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ASME Reference Tables

ASME B36.10M — Pipe Schedule Chart

Complete reference table for welded and seamless wrought steel pipe dimensions per ASME B36.10M-2018. Covers all standard pipe schedules (SCH 10 through SCH 160, STD, XS, XXS) from NPS 1/8" to NPS 80", with outside diameter, wall thickness, weight per metre, and inside diameter.

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ASME B36.10M (Welded and Seamless Wrought Steel Pipe) defines the standard outside diameters and wall thicknesses for carbon and alloy steel pipe. Schedule numbers are a dimensionless index; they do not represent wall thickness directly — two different NPS sizes with the same schedule number will have different wall thicknesses.

The tables below cover 14 schedule designations and 295 NPS × schedule combinations. Rows with no defined wall for a given schedule are omitted. Data per ASME B36.10M-2018.

Table data verified 2026-07-01 — ASME B36.10M-2018.

Filter by NPS or OD
Jump to schedule
Schedule 10Schedule 20Schedule 30Schedule 40STD (Standard)Schedule 60Schedule 80XS (Extra Strong)Schedule 100Schedule 120Schedule 140Schedule 160XXS (Double Extra Strong)Schedule 5

Schedule 10

ASME B36.10M Schedule 10 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 1.24 0.28 0.19 7.8
1/4" 13.72 0.54 1.65 0.49 0.33 10.4
3/8" 17.14 0.675 1.65 0.63 0.42 13.8
1/2" 21.34 0.84 2.11 1.00 0.67 17.1
3/4" 26.67 1.05 2.11 1.28 0.86 22.4
1" 33.4 1.315 2.77 2.09 1.41 27.9
1-1/4" 42.16 1.66 2.77 2.69 1.81 36.6
1-1/2" 48.26 1.9 2.77 3.11 2.09 42.7
2" 60.32 2.375 2.77 3.93 2.64 54.8
2-1/2" 73.02 2.875 3.05 5.26 3.53 66.9
3" 88.9 3.5 3.05 6.46 4.34 82.8
3-1/2" 101.6 4 3.05 7.41 4.98 95.5
4" 114.3 4.5 3.05 8.37 5.62 108.2
5" 141.3 5.563 3.40 11.56 7.78 134.5
6" 168.27 6.625 3.40 13.82 9.30 161.5
8" 219.07 8.625 3.76 19.97 13.41 211.6
10" 273.05 10.75 4.19 27.78 18.67 264.7
12" 323.85 12.75 4.57 35.98 24.19 314.7
14" 355.6 14 6.35 54.69 36.75 342.9
16" 406.4 16 6.35 62.65 42.09 393.7
18" 457.2 18 6.35 70.60 47.44 444.5
20" 508 20 6.35 78.56 52.70 495.3
22" 558.8 22 6.35 86.51 58.13 546.1
24" 609.6 24 6.35 94.47 63.47 596.9
26" 660.4 26 7.92 127.44 85.68 644.6
28" 711.2 28 7.92 137.36 92.35 695.4
30" 762 30 7.92 147.29 99.02 746.2
32" 812.8 32 7.92 157.21 105.69 797.0
34" 863.6 34 7.92 167.13 112.36 847.8
36" 914.4 36 7.92 177.05 119.03 898.6

Schedule 20

ASME B36.10M Schedule 20 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
8" 219.07 8.625 6.35 33.31 22.38 206.4
10" 273.05 10.75 6.35 41.77 28.06 260.4
12" 323.85 12.75 6.35 49.72 33.41 311.1
14" 355.6 14 7.92 67.91 45.65 339.8
16" 406.4 16 7.92 77.83 52.32 390.6
18" 457.2 18 7.92 87.75 58.99 441.4
20" 508 20 9.52 117.03 78.67 489.0
22" 558.8 22 9.52 128.96 86.69 539.8
24" 609.6 24 9.52 140.89 94.71 590.6
26" 660.4 26 12.70 202.86 136.30 635.0
28" 711.2 28 12.70 218.77 146.99 685.8
30" 762 30 12.70 234.68 157.68 736.6
32" 812.8 32 12.70 250.59 168.37 787.4
34" 863.6 34 12.70 266.50 179.06 838.2
36" 914.4 36 12.70 282.41 189.75 889.0

