British Standard pipeline. It is widely selected and used in Europe, Australia, and a lot of other countries. There are two variants of BSP: BSPT (conical) and BSPP (parallel). The main differences between BSP and NPT is the the thread angle and sealing methods.
BSPT thread is the same as NPT, they are all tapered. But the thread angle of BSPT is 55 degree, the peaks and valleys of the thread are circular, not flat.

How BSP Seals Work

Different from NPT, BSP seal fittings are usually matched rubber washers or O-ring at the bottom of the fittings, which can prevent leaking between the threads. But BSPT connections are relying on tightening threads to form a reliable seal,rather than any other sealant.

Key Differences Between NPT and BSP Seals

It’s essential that to understand the differences between NPT and BSP. The following are the main differences between them:

1. Thread Angle

NPT Threads: Thread angle is 60 degree, have flat peaks and valleys.

BSP Threads: Thread angle is 55 degree ,have rounded peaks and valleys.

2. Sealing Method

NPT Seals: Seal is formed by mechanical wedging through threads. Usually, thread sealant or PTFE adhesive is needed to increase safety.

BSP Seals: Sealing is ensured through compression of tapered threads, usually sealed with rubber gaskets or O-rings. BSPP seal fittings require gaskets or washers.

3. Thread Form

NPT: Tapered threads

BSPT: tapered thread with different pitches

BSPP: Parallel threads are usually sealed with gaskets

4. Compatibility

Compatibility between NPT and BSP:NPT and BSP cannot replace each other in use. Although NPT external thread fittings can be installed into BSPT fittings, they do not provide proper sealing due to differences in pitch, angle, and shape.

Common Applications of NPT and BSP Seals

Each thread type is suitable for different sets of applications. Choosing appropriate seals in industrial settings can ensure the reliability and safety of the system.

NPT Applications

NPT threads are commonly used in the following applications in the Americas:

1.Pipeline systems for residential and commercial buildings.
2.Oil and gas pipelines.
3.Automobiles and industrial equipment.

BSP Applications

BSP threads are commonly used in Europe and other countries , especially in:

1.Piping and HVAC systems.
2.Hydraulic and pneumatic applications.
3.Industrial machinery and equipment.

How to Identify NPT and BSP Threads

Maybe, it’s hard to distinguish NPT and BSP thread, so you can refer to the following aspects to confirm:

1.By thread Angle: Use a pitch gauge to measure the angle between threads.
60 degrees is NPT
55 degrees is BSP

2.Appearance inspection: NPT threads have flat peaks and valleys, but BSP threads have circular peaks and valleys.

3.Check accessories: Although NPT and BSP threads may look similar, they are incompatible, so be careful when attempting to assemble them together.

Which Seal Should You Use?

How to choose between NPT and BSP? This depends on the geographical location, type of pipeline, and specific requirements. Here is a quick guide to help you make a decision:

Choose NPT: In the North American region, the preferred mechanical seal that requires additional sealant is NPT seals.

Choose BSP:In Europe and other regions, BSP is generally chosen, and in systems that use O-rings or gaskets for sealing, BSP must be selected

Summary

In total, it’s important to know the differences between NPT and BSP seals , such as sealing angles, types and regional preference. The 60 degree threaded angle is designed for NPT which sealed depending on wedge thread. The 55 degree thread angle is designed for BSP, which sealed depending on rubber washer or O-ring. According to theses differences, we can choose the sealing threaded pipe connections.

If you work in the industrial equipment or piping, it’s necessary to know the two types of thread to make sure your systems leak-free and functioning properly.

If you have any questions about this , you can check the standards or contact us.