Dimensions
Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 40.48 lb/ft here, 0.1% from the published 40.52 lb/ft. The published figure is the one printed above.
NPS 10 schedule 40 in numbers
NPS 10 schedule 40 pipe measures 10.750 in (273.05 mm) across the outside with a 0.365 in wall, so the bore is 10.020 in (254.51 mm). That bore gives a flow area of 78.85 in² and holds 4.096 US gallons per foot (50.87 litres per metre). The outside diameter is 29.5 times the wall, and the steel itself has a cross-section of 11.91 in² and weighs 40.52 lb per foot plain end. One trade size up, NPS 12 in the same schedule carries 1.42 times the flow area.
Schedule 30 is the next lighter wall at NPS 10: 0.307 in, 0.058 in thinner, which opens the bore to 10.136 in and adds 2.3% to the flow area, for 15% less weight per foot.
Extra strong (XS) is the next heavier wall at NPS 10: 0.500 in, 0.135 in thicker, which narrows the bore to 9.750 in and cuts 5.3% from the flow area, for 35% more weight per foot.
Next trade size up in this schedule: NPS 12 schedule 40, bore 11.938 in.
Worked out from the dimensions
Plain geometry of a hollow circle with OD = 10.750 in and ID = 10.020 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 40 the wall is 0.365 inches, so the bore comes out at 10.020 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 40 pipe?
0.365 inches (9.27 mm). The outside diameter is 10.750 inches (273.05 mm) whatever the schedule, so this wall leaves an inside diameter of 10.020 inches.
What is the inside diameter of 10 inch schedule 40 pipe?
10.020 inches (254.51 mm). Inside diameter is outside diameter minus twice the wall: 10.750 - 2 x 0.365 = 10.020 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 10.020 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
How much does 10 inch schedule 40 pipe weigh?
40.52 pounds per foot plain end (60.29 kg per metre), for carbon steel. The figure excludes coatings, linings and fittings.
Is schedule 40 the same as STD or 40S at this size?
Yes, at NPS 10. STD and 40S are the same 0.365 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: