BSP vs NPT - What Is the Difference Between the Threads and Why Must They Not Be Connected?
BSP or NPT? This is one of the most frequently asked questions.
At first glance, BSP and NPT threads look very similar. Many users try to connect them because the component "screws in a few turns". Unfortunately, such a connection very often results in leakage or thread damage.
If you work with hydraulic, pneumatic or industrial installations, it is worth knowing the basic differences.
What is a BSP thread?
BSP (British Standard Pipe) is a European pipe thread standard.
The most common designations are:
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G – parallel thread (BSPP)
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Rp – parallel thread
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R – tapered thread
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Rc – tapered thread
BSP thread has:
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an angle of 55° (Whitworth profile)
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is used in most equipment manufactured in Europe.
What is an NPT thread?
NPT (National Pipe Thread) is an American pipe thread standard.
Characteristic features:
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angle 60°
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tapered thread
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ANSI/ASME standard
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very popular in the USA, Canada and high-pressure installations.
Why Don't BSP and NPT Fit Together?
Although some sizes have a similar number of threads per inch, differences in angle and diameter mean that the connection will not be tight. Forcing the connection may damage the threads.
How to Properly Connect BSP to NPT?
The safest solution is to use a BSP → NPT adapter.
The POLBERIS offer includes, among others:
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BSP → NPT adapter (straight fitting),
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BSP/NPT reducers,
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BSP/NPT reducing nipples,
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BSP/NPT elbows.
Thanks to them, installations made according to different standards can be safely connected.
POLBERIS Products Worth Linking
Based on the photos you sent, I would link the following in the article:
Straight BSP → NPT Adapter
Phrases:
BSP → NPT Reducer
Phrases:
BSP → NPT Reducing Nipple
Phrases:
NPT Elbow
Phrases:
How to Identify a Thread?
If you are not sure:
✔ measure the diameter,
✔ count the number of threads per inch,
✔ check the thread angle with an appropriate gauge,
✔ read the manufacturer's markings.
If you still have doubts, send a photo or dimensions – POLBERIS specialists will help you select the appropriate component.
Why Buy Adapters from POLBERIS?
✔ wide selection of BSP ↔ NPT transitions,
✔ carbon steel and stainless steel,
✔ threads for hydraulic, pneumatic and industrial installations,
✔ fast shipping,
✔ professional advice.