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Pipe & Pneumatic Fittings · ISO 228 (G) · Application guide

What Are BSP Pipe Thread Fittings Used For?

Typical applications, the industries that specify bsp pipe thread fittings, and how to choose the right size, material and finish for the joint.

BSP Pipe Thread Fittings are used for joining and sealing fluid or pneumatic lines. They are manufactured to ISO 228 (G), and selection is driven by the screw size, the fit and tolerance the assembly requires, and the service environment.

Primary duty
Joining and sealing fluid or pneumatic lines
Governing standard
ISO 228 (G)
Screw size range
1 to 312
Category
Pipe & Pneumatic Fittings

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are BSP Pipe Thread Fittings Used For? application image

BSP Pipe Thread Fittings are used primarily for joining and sealing fluid or pneumatic lines. This page lists the industries and assemblies where they are specified, the selection criteria that matter for each application, installation practice, and the cases where a different fastener type is the correct choice. Parts are supplied to ISO 228 (G). Stocked across roughly 1 to 312, they cover general to heavy-duty work.

Typical Applications for BSP Pipe Thread Fittings

The most common settings where these are specified:

  • 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.
  • Process & plant piping: tapped connections on manifolds and equipment.

How to Specify BSP Pipe Thread Fittings for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans 1–312; 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.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (ISO 228 (G))

SizeNominal size (in)Major diameter (mm)Pitch (mm)Threads per inch (TPI)Tap drill (mm)Reference standardNotes
G1/161/167.7230.907286.8ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1/81/89.7280.907288.8ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1/41/413.1571.3371911.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G3/83/816.6621.3371915.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1/21/220.9551.8141418.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G5/85/822.9111.8141420.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G3/43/426.4411.8141424.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G7/87/830.2011.8141427.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1133.2492.3091130.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1-1/81-1/837.8972.3091135.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1-1/41-1/441.912.3091139.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1-1/21-1/247.8032.3091145.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G1-3/41-3/453.7462.3091151.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G2259.6142.3091157.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G2-1/42-1/465.712.3091163.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G2-1/22-1/275.1842.3091172.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G2-3/42-3/481.5342.3091179.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G3387.8842.3091185.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G3-1/23-1/2100.332.3091197.5ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G44113.032.30911110.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G55138.432.30911135.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
G66163.832.30911160.0ISO 228-1 / DIN ISO 228Parallel pipe thread (G), sealed by gasket
Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Which industries use BSP Pipe Thread Fittings?

They are commonly specified in process & plant piping, general machine building and maintenance & repair (mro), among other sectors.

How do I choose the right size of BSP Pipe Thread Fittings?

Match the nominal size to the mating thread or hole. This product is available from 1 to 312; the full dimension table on this page lists each size.

Can I mix BSP and NPT BSP Pipe Thread Fittings?

Not directly — the thread forms differ in angle and taper. Use a dedicated BSP-to-NPT adapter, and seal with the method suited to the thread (tape, sealant or O-ring).

What material should BSP Pipe Thread Fittings be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Can I get a quote for BSP Pipe Thread Fittings in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.