Buttweld end caps seal the end of a pipe or fitting. Available in all grades from carbon steel WPB to Inconel 625, all schedules, all sizes from ½" to 48" NB. ASME B16.9 standard.
An end cap is used to close (seal) the end of a piping system or pipeline. Unlike flanged blinds, buttweld caps are permanently welded — giving a leak-tight, permanent closure with the same pressure rating as the pipe itself.
For permanent closures where the end of a line will not need to be reopened. More economical and leak-proof than using a flange and blind. Common at dead-ends of headers, bypass lines, and temporary isolation points in pipelines.
The cap grade must match the pipe and fitting grade. Using a WPB cap on a stainless steel line is not permitted — always match grades. We stock all grades to ensure your complete system is consistent.
Buttweld caps have the same pressure rating as the pipe with matching schedule. No derating is applied for properly welded caps. Dimensions per ASME B16.9 ensure dimensional compatibility with pipe and fittings.
Every cap is marked per ASME B16.9: manufacturer's name, size, schedule/wall, material grade, and heat number for traceability.
| NPS | OD (mm) | Length E (mm) | Sch 40 Wall (mm) | Sch 80 Wall (mm) |
|---|---|---|---|---|
| ½" | 21.3 | 22 | 2.77 | 3.73 |
| ¾" | 26.7 | 25 | 2.87 | 3.91 |
| 1" | 33.4 | 29 | 3.38 | 4.55 |
| 1½" | 48.3 | 38 | 3.68 | 5.08 |
| 2" | 60.3 | 41 | 3.91 | 5.54 |
| 3" | 88.9 | 51 | 5.49 | 7.62 |
| 4" | 114.3 | 64 | 6.02 | 8.56 |
| 6" | 168.3 | 76 | 7.11 | 10.97 |
| 8" | 219.1 | 89 | 8.18 | 12.70 |
| 10" | 273.1 | 102 | 9.27 | 15.09 |
| 12" | 323.9 | 114 | 9.53 | 17.48 |
| 16" | 406.4 | 140 | 9.53 | — |
| 20" | 508.0 | 165 | 9.53 | — |
| 24" | 609.6 | 190 | 9.53 | — |
Send grade, size (NPS), schedule, quantity. We respond within 4 hours with pricing and availability.