Schedule 30

ASME B36.10M Schedule 30 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 1.45 0.32 0.21 7.4
1/4" 13.72 0.54 1.85 0.54 0.36 10.0
3/8" 17.14 0.675 1.85 0.70 0.47 13.4
1/2" 21.34 0.84 2.41 1.13 0.76 16.5
3/4" 26.67 1.05 2.41 1.44 0.97 21.9
1" 33.4 1.315 2.90 2.18 1.46 27.6
1-1/4" 42.16 1.66 2.97 2.87 1.93 36.2
1-1/2" 48.26 1.9 3.17 3.52 2.37 41.9
2" 60.32 2.375 3.17 4.47 3.01 54.0
2-1/2" 73.02 2.875 4.78 8.04 5.40 63.5
3" 88.9 3.5 4.78 9.92 6.66 79.3
3-1/2" 101.6 4 4.78 11.41 7.66 92.0
4" 114.3 4.5 4.78 12.91 8.67 104.7
8" 219.07 8.625 7.04 36.81 24.72 205.0
10" 273.05 10.75 7.80 51.02 34.27 257.4
12" 323.85 12.75 8.38 65.20 43.81 307.1
14" 355.6 14 9.52 81.25 54.62 336.6
16" 406.4 16 9.52 93.18 62.64 387.4
18" 457.2 18 11.13 122.44 82.23 434.9
20" 508 20 12.70 155.13 104.23 482.6
22" 558.8 22 12.70 171.04 114.92 533.4
24" 609.6 24 14.27 209.51 140.81 581.1
28" 711.2 28 15.88 272.30 182.90 679.4
30" 762 30 15.88 292.20 196.26 730.2
32" 812.8 32 15.88 312.09 209.62 781.0
34" 863.6 34 15.88 331.99 222.99 831.8
36" 914.4 36 15.88 351.88 236.35 882.6

Schedule 40

Equivalent to STD (Standard) for NPS ≤ 10"

ASME B36.10M Schedule 40 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 1.73 0.37 0.24 6.8
1/4" 13.72 0.54 2.24 0.63 0.43 9.2
3/8" 17.14 0.675 2.31 0.84 0.57 12.5
1/2" 21.34 0.84 2.77 1.27 0.85 15.8
3/4" 26.67 1.05 2.87 1.68 1.13 20.9
1" 33.4 1.315 3.38 2.50 1.68 26.6
1-1/4" 42.16 1.66 3.56 3.39 2.27 35.0
1-1/2" 48.26 1.9 3.68 4.05 2.72 40.9
2" 60.32 2.375 3.91 5.44 3.66 52.5
2-1/2" 73.02 2.875 5.16 8.64 5.80 62.7
3" 88.9 3.5 5.49 11.29 7.58 77.9
3-1/2" 101.6 4 5.74 13.57 9.12 90.1
4" 114.3 4.5 6.02 16.08 10.80 102.3
5" 141.3 5.563 6.55 21.77 14.63 128.2
6" 168.27 6.625 7.11 28.26 18.99 154.1
8" 219.07 8.625 8.18 42.54 28.58 202.7
10" 273.05 10.75 9.27 60.30 40.52 254.5
12" 323.85 12.75 10.31 79.72 53.57 303.2
14" 355.6 14 11.13 94.55 63.50 333.3
16" 406.4 16 12.70 123.31 82.85 381.0
18" 457.2 18 14.27 155.88 104.76 428.7
20" 508 20 15.09 183.43 123.23 477.8
24" 609.6 24 17.48 255.25 171.45 574.6
32" 812.8 32 17.48 342.85 230.29 777.8
34" 863.6 34 17.48 364.75 245.00 828.6
36" 914.4 36 19.05 420.64 282.62 876.3

STD (Standard)

Equivalent to SCH 40 for NPS ≤ 10"; equivalent to 9.53 mm wall for NPS ≥ 14"

