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Engineering Data Sheet
Roll Groove Dimensional Standards
Complete groove dimension tables for carbon steel pipe and a full range of pipe materials, compiled by Welping. All measurements are expressed in millimeters (mm).
Groove Geometry Essentials for Dependable Pipe Joints
Cold-formed roll grooves are the industry-standard way to prepare pipe ends for fire protection, HVAC, and industrial installations. A correctly machined groove locks the coupling in place, delivering tight, durable joints while cutting down on installation time and site labor.
Two comprehensive tables are provided here: the Original Groove System (OGS), which covers carbon steel pipe and all materials from 1" to 42", and the Advanced Groove System (AGS), which covers carbon steel and stainless steel pipe (Schedule 10S) from 14" to 78".
- OGS series spans 1" to 42" — 42 listed sizes
- AGS series spans 14" to 78" — 37 listed sizes
- Every value checked and expressed in millimeters
- Edition 2.0 — released November 2025
OGS Roll Groove Specifications
The Original Groove System (OGS) applies to carbon steel pipe and all other pipe materials, with a size range of 1" to 42". Values in the table below are given in millimeters.
OGS Groove Profile at a Glance
This drawing identifies the four critical dimensions of the Original Groove System: gasket seat “A”, groove width “B”, groove diameter “C”, and groove depth “D”. Figures are in millimeters per the Welping standard (Edition 2.0).
| Pipe Size | Pipe Outside Diameter | Actual Pipe Outside Diameter (mm) | Gasket Seat “A” (mm) | Groove Width “B” (mm) | Groove Diameter “C” (mm) | Groove Depth “D” (ref) | Min. Allow. Wall Thick “T” | Max. Allow. Flare Dia. “F” | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Max. | Min. | Basic | Max. | Min. | Basic | Max. | Min. | Max. | Min. | |||||
| 1" | 33.7mm | 34.11 | 33.02 | 15.88 | 16.64 | 15.12 | 7.14 | 7.9 | 6.38 | 30.23 | 29.85 | 1.6 | 1.65 | 34.5 |
| 1-1/4" | 42.4mm | 42.9 | 41.8 | 15.88 | 16.64 | 15.12 | 7.14 | 7.9 | 6.38 | 38.99 | 38.61 | 1.6 | 1.65 | 45 |
| 1-1/2" | 48.3mm | 48.78 | 47.78 | 15.88 | 16.64 | 15.12 | 7.14 | 7.9 | 6.38 | 45.09 | 44.71 | 1.6 | 1.65 | 51.1 |
| 2" | 57.0mm | 57.61 | 56.39 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 53.85 | 53.47 | 1.60 | 1.65 | 59.7 |
| 2" | 60.3mm | 60.91 | 59.69 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 57.15 | 56.77 | 1.60 | 1.65 | 63 0 |
| 2-1/2" | 73.0mm | 73.74 | 72.26 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 69.09 | 68.63 | 1.98 | 2.11 | 75.7 |
| 2-1/2" | 76.1mm | 76.86 | 75.34 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 72.26 | 71.8 | 1.98 | 2.11 | 78.7 |
