TECHNICAL TOOL
DN / NPS / SCH tube dimensions
DN, NPS, outer diameter and wall thickness correspondences by schedule, every standard you need in one table.
ASME B36.19M (S series) and B36.10M heavy series
DN6 to DN600. Columns 5S/10S/40S/80S come from ASME B36.19M (stainless); 40/80/120/160/XXS come from ASME B36.10M, reused for heavy-wall stainless tube.
Unit
| NPS | DN | OD (mm) | 5S | 10S | 40 | 40S | 80 | 80S | 120 | 160 | XXS |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/8" | 6 | 10.3 | — | 1.24 | 1.73 | 1.73 | 2.41 | 2.41 | — | — | — |
| 1/4" | 8 | 13.7 | — | 1.65 | 2.24 | 2.24 | 3.02 | 3.02 | — | — | — |
| 3/8" | 10 | 17.1 | — | 1.65 | 2.31 | 2.31 | 3.2 | 3.2 | — | — | — |
| 1/2" | 15 | 21.3 | 1.65 | 2.11 | 2.77 | 2.77 | 3.73 | 3.73 | — | 4.78 | 7.47 |
| 3/4" | 20 | 26.7 | 1.65 | 2.11 | 2.87 | 2.87 | 3.91 | 3.91 | — | 5.56 | 7.82 |
| 1" | 25 | 33.4 | 1.65 | 2.77 | 3.38 | 3.38 | 4.55 | 4.55 | — | 6.35 | 9.09 |
| 1 1/4" | 32 | 42.2 | 1.65 | 2.77 | 3.56 | 3.56 | 4.85 | 4.85 | — | 6.35 | 9.7 |
| 1 1/2" | 40 | 48.3 | 1.65 | 2.77 | 3.68 | 3.68 | 5.08 | 5.08 | — | 7.14 | 10.16 |
| 2" | 50 | 60.3 | 1.65 | 2.77 | 3.91 | 3.91 | 5.54 | 5.54 | — | 8.74 | 11.07 |
| 2 1/2" | 65 | 73 | 2.11 | 3.05 | 5.16 | 5.16 | 7.01 | 7.01 | — | 9.53 | 14.02 |
| 3" | 80 | 88.9 | 2.11 | 3.05 | 5.49 | 5.49 | 7.62 | 7.62 | — | 11.13 | 15.24 |
| 4" | 100 | 114.3 | 2.11 | 3.05 | 6.02 | 6.02 | 8.56 | 8.56 | 11.13 | 13.49 | 17.12 |
| 5" | 125 | 141.3 | 2.77 | 3.4 | 6.55 | 6.55 | 9.53 | 9.53 | 12.7 | 15.88 | 19.05 |
| 6" | 150 | 168.3 | 2.77 | 3.4 | 7.11 | 7.11 | 10.97 | 10.97 | 14.27 | 18.26 | 21.95 |
| 8" | 200 | 219.1 | 2.77 | 3.76 | 8.18 | 8.18 | 12.7 | 12.7 | 18.26 | 23.01 | 22.23 |
| 10" | 250 | 273 | 3.4 | 4.19 | 9.27 | 9.27 | 15.09 | 12.7 | 21.44 | 28.58 | — |
| 12" | 300 | 323.8 | 3.96 | 4.57 | 10.31 | 9.53 | 17.48 | 12.7 | 25.4 | 33.32 | — |
| 14" | 350 | 355.6 | 3.96 | 4.78 | 11.13 | — | 19.05 | — | 27.79 | 35.71 | — |
| 16" | 400 | 406.4 | 4.19 | 4.78 | 12.7 | — | 21.44 | — | 30.96 | 40.49 | — |
| 18" | 450 | 457 | 4.19 | 4.78 | 14.27 | — | 23.83 | — | 34.93 | 45.24 | — |
| 20" | 500 | 508 | 4.78 | 5.54 | 15.09 | — | 26.19 | — | 38.1 | 50.01 | — |
| 24" | 600 | 610 | 5.54 | 6.35 | 17.48 | — | 30.96 | — | 46.02 | 59.54 | — |
ISO 1127 tolerances
Les tolérances expliquent l'écart entre poids théorique et poids réel facturé. À citer dans la section Limites du calculateur de poids.
