Pipe Cap
Product Description
Closes the end of a pipe, either temporarily during construction or permanently as a system boundary. Butt-weld or threaded end options.
Available in standard sizes with custom options per drawing. Each item is 100% inspected and supplied with material certificates.
Applications
Pipe caps close the terminal end of a piping system, serving as permanent pressure-containing boundaries or temporary closures during hydrotesting and construction. They are used at dead-end runs in refinery pipe racks, pipeline termination points, pressure vessel nozzle ends, and distribution header extremities. Hemispherical or elliptical head shapes distribute internal pressure evenly per ASME B16.9 design.
Typical applications include the end of natural gas distribution mains, process piping dead ends in chemical plants, heat exchanger tube channel closures, and fire water loop termini. In oil and gas gathering, caps seal test headers at well pads and production manifolds. Carbon steel WPB handles media from -29°C to 425°C; stainless WP304/WP316 extends to 600°C and corrosive service.
Threaded-end caps are also available for small-bore instrument and drain line closures. Butt-weld caps are supplied with beveled ends per ASME B16.25 for field welding. Sizes range from NPS 1/2″ to 48″ with wall thicknesses from SCH 10 to XXS matching the host pipe schedule.
Quality Assurance & Certification
Each pipe cap is forged or spun to ASME B16.9 dimensions, with the head contour and wall thickness engineered for pressure integrity. Wall thinning at the crown is controlled within standard tolerances. We supply EN 10204 3.1 mill test certificates documenting heat chemistry, tensile strength, and Charpy impact properties. Heat number marking on the bevel end provides traceability.
NDT options include ultrasonic thickness measurement at the crown, radiographic inspection on welded caps, and liquid penetrant testing on stainless surfaces. For pressure vessel and boiler code service, additional NDT (RT or UT) can be specified per ASME Section V. Third-party inspection by TUV, SGS, or BV is available.
Bevel ends are protected with plastic caps. Carbon steel caps receive anti-rust oil; stainless units are film-wrapped. They are packed in wooden crates for ocean freight, each marked with size, schedule, material grade, heat number, and ASME B16.9 compliance.
ASME Standard Data
This product is a buttwelding cap, manufactured to ASME B16.9 — Factory-Made Wrought Buttwelding Fittings.
1. Scope (ASME B16.9, para. 1.1)
“This Standard covers overall dimensions, tolerances, ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1/2 through NPS 48 (DN 15 through DN 1200).”
2. Material Groupings (ASME B16.9, Table 5-1)
| Group No. | Material | ASTM / ASME Standards |
|---|---|---|
| 1 | Carbon and low-alloy steels | ASTM A234/A234M; ASTM A420/A420M |
| 2 | Austenitic and duplex stainless steels | ASTM A403/A403M; ASTM A815/A815M |
| 3 | Nickel alloys | ASTM B366/B366M |
| 4 | Aluminum alloys | ASTM B361 |
| 5 | Titanium alloys | ASTM B363 |
Source: ASME B16.9-2018, Table 5-1 (Material Groupings). Common YAJIADA cap materials and their groups: A234 WPB → Group 1; A420 WPL6 → Group 1; A403 WP304 / WP316 → Group 2; A815 S31803 / S32750 (duplex) → Group 2; B366 nickel alloys → Group 3.
3. Dimensional Data Status
ASME B16.9 Table 6.1-10 (Cap) dimensional data pending verification. Cap overall dimensions (K, Y, E, etc.) will be transcribed from the original ASME B16.9 PDF after manual cross-check; the OCR-extracted source currently has the dimensional tables missing and they are not published here.
4. Supplemental — Forged (socket-weld / threaded) Cap Range (ASME B16.11, Table 7)
| Cap Type | SW 3000 | SW 6000 | SW 9000 | Threaded 2000 | Threaded 3000 | Threaded 6000 |
|---|---|---|---|---|---|---|
| Forged cap (same row as elbows / tees / couplings / bosses / couplets) | 1/8–4 | 1/8–2 | 1/2–2 | 1/8–4 | 1/8–4 | 1/8–4 |
Source: ASME B16.11-2016, Table 7. This NPS range applies to forged (socket-weld / threaded) caps only — it does NOT apply to the buttwelding cap covered by ASME B16.9 in sections 1–3 above. Forged cap end dimensions (laying length E, outside dia G / D) are currently pending verification against the original B16.11 PDF.
Request a Quote for This Product
Tell us your standard, size, material and quantity — our team will reply within 24 hours.
Frequently Asked Questions
Carbon steel, stainless steel 304/316, alloy steel, and low-temperature grades. Special materials available on request.
Yes, custom sizes, threads, materials, and finishes per drawing with 15–30 day lead time.
Yes — EN 10204 3.1 MTC and third-party inspection (BV / SGS / TUV) available.
