Schedule 5S vs Schedule 10S Pipe
The two thin-wall stainless schedules of ASME B36.19M — what separates them dimensionally, and which one belongs in a process line.
- Sizes with both
- 21
- 10S weight penalty
- +33% on average
- Standard
- ASME B36.19M
- Largest size published
- NPS 30
Short answer. 5S is the thinnest wall B36.19M publishes and 10S is the next step up — about 33% heavier on average, at the same outside diameter. Both are welded stainless walls with no corrosion allowance. 5S suits low-pressure vents, drains and sanitary work; 10S is the general-purpose stainless process wall and the one most warehouses stock.
Same outside diameter, same standard, different wall
B36.19M does not publish its own outside diameters — it uses B36.10M's. The S-schedules are wall thickness series layered onto the same dimensional envelope, which is why stainless pipe takes the same B16.9 fittings and B16.5 flanges as carbon steel of the same NPS.
Where B36.19M and B36.10M overlap, the walls largely coincide: 5S matches its B36.10M counterpart in 21 sizes and 10S in 24. The value of the S designation is not a different number — it is the stainless material, tolerance and finish requirements that come with it. See the B36.19M reference for the size-by-size divergences.
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| NPS | OD | 5S wall | 10S wall | 5S bore | 10S bore | 5S weight | 10S weight | Weight change |
|---|---|---|---|---|---|---|---|---|
| NPS 1/2 | 0.84021.34 mm | 0.0651.65 mm | 0.0832.11 mm | 0.71018.03 mm | 0.67417.12 mm | 0.540.80 kg/m | 0.671.00 kg/m | +25% |
| NPS 3/4 | 1.05026.67 mm | 0.0651.65 mm | 0.0832.11 mm | 0.92023.37 mm | 0.88422.45 mm | 0.681.02 kg/m | 0.861.28 kg/m | +25% |
| NPS 1 | 1.31533.40 mm | 0.0651.65 mm | 0.1092.77 mm | 1.18530.10 mm | 1.09727.86 mm | 0.871.29 kg/m | 1.402.09 kg/m | +62% |
| NPS 1 1/4 | 1.66042.16 mm | 0.0651.65 mm | 0.1092.77 mm | 1.53038.86 mm | 1.44236.63 mm | 1.111.65 kg/m | 1.812.69 kg/m | +63% |
| NPS 1 1/2 | 1.90048.26 mm | 0.0651.65 mm | 0.1092.77 mm | 1.77044.96 mm | 1.68242.72 mm | 1.271.90 kg/m | 2.083.10 kg/m | +64% |
| NPS 2 | 2.37560.32 mm | 0.0651.65 mm | 0.1092.77 mm | 2.24557.02 mm | 2.15754.79 mm | 1.602.39 kg/m | 2.643.93 kg/m | +64% |
| NPS 2 1/2 | 2.87573.02 mm | 0.0832.11 mm | 0.1203.05 mm | 2.70968.81 mm | 2.63566.93 mm | 2.473.68 kg/m | 3.535.25 kg/m | +43% |
| NPS 3 | 3.50088.90 mm | 0.0832.11 mm | 0.1203.05 mm | 3.33484.68 mm | 3.26082.80 mm | 3.034.51 kg/m | 4.336.45 kg/m | +43% |
| NPS 3 1/2 | 4.000101.60 mm | 0.0832.11 mm | 0.1203.05 mm | 3.83497.38 mm | 3.76095.50 mm | 3.475.17 kg/m | 4.977.40 kg/m | +43% |
| NPS 4 | 4.500114.30 mm | 0.0832.11 mm | 0.1203.05 mm | 4.334110.08 mm | 4.260108.20 mm | 3.925.83 kg/m | 5.618.35 kg/m | +43% |
| NPS 5 | 5.563141.30 mm | 0.1092.77 mm | 0.1343.40 mm | 5.345135.76 mm | 5.295134.49 mm | 6.359.45 kg/m | 7.7711.56 kg/m | +22% |