| 3" | 88.9mm | 89.79 | 88.11 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 84.94 | 84.48 | 1.98 | 2.11 | 91.4 |
| 3-1/2" | 101.6mm | 101.62 | 100.81 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 97.38 | 96.87 | 2.11 | 2.11 | 104.1 |
| 4" | 108.0mm | 109.09 | 107.21 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 103.73 | 103.22 | 2.11 | 2.11 | 110.5 |
| 4" | 114.3mm | 115.44 | 113.51 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 110.08 | 109.57 | 2.11 | 2.11 | 116.8 |
| 5" | 127.0mm | 128.27 | 126.21 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 122.78 | 122.27 | 2.11 | 2.41 | 129.5 |
| 5" | 133.0mm | 134.35 | 132.21 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 129.13 | 128.62 | 2.11 | 2.77 | 135.9 |
| 5" | 139.7mm | 141.12 | 138.91 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 135.48 | 134.97 | 2.11 | 2.77 | 142.2 |
| 5" | 141.3mm | 142.72 | 140.51 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 137.03 | 136.47 | 2.13 | 2.77 | 143.8 |
| 6" | 152.4mm | 153.82 | 151.61 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 148.08 | 147.52 | 2.16 | 2.77 | 154.9 |
| 6" | 159.0mm | 160.6 | 158.21 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 154.68 | 154.12 | 2.16 | 2.77 | 161.3 |
| 6" | 165.1mm | 166.7 | 164.31 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 160.9 | 160.34 | 2.16 | 2.77 | 167.6 |
| 6" | 168.3mm | 169.9 | 167.51 | 15.88 | 16.64 | 15.12 | 8.74 | 9.5 | 7.98 | 163.96 | 163.4 | 2.16 | 2.77 | 170.9 |
| 8" | 203.2mm | 204.8 | 202.41 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 198.53 | 197.89 | 2.34 | 2.77 | 207.5 |
| 8" | 216.3mm | 217.9 | 215.51 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 211.61 | 210.97 | 2.34 | 2.77 | 220.7 |
| 8" | 219.1mm | 220.7 | 218.31 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 214.4 | 213.76 | 2.34 | 2.77 | 223.5 |
| 10" | 254.0mm | 255.6 | 253.21 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 249.23 | 248.54 | 2.39 | 3.4 | 258.3 |
| 10" | 267.4mm | 269.0 | 266.61 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 262.6 | 261.91 | 2.39 | 3.4 | 271.8 |
| 10" | 273.0mm | 274.6 | 272.21 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 268.28 | 267.59 | 2.39 | 3.4 | 277.4 |
| 12" | 304.8mm | 306.4 | 304.01 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 299.24 | 298.48 | 2.77 | 3.96 | 309.1 |
| 12" | 318.5mm | 320.1 | 317.71 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 312.90 | 312.14 | 2.77 | 3.96 | 322.8 |
| 12" | 323.9mm | 325.5 | 323.11 | 19.05 | 19.81 | 18.29 | 11.91 | 12.67 | 11.15 | 318.29 | 317.53 | 2.77 | 3.96 | 328.2 |
