{ "version": "2026-10-20", "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.", "slug": "butt-weld-caps", "name": "Butt-weld caps (ASME B16.9), NPS 1/2 to 12: overall length E and E1 by wall thickness", "kind": "standard", "category": "Tri-clamp & pipe", "group": "Pipe, tube & threads", "year": null, "question": "How long is a butt-weld pipe cap (length E) for Schedule 40 and 80?", "tags": [ "pipe", "pipe fitting", "butt weld", "cap", "end cap", "b16.9", "standard" ], "aliases": [ "butt weld cap dimensions", "pipe cap length", "b16.9 cap e dimension", "weld cap height", "end cap schedule 40 dimensions", "sch 80 weld cap length", "butt weld cap e1", "steel pipe cap length by size", "wpb cap dimensions", "2 inch butt weld cap length" ], "overall_mm": { "length": null, "width": null, "height": null }, "official_cad": false, "xem_status": "not-scanned", "les": false, "free_files": 0, "url": "https://xemstudio.com/objects/butt-weld-caps/", "sheet_txt": "https://xemstudio.com/objects/butt-weld-caps/sheet.txt", "sheet": { "basis": "Length E / E1 (mm) and the wall that separates them from Wermac's ASME B16.9 cap table; Schedule 40 and 80 heights H (in) and walls T from Texas Flange; numbers only", "overall_mm": { "length": null, "width": null, "height": null }, "notes": [ "B16.9 gives each cap size two lengths: E for walls up to a limit and E1 for thicker walls. Wermac prints both and the limiting wall (column 'wall limit'): E applies when the fitting wall is not more than the limit, E1 when it is more. Texas Flange's per-schedule heights H (weld face to the top of the dome) agree with this rule: for NPS 10 Sch 40 (wall 0.365 in, under the 12.7 mm limit) H = 5.00 in = E 127 mm; for NPS 10 Sch 80 (wall 0.594 in, over the limit) H = 6.00 in = E1 152 mm. Sch 80 at NPS 2 (wall 0.218 in = 5.54 mm, under the 5.59 mm limit) is still the short E (1.50 in = 38 mm). One boundary case disagrees: NPS 6 Sch 80 has a 0.432 in (10.97 mm) wall, 0.05 mm over Wermac's 10.92 mm limit, so the rule gives E1 = 102 mm while Texas Flange prints H = 3.50 in (89 mm, the short E); both are shown and neither is resolved here.", "Wermac lists the limit as 12.70 mm from NPS 8 up through NPS 24; above NPS 24 it prints no E1 (by agreement between maker and buyer), and this page stops at NPS 12.", "Where inch and mm disagree it is rounding: Texas Flange's 1.50 in at NPS 1 is Wermac's 38 mm (1.496 in).", "No file: E, OD and wall define the length, the weld end and the wall, but not the crown. Where the straight part ends and the dome (and its knuckle radius) begin is not given as numbers in any source read, so a drawn dome would be an invention. McMaster-Carr sells butt-weld end caps with per-part STEP; its category is linked, not copied.", "OD: Wermac prints mm (21.3 ... 323.8), Texas Flange inches as printed (0.84 ... 12.75); both are rounded figures." ], "table": { "columns": [ "NPS", "OD, mm (in)", "E, mm", "E1, mm", "wall limit between E and E1, mm", "Sch 40 height H, in (Texas Flange)", "Sch 80 height H, in (Texas Flange)" ], "rows": [ [ "1/2", "21.3 (0.84 in)", "25", "25", "4.57", "1.00 (wall 0.109)", "1.00 (wall 0.147)" ], [ "3/4", "26.7 (1.05 in)", "25", "25", "3.81", "1.00 (wall 0.113)", "1.00 (wall 0.154)" ], [ "1", "33.4 (1.32 in)", "38", "38", "4.57", "1.50 (wall 0.133)", "1.50 (wall 0.179)" ], [ "1-1/4", "42.2 (1.66 in)", "38", "38", "4.83", "1.50 (wall 0.140)", "1.50 (wall 0.191)" ], [ "1-1/2", "48.3 (1.90 