BSPT vs. NPT — What's the Difference?
By Tayyaba Rehman & Fiza Rafique — Published on May 13, 2024
BSPT (British Standard Pipe Taper) threads are used for sealing pressure-tight joints by mating with compatible threads, common in systems requiring a hydraulic seal in the UK and Europe. NPT (National Pipe Taper) threads, used predominantly in the US.
Difference Between BSPT and NPT
Table of Contents
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Key Differences
BSPT threads, defined by the British Standard, are designed for pipes and fittings creating a pressure-tight seal without the need for an additional sealing mechanism. They have a thread angle of 55 degrees and are commonly found in water and gas piping systems outside of North America.
NPT threads, adhering to the American National Standard, have a 60-degree thread angle and are standard for plumbing and industrial applications in the United States, often requiring Teflon tape or pipe dope to ensure a leak-proof seal.
The difference in thread angles between BSPT and NPT (55 degrees for BSPT vs. 60 degrees for NPT) affects the compatibility and sealing capability of fittings from these two systems. This means that while they may sometimes be physically joined, a proper seal is not guaranteed without the use of adapters or sealants.
BSPT fittings are tapered similarly to NPT fittings to ensure a tight seal, but the difference in pitch and angle means they are not directly interchangeable. For a secure fit, appropriate matching of threads or the use of suitable adapters is essential.
BSPT threads are often used in applications where a hydraulic seal is critical, such as in the petrochemical, automotive, and construction industries in Europe and Asia. NPT threads find their application across a broad range of industries in the U.S., including manufacturing, oil and gas, and agriculture, where a secure, pressure-tight seal is necessary for efficient and safe operations.
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One notable subtype of BSPT is the BSPP (British Standard Pipe Parallel), which has parallel threads and is used where a pressure-tight seal is not required on the threads. In contrast, all NPT threads are tapered, highlighting the importance of understanding the specific requirements of a piping system when selecting fittings.
Comparison Chart
Thread Angle
55 degrees
60 degrees
Common Usage
UK, Europe, and Asia
United States
Sealing Mechanism
Pressure-tight seal without additional sealant
Often requires Teflon tape or pipe dope for a leak-proof seal
Applications
Water, gas, and hydraulic systems
Plumbing, industrial, and agricultural applications
Compatibility
Not directly interchangeable with NPT
Not directly interchangeable with BSPT
Compare with Definitions
BSPT
Common in the UK, Europe, and Asia for plumbing and industrial applications.
Our equipment uses BSPT threads to comply with European standards.
NPT
Teflon tape or pipe dope is often necessary for sealing.
To prevent leaks, we applied pipe dope to the NPT threads.
BSPT
Requires precise matching for a pressure-tight connection.
Ensure the threads match exactly to avoid cross-threading and leaks.
NPT
NPT threads are a standard in the US for creating pressure-tight seals in plumbing.
All plumbing fittings must use NPT threads to meet code.
BSPT
Not directly interchangeable with NPT without adapters.
We needed an adapter to connect the BSPT valve to our NPT system.
NPT
They have a 60-degree thread angle, requiring sealant for a leak-proof connection.
Apply Teflon tape to the NPT threads before installation.
BSPT
They feature a 55-degree thread angle for effective sealing.
BSPT's 55-degree angle ensures a reliable seal in high-pressure systems.
NPT
Widely used in industrial and agricultural applications across the US.
The irrigation system uses NPT fittings for all connections.
BSPT
BSPT threads are designed to create a tight seal in hydraulic and pneumatic systems.
The hydraulic lines were secured with BSPT fittings to prevent leaks.
NPT
Adapters are required to connect with BSPT threads.
An NPT to BSPT adapter was used to integrate the imported pump.
Common Curiosities
Can BSPT and NPT threads be used together?
They are not directly compatible due to differences in angle and pitch, though adapters can be used to connect them.
Do BSPT connections require sealant?
Generally, BSPT connections can form a pressure-tight seal without additional sealants, unlike NPT connections, which often require Teflon tape or pipe dope.
What is BSPT?
BSPT stands for British Standard Pipe Taper, a type of threaded connection used to seal pipes in hydraulic systems.
What is the thread angle of NPT?
NPT threads have a 60-degree angle.
How do BSPT and NPT differ?
The main differences are in thread angle (55 degrees for BSPT vs. 60 degrees for NPT) and usage regions (BSPT is common in the UK, Europe, and Asia, while NPT is used in the US).
Is a sealant always required for NPT threads?
While not always required, Teflon tape or pipe dope is commonly used with NPT threads to ensure a leak-proof seal.
What is the thread angle of BSPT?
BSPT threads have a 55-degree angle.
Why might one choose BSPT over NPT, or vice versa?
The choice often depends on regional standards and the specific requirements of the plumbing or hydraulic system.
What is NPT?
NPT stands for National Pipe Taper, a standard for tapered threads used to seal pipes in the US.
What applications commonly use NPT threads?
NPT threads are used across a broad range of industries in the US, including plumbing, industrial, and agricultural applications.
Are BSPT and NPT the only types of pipe threads?
No, there are other types, such as BSPP (British Standard Pipe Parallel) and metric threads, each with specific applications.
Can any sealant be used with BSPT or NPT threads?
It's important to use the correct type of sealant for the material and application to prevent leaks and ensure durability.
Where are BSPT threads most commonly used?
BSPT threads are widely used in the UK, Europe, and Asia for applications requiring a hydraulic seal.
Can I replace a BSPT fitting with an NPT fitting directly?
Direct replacement is not advisable without considering thread compatibility; adapters are often necessary.
How do I identify BSPT vs. NPT threads?
Identification usually involves measuring the thread angle and pitch, with specialized tools or gauges.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
