Application guide for BSP Pipe Thread Fittings to ISO 228 (G). The core duty of the type is joining and sealing fluid or pneumatic lines. The typical industries, the how-to-specify checklist, assembly practice and the exclusion cases are set out below. Stocked across roughly M1 to M312, they cover general to heavy-duty work.
Typical Applications for BSP Pipe Thread Fittings
The most common settings where these are specified:
- General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
- Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
- Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.
- Pneumatic systems: connecting air lines, cylinders and valves on automation rigs.
- Hydraulic & fluid power: sealed, pressure-rated joints in fluid lines.
How to Specify BSP Pipe Thread Fittings for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M1–M312; check the full table below for the exact dimensions of each size.
- Thread & pressure: Match the thread form (BSP/NPT/metric) and pressure rating to the line, and seal appropriately (tape, sealant or O-ring).
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to ISO 228 (G). Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Installation & Assembly Practice
- Seal tapered threads with PTFE tape or anaerobic sealant applied clear of the first thread; parallel threads seal on a washer or O-ring, not on the thread.
- Tighten to the fitting manufacturer's torque — over-tightening tapered threads splits female ports.
Common Selection Mistakes with BSP Pipe Thread Fittings
- Mating BSP and NPT threads directly — the 55°/60° forms do not seal against each other.
- Exceeding the pressure rating of the lowest-rated component in the line.
Where BSP Pipe Thread Fittings Are Not the Right Choice
Do not mix thread forms (BSP into NPT) without an adapter, and do not exceed the pressure rating of the lowest-rated component.

