What is the difference between BSPP, BSPT and NPT Fittings?
“BSP”, “NPT”, “BSPP”, and “BSPT”—all these different standards can be very confusing!
BSP and NPT Fittings: what is the difference?
The differences between BSP and NPT fittings is the result of several factors:
- Geographical region
Of these, the most significant is geographical location. As a result of this, nowadays there is a global division of standards into countries using NPT fittings and those that use BSP.
NPT stands for “National Pipe Thread” and is the standard in the USA and Canada.
Angle cross threads of NPT fittings are at 60° and they have flattened peaks and troughs.
There can be some confusion due to the tapered thread’s description as NPT (“National Pipe Taper”), whereas the straight version is NPS (“National Pipe Straight”). There are also a couple of variations NPLTF (“National Pipe Taper Fuel”) and NPSM (“National Pipe Straight Mechanical”) just to confuse things even more. Designed to provide better leak-proof seals without the use of sealants, they are the same shape but have adjusted crest and root heights.
The male adaptors have taper threads that fit into the female adaptors forming a seal when twisted together. Tapered fittings find use mainly on the ends of pipes, nipples and fitting such as couplings, elbows, and tees.
NPS parallel threads need gaskets or O-rings to seal them.
BSP stands for “British Standard Pipe” and is the standard in the UK, Europe, Asia, and Australia.
They are similar to the NPT but have angle cross threads of 55° and have rounded peaks and valleys.
They have the designations BSPT for tapered threads and BSPP for parallel threads.
BSPT fittings require sealants whereas the BSPP use banded seal rings to seal fittings in between the shoulder on the male and the face of the female and do not require sealants.
Can you use them together?
Most definitely NOT. Never mix these fittings, as this could result in dangerous leakage.
When would you use one or the other?
If you are using anything manufactured in the USA or Canada, then use NPT fittings. If you are using equipment made anywhere else in the world, then you should use BSP fittings.
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