| 14" | 355.6mm | 357.2 | 354.81 | 23.83 | 24.59 | 23.07 | 11.91 | 12.67 | 11.15 | 350.04 | 349.28 | 2.77 | 3.96 | 359.7 |
| 14" | 377.0mm | 378.6 | 376.21 | 23.83 | 24.59 | 23.07 | 11.91 | 12.67 | 11.15 | 371.44 | 370.68 | 2.77 | 4.19 | 381.1 |
| 15" | 381.0mm | 382.6 | 379.4 | 23.83 | 24.59 | 23.07 | 11.91 | 12.67 | 11.15 | 375.44 | 374.68 | 2.77 | 4.19 | 385.1 |
| 16" | 406.4mm | 408.0 | 405.61 | 23.83 | 24.59 | 23.07 | 11.91 | 12.67 | 11.15 | 400.84 | 400.08 | 2.77 | 4.19 | 410.5 |
| 18" | 457.2mm | 455.6 | 453.21 | 25.4 | 26.16 | 24.64 | 11.91 | 12.67 | 11.15 | 451.64 | 450.88 | 2.77 | 4.19 | 461.3 |
| 20" | 508mm | 506.4 | 504.01 | 25.4 | 26.16 | 24.64 | 11.91 | 12.67 | 11.15 | 502.44 | 501.68 | 2.77 | 4.78 | 512.1 |
| 22" | 559mm | 557.4 | 555.01 | 25.4 | 26.16 | 24.64 | 12.7 | 13.46 | 11.94 | 550.06 | 549.3 | 4.37 | 4.78 | 563.9 |
| 24" | 610mm | 611.6 | 609.21 | 25.4 | 26.16 | 24.64 | 12.7 | 13.46 | 11.94 | 600.86 | 600.1 | 4.37 | 5.54 | 614.7 |
| 26" | 660.4mm | 662.76 | 659.61 | 44.45 | 45.21 | 43.69 | 15.88 | 16.64 | 15.12 | 647.7 | 646.1 | 6.35 | 6.35 | 665.5 |
| 28" | 711.0mm | 713.36 | 710.21 | 44.45 | 45.21 | 43.69 | 15.88 | 16.64 | 15.12 | 698.5 | 696.9 | 6.35 | 6.35 | 716.3 |
| 30" | 762.0mm | 764.36 | 761.21 | 44.45 | 45.21 | 43.69 | 15.88 | 16.64 | 15.12 | 749.3 | 747.7 | 6.35 | 6.35 | 767.1 |
| 32" | 813.0mm | 815.36 | 812.21 | 44.45 | 45.21 | 43.69 | 15.88 | 16.64 | 15.12 | 800.1 | 798.5 | 6.35 | 6.35 | 817.9 |
| 36" | 914.0mm | 916.36 | 913.21 | 44.45 | 45.21 | 43.69 | 15.88 | 16.64 | 15.12 | 901.7 | 900.1 | 6.35 | 6.35 | 919.5 |
| 42" | 1067.0mm | 1069.36 | 1066.21 | 50.8 | 51.56 | 50.04 | 15.88 | 16.64 | 15.12 | 1054.1 | 1052.5 | 6.35 | 6.35 | 1071.8 |
A – Gasket Seat
B – Groove Width
C – Groove Diameter
D – Groove Depth (ref)
T – Min. Allowable Wall Thickness
F – Max. Allowable Flare Diameter
AGS Roll Groove Specifications
The Advanced Groove System (AGS) serves carbon steel pipe and stainless steel pipe (Schedule 10S), in sizes from 14" to 78". All figures below are in millimeters.
AGS Groove Profile at a Glance
This drawing shows the critical dimensions of the Advanced Groove System: gasket seat “A”, groove width “B”, groove diameter “C”, and nominal wall thickness for grooving “T”. Figures are in millimeters per the Welping standard (Edition 2.0).
| Pipe Size | Pipe Outside Diameter | Actual Pipe Outside Diameter (mm) | Gasket Seat “A” (mm) | Groove Width “B” | Groove Diameter “C” (mm) | Nominal Wall Thickness for Grooving “T” | Max. Allow. Flare Dia. “F” | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Max. | Min. | Basic | Max. | Min. | Max. | Min. | Carbon Steel | S.S Steel Sch.10S | ||||
| 14" | 355.6mm | 358.0 | 354.8 | 38.1 | 38.89 | 36.5 | 11.6 | 342.9 | 341.8 | 5.6–19.1 | 4.8 | 361.4 |