ASME B36.10M STD (Standard) Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 1.73 0.37 0.24 6.8
1/4" 13.72 0.54 2.24 0.63 0.43 9.2
3/8" 17.14 0.675 2.31 0.84 0.57 12.5
1/2" 21.34 0.84 2.77 1.27 0.85 15.8
3/4" 26.67 1.05 2.87 1.68 1.13 20.9
1" 33.4 1.315 3.38 2.50 1.68 26.6
1-1/4" 42.16 1.66 3.56 3.39 2.27 35.0
1-1/2" 48.26 1.9 3.68 4.05 2.72 40.9
2" 60.32 2.375 3.91 5.44 3.66 52.5
2-1/2" 73.02 2.875 5.16 8.64 5.80 62.7
3" 88.9 3.5 5.49 11.29 7.58 77.9
3-1/2" 101.6 4 5.74 13.57 9.12 90.1
4" 114.3 4.5 6.02 16.08 10.80 102.3
5" 141.3 5.563 6.55 21.77 14.63 128.2
6" 168.27 6.625 7.11 28.26 18.99 154.1
8" 219.07 8.625 8.18 42.54 28.58 202.7
10" 273.05 10.75 9.27 60.30 40.52 254.5
12" 323.85 12.75 9.52 73.80 49.61 304.8
14" 355.6 14 9.52 81.25 54.62 336.6
16" 406.4 16 9.52 93.18 62.64 387.4
18" 457.2 18 9.52 105.11 70.65 438.2
20" 508 20 9.52 117.03 78.67 489.0
22" 558.8 22 9.52 128.96 86.69 539.8
24" 609.6 24 9.52 140.89 94.71 590.6
26" 660.4 26 9.52 152.81 102.72 641.4
28" 711.2 28 9.52 164.74 110.74 692.2
30" 762 30 9.52 176.67 118.76 743.0
32" 812.8 32 9.52 188.59 126.78 793.8
34" 863.6 34 9.52 200.52 134.79 844.6
36" 914.4 36 9.52 212.45 142.81 895.4
38" 965.2 38 9.52 224.37 150.83 946.2
40" 1016 40 9.52 236.30 158.85 997.0
42" 1066.8 42 9.52 248.23 166.86 1047.8
44" 1117.6 44 9.52 260.15 174.88 1098.6
46" 1168.4 46 9.52 272.08 182.90 1149.4
48" 1219.2 48 9.52 284.01 190.92 1200.2

Schedule 60

ASME B36.10M Schedule 60 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
8" 219.07 8.625 10.31 53.08 35.67 198.4
10" 273.05 10.75 12.70 81.54 54.79 247.7
12" 323.85 12.75 14.27 108.95 73.22 295.3
14" 355.6 14 15.09 126.72 85.13 325.4
16" 406.4 16 16.66 160.13 107.60 373.1
18" 457.2 18 19.05 205.84 138.30 419.1
20" 508 20 20.62 247.84 166.56 466.8
22" 558.8 22 22.22 294.03 197.60 514.4
24" 609.6 24 24.61 355.04 238.57 560.4

Schedule 80

Equivalent to XS (Extra Strong) for NPS ≤ 8"

ASME B36.10M Schedule 80 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 2.41 0.47 0.31 5.5
1/4" 13.72 0.54 3.02 0.80 0.54 7.7
3/8" 17.14 0.675 3.20 1.10 0.74 10.7
1/2" 21.34 0.84 3.73 1.62 1.09 13.9
3/4" 26.67 1.05 3.91 2.19 1.48 18.9
1" 33.4 1.315 4.55 3.24 2.17 24.3
1-1/4" 42.16 1.66 4.85 4.46 3.00 32.5
1-1/2" 48.26 1.9 5.08 5.41 3.63 38.1
2" 60.32 2.375 5.54 7.48 5.03 49.2
2-1/2" 73.02 2.875 7.01 11.41 7.67 59.0
3" 88.9 3.5 7.62 15.27 10.26 73.7
3-1/2" 101.6 4 8.08 18.64 12.52 85.4
4" 114.3 4.5 8.56 22.32 15.00 97.2
5" 141.3 5.563 9.52 30.94 20.80 122.3
6" 168.27 6.625 10.97 42.56 28.60 146.3
8" 219.07 8.625 12.70 64.64 43.43 193.7
10" 273.05 10.75 15.09 96.00 64.49 242.9
12" 323.85 12.75 17.48 132.07 88.71 288.9
14" 355.6 14 19.05 158.11 106.23 317.5
16" 406.4 16 21.44 203.54 136.74 363.5
18" 457.2 18 23.83 254.68 171.08 409.5
20" 508 20 26.19 311.19 209.06 455.6
22" 558.8 22 28.57 373.59 251.05 501.7
24" 609.6 24 30.96 441.80 296.86 547.7

XS (Extra Strong)

Equivalent to SCH 80 for NPS ≤ 8"; equivalent to 12.70 mm wall for NPS ≥ 14"

