ASME B36.10M (welded and seamless wrought steel pipe) · DN 550
Outside diameter 22.000" (558.80 mm), wall 0.250" (6.35 mm), inside diameter 21.500" (546.10 mm), 58.13 lb per foot.
| Trade size | NPS 22 · DN 550 |
|---|---|
| Schedule | Schedule 10 |
| Standard | ASME B36.10M (welded and seamless wrought steel pipe) |
| Outside diameter | 22.000" · 558.80 mm · designated 559 mm in the metric column |
| Wall thickness | 0.250" · 6.35 mm |
| Inside diameter | 21.500" · 546.10 mm |
| Weight, plain end | 58.13 lb/ft · 86.55 kg/m |
Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 58.07 lb/ft here, 0.1% from the published 58.13 lb/ft. The published figure is the one printed above.
NPS 22 schedule 10 pipe measures 22.000 in (558.80 mm) across the outside with a 0.250 in wall, so the bore is 21.500 in (546.10 mm). That bore gives a flow area of 363.1 in² and holds 18.86 US gallons per foot (234.2 litres per metre). The outside diameter is 88.0 times the wall, and the steel itself has a cross-section of 17.08 in² and weighs 58.13 lb per foot plain end. One trade size up, NPS 24 in the same schedule carries 1.19 times the flow area.
Schedule 10S is the next lighter wall at NPS 22: 0.218 in, 0.032 in thinner, which opens the bore to 21.564 in and adds 0.6% to the flow area.
Standard wall (STD) is the next heavier wall at NPS 22: 0.375 in, 0.125 in thicker, which narrows the bore to 21.250 in and cuts 2.3% from the flow area, for 49% more weight per foot.
Next trade size up in this schedule: NPS 24 schedule 10, bore 23.500 in.
| Flow area | 363.1 in² |
|---|---|
| Capacity | 18.86 US gal/ft · 234.2 L/m |
| Metal area | 17.08 in² |
| Moment of inertia | 1010 in⁴ |
| Section modulus | 91.84 in³ |
| Radius of gyration | 7.690 in |
| Outside surface | 5.760 ft² per foot |
Plain geometry of a hollow circle with OD = 22.000 in and ID = 21.500 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 22 pipe has an outside diameter of 22.000 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 0.250 inches, so the bore comes out at 21.500 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 22.000 inches throughout - only the wall and the bore move.
| Schedule | Wall (in) | ID (in) | Weight (lb/ft) |
|---|---|---|---|
| Schedule 5 · 5S | 0.188 | 21.624 | 43.84 |
| Schedule 60 | 0.875 | 20.250 | 197.60 |
| Schedule 80 | 1.125 | 19.750 | 251.05 |
| Schedule 100 | 1.375 | 19.250 | 303.16 |
| Schedule 120 | 1.625 | 18.750 | 353.94 |
| Schedule 140 | 1.875 | 18.250 | 403.38 |
| Schedule 160 | 2.125 | 17.750 | 451.49 |
| Standard wall (STD) · 20 | 0.375 | 21.250 | 86.69 |
| Extra strong (XS) · 30 | 0.500 | 21.000 | 114.92 |
| Schedule 10S | 0.218 | 21.564 | not published |
0.250 inches (6.35 mm). The outside diameter is 22.000 inches (558.80 mm) whatever the schedule, so this wall leaves an inside diameter of 21.500 inches.
21.500 inches (546.10 mm). Inside diameter is outside diameter minus twice the wall: 22.000 - 2 x 0.250 = 21.500 inches.
No. NPS 22 is a trade size, not a measurement. The pipe measures 22.000 inches across the outside and 21.500 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
58.13 pounds per foot plain end (86.55 kg per metre), for carbon steel. The figure excludes coatings, linings and fittings.
2 schedules at NPS 22 appear in only one of the published tables cross-checked for this section, so they are named rather than printed: 40S, 80S. Everything shown above carries at least two independent sources.
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 4 independent published sources:
Nearby sizes