Outside diameters and wall thicknesses are taken from ISO 4200 and grouped into three series: series 1, where all the piping fittings needed are standardised; series 2, where only some are; series 3, for special applications with few standardised fittings available. The full diameter table per series is proprietary ISO content (paid standard) — [TO VERIFY: exact values per series, to confirm against the standard's text before publication].
| Class | Tolerance |
|---|---|
| D1 | ±1,5 % avec minimum ±0,75 mm |
| D2 | ±1,0 % avec minimum ±0,50 mm |
| D3 | ±0,75 % avec minimum ±0,30 mm |
| D4 | ±0,50 % avec minimum ±0,10 mm |
| Class | Tolerance |
|---|---|
| T1 | ±15 % avec minimum ±0,60 mm |
| T2 | ±12,5 % avec minimum ±0,40 mm |
| T3 | ±10 % avec minimum ±0,20 mm |
| T4 | ±7,5 % avec minimum ±0,15 mm |
DIN 11850 Reihe 2 — food-grade tube
| DN | OD (mm) | Wall (mm) |
|---|---|---|
| 10 | 13 | 1.5 |
| 15 | 19 | 1.5 |
| 20 | 23 | 1.5 |
| 25 | 29 | 1.5 |
| 32 | 35 | 1.5 |
| 40 | 41 | 1.5 |
| 50 | 53 | 1.5 |
| 65 | 70 | 2 |
| 80 | 85 | 2 |
| 100 | 104 | 2 |
| 125 | 129 | 2 |
| 150 | 154 | 2 |
SMS 3008 / ISO 2037 — sanitary tube
| OD (mm) | Wall (mm) |
|---|---|
| 25 | 1.2 |
| 38 | 1.2 |
| 51 | 1.2 |
| 63.5 | 1.6 |
| 76.1 | 1.6 |
| 101.6 | 2 |
| OD (mm) | Wall (mm) |
|---|---|
| 12.7 | 1.6 |
| 19.05 | 1.6 |
| 25.4 | 1.6 |
| 38.1 | 1.6 |
| 50.8 | 1.6 |
| 63.5 | 1.6 |
| 76.1 | 1.6 |
| 101.6 | 2 |
Heat exchanger tube — ASTM A213 / A249
BWG = Birmingham Wire Gauge, usage historique encore courant en échangeur.
| OD (mm) | BWG | Wall (mm) |
|---|---|---|
| 15.88 | 20 | 0.89 |
| 15.88 | 18 | 1.24 |
| 15.88 | 16 | 1.65 |
| 19.05 | 20 | 0.89 |
| 19.05 | 18 | 1.24 |
| 19.05 | 16 | 1.65 |
| 19.05 | 14 | 2.11 |
| 25.4 | 18 | 1.24 |
| 25.4 | 16 | 1.65 |
| 25.4 | 14 | 2.11 |
| 25.4 | 12 | 2.77 |
| 31.75 | 16 | 1.65 |
| 31.75 | 14 | 2.11 |
| 38.1 | 14 | 2.11 |
| 38.1 | 12 | 2.77 |
Limits of this table
Frequently asked questions
- What is the difference between DN and NPS?
- DN (nominal diameter) is the European metric designation, NPS (nominal pipe size) the American equivalent in inches. Both refer to the same tube family; their correspondence is not a direct mathematical conversion, it follows the standard table.
- What does the S mean in 10S, 40S, 80S?
- The S flags the stainless series of ASME B36.19M (Stainless). Schedules without S — 40, 80, 120, 160, XXS — come from ASME B36.10M, the historical carbon steel series, reused for heavy-wall stainless tube.
- Is 40S always identical to 40?
- No: the two series match on small diameters but diverge above NPS 10" (DN250) for schedule 40, and above NPS 8" (DN200) for schedule 80. Never conflate the two above these sizes — see the warning under the table.
- Where do the D1–D4 and T1–T4 tolerances come from?
- From ISO 1127, which sets the acceptable deviations on diameter (D classes) and wall thickness (T classes) of stainless tube. They explain the gap between a calculator's theoretical weight and the real invoiced weight.
- Does this table cover heat exchanger tubes?
- Yes, in a separate tab: the common 15.88 / 19.05 / 25.4 mm diameters with their wall thicknesses in BWG (Birmingham Wire Gauge), the unit still used in this segment.
- Can I export this table?
- Yes, the "Export CSV" button above the ASME B36.19M table exports the currently visible rows, in the current sort order.