ASME B36.10M XS (Extra Strong) Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 2.41 0.47 0.31 5.5
1/4" 13.72 0.54 3.02 0.80 0.54 7.7
3/8" 17.14 0.675 3.20 1.10 0.74 10.7
1/2" 21.34 0.84 3.73 1.62 1.09 13.9
3/4" 26.67 1.05 3.91 2.19 1.48 18.9
1" 33.4 1.315 4.55 3.24 2.17 24.3
1-1/4" 42.16 1.66 4.85 4.46 3.00 32.5
1-1/2" 48.26 1.9 5.08 5.41 3.63 38.1
2" 60.32 2.375 5.54 7.48 5.03 49.2
2-1/2" 73.02 2.875 7.01 11.41 7.67 59.0
3" 88.9 3.5 7.62 15.27 10.26 73.7
3-1/2" 101.6 4 8.08 18.64 12.52 85.4
4" 114.3 4.5 8.56 22.32 15.00 97.2
5" 141.3 5.563 9.52 30.94 20.80 122.3
6" 168.27 6.625 10.97 42.56 28.60 146.3
8" 219.07 8.625 12.70 64.64 43.43 193.7
10" 273.05 10.75 12.70 81.54 54.79 247.7
12" 323.85 12.75 12.70 97.45 65.48 298.4
14" 355.6 14 11.91 100.95 67.84 331.8
16" 406.4 16 12.70 123.31 82.85 381.0
18" 457.2 18 12.70 139.22 93.54 431.8
20" 508 20 12.70 155.13 104.23 482.6
22" 558.8 22 12.70 171.04 114.92 533.4
24" 609.6 24 12.70 186.95 125.61 584.2
26" 660.4 26 12.70 202.86 136.30 635.0
28" 711.2 28 12.70 218.77 146.99 685.8
30" 762 30 12.70 234.68 157.68 736.6
32" 812.8 32 12.70 250.59 168.37 787.4
34" 863.6 34 12.70 266.50 179.06 838.2
36" 914.4 36 12.70 282.41 189.75 889.0
38" 965.2 38 12.70 298.32 200.44 939.8
40" 1016 40 12.70 314.23 211.13 990.6
42" 1066.8 42 12.70 330.15 221.82 1041.4
44" 1117.6 44 12.70 346.06 232.51 1092.2
46" 1168.4 46 12.70 361.97 243.20 1143.0
48" 1219.2 48 12.70 377.88 253.89 1193.8

Schedule 100

ASME B36.10M Schedule 100 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
8" 219.07 8.625 15.09 75.91 51.00 188.9
10" 273.05 10.75 18.26 114.74 77.10 236.5
12" 323.85 12.75 21.44 159.90 107.42 281.0
14" 355.6 14 23.83 194.98 130.98 307.9
16" 406.4 16 26.19 245.57 164.98 354.0
18" 457.2 18 29.36 309.78 208.15 398.5
20" 508 20 32.54 381.55 256.34 442.9
22" 558.8 22 34.92 451.15 303.16 489.0
24" 609.6 24 38.89 547.36 367.74 531.8

Schedule 120

ASME B36.10M Schedule 120 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
4" 114.3 4.5 11.13 28.32 19.02 92.0
5" 141.3 5.563 12.70 40.28 27.06 115.9
6" 168.27 6.625 14.27 54.20 36.43 139.7
8" 219.07 8.625 18.26 90.43 60.77 182.6
10" 273.05 10.75 21.44 133.04 89.38 230.2
12" 323.85 12.75 25.40 186.95 125.61 273.1
14" 355.6 14 27.79 224.66 150.93 300.0
16" 406.4 16 30.96 286.66 192.61 344.5
18" 457.2 18 34.92 363.66 244.37 387.4
20" 508 20 38.10 441.52 296.65 431.8
22" 558.8 22 41.27 526.73 353.94 476.3
24" 609.6 24 46.02 639.62 429.79 517.6

Schedule 140

ASME B36.10M Schedule 140 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
8" 219.07 8.625 20.62 100.92 67.82 177.8
10" 273.05 10.75 25.40 155.13 104.23 222.3
12" 323.85 12.75 28.57 208.05 139.81 266.7
14" 355.6 14 31.75 253.58 170.37 292.1
16" 406.4 16 36.53 333.21 223.85 333.3
18" 457.2 18 39.67 408.48 274.48 377.9
20" 508 20 44.45 508.15 341.41 419.1
22" 558.8 22 47.62 600.32 403.38 463.6
24" 609.6 24 52.37 719.68 483.57 504.9

