ASME B36.10M (welded and seamless wrought steel pipe) · DN 200
Outside diameter 8.625" (219.07 mm), wall 0.906" (23.01 mm), inside diameter 6.813" (173.05 mm), 74.76 lb per foot.
| Trade size | NPS 8 · DN 200 |
|---|---|
| Schedule | Schedule 160 |
| Standard | ASME B36.10M (welded and seamless wrought steel pipe) |
| Outside diameter | 8.625" · 219.07 mm · designated 219.1 mm in the metric column |
| Wall thickness | 0.906" · 23.01 mm |
| Inside diameter | 6.813" · 173.05 mm |
| Weight, plain end | 74.76 lb/ft · 111.27 kg/m |
Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 74.69 lb/ft here, 0.1% from the published 74.76 lb/ft. The published figure is the one printed above.
NPS 8 schedule 160 pipe measures 8.625 in (219.07 mm) across the outside with a 0.906 in wall, so the bore is 6.813 in (173.05 mm). That bore gives a flow area of 36.46 in² and holds 1.894 US gallons per foot (23.52 litres per metre). The outside diameter is 9.5 times the wall, and the steel itself has a cross-section of 21.97 in² and weighs 74.76 lb per foot plain end. One trade size up, NPS 10 in the same schedule carries 1.56 times the flow area.
Double extra strong (XXS) is the next lighter wall at NPS 8: 0.875 in, 0.031 in thinner, which opens the bore to 6.875 in and adds 1.8% to the flow area, for 3.0% less weight per foot.
Next trade size up in this schedule: NPS 10 schedule 160, bore 8.500 in.
| Flow area | 36.46 in² |
|---|---|
| Capacity | 1.894 US gal/ft · 23.52 L/m |
| Metal area | 21.97 in² |
| Moment of inertia | 165.9 in⁴ |
| Section modulus | 38.47 in³ |
| Radius of gyration | 2.748 in |
| Outside surface | 2.258 ft² per foot |
Plain geometry of a hollow circle with OD = 8.625 in and ID = 6.813 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 8 pipe has an outside diameter of 8.625 inches, and it keeps that outside diameter in every schedule made. What the schedule number changes is the wall: at schedule 160 the wall is 0.906 inches, so the bore comes out at 6.813 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 8.625 inches throughout - only the wall and the bore move.
| Schedule | Wall (in) | ID (in) | Weight (lb/ft) |
|---|---|---|---|
| Schedule 5 · 5S | 0.109 | 8.407 | 9.92 |
| Schedule 10 · 10S | 0.148 | 8.329 | 13.41 |
| Schedule 20 | 0.250 | 8.125 | 22.38 |
| Schedule 30 | 0.277 | 8.071 | 24.72 |
| Schedule 40 · STD, 40S | 0.322 | 7.981 | 28.58 |
| Schedule 60 | 0.406 | 7.813 | 35.67 |
| Schedule 80 · XS, 80S | 0.500 | 7.625 | 43.43 |
| Schedule 100 | 0.594 | 7.437 | 51.00 |
| Schedule 120 | 0.719 | 7.187 | 60.77 |
| Schedule 140 | 0.812 | 7.001 | 67.82 |
| Double extra strong (XXS) | 0.875 | 6.875 | 72.49 |
0.906 inches (23.01 mm). The outside diameter is 8.625 inches (219.07 mm) whatever the schedule, so this wall leaves an inside diameter of 6.813 inches.
6.813 inches (173.05 mm). Inside diameter is outside diameter minus twice the wall: 8.625 - 2 x 0.906 = 6.813 inches.
No. NPS 8 is a trade size, not a measurement. The pipe measures 8.625 inches across the outside and 6.813 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
74.76 pounds per foot plain end (111.27 kg per metre), for carbon steel. The figure excludes coatings, linings and fittings.
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:
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