BSP Pipe & Hose Fittings Guide

Choosing the right BSP pipe or hose fitting starts with matching the thread form, connection type and hose size rather than relying on outside diameter alone. This guide explains the main points to check before ordering fittings for workshop, plumbing and general fluid-handling projects.

What does BSP mean?

BSP stands for British Standard Pipe. Two commonly encountered forms are BSPP, which uses a parallel thread, and BSPT, which uses a tapered thread. Product drawings, thread markings and the exact fitting specification should be checked before combining components. Similar-looking threads are not automatically interchangeable.

Male and female BSP threads

A male BSP fitting has an external thread, while a female BSP fitting has an internal thread. Adapters, elbows, sockets, unions and valves can use male, female or mixed connections. Before ordering, confirm both ends of the connection and note whether you need a straight fitting, reducer or directional fitting.

Choosing hose barb size

Hose barb size should be selected to suit the hose inside diameter, not the hose outside diameter. A correctly selected barb allows the hose to fit over the ridged tail and should be secured using a suitable clamp where the application requires it. For reducer barbs, check the hose inside diameter on both sides.

Common fitting types

Straight adapters connect components in line. Reducers join different connection sizes. Elbows change direction where space is limited. Unions allow sections of pipework to be separated more conveniently. Inline valves provide a simple shut-off point within a hose or pipe run.

Brass or 304 stainless steel?

Brass is widely used for compact threaded and hose connections and is easy to machine. 304 stainless steel offers good general corrosion resistance and is commonly chosen where a stainless construction is preferred. The best material depends on the operating environment, connected materials and the media being handled. For regulated, safety-critical, pressure-rated or chemically demanding systems, verify the exact product specification before use.

How to identify the size

BSP nominal size does not directly equal the measured outside diameter of the thread. Measuring the thread outside diameter can help identify a fitting, but it should be compared with an appropriate BSP reference or the product drawing. Also check thread pitch where necessary. For hose-tail fittings, confirm the hose inside diameter separately from the BSP thread size.

Sealing threaded connections

The correct sealing method depends on the thread form, fitting design and application. Some connections seal on the thread, while others rely on a washer, face seal or other sealing surface. Use a sealing method that is appropriate for the exact components and service conditions rather than assuming one method suits every BSP connection.

Quick selection checklist

Confirm male or female connection on each side.
Confirm BSP thread size and, where relevant, parallel or tapered thread form.
For hose barbs, match the barb to the hose inside diameter.
Choose straight, reducer, elbow, union or valve geometry to suit the installation.
Select brass or stainless steel based on the application and environment.
Check the exact product specification where pressure, temperature, media compatibility or safety requirements apply.

Shop BSP fittings and hose connectors

Browse our Pipe Fittings collection for threaded adapters, reducers, elbows, unions and related connectors.

If an installation has a specified working pressure, certification, regulatory requirement or critical safety function, confirm those requirements against the exact fitting specification before purchase and installation.