ASME B16.9-2024 Table 6.1-10 — Dimensions of Caps
Length E for butt-welding caps, NPS 1/2–48, with limiting wall thickness. E depends on the marked nominal wall thickness relative to the limiting value.
| NPS | Outside Diameter at Bevel | Limiting Wall Thickness | Length E (wall ≤ limiting) | Length E (wall > limiting) |
|---|---|---|---|---|
| 1/2 | 21.30 mm (0.84 in.) | 4.57 mm (0.18 in.) | 25 mm (1 in.) | 25 mm (1 in.) |
| 3/4 | 26.70 mm (1.05 in.) | 3.81 mm (0.15 in.) | 25 mm (1 in.) | 25 mm (1 in.) |
| 1 | 33.40 mm (1.32 in.) | 4.57 mm (0.18 in.) | 38 mm (1.50 in.) | 38 mm (1.50 in.) |
| 1-1/4 | 42.20 mm (1.66 in.) | 4.83 mm (0.19 in.) | 38 mm (1.50 in.) | 38 mm (1.50 in.) |
| 1-1/2 | 48.30 mm (1.90 in.) | 5.08 mm (0.20 in.) | 38 mm (1.50 in.) | 38 mm (1.50 in.) |
| 2 | 60.30 mm (2.38 in.) | 5.59 mm (0.22 in.) | 38 mm (1.50 in.) | 44 mm (1.75 in.) |
| 2-1/2 | 73 mm (2.88 in.) | 7.11 mm (0.28 in.) | 38 mm (1.50 in.) | 51 mm (2 in.) |
| 3 | 88.90 mm (3.50 in.) | 7.62 mm (0.30 in.) | 51 mm (2 in.) | 64 mm (2.50 in.) |
| 3-1/2 | 101.60 mm (4 in.) | 8.13 mm (0.32 in.) | 64 mm (2.50 in.) | 76 mm (3 in.) |
| 4 | 114.30 mm (4.50 in.) | 8.64 mm (0.34 in.) | 64 mm (2.50 in.) | 76 mm (3 in.) |
| 5 | 141.30 mm (5.56 in.) | 9.65 mm (0.38 in.) | 76 mm (3 in.) | 89 mm (3.50 in.) |
| 6 | 168.30 mm (6.62 in.) | 10.92 mm (0.43 in.) | 89 mm (3.50 in.) | 102 mm (4 in.) |
| 8 | 219.10 mm (8.62 in.) | 12.70 mm (0.50 in.) | 102 mm (4 in.) | 127 mm (5 in.) |
| 10 | 273 mm (10.75 in.) | 12.70 mm (0.50 in.) | 127 mm (5 in.) | 152 mm (6 in.) |
| 12 | 323.80 mm (12.75 in.) | 12.70 mm (0.50 in.) | 152 mm (6 in.) | 178 mm (7 in.) |
| 14 | 355.60 mm (14 in.) | 12.70 mm (0.50 in.) | 165 mm (6.50 in.) | 191 mm (7.50 in.) |
| 16 | 406.40 mm (16 in.) | 12.70 mm (0.50 in.) | 178 mm (7 in.) | 203 mm (8 in.) |
| 18 | 457 mm (18 in.) | 12.70 mm (0.50 in.) | 203 mm (8 in.) | 229 mm (9 in.) |
| 20 | 508 mm (20 in.) | 12.70 mm (0.50 in.) | 229 mm (9 in.) | 254 mm (10 in.) |
| 22 | 559 mm (22 in.) | 12.70 mm (0.50 in.) | 254 mm (10 in.) | 254 mm (10 in.) |
| 24 | 610 mm (24 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | 305 mm (12 in.) |
| 26 | 660 mm (26 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 28 | 711 mm (28 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 30 | 762 mm (30 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 32 | 813 mm (32 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 34 | 864 mm (34 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 36 | 914 mm (36 in.) | 12.70 mm (0.50 in.) | 267 mm (10.50 in.) | Manufacturer’s option |
| 38 | 965 mm (38 in.) | 12.70 mm (0.50 in.) | 305 mm (12 in.) | Manufacturer’s option |
| 40 | 1016 mm (40 in.) | 12.70 mm (0.50 in.) | 305 mm (12 in.) | Manufacturer’s option |
| 42 | 1067 mm (42 in.) | 12.70 mm (0.50 in.) | 305 mm (12 in.) | Manufacturer’s option |
| 44 | 1118 mm (44 in.) | 12.70 mm (0.50 in.) | 343 mm (13.50 in.) | Manufacturer’s option |
| 46 | 1168 mm (46 in.) | 12.70 mm (0.50 in.) | 343 mm (13.50 in.) | Manufacturer’s option |
| 48 | 1219 mm (48 in.) | 12.70 mm (0.50 in.) | 343 mm (13.50 in.) | Manufacturer’s option |
Source: ASME B16.9-2024 Table 6.1-10, p. 32. For NPS 26 and larger with limiting wall thickness > 12.7 mm (0.50 in.), length E is at the manufacturer’s option unless otherwise agreed.