MY ACCOUNT
CONTACT US
THE ROLLING BEERS BLOG
A PROJECT ?
You’ve just bought a brewing pump or an accessory from an American website, you try to screw it onto your European 1/2" vessel valve, and then… it jams. The fitting turns half a rotation, then locks completely.
Don’t panic: you’re simply facing the difference between BSP and NPT threads. Although they look almost identical, they are totally incompatible.
To identify the correct thread for your setup, follow our detailed guide.
1. What is BSP threading? (The European standard)
BSP (British Standard Pipe) is the most widely used threading standard in Europe, Asia and most of the world for both homebrewing and professional brewing.
- Thread shape: BSP threads have an angle of 55°.
- Thread type: The most common in brewing is cylindrical BSP (marked G or BSPP). Male and female threads are perfectly parallel. To ensure sealing, a flat gasket at the bottom of the thread or PTFE (Teflon) tape on the threads is essential.
2. What is NPT threading? (The American standard)
NPT (National Pipe Thread) is the American national standard. You will find it almost systematically on equipment from American brands (such as Blichmann, Kegland, or certain imported brewing pumps).
- Thread shape: NPT threads have an angle of 60°.
- Thread type: NPT threads are tapered. The male fitting narrows slightly toward the end, while the female fitting widens toward the entrance. This tapered profile provides sealing: as you tighten, the threads literally crush against each other to block liquid flow (adding Teflon tape is still recommended to perfect sealing and ease disassembly).
3. Why are they incompatible?
It is physically impossible to properly screw a male NPT fitting into a female BSP fitting (and vice versa). Here’s why:
- Thread angle: 55° (BSP) vs 60° (NPT). The threads do not match face‑to‑face.
- Thread pitch (threads per inch): For the same nominal size (e.g., 1/2"), the number of threads per inch is not always identical. A 1/2" BSP has 14 TPI, and a 1/2" NPT also has 14 (which is why they “start” to screw together), but a 3/4" BSP has 14 vs 14 for NPT. On other sizes, the thread count differs completely, making assembly impossible from the first millimeter.
- Taper: Forcing a tapered NPT fitting into a parallel BSP thread will irreversibly destroy the stainless‑steel threads of your equipment.
4. Comparison table: BSP vs NPT
Here is a visual summary to help you tell them apart:
| Characteristic | BSP Standard (G / G‑Thread) | NPT Standard (NPT‑Thread) |
|---|---|---|
| Geographical origin | United Kingdom, Europe, Asia | United States, Canada |
| Thread shape | Parallel / Cylindrical (most common) | Tapered (threads tighten) |
| Thread angle | 55° | 60° |
| Sealing method | Flat gasket or Teflon tape | Compression of tapered threads + Teflon |
Rolling Beers Team Tips
What if you mixed both standards? If you have a vessel equipped with a European BSP valve and you’ve just bought a great American NPT accessory, do NOT force the threading. Forcing stainless steel against stainless steel will cause permanent galling, making your parts unusable. The solution is simple: there are BSP‑to‑NPT thread adapters that allow you to transition cleanly and safely. We’ll explain how to choose them in detail in our next article!