BSP, short for British Standard Pipe, is a standard for pipe fittings popular in the UK, Europe, Asia, Australia, New Zealand, and South Africa. This standard is known for its distinctive 55-degree thread angle. Under BSP, there are two main types of threading – BSPP (British Standard Pipe Parallel) and BSPT (British Standard Pipe Taper).
Let’s delve deeper into BSPP and BSPT to understand their unique features:
BSPP Thread:
BSPP, or British Standard Pipe Parallel, refers to a parallel thread standard. The threads have a 55-degree angle, maintaining a parallel configuration. When connecting BSPP fittings, a bonded seal ring or a 60-degree cone is employed to ensure a tight seal. This seal is created when the bonded ring is compressed between a shoulder on the male fitting and the face of the female fitting.
When it comes to BSPP pressure gauges, they have longer male threads. A copper crush washer is used, which gets compressed between the bottom of the male and female fittings, creating a pressure-tight seal. One of the advantages of BSPP is that you don’t need any thread sealant to achieve a seal. Ralston Instruments offers a range of BSPP adapters including male and female BSPP adapters, as well as female BSPP gauge and Quick-disconnect gauge adapters.
BSPT Thread:
On the other hand, BSPT or British Standard Pipe Taper, as the name suggests, features a tapered thread. Similar to BSPP, the thread angle is 55 degrees. Unlike BSPP, BSPT creates a seal through the tightening of the threads, hence doesn’t require any O-ring or bonded seal.
BSPT and NPT (National Pipe Thread) might seem similar, but there are notable differences. The angle across the thread flanks in BSPT is 55 degrees, while it’s 60 degrees in NPT. Also, for many BSPT pipe sizes, the thread pitch differs from NPT. This means, an NPT male fitting might fit into a BSPT female fitting or vice versa, but they won’t provide a perfect seal. Therefore, a thread sealant is necessary to ensure a tight seal between male and female BSPT fittings.
BSPT fittings are more commonly used in China and Japan. They are rare in North America unless the equipment is imported. Ralston Instruments provides adapters for both male and female BSPT fittings.
For further information on BSPP and BSPT hydraulic fittings and adapters, our sales team is here to assist you!