| 14" | 377.0mm | 379.4 | 376.2 | 38.1 | 38.89 | 36.5 | 11.6 | 364.3 | 363.2 | 5.5–19.1 | – | 382.8 |
| 16" | 406.4mm | 408.8 | 405.6 | 38.1 | 38.89 | 36.5 | 11.6 | 393.7 | 392.6 | 6.4–19.1 | 4.8 | 412.2 |
| 16" | 426.0mm | 428.4 | 425.2 | 38.1 | 38.89 | 36.5 | 11.6 | 413.3 | 412.2 | 6.5–19.1 | – | 431.8 |
| 18" | 457.2mm | 459.6 | 456.4 | 38.1 | 38.89 | 36.5 | 11.6 | 444.5 | 443.4 | 6.4–19.1 | 4.8 | 463.0 |
| 18" | 480.0mm | 482.4 | 479.2 | 38.1 | 38.89 | 36.5 | 11.6 | 467.3 | 466.2 | 6.5–19.1 | – | 485.9 |
| 20" | 508.0mm | 510.4 | 507.2 | 38.1 | 38.89 | 36.5 | 11.6 | 495.3 | 494.2 | 6.4–19.1 | 5.5 | 513.8 |
| 20" | 530.0mm | 532.4 | 529.2 | 38.1 | 38.89 | 36.5 | 11.6 | 517.3 | 516.2 | 6.5–19.1 | – | 535.7 |
| 22" | 558.8mm | 561.2 | 558.0 | 38.1 | 38.89 | 36.5 | 11.6 | 546.1 | 545.0 | 6.4–19.1 | 5.5 | 564.6 |
| 24" | 609.6mm | 612.0 | 608.8 | 38.1 | 38.89 | 36.5 | 11.6 | 596.9 | 595.8 | 6.4–19.1 | 5.5 | 615.4 |
| 24" | 630.0mm | 632.4 | 629.2 | 38.1 | 38.89 | 36.5 | 11.6 | 617.3 | 616.2 | 6.5–19.1 | – | 635.8 |
| 26" | 660.4mm | 662.0 | 658.8 | 44.5 | 45.29 | 42.9 | 13.6 | 645.9 | 644.4 | 8.0–19.1 | – | 668.0 |
| 28" | 711.2mm | 712.8 | 709.6 | 44.5 | 45.29 | 42.9 | 13.6 | 696.7 | 695.2 | 8.0–19.1 | – | 718.8 |
| 28" | 720.0mm | 721.6 | 718.4 | 44.5 | 45.29 | 42.9 | 13.6 | 705.5 | 704.0 | 8.0–19.1 | – | 727.6 |
| 30" | 762.0mm | 763.6 | 760.4 | 44.5 | 45.29 | 42.9 | 13.6 | 747.5 | 746.0 | 8.0–19.1 | – | 769.6 |
| 32" | 812.8mm | 814.4 | 811.2 | 44.5 | 45.29 | 42.9 | 13.6 | 798.3 | 796.8 | 8.0–19.1 | – | 820.4 |
| 32" | 820.0mm | 821.6 | 818.4 | 44.5 | 45.29 | 42.9 | 13.6 | 805.5 | 804.0 | 8.0–19.1 | – | 827.6 |
| 34" | 863.6mm | 865.2 | 862.0 | 44.5 | 45.29 | 42.9 | 13.6 | 849.1 | 847.6 | 8.0–19.1 | – | 871.2 |
| 36" | 914.4mm | 916.0 | 912.8 | 44.5 | 45.29 | 42.9 | 13.6 | 899.9 | 898.4 | 8.0–19.1 | – | 922.0 |
| 36" | 920.0mm | 921.6 | 918.4 | 44.5 | 45.29 | 42.9 | 13.6 | 905.5 | 904.0 | 8.0–19.1 | – | 927.6 |
| 38" | 965.0mm | 966.6 | 963.4 | 44.5 | 45.29 | 42.9 | 13.6 | 950.7 | 949.2 | 8.0–19.1 | – | 972.8 |
| 40" | 1016.0mm | 1017.6 | 1014.4 | 50.8 | 51.59 | 49.2 | 14.3 | 1000.1 | 998.6 | 8.0–19.1 | – | 1023.6 |
| 42" | 1066.8mm | 1068.4 | 1065.2 | 50.8 | 51.59 | 49.2 | 14.3 | 1050.9 | 1049.4 | 8.0–19.1 | – | 1074.4 |
| 44" | 1117.6mm | 1119.2 | 1116.0 | 50.8 | 51.59 | 49.2 | 14.3 | 1101.7 | 1100.2 | 8.0–19.1 | – | 1125.2 |
| 46" | 1168.4mm | 1170.0 | 1166.8 | 50.8 | 51.59 | 49.2 | 14.3 | 1152.5 | 1151.0 | 8.0–19.1 | – | 1176.0 |
| 48" | 1219.2mm | 1220.8 | 1217.6 | 50.8 | 51.59 | 49.2 | 14.3 | 1203.3 | 1201.8 | 8.0–19.1 | – | 1226.8 |
| 50" | 1270.0mm | 1271.6 | 1268.4 | 50.8 | 51.59 | 49.2 | 14.3 | 1254.1 | 1252.6 | 8.0–19.1 | – | 1277.6 |
