Introduction to BSP Threads

For valves below 2 inches, threaded connections are usually used. Sedelon not only produces NPT threaded connections, but also BSP threaded connections.

BSP thread originated from the thread standard system proposed by Whitworth in the 19th century in England, with a thread angle of 55 ° and nominal dimensions marked in inches. It is a representative of British pipe threads. According to the sealing method and structural form, BSP threads are mainly divided into the following two categories:

1. ‌BSPP (British Standard Pipe Parallel) ‌

Also known as "cylindrical pipe thread", both internal and external threads have parallel (cylindrical) thread.

‌Thread Angle‌: 55°

‌Sealing Method‌: Does not rely on the thread itself for sealing; requires external sealing elements such as O-rings, gaskets, or PTFE tape.

‌Designation‌: Typically denoted by ‌G‌, e.g., G1/2 indicates a BSPP thread with a nominal diameter of 1/2 inch.

‌Applications‌: Suitable for general fluid connections under non-high-pressure and non-high-temperature conditions, commonly found in water and air systems.

2. ‌BSPT (British Standard Pipe Taper)

Also known as "conical pipe thread", the external thread is tapered, while the internal thread can be either tapered or parallel.

‌Thread Angle‌: 55°

‌Taper Ratio‌: 1:16 (diameter changes by 1 unit per 16 units of length)

‌Sealing Method‌: Achieves self-sealing through compression deformation of the tapered thread surface, often enhanced with sealant or PTFE tape.

‌Designation‌: Uses ‌R-series‌ codes, such as Rp (parallel internal), Rc (tapered internal), and R1/R2 (tapered external).

‌Applications‌: Widely used in high-sealability systems like water, gas, and oil pipelines, especially prevalent in Europe and Commonwealth countries.