in)", "38", "38", "5.08", "1.50 (wall 0.145)", "1.50 (wall 0.200)" ], [ "2", "60.3 (2.38 in)", "38", "44", "5.59", "1.50 (wall 0.154)", "1.50 (wall 0.218)" ], [ "2-1/2", "73.0 (2.88 in)", "38", "51", "7.11", "1.50 (wall 0.203)", "1.50 (wall 0.276)" ], [ "3", "88.9 (3.50 in)", "51", "64", "7.62", "2.00 (wall 0.216)", "2.00 (wall 0.300)" ], [ "3-1/2", "101.6 (4.00 in)", "64", "76", "8.13", "2.50 (wall 0.226)", "2.50 (wall 0.318)" ], [ "4", "114.3 (4.50 in)", "64", "76", "8.64", "2.50 (wall 0.237)", "2.50 (wall 0.337)" ], [ "5", "141.3 (5.56 in)", "76", "89", "9.65", "3.00 (wall 0.258)", "3.00 (wall 0.375)" ], [ "6", "168.3 (6.62 in)", "89", "102", "10.92", "3.50 (wall 0.280)", "3.50 (wall 0.432)" ], [ "8", "219.1 (8.62 in)", "102", "127", "12.70", "4.00 (wall 0.322)", "4.00 (wall 0.500)" ], [ "10", "273.0 (10.75 in)", "127", "152", "12.70", "5.00 (wall 0.365)", "6.00 (wall 0.594)" ], [ "12", "323.8 (12.75 in)", "152", "178", "12.70", "6.00 (wall 0.406)", "7.00 (wall 0.688)" ] ] } }, "sheet_text": "Butt-weld caps (ASME B16.9), NPS 1/2 to 12: overall length E and E1 by wall thickness — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/butt-weld-caps/ (sheet CC BY 4.0)\nBasis: Length E / E1 (mm) and the wall that separates them from Wermac's ASME B16.9 cap table; Schedule 40 and 80 heights H (in) and walls T from Texas Flange; numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- B16.9 gives each cap size two lengths: E for walls up to a limit and E1 for thicker walls. Wermac prints both and the limiting wall (column 'wall limit'): E applies when the fitting wall is not more than the limit, E1 when it is more. Texas Flange's per-schedule heights H (weld face to the top of the dome) agree with this rule: for NPS 10 Sch 40 (wall 0.365 in, under the 12.7 mm limit) H = 5.00 in = E 127 mm; for NPS 10 Sch 80 (wall 0.594 in, over the limit) H = 6.00 in = E1 152 mm. Sch 80 at NPS 2 (wall 0.218 in = 5.54 mm, under the 5.59 mm limit) is still the short E (1.50 in = 38 mm). One boundary case disagrees: NPS 6 Sch 80 has a 0.432 in (10.97 mm) wall, 0.05 mm over Wermac's 10.92 mm limit, so the rule gives E1 = 102 mm while Texas Flange prints H = 3.50 in (89 mm, the short E); both are shown and neither is resolved here.\n- Wermac lists the limit as 12.70 mm from NPS 8 up through NPS 24; above NPS 24 it prints no E1 (by agreement between maker and buyer), and this page stops at NPS 12.\n- Where inch and mm disagree it is rounding: Texas Flange's 1.50 in at NPS 1 is Wermac's 38 mm (1.496 in).\n- No file: E, OD and wall define the length, the weld end and the wall, but not the crown. Where the straight part ends and the dome (and its knuckle radius) begin is not given as numbers in any source read, so a drawn dome would be an invention. McMaster-Carr sells butt-weld end caps with per-part STEP; its category is linked, not copied.\n- OD: Wermac prints mm (21.3 ... 323.8), Texas Flange inches as printed (0.84 ... 12.75); both are rounded figures.