Camlock couplings (also known as cam and groove couplings) are widely used in the UK for quick and secure fluid transfer in industrial applications. Unlike the U.S., where the National Pipe Thread (NPT) standard dominates, the UK primarily follows the British Standard Pipe (BSP) thread standard for camlock connections. This article explores the BSP standard, its significance in UK camlock systems, and best practices for proper usage.
The BSP Standard in British Camlock Systems
The British Standard Pipe (BSP) is the most common thread type for camlock couplings in the UK and many Commonwealth countries. Governed by BS EN ISO 228-1 (parallel threads) and BS EN 10226 (tapered threads), BSP comes in two main variants:
1. BSPP (British Standard Pipe Parallel) – Also known as G-threads, these have a constant diameter and rely on a sealing washer or O-ring to prevent leaks.
2. BSPT (British Standard Pipe Tapered) – Similar to NPT but with a 55-degree thread angle (instead of NPT’s 60-degree angle), these create a seal through thread deformation.
In UK camlock systems, BSP threads are typically found on:
– Hose adapters
– Pipe connections
– Coupler and adapter stems
Why BSP Dominates UK Camlock Applications
Several factors contribute to BSP’s prevalence in the UK:
1. Historical Adoption – BSP has been the standard in British engineering since the early 20th century.
2. Compatibility – Matches existing UK piping and hydraulic systems.
3. Regulatory Compliance – Required for many British and European industrial applications.
4. Sealing Method – BSPP’s washer-based sealing is reliable for high-pressure applications, while BSPT provides a strong mechanical seal.
BSP vs. Other Thread Standards in Camlock Couplings
While BSP is standard in the UK, camlock users should be aware of key differences with other global standards:
| Feature | BSP (UK) | NPT (USA) | Metric (Europe/Asia) |
| Thread Angle | 55° | 60° | 60° (metric tapered) |
| Sealing Method | Washer (BSPP) / Thread (BSPT) | Thread taper + sealant | O-ring or taper |
| Common Use | UK, Europe, Commonwealth | USA, Canada | Germany, China, Japan |
Key Considerations:
– BSPP (G-thread) requires a sealing washer, while BSPT (R-thread) seals via thread engagement.
– BSP and NPT are not interchangeable—using the wrong thread can cause leaks or damage.
– Metric threads are increasingly used in European-made camlock fittings but are less common in traditional UK systems.
In the UK, BSP threads are the standard for camlock couplings, ensuring compatibility with existing industrial infrastructure. Understanding the differences between BSPP and BSPT, as well as how they compare to NPT and metric threads, is crucial for proper installation and maintenance. By following best practices—such as using the correct sealing method and avoiding cross-threading—users can maximize the efficiency and longevity of their camlock systems in British applications.
For industries operating in both UK and U.S. markets, recognizing these thread differences prevents costly mismatches and ensures smooth, leak-free fluid transfer operations.
