ASME B36.10M (welded and seamless wrought steel pipe) · DN 125
Outside diameter 5.563" (141.30 mm), wall 0.134" (3.40 mm), inside diameter 5.295" (134.50 mm), 7.78 lb per foot.
| Trade size | NPS 5 · DN 125 |
|---|---|
| Schedule | Schedule 10 · same wall as 10S |
| Standard | ASME B36.10M (welded and seamless wrought steel pipe) |
| Outside diameter | 5.563" · 141.30 mm |
| Wall thickness | 0.134" · 3.40 mm |
| Inside diameter | 5.295" · 134.50 mm |
| Weight, plain end | 7.78 lb/ft · 11.56 kg/m |
Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 7.77 lb/ft here, 0.1% from the published 7.78 lb/ft. The published figure is the one printed above.
NPS 5 schedule 10 pipe measures 5.563 in (141.30 mm) across the outside with a 0.134 in wall, so the bore is 5.295 in (134.50 mm). That bore gives a flow area of 22.02 in² and holds 1.144 US gallons per foot (14.21 litres per metre). The outside diameter is 41.5 times the wall, and the steel itself has a cross-section of 2.285 in² and weighs 7.78 lb per foot plain end. One trade size up, NPS 6 in the same schedule carries 1.44 times the flow area.
Schedule 5 is the next lighter wall at NPS 5: 0.109 in, 0.025 in thinner, which opens the bore to 5.345 in and adds 1.9% to the flow area, for 18% less weight per foot.
Schedule 40 is the next heavier wall at NPS 5: 0.258 in, 0.124 in thicker, which narrows the bore to 5.047 in and cuts 9.1% from the flow area, for 88% more weight per foot.
Next trade size up in this schedule: NPS 6 schedule 10, bore 6.357 in.
| Flow area | 22.02 in² |
|---|---|
| Capacity | 1.144 US gal/ft · 14.21 L/m |
| Metal area | 2.285 in² |
| Moment of inertia | 8.425 in⁴ |
| Section modulus | 3.029 in³ |
| Radius of gyration | 1.920 in |
| Outside surface | 1.456 ft² per foot |
Plain geometry of a hollow circle with OD = 5.563 in and ID = 5.295 in: flow area π/4·ID², metal area π/4·(OD² − ID²), moment of inertia π/64·(OD⁴ − ID⁴), section modulus I ÷ (OD/2), radius of gyration √(I ÷ metal area), capacity flow area × 12 ÷ 231 (231 in³ to the US gallon). Nominal dimensions, so mill tolerance and corrosion allowance are not included.
Nominal Pipe Size is a label, not a measurement. NPS 5 pipe has an outside diameter of 5.563 inches, and it keeps that outside diameter in every schedule made. What the schedule number changes is the wall: at schedule 10 the wall is 0.134 inches, so the bore comes out at 5.295 inches.
That is the practical consequence. Fittings, flanges, supports and threading dies are sized to the outside diameter, so they fit any schedule of the same trade size. Flow, pressure drop and anything that has to pass through the pipe depend on the inside diameter, which changes with every schedule. Order by trade size and schedule; work your hydraulics from the bore.
Same outside diameter of 5.563 inches throughout - only the wall and the bore move.
| Schedule | Wall (in) | ID (in) | Weight (lb/ft) |
|---|---|---|---|
| Schedule 5 · 5S | 0.109 | 5.345 | 6.36 |
| Schedule 40 · STD, 40S | 0.258 | 5.047 | 14.63 |
| Schedule 80 · XS, 80S | 0.375 | 4.813 | 20.80 |
| Schedule 120 | 0.500 | 4.563 | 27.06 |
| Schedule 160 | 0.625 | 4.313 | 32.99 |
| Double extra strong (XXS) | 0.750 | 4.063 | 38.59 |
0.134 inches (3.40 mm). The outside diameter is 5.563 inches (141.30 mm) whatever the schedule, so this wall leaves an inside diameter of 5.295 inches.
5.295 inches (134.50 mm). Inside diameter is outside diameter minus twice the wall: 5.563 - 2 x 0.134 = 5.295 inches.
No. NPS 5 is a trade size, not a measurement. The pipe measures 5.563 inches across the outside and 5.295 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
7.78 pounds per foot plain end (11.56 kg per metre), for carbon steel. The figure excludes coatings, linings and fittings.
Yes, at NPS 5. 10S is the same 0.134 inch wall here. That coincidence is per size and does not hold everywhere: standard wall and schedule 40 part company above NPS 10, and extra strong and schedule 80 part company above NPS 8.
This table runs from NPS 1/8 to NPS 24 and stops there. ASME B36.10M itself continues to NPS 80; those larger sizes are not carried here, so a size above NPS 24 is missing rather than undefined.
Dimensions are as defined by ASME B36.10M (welded and seamless wrought steel pipe). This site is an independent reference and is not affiliated with, endorsed by or approved by any standards body.
Every value on this page was cross-checked against 5 independent published sources:
Nearby sizes