| 54" | 1371.6mm | 1373.2 | 1370.0 | 63.5 | 64.29 | 61.9 | 14.3 | 1357.1 | 1355.6 | 9.5–19.1 | – | 1379.2 |
| 56" | 1422.4mm | 1424.0 | 1420.8 | 63.5 | 64.29 | 61.9 | 14.3 | 1407.9 | 1406.4 | 9.5–19.1 | – | 1430.0 |
| 58" | 1473.2mm | 1474.8 | 1471.6 | 63.5 | 64.29 | 61.9 | 14.3 | 1458.7 | 1457.2 | 9.5–19.1 | – | 1480.8 |
| 60" | 1524.0mm | 1525.6 | 1522.4 | 63.5 | 64.29 | 61.9 | 14.3 | 1509.5 | 1508.0 | 9.5–19.1 | – | 1531.6 |
| 62" | 1574.8mm | 1576.4 | 1573.2 | 63.5 | 64.29 | 61.9 | 14.3 | 1560.3 | 1558.8 | 9.5–19.1 | – | 1582.4 |
| 64" | 1625.6mm | 1627.2 | 1624.0 | 63.5 | 64.29 | 61.9 | 14.3 | 1611.1 | 1609.6 | 12.7–19.1 | – | 1633.2 |
| 66" | 1676.4mm | 1678.0 | 1674.8 | 63.5 | 64.29 | 61.9 | 14.3 | 1661.9 | 1660.4 | 12.7–19.1 | – | 1684.0 |
| 68" | 1727.2mm | 1728.8 | 1725.6 | 63.5 | 64.29 | 61.9 | 14.3 | 1712.7 | 1711.2 | 12.7–19.1 | – | 1734.8 |
| 72" | 1828.8mm | 1830.4 | 1827.2 | 63.5 | 64.29 | 61.9 | 14.3 | 1814.3 | 1812.8 | 12.7–19.1 | – | 1836.4 |
| 78" | 1981.2mm | 1982.8 | 1979.6 | 63.5 | 64.29 | 61.9 | 14.3 | 1966.7 | 1965.2 | 12.7–19.1 | – | 1990.3 |
A – Gasket Seat
B – Groove Width
C – Groove Diameter
T – Nominal Wall Thickness for Grooving (Carbon Steel / S.S Steel Sch.10S)
F – Max. Allowable Flare Diameter
Industries That Rely on These Groove Standards
Both OGS and AGS tables support grooved piping installations in some of the most demanding sectors:
- Fire Protection — sprinkler and standpipe networks built to NFPA requirements
- HVAC & Refrigeration — chilled water, condenser water, and heating loops
- Industrial Piping — mining, chemical, and processing plants handling heavy-wall pipe
- Water & Wastewater — municipal and commercial distribution systems
Groove quality directly affects coupling performance, so it pays to get the numbers right. Before grooving, measure the actual outside diameter of the pipe and double-check that the wall thickness meets the minimum value shown for the system you are using.
1. Check the Pipe OD
Take the actual outside diameter of the pipe and find the closest matching row in the chart.
2. Confirm Wall Thickness
Make sure the pipe wall is at least as thick as the minimum value “T” given for your groove system.
3. Configure the Rollers
Adjust the grooving machine rollers to the groove width “B” and diameter “C” specified in the chart.
4. Inspect the Finished Groove
Use a go/no-go gauge to verify that the groove depth and diameter stay within the listed tolerances.
Questions About Groove Dimensions?
Our engineers can help you verify the correct groove geometry for your pipe material, wall thickness, and chosen coupling. Downloadable OGS and AGS specification documents are also available for both systems.