Butt-weld cap and dished end dimensions: ASME B16.9 and EN 10253-1
Heights, wall and weight of our caps and dished ends, ½" to 8", in both standards. Under ASME, a cap’s length also depends on its wall.
ASME B16.9 caps
Length E runs from the weld end to the top of the dish. It applies up to a limiting wall; above it the cap is longer and its dimension becomes E1. A 6" XS cap (10.97 mm) exceeds the 10.92 mm limit and therefore measures 102 mm instead of 89.
| NPS | OD (mm) | Length E (mm) | E up to wall (mm) | Length E1 above (mm) |
|---|---|---|---|---|
| ½" | 21.3 | 25 | 4.57 | 25 |
| ¾" | 26.7 | 25 | 3.81 | 25 |
| 1" | 33.4 | 38 | 4.57 | 38 |
| 1¼" | 42.2 | 38 | 4.83 | 38 |
| 1½" | 48.3 | 38 | 5.08 | 38 |
| 2" | 60.3 | 38 | 5.59 | 44 |
| 2½" | 73.0 | 38 | 7.11 | 51 |
| 3" | 88.9 | 51 | 7.62 | 64 |
| 4" | 114.3 | 64 | 8.64 | 76 |
| 5" | 141.3 | 76 | 9.65 | 89 |
| 6" | 168.3 | 89 | 10.92 | 102 |
| 8" | 219.1 | 102 | 12.70 | 127 |
Caps to ASME B16.9. Tolerance on E: ± 3 mm up to 4", ± 6 mm from 5" to 8".
EN 10253-1 caps and dished ends
The European standard has a deep cap, height K2, and a flatter dished end, height K1. Both are butt-welded to the pipe and made in S235, black or galvanized.
| NPS | OD D (mm) | Dished end K1 (mm) | Cap K2 (mm) | Wall T (mm) | Dished end weight (kg) | Cap weight (kg) |
|---|---|---|---|---|---|---|
| ½" | 21.3 | 11 | 25 | 2.0 | 0.02 | 0.05 |
| ¾" | 26.9 | 11 | 25 | 2.3 | 0.02 | 0.07 |
| 1" | 33.7 | 11 | 25 | 2.6 | 0.03 | 0.09 |
| 1¼" | 42.4 | 11 | 25 | 2.6 | 0.04 | 0.13 |
| 1½" | 48.3 | 11.5 | 38 | 2.6 | 0.05 | 0.20 |
| 2" | 60.3 | 16.5 | 38 | 2.9 | 0.10 | 0.28 |
| 2½" | 76.1 | 18.5 | 38 | 2.9 | 0.16 | 0.34 |
| 3" | 88.9 | 23 | 51 | 3.2 | 0.24 | 0.53 |
| 4" | 114.3 | 26 | 64 | 3.6 | 0.42 | 1.00 |
| 5" | 139.7 | 35.5 | 76 | 4.0 | 0.80 | 1.70 |
| 6" | 168.3 | 44.5 | 89 | 4.5 | 1.40 | 2.65 |
| 8" | 219.1 | 68.5 | 102 | 6.3 | 2.90 | 5.55 |
Dished ends and caps to EN 10253-1, in S235: K1 and K2 are overall heights.
Comparing the two standards
The EN 10253-1 cap has the same height as the ASME cap for almost every size: 38 mm at 2", 64 mm at 4", 102 mm at 8". At 1" and 1¼" it is shorter (25 mm versus 38). The dished end has no ASME B16.9 equivalent: it is the choice when space at the end of the line is tight.
Cap or blind flange: a cap closes a line for good, with no gasket; a blind flange can be removed. For a line to be extended, choose the flange.
Dimensions by size
Caps and dished ends
Standards
- ASME B16.9: caps, lengths E and E1, tolerances.
- EN 10253-1: non-alloy steel caps and dished ends.
Frequently asked questions
What is the difference between a cap and a dished end?
Under EN 10253-1 the cap is deep (K2) and the dished end flatter (K1): 64 mm versus 26 mm at 114.3, for example.
When does length E1 apply?
Under ASME B16.9, when the wall exceeds the limit for the size, for example above 10.92 mm at 6".
What is your largest cap?
219.1 mm (8"), to EN 10253-1 and ASME B16.9.
Other charts
Butt-weld elbow dimensions: ASME B16.9 and EN 10253-1An elbow’s take-off is its centre-to-end: from the bend centre to the plane of the end.
Butt-weld equal tee dimensions: ASME B16.9 and EN 10253-1On an equal tee, the centre-to-end is the same on all three outlets.
Butt-weld reducer dimensions: ASME B16.9 and EN 10253-1Under ASME B16.9, length H depends on the large end only: 102 mm for any 4" reducer.