| NPS 6 | 6.625168.27 mm | 0.1092.77 mm | 0.1343.40 mm | 6.407162.74 mm | 6.357161.47 mm | 7.5911.29 kg/m | 9.2913.82 kg/m | +22% |
| NPS 8 | 8.625219.07 mm | 0.1092.77 mm | 0.1483.76 mm | 8.407213.54 mm | 8.329211.56 mm | 9.9114.75 kg/m | 13.4019.94 kg/m | +35% |
| NPS 10 | 10.750273.05 mm | 0.1343.40 mm | 0.1654.19 mm | 10.482266.24 mm | 10.420264.67 mm | 15.1922.61 kg/m | 18.6527.76 kg/m | +23% |
| NPS 12 | 12.750323.85 mm | 0.1563.96 mm | 0.1804.57 mm | 12.438315.93 mm | 12.390314.71 mm | 20.9831.23 kg/m | 24.1735.96 kg/m | +15% |
| NPS 14 | 14.000355.60 mm | 0.1563.96 mm | 0.1884.78 mm | 13.688347.68 mm | 13.624346.05 mm | 23.0734.33 kg/m | 27.7341.27 kg/m | +20% |
| NPS 16 | 16.000406.40 mm | 0.1654.19 mm | 0.1884.78 mm | 15.670398.02 mm | 15.624396.85 mm | 27.9041.53 kg/m | 31.7547.25 kg/m | +14% |
| NPS 18 | 18.000457.20 mm | 0.1654.19 mm | 0.1884.78 mm | 17.670448.82 mm | 17.624447.65 mm | 31.4346.77 kg/m | 35.7653.22 kg/m | +14% |
| NPS 20 | 20.000508.00 mm | 0.1884.78 mm | 0.2185.54 mm | 19.624498.45 mm | 19.564496.93 mm | 39.7859.20 kg/m | 46.0668.54 kg/m | +16% |
| NPS 24 | 24.000609.60 mm | 0.2185.54 mm | 0.2506.35 mm | 23.564598.53 mm | 23.500596.90 mm | 55.3782.40 kg/m | 63.4194.37 kg/m | +15% |
| NPS 30 | 30.000762.00 mm | 0.2506.35 mm | 0.3127.92 mm | 29.500749.30 mm | 29.376746.15 mm | 79.43118.21 kg/m | 98.93147.22 kg/m | +25% |
Bore and weight are derived from the B36.10M outside diameter and the B36.19M wall.
5S is specified for
- Low-pressure vents, drains and overflow
- Sanitary and high-purity lines where surface finish, not wall, governs
- Large-diameter ducting and tank connections
- Weight-critical stainless work
- Service where the pipe is fully supported and protected
10S is specified for
- General stainless process piping — the default S-schedule
- Lines needing a modest pressure rating with no corrosion allowance
- Anywhere the extra wall buys handling robustness on site
- Systems joined by orbital or manual TIG welding
- Stock availability: 10S is far more widely warehoused
See also: Schedule 5S dimensions · Schedule 10S dimensions · 304 vs 316 · material selection.
Common questions
What is the difference between Schedule 5S and 10S?
Wall thickness only. 10S is roughly 33% heavier than 5S at the same outside diameter, giving a higher pressure rating and a smaller bore. Both are stainless walls published by ASME B36.19M.
Is 5S the same as Schedule 5?
In the sizes where both are published the walls generally match, but 5S carries B36.19M's stainless material and tolerance requirements. B36.19M also stops at NPS 30, so above that a thin stainless wall is specified by B36.10M schedule instead.
Can 5S pipe be threaded?
No. Neither 5S nor 10S has enough wall to thread. Stainless S-schedule pipe is welded, or joined with flanges or clamp fittings.
Which is more commonly stocked?
10S, by a wide margin. It is the general-purpose stainless process wall, so it is the one distributors carry across the full size range.