Schedule 160

Equivalent to XXS for some NPS sizes

ASME B36.10M Schedule 160 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 3.15 0.55 0.37 4.0
1/4" 13.72 0.54 3.68 0.91 0.61 6.4
3/8" 17.14 0.675 4.01 1.30 0.87 9.1
1/2" 21.34 0.84 4.78 1.95 1.31 11.8
3/4" 26.67 1.05 5.56 2.89 1.95 15.6
1" 33.4 1.315 6.35 4.24 2.85 20.7
1-1/4" 42.16 1.66 6.35 5.61 3.77 29.5
1-1/2" 48.26 1.9 7.14 7.24 4.86 34.0
2" 60.32 2.375 8.74 11.12 7.47 42.8
2-1/2" 73.02 2.875 9.52 14.91 10.02 54.0
3" 88.9 3.5 11.13 21.35 14.34 66.6
4" 114.3 4.5 13.49 33.54 22.53 87.3
5" 141.3 5.563 15.88 49.12 32.99 109.5
6" 168.27 6.625 18.26 67.55 45.39 131.8
8" 219.07 8.625 23.01 111.26 74.76 173.1
10" 273.05 10.75 28.57 172.26 115.75 215.9
12" 323.85 12.75 33.32 238.73 160.42 257.2
14" 355.6 14 35.71 281.72 189.29 284.2
16" 406.4 16 40.49 365.38 245.48 325.4
18" 457.2 18 45.24 459.62 308.79 366.7
20" 508 20 50.01 564.85 379.53 408.0
22" 558.8 22 53.97 671.92 451.49 450.9
24" 609.6 24 59.54 807.68 542.64 490.5

XXS (Double Extra Strong)

Equivalent to SCH 160 for some NPS sizes; reserved for high-pressure service

ASME B36.10M XXS (Double Extra Strong) Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/8" 10.29 0.405 4.83 0.65 0.44 0.6
1/4" 13.72 0.54 6.05 1.14 0.77 1.6
3/8" 17.14 0.675 6.40 1.70 1.14 4.3
1/2" 21.34 0.84 7.47 2.56 1.72 6.4
3/4" 26.67 1.05 7.82 3.64 2.44 11.0
1" 33.4 1.315 9.09 5.45 3.66 15.2
1-1/4" 42.16 1.66 9.70 7.76 5.22 22.8
1-1/2" 48.26 1.9 10.16 9.55 6.41 27.9
2" 60.32 2.375 11.07 13.45 9.04 38.2
2-1/2" 73.02 2.875 14.02 20.40 13.71 45.0
3" 88.9 3.5 15.24 27.68 18.60 58.4
4" 114.3 4.5 17.12 41.03 27.57 80.1
5" 141.3 5.563 19.05 57.43 38.59 103.2
6" 168.27 6.625 21.95 79.21 53.21 124.4
8" 219.07 8.625 22.22 107.87 72.49 174.6
10" 273.05 10.75 25.40 155.13 104.23 222.3
12" 323.85 12.75 25.40 186.95 125.61 273.1

Schedule 5

ASME B36.10M Schedule 5 Pipe Schedule — Wall Thickness, Weight per Metre and ID by NPS (ASME B36.10M-2018)
NPS OD (mm) OD (in) Wall (mm) Weight (kg/m) Weight (lb/ft) ID (mm)
1/2" 21.34 0.84 1.65 0.80 0.54 18.0
3/4" 26.67 1.05 1.65 1.02 0.68 23.4
1" 33.4 1.315 1.65 1.29 0.87 30.1
1-1/4" 42.16 1.66 1.65 1.65 1.11 38.9
1-1/2" 48.26 1.9 1.65 1.90 1.28 45.0
2" 60.32 2.375 1.65 2.39 1.61 57.0
2-1/2" 73.02 2.875 2.11 3.69 2.48 68.8
3" 88.9 3.5 2.11 4.52 3.03 84.7
3-1/2" 101.6 4 2.11 5.18 3.48 97.4
4" 114.3 4.5 2.11 5.84 3.92 110.1
5" 141.3 5.563 2.77 9.46 6.36 135.8
6" 168.27 6.625 2.77 11.31 7.59 162.7
8" 219.07 8.625 2.77 14.78 9.92 213.5
10" 273.05 10.75 3.40 22.61 15.21 266.3
12" 323.85 12.75 3.96 31.24 21.00 315.9
14" 355.6 14 3.96 34.34 23.09 347.7
16" 406.4 16 4.19 41.56 27.93 398.0
18" 457.2 18 4.19 46.81 31.46 448.8
20" 508 20 4.78 59.32 39.82 498.4
22" 558.8 22 4.78 65.31 43.84 549.2
24" 609.6 24 5.54 82.53 55.42 598.5
30" 762 30 6.35 118.34 79.51 749.3

Notes

Frequently Asked Questions

What is the difference between NPS and DN in pipe sizing?