\n\nNPS OD, mm (in) E, mm E1, mm wall limit between E and E1, mm Sch 40 height H, in (Texas Flange) Sch 80 height H, in (Texas Flange)\n1/2 21.3 (0.84 in) 25 25 4.57 1.00 (wall 0.109) 1.00 (wall 0.147)\n3/4 26.7 (1.05 in) 25 25 3.81 1.00 (wall 0.113) 1.00 (wall 0.154)\n1 33.4 (1.32 in) 38 38 4.57 1.50 (wall 0.133) 1.50 (wall 0.179)\n1-1/4 42.2 (1.66 in) 38 38 4.83 1.50 (wall 0.140) 1.50 (wall 0.191)\n1-1/2 48.3 (1.90 in) 38 38 5.08 1.50 (wall 0.145) 1.50 (wall 0.200)\n2 60.3 (2.38 in) 38 44 5.59 1.50 (wall 0.154) 1.50 (wall 0.218)\n2-1/2 73.0 (2.88 in) 38 51 7.11 1.50 (wall 0.203) 1.50 (wall 0.276)\n3 88.9 (3.50 in) 51 64 7.62 2.00 (wall 0.216) 2.00 (wall 0.300)\n3-1/2 101.6 (4.00 in) 64 76 8.13 2.50 (wall 0.226) 2.50 (wall 0.318)\n4 114.3 (4.50 in) 64 76 8.64 2.50 (wall 0.237) 2.50 (wall 0.337)\n5 141.3 (5.56 in) 76 89 9.65 3.00 (wall 0.258) 3.00 (wall 0.375)\n6 168.3 (6.62 in) 89 102 10.92 3.50 (wall 0.280) 3.50 (wall 0.432)\n8 219.1 (8.62 in) 102 127 12.70 4.00 (wall 0.322) 4.00 (wall 0.500)\n10 273.0 (10.75 in) 127 152 12.70 5.00 (wall 0.365) 6.00 (wall 0.594)\n12 323.8 (12.75 in) 152 178 12.70 6.00 (wall 0.406) 7.00 (wall 0.688)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wermac: ASME B16.9 butt-weld cap dimensions: E, E1 and the wall that separates them (mm) — web — Publisher's page; dimensions are facts — https://wermac.org/fittings/dim_caps.html\n- Texas Flange (manufacturer / distributor): Butt-weld caps: OD, ID, wall T and height H for STD, XS, Sch 40, 80, 160, XXS — web — Publisher's page; dimensions are facts — https://texasflange.com/butt-weld-fittings/cap/\n- McMaster-Carr: Butt-weld end caps (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/end-caps/fitting-connection~butt-weld/\n\nNo true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.\nAPI: https://xemstudio.com/api/geometry?object=butt-weld-caps\n", "sources": [ { "publisher": "Wermac", "title": "ASME B16.9 butt-weld cap dimensions: E, E1 and the wall that separates them (mm)", "url": "https://wermac.org/fittings/dim_caps.html", "formats": [ "web" ], "license": "Publisher's page; dimensions are facts", "license_verified": true, "hosted": false }, { "publisher": "Texas Flange (manufacturer / distributor)", "title": "Butt-weld caps: OD, ID, wall T and height H for STD, XS, Sch 40, 80, 160, XXS", "url": "https://texasflange.com/butt-weld-fittings/cap/", "formats": [ "web" ], "license": "Publisher's page; dimensions are facts", "license_verified": true, "hosted": false }, { "publisher": "McMaster-Carr", "title": "Butt-weld end caps (free STEP/IGES per part, for your own design use; no redistribution)", "url": "https://www.mcmaster.com/products/end-caps/fitting-connection~butt-weld/", "formats": [ "STEP", "IGES", "PDF" ], "license": "McMaster-Carr site terms: personal design use, no redistribution", "license_verified": false, "hosted": false } ], "xem": { "status": "not-scanned", "sheet_free": true, "mesh_price_usd": null, "step_price_usd": null, "tolerance_mm": null }, "related": [ "butt-weld-elbows-long-radius", "butt-weld-equal-tees", "butt-weld-reducers", "schedule-40-pipe", "pvc-schedule-40-fittings-laying-lengths" ], "fits": [], "dimensions": "exact (nominal, no tolerance added)", "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no tolerance added. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn. Typical accuracy by process and ISO 286 fits: https://xemstudio.com/tolerances/", "mating": [], "faq": [ { "q": "How long is a 2 inch Schedule 40 butt-weld cap?", "a": "E = 38 mm (1.50 in) for Sch 40 and Sch 80 (walls under the 5.59 mm limit); a thicker wall (over 5.59 mm) uses E1 = 44 mm." }, { "q": "What is E1 on a weld cap?", "a": "The longer length used when the fitting wall is thicker than the size's limit (for example over 12.7 mm from NPS 8 up)." } ], "files_license": null, "offers": [], "markdown": "https://xemstudio.com/objects/butt-weld-caps/index.md" }