Pipe & Flange Wall Thickness Schedule Chart

ASME B36.10 / B36.19 Reference

Standard Wall Thickness Schedules for Weld Neck Flanges & Piping

Weld Neck and Socket Weld flanges must be ordered with a bore thickness matching the mating pipe schedule. Below is the complete schedule chart in inches for ASME B36.10M carbon/alloy steel pipe and ASME B36.19M stainless steel piping.

Complete Wall Thickness Schedule (NPS ½" to 24")

Nominal Size (NPS) Outside Diameter (OD) Schedule 10 / 10S Schedule 40 / STD Schedule 80 / XS Schedule 160 XXS Thickness
1/2" 0.840"0.083"0.109"0.147"0.188"0.294"
3/4" 1.050"0.083"0.113"0.154"0.219"0.308"
1" 1.315"0.109"0.133"0.179"0.250"0.358"
1-1/4" 1.660"0.109"0.140"0.191"0.250"0.382"
1-1/2" 1.900"0.109"0.145"0.200"0.281"0.400"
2" 2.375"0.109"0.154"0.218"0.344"0.436"
2-1/2" 2.875"0.120"0.203"0.276"0.375"0.552"
3" 3.500"0.120"0.216"0.300"0.438"0.600"
3-1/2" 4.000"0.120"0.226"0.318"--0.636"
4" 4.500"0.120"0.237"0.337"0.531"0.674"
5" 5.563"0.134"0.258"0.375"0.625"0.750"
6" 6.625"0.134"0.280"0.432"0.719"0.864"
8" 8.625"0.148"0.322"0.500"0.906"0.875"
10" 10.750"0.165"0.365"0.500"1.125"1.000"
12" 12.750"0.180"0.375"0.500"1.312"1.000"
14" 14.000"0.188"0.375"0.500"1.406"--
16" 16.000"0.188"0.375"0.500"1.562"--
18" 18.000"0.188"0.375"0.500"1.781"--
20" 20.000"0.218"0.375"0.500"1.968"--
24" 24.000"0.250"0.375"0.500"2.344"--

📌 Weld Neck Bore Specification Note

When ordering Weld Neck flanges, always specify the exact pipe schedule (e.g., Sch 40, Sch 80, Sch 160) or exact inner bore diameter (ID) to ensure smooth transition and avoid turbulence at the weld butt joint.

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