NPS (Nominal Pipe Size) is the imperial designation used in North American standards; DN (Diamètre Nominal) is the metric equivalent used in ISO and European standards. They refer to the same standardised pipe sizes: NPS 2 = DN 50, NPS 4 = DN 100, NPS 6 = DN 150, NPS 8 = DN 200, NPS 12 = DN 300, NPS 16 = DN 400, NPS 24 = DN 600. Above NPS 14, the OD equals the NPS in inches (e.g., NPS 16 has OD = 406.4mm = 16 inches). Below NPS 14, the OD does not numerically equal the NPS designation.

What is the difference between Schedule 40 and Schedule 80 pipe?

Schedule 40 and Schedule 80 designate wall thickness categories within ASME B36.10M. For NPS 6 (168.3mm OD), Schedule 40 has a wall of 7.11mm while Schedule 80 has 10.97mm. Schedule 80 corresponds to the Extra Strong (XS) wall designation for sizes up to NPS 8. The higher wall thickness of Schedule 80 gives approximately 40–55% greater pressure-bearing capacity than Schedule 40 for the same OD and material grade. Above NPS 10, schedule numbers and the Standard/Extra Strong/Double Extra Strong (STD/XS/XXS) designations are used in parallel, and not all schedules are available for all sizes.

What is the formula for steel pipe weight per metre in ASME B36.10M?

The nominal weight of steel pipe per metre is W = 0.02466 × t × (OD − t) kg/m, where OD and t are in millimetres. This is based on a steel density of 7850 kg/m³. For example, NPS 8 Schedule 40 pipe (OD = 219.1mm, t = 8.18mm): W = 0.02466 × 8.18 × (219.1 − 8.18) ≈ 42.5 kg/m. ASME B36.10M tabulates nominal plain-end weights; actual weights including thread and coupling or coating are higher. The same formula is used in API 5CT, API 5L, and ISO specifications.

Does ASME B36.10M cover stainless steel pipe?

No. ASME B36.10M covers welded and seamless wrought carbon and alloy steel pipe. Stainless steel pipe dimensions are covered by ASME B36.19M, which uses the same nominal outside diameters as B36.10M but defines stainless-specific schedule numbers (5S, 10S, 40S, 80S). For a given NPS, the OD is identical in both standards, so flanges, fittings, and connections are interchangeable. The wall thicknesses defined in B36.19M differ from B36.10M schedules of the same number — for example, B36.19M Schedule 40S is not the same wall as B36.10M Schedule 40 for all sizes.

What is the difference between ASME B36.10M and ASME B36.19M?

ASME B36.10M standardises the dimensions of welded and seamless wrought steel pipe (carbon and alloy steel), while ASME B36.19M standardises stainless steel pipe. Both use the same nominal outside diameters for a given NPS, so components are dimensionally compatible across the two standards. The key difference is the schedule set: B36.19M adds the stainless-specific schedules 5S, 10S, 40S, and 80S, which generally provide thinner walls suited to the higher strength and corrosion resistance of stainless steel. Where the two standards share a schedule number, the wall thickness is not necessarily identical, so the correct standard must be cited when specifying stainless pipe.

What do STD, XS, and XXS mean in pipe schedules?

STD (Standard), XS (Extra Strong), and XXS (Double Extra Strong) are the original wall-thickness designations that predate the numbered schedule system and are retained in ASME B36.10M. For sizes up to NPS 10, STD is equivalent to Schedule 40; for sizes up to NPS 8, XS is equivalent to Schedule 80. Above these sizes the wall thicknesses diverge: STD holds a constant 9.53 mm wall and XS a constant 12.70 mm wall for NPS 14 and larger, regardless of diameter. XXS has no single equivalent schedule number — its wall is roughly double the XS wall for smaller sizes and it is used for high-pressure service. When both a schedule number and a letter designation exist for a size, they are used interchangeably.

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