Pipe End Caps
NUMET ALLOYS manufactures heavy-duty pipe end caps designed to permanently and safely seal the terminals of industrial piping systems. Forged and deep-drawn to withstand the full hydrostatic pressure of the pipeline, our end caps provide absolute system isolation while maintaining a highly compact, space-saving footprint.
Detailed Technical Specifications
Hemispherical: Optimal for maximum pressure containment (no sharp stress curves).
Flat Caps: Available for low-pressure or structural applications.
Stainless Steel: ASTM A403 WP304/304L, WP316/316L, WP321, WP347
Alloy & Duplex: ASTM A234 WP5, WP11, WP22, UNS S31803
Welded (Multi-Piece Construction): 24" NB to 60" NB (100% X-Ray Tested)
Dimensions (ASME B16.9)
ASME B16.9 gives end caps two lengths. Length E applies where the wall thickness does not exceed the limit shown; heavier walls use the longer length E1. Cap crowns are ellipsoidal in accordance with the ASME Boiler and Pressure Vessel Code.
Butt Weld Caps — Length (E / E1)
ASME B16.9| SizeNPS | Outside Dia.mm | Length Emm | Length Einch | Wall Limitmm | Length E1mm | Length E1inch |
|---|---|---|---|---|---|---|
| 1/2 | 21.3 | 25 | 1.00 | 4.57 | 25 | 1.00 |
| 3/4 | 26.7 | 25 | 1.00 | 3.81 | 25 | 1.00 |
| 1 | 33.4 | 38 | 1.50 | 4.57 | 38 | 1.50 |
| 1-1/4 | 42.2 | 38 | 1.50 | 4.83 | 38 | 1.50 |
| 1-1/2 | 48.3 | 38 | 1.50 | 5.08 | 38 | 1.50 |
| 2 | 60.3 | 38 | 1.50 | 5.59 | 44 | 1.75 |
| 2-1/2 | 73.0 | 38 | 1.50 | 7.11 | 51 | 2.00 |
| 3 | 88.9 | 51 | 2.00 | 7.62 | 64 | 2.50 |
| 3-1/2 | 101.6 | 64 | 2.50 | 8.13 | 76 | 3.00 |
| 4 | 114.3 | 64 | 2.50 | 8.64 | 76 | 3.00 |
| 5 | 141.3 | 76 | 3.00 | 9.65 | 89 | 3.50 |
| 6 | 168.3 | 89 | 3.50 | 10.92 | 102 | 4.00 |
| 8 | 219.1 | 102 | 4.00 | 12.70 | 127 | 5.00 |
| 10 | 273.1 | 127 | 5.00 | 12.70 | 152 | 6.00 |
| 12 | 323.9 | 152 | 6.00 | 12.70 | 178 | 7.00 |
| 14 | 355.6 | 165 | 6.50 | 12.70 | 191 | 7.50 |
| 16 | 406.4 | 178 | 7.00 | 12.70 | 203 | 8.00 |
| 18 | 457.2 | 203 | 8.00 | 12.70 | 229 | 9.00 |
| 20 | 508.0 | 229 | 9.00 | 12.70 | 254 | 10.00 |
| 22 | 558.8 | 254 | 10.00 | 12.70 | On request | — |
| 24 | 609.6 | 267 | 10.50 | 12.70 | 305 | 12.00 |
Reading the table: use length E when the specified wall thickness is equal to or less than the wall limit column; use E1 when it is greater. For NPS 26 and larger, the length for heavier walls is agreed between manufacturer and purchaser. NPS 22 heavy-wall length is confirmed at the time of enquiry.
Dimensions are nominal values from the referenced standard and are shown for reference only; tolerances apply as specified in the standard. Sizes above 24" NB and non-standard combinations are manufactured to order. For certified drawings against your line list, contact our technical team.
Core Advantages
Minimal Space Footprint
Unlike bulky blind components that require heavy bolts and extra clearance, welded end caps provide a permanent, lightweight seal in tightly engineered spaces.
Maximum Pressure Containment
Ellipsoidal and hemispherical geometries distribute internal pressure evenly across the surface area, preventing localized stress concentrations and fatigue failures.
Future-Proof Pipeline Design
Ideal for sealing pipe headers and manifolds intended for future expansion. The cap can be easily cut off later to allow pipeline extensions without replacing complex assemblies.