Butt-Weld Cap - Butt-Weld Pipe Fitting
A butt-weld cap provides a permanent, pressure-rated seal for the end of a pipe or fitting. Welded directly to the pipe end, it delivers a strong, leak-free termination for dead-end lines and future tie-in points. Manufactured to BS EN 10253-2 and ASME B16.9, each cap is bevelled to accept a full-penetration butt weld and supplied with full material traceability.
All butt-weld caps are bevelled to a standard 37° weld-end preparation for full-penetration welding. Each fitting is supplied with heat numbers and material test certificates for complete traceability through the supply chain.
Standards & Materials
Produced in accordance with BS EN 10253-2 and ASME B16.9 in a range of carbon and stainless steel grades suitable for UK pipework installations.
| Attribute | Specification |
|---|---|
| Manufacturing Standard | BS EN 10253-2 / ASME B16.9 |
| Carbon Steel | ASTM A234 WPB |
| Stainless Steel | ASTM A403 WP304/304L/316/316L |
| Special Grades | Duplex & Super Duplex (UNS S31803 / S32205 / S32750), Alloy 20, Inconel 625 / 825, Monel 400, Hastelloy C-276 - available on request |
| Fabrication | Seamless or welded |
| Test Pressure | Up to 1500 psi |
| Weld-End Preparation | 37° bevelled to ASME B16.25 |
Dimensions & Sizes
Available from 1/2" (DN15) to 24" (DN600) in schedules 10, 40 and 80. The table below gives the overall height (E) and Schedule 40 wall thickness for representative sizes, to ASME B16.9.
| Nominal Size | DN | Cap Height E (mm) | SCH 40 Wall (mm) |
|---|---|---|---|
| ½" | 15 | 25 | 2.77 |
| 1" | 25 | 38 | 3.38 |
| 2" | 50 | 64 | 3.91 |
| 3" | 80 | 89 | 5.49 |
| 4" | 100 | 102 | 6.02 |
| 6" | 150 | 152 | 7.11 |
| 8" | 200 | 178 | 8.18 |
Performance & Benefits
Butt-weld caps provide a smooth, flush termination that eliminates potential leak paths associated with threaded or socket-weld alternatives. The full-penetration butt weld produces a joint as strong as the pipe itself, making caps the preferred choice for high-pressure and high-temperature dead-end services across UK petrochemical, power and utility installations.
Typical Applications
Specified across oil and gas, chemical and utility pipework throughout the UK for closing off lines, capping future branches, and isolating sections during maintenance. Common uses include pressure vessel nozzles, reactor vessel closures, heater coil end caps, and blanking off redundant pipe runs in refineries and processing plants.
Quality Assurance & Traceability
Every fitting is manufactured to BS EN 10253-2 and ASME B16.9 and supplied with full material traceability and EN 10204 Type 3.1 test certificates. Heat numbers are recorded throughout production to support inspection, QA and UK project-compliance requirements.
Supply & Delivery
Stocked at our Sheffield, UK facility and delivered nationwide across England, Scotland and Wales. We offer fast dispatch from stock with tracked UK delivery to site, and next-day options for common sizes.
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Which sizes and schedules are available?
Available from ½" (DN15) to 24" (DN600) in schedule 10, 40 and 80, in both metric and imperial sizes to suit UK installations.
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Can you provide material certificates?
Yes. Material test certificates and full traceability documentation are available with every order, to project and quality-management requirements.
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Can a butt-weld cap be removed and reused?
Butt-weld caps are designed as permanent fittings. Once welded in place, removal requires cutting the weld, which damages the cap and the pipe end. They are not intended for repeated removal and reuse; for applications needing frequent access, a blind flange on a stub end is the recommended solution.
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Do you deliver across the UK?
We deliver nationwide throughout England, Scotland and Wales, with fast dispatch from stock and tracked deliveries to site.