Dimensions
Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 18.65 lb/ft here, 0.1% from the published 18.67 lb/ft. The published figure is the one printed above.
NPS 10 schedule 10 in numbers
NPS 10 schedule 10 pipe measures 10.750 in (273.05 mm) across the outside with a 0.165 in wall, so the bore is 10.420 in (264.67 mm). That bore gives a flow area of 85.28 in² and holds 4.430 US gallons per foot (55.02 litres per metre). The outside diameter is 65.2 times the wall, and the steel itself has a cross-section of 5.487 in² and weighs 18.67 lb per foot plain end. One trade size up, NPS 12 in the same schedule carries 1.41 times the flow area.
Schedule 5 is the next lighter wall at NPS 10: 0.134 in, 0.031 in thinner, which opens the bore to 10.482 in and adds 1.2% to the flow area, for 19% less weight per foot.
Schedule 20 is the next heavier wall at NPS 10: 0.250 in, 0.085 in thicker, which narrows the bore to 10.250 in and cuts 3.2% from the flow area, for 50% more weight per foot.
Next trade size up in this schedule: NPS 12 schedule 10, bore 12.390 in.
Worked out from the dimensions
Plain geometry of a hollow circle with OD = 10.750 in and ID = 10.420 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.
Why 10 inch pipe is not 10 inches
Nominal Pipe Size is a label, not a measurement. NPS 10 pipe has an outside diameter of 10.750 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 0.165 inches, so the bore comes out at 10.420 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.
Other schedules in NPS 10
Same outside diameter of 10.750 inches throughout - only the wall and the bore move.
Frequently asked questions
What is the wall thickness of 10 inch schedule 10 pipe?
0.165 inches (4.19 mm). The outside diameter is 10.750 inches (273.05 mm) whatever the schedule, so this wall leaves an inside diameter of 10.420 inches.
What is the inside diameter of 10 inch schedule 10 pipe?
10.420 inches (264.67 mm). Inside diameter is outside diameter minus twice the wall: 10.750 - 2 x 0.165 = 10.420 inches.
Is 10 inch pipe actually 10 inches?
No. NPS 10 is a trade size, not a measurement. The pipe measures 10.750 inches across the outside and 10.420 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
How much does 10 inch schedule 10 pipe weigh?
18.67 pounds per foot plain end (27.78 kg per metre), for carbon steel. The figure excludes coatings, linings and fittings.
Is schedule 10 the same as 10S at this size?
Yes, at NPS 10. 10S is the same 0.165 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.
Where this table stops
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.
Where these figures come from
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:
Sources disagree here. Published tables split on the last digit here - 4.19 mm (b3610m-wermac), 4.191 mm (b3610m-wikipedia). The figure printed is 0.165 in (4.19 mm), carried by the majority of the sources. The two readings describe the same wall: they differ by less than a thousandth of an inch, far inside the mill tolerance of minus 12.5 percent on wall thickness.
Last-digit inch walls across the whole table: 0.594, 0.688, 0.719, 0.844, 0.938, 1.094, 1.219, 1.438, 1.969, 2.344 in (b3610m-fbc) against 0.593, 0.687, 0.718, 0.843, 0.937, 1.093, 1.218, 1.437, 1.968, 2.343 in (b3610m-wikipedia). Two families of inch figures are in circulation, one a thousandth of an inch below the other, and they come from rounding the millimetre wall the standard tabulates rather than from any difference in the pipe. The higher family is what the majority of the sources read here carry and is what this site prints; the affected rows say so individually. Nothing turns on the choice: the wall tolerance is minus 12.5 percent, which at a half-inch wall is sixty times the gap.
NPS 14 extra strong (XS): 0.469 in (b3610m-fbc) against 0.500 in (b3610m-etb) against 0.500 in (b3610m-wikipedia). 0.500 in is printed here. Two of the three inch sources give it, both millimetre sources give 12.70 mm which is 0.500 in, and extra strong is a 0.500 in wall at every size from NPS 12 up. The 0.469 in reading looks like a misplaced row in that one chart, but it is recorded rather than deleted.