NPS 9 Standard (STD) Pipe
9.625 in (244.5 mm) outside diameter on a 0.342 in (8.7 mm) wall, giving a 8.941 in (227.1 mm) bore and 33.91 lb/ft (50.46 kg/m) empty. ASME B36.10M.
- Nominal size
- NPS 9 (DN 225)
- Schedule
- Standard (STD)
- Outside diameter
- 9.625 in (244.5 mm)
- Wall thickness
- 0.342 in (8.7 mm)
- Inside diameter
- 8.941 in (227.1 mm)
- Weight, empty
- 33.91 lb/ft (50.46 kg/m)
- Weight, water filled
- 61.13 lb/ft (90.97 kg/m)
- Flow area
- 62.786 in² (40507 mm²)
In NPS 9 this wall thickness is also designated Schedule 40. That is the same pipe under another name, not a different product — but the coincidence is specific to this size and does not hold across the range.
Every schedule in NPS 9
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Schedule | Wall thickness | Inside diameter | Weight, empty | Water (US gal/ft) |
|---|---|---|---|---|
| Sch 40 | 0.3428.69 mm | 8.941227.10 mm | 33.9150.46 kg/m | 3.262 |
| STD this page | 0.3428.69 mm | 8.941227.10 mm | 33.9150.46 kg/m | 3.262 |
| Sch 80 | 0.50012.70 mm | 8.625219.07 mm | 48.7372.52 kg/m | 3.035 |
| XS | 0.50012.70 mm | 8.625219.07 mm | 48.7372.52 kg/m | 3.035 |
Weight is plain-end carbon steel, w = 10.6802 × t × (OD − t) lb/ft.
Common questions
What is the inside diameter of NPS 9 standard (std) pipe?
8.941 in (227.1 mm). The outside diameter is fixed at 9.625 in (244.5 mm) by ASME B36.10M, and the 0.342 in (8.7 mm) wall takes 0.684 in off it — 0.342 in from each side — leaving that bore.
How much does NPS 9 standard (std) pipe weigh?
33.91 lb/ft (50.46 kg/m) empty, as plain-end carbon steel. Full of water it comes to 61.13 lb/ft (90.97 kg/m), because the bore holds 3.262 US gallons per foot. One short ton of this pipe is about 59 ft.
Does NPS 9 standard (std) pipe use special flanges or fittings?
No. Flanges and buttweld fittings are dimensioned from NPS, so NPS 9 hardware fits this pipe in any schedule. The one thing that does follow the schedule is the bore of a weld neck flange or a fitting end prep, which has to be 8.941 in (227.1 mm) to match.