PipeData

Schedule 40S Pipe Dimensions

ASME B36.19M stainless steel pipe in 40S, NPS 1/8 through NPS 24 — with the B36.10M Schedule 40 wall alongside, because the two are routinely swapped by mistake.

Schedule
40S
Standard
ASME B36.19M
Material
Stainless steel
Sizes published
23 (NPS 1/8 to NPS 24)
Thinnest wall
0.068 in (1.7 mm) at NPS 1/8
Thickest wall
0.375 in (9.5 mm) at NPS 12

Dimensions are given in inches, with the millimetre equivalent beneath in grey.

ASME B36.19M schedule 40S stainless pipe dimensions, with the B36.10M Schedule 40 comparison.
SizeDNOutside diameter40S wallInside diameterWeight, emptyvs Schedule 40
NPS 1/8DN 60.40510.29 mm0.0681.73 mm0.2696.83 mm0.250.37 kg/msame as Sch 40
NPS 1/4DN 80.54013.72 mm0.0882.24 mm0.3649.25 mm0.430.64 kg/msame as Sch 40
NPS 3/8DN 100.67517.14 mm0.0912.31 mm0.49312.52 mm0.580.86 kg/msame as Sch 40
NPS 1/2DN 150.84021.34 mm0.1092.77 mm0.62215.80 mm0.861.29 kg/msame as Sch 40
NPS 3/4DN 201.05026.67 mm0.1132.87 mm0.82420.93 mm1.151.71 kg/msame as Sch 40
NPS 1DN 251.31533.40 mm0.1333.38 mm1.04926.64 mm1.712.54 kg/msame as Sch 40
NPS 1 1/4DN 321.66042.16 mm0.1403.56 mm1.38035.05 mm2.313.44 kg/msame as Sch 40
NPS 1 1/2DN 401.90048.26 mm0.1453.68 mm1.61040.89 mm2.764.11 kg/msame as Sch 40
NPS 2DN 502.37560.32 mm0.1543.91 mm2.06752.50 mm3.715.52 kg/msame as Sch 40
NPS 2 1/2DN 652.87573.02 mm0.2035.16 mm2.46962.71 mm5.898.76 kg/msame as Sch 40
NPS 3DN 803.50088.90 mm0.2165.49 mm3.06877.93 mm7.7011.45 kg/msame as Sch 40
NPS 3 1/2DN 904.000101.60 mm0.2265.74 mm3.54890.12 mm9.2513.77 kg/msame as Sch 40
NPS 4DN 1004.500114.30 mm0.2376.02 mm4.026102.26 mm10.9616.31 kg/msame as Sch 40
NPS 5DN 1255.563141.30 mm0.2586.55 mm5.047128.19 mm14.8522.10 kg/msame as Sch 40
NPS 6DN 1506.625168.27 mm0.2807.11 mm6.065154.05 mm19.2828.69 kg/msame as Sch 40
NPS 8DN 2008.625219.07 mm0.3228.18 mm7.981202.72 mm29.0143.17 kg/msame as Sch 40
NPS 10DN 25010.750273.05 mm0.3659.27 mm10.020254.51 mm41.1361.21 kg/msame as Sch 40
NPS 12DN 30012.750323.85 mm0.3759.52 mm12.000304.80 mm50.3574.93 kg/mSch 40 is 0.406
NPS 14DN 35014.000355.60 mm0.3759.52 mm13.250336.55 mm55.4482.50 kg/mSch 40 is 0.438
NPS 16DN 40016.000406.40 mm0.3759.52 mm15.250387.35 mm63.5894.61 kg/mSch 40 is 0.500
NPS 18DN 45018.000457.20 mm0.3759.52 mm17.250438.15 mm71.71106.72 kg/mSch 40 is 0.562
NPS 20DN 50020.000508.00 mm0.3759.52 mm19.250488.95 mm79.85118.83 kg/mSch 40 is 0.594
NPS 24DN 60024.000609.60 mm0.3759.52 mm23.250590.55 mm96.13143.05 kg/mSch 40 is 0.688

Weight is plain-end austenitic stainless, taken as 1.5% heavier than the carbon steel formula w = 10.69 × t × (OD − t) lb/ft.

40S is not the same as Schedule 40 everywhere. The two agree in 17 of the 23 sizes published, and disagree at NPS 12 (0.375 in against 0.406 in), NPS 14 (0.375 in against 0.438 in), NPS 16 (0.375 in against 0.500 in), NPS 18 (0.375 in against 0.562 in), NPS 20 (0.375 in against 0.594 in) and NPS 24 (0.375 in against 0.688 in). Substituting one for the other in those sizes puts the wrong wall in the line.

Guides and comparisons for this page

Schedule 5S vs Schedule 10SThe two light stainless walls side by side.Carbon steel vs stainless steel pipeStrength, temperature and corrosion trade-offs.304 vs 316 stainless steel pipeWhat the molybdenum in 316 buys.What a pipe schedule actually isWhy a schedule is a wall series and not a thickness.

Common questions

Is 40S the same as Schedule 40?

Not in every size. They agree in 17 sizes and disagree at NPS 12, NPS 14, NPS 16, NPS 18, NPS 20 and NPS 24. The S suffix always signals stainless pipe to ASME B36.19M, which also stops at NPS 24 in this schedule where B36.10M continues.

What sizes does 40S come in?

NPS 1/8 through NPS 24 — 23 sizes. B36.19 is a shorter standard than B36.10: B36.19 publishes 40S and 80S through NPS 24, except NPS 22, and 5S and 10S through NPS 30. Beyond that, stainless pipe is ordered to a B36.10 schedule.

Why is 40S pipe used?

Stainless costs several times what carbon steel does, so stainless lines are run as thin as the pressure allows. The S-schedules exist to give that thin end of the range a designation — 10S in particular is the workhorse wall for low-pressure stainless process and sanitary piping.

Other stainless schedules

Sch 5SSch 10SSch 80S

How B36.19M compares with B36.10M →