Pipe schedules
NPS 4 schedule 40 pipe is 114.3 mm outside with a 6.02 mm wall, so its bore is 102.26 mm and it weighs 16.08 kg/m. Choose carbon or stainless, the size and the schedule for the outside diameter, wall and bore, the mass and the water a metre holds, and the drilling of the flange it takes.
- Wall t, Sch 40
- Outside diameter
- Bore
- Mass per metre
- Mass of 6000 mm
- 96.5kg
- Water per metre
- 8.21L/m
- ASME B16.5 Class 150 OD
- 228.6mm (9.000 in)
- Bolt circle (PCD)
- 190.5mm (7.500 in)
- Holes
- 8 × 19.1mm (0.750 in)
- Bolts
- 8 × 5/8 in
How it’s calculated
Bore = OD − 2t. Mass per metre = π·(OD − t)·t·ρ / 1000 kg/m (OD and t in mm; ρ 7.85 g/cm³ carbon, 8.00 stainless): plain end, no coating. Water per metre = π·bore²/4 / 1000 L/m.
Carbon steel pipe walls, mm
| NPS | DN | OD mm | Sch 10 | Sch 20 | Sch 30 | STD | Sch 40 | Sch 60 | XS | Sch 80 | Sch 100 | Sch 120 | Sch 140 | Sch 160 | XXS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2-1/2 | 65 | 73.0 | 3.05 | – | 4.78 | 5.16 | 5.16 | – | 7.01 | 7.01 | – | – | – | 9.53 | 14.02 |
| 3 | 80 | 88.9 | 3.05 | – | 4.78 | 5.49 | 5.49 | – | 7.62 | 7.62 | – | – | – | 11.13 | 15.24 |
| 3-1/2 | 90 | 101.6 | 3.05 | – | 4.78 | 5.74 | 5.74 | – | 8.08 | 8.08 | – | – | – | – | – |
| 4 | 100 | 114.3 | 3.05 | – | 4.78 | 6.02 | 6.02 | – | 8.56 | 8.56 | – | 11.13 | – | 13.49 | 17.12 |
| 5 | 125 | 141.3 | 3.40 | – | – | 6.55 | 6.55 | – | 9.53 | 9.53 | – | 12.70 | – | 15.88 | 19.05 |
| 6 | 150 | 168.3 | 3.40 | – | – | 7.11 | 7.11 | – | 10.97 | 10.97 | – | 14.27 | – | 18.26 | 21.95 |
| 8 | 200 | 219.1 | 3.76 | 6.35 | 7.04 | 8.18 | 8.18 | 10.31 | 12.70 | 12.70 | 15.09 | 18.26 | 20.62 | 23.01 | 22.23 |
Sizes 10 to 16 of 24: choose another size for its neighbours.
Why is the bore different from the size?
A nominal pipe size names the pipe; it is not a measurement. Every schedule of one size has the same outside diameter, so it fits the same fittings and flanges, and a heavier schedule puts the extra wall on the inside. From NPS 14 up the outside diameter is the size in inches; below it, it is larger. DN is the same size in the metric naming.