NPS 3/8 Schedule 40 Pipe
0.675 in (17.1 mm) outside diameter on a 0.091 in (2.3 mm) wall, giving a 0.493 in (12.5 mm) bore and 0.57 lb/ft (0.84 kg/m) empty. ASME B36.10M.
- Nominal size
- NPS 3/8 (DN 10)
- Schedule
- Schedule 40
- Outside diameter
- 0.675 in (17.1 mm)
- Wall thickness
- 0.091 in (2.3 mm)
- Inside diameter
- 0.493 in (12.5 mm)
- Weight, empty
- 0.57 lb/ft (0.84 kg/m)
- Weight, water filled
- 0.65 lb/ft (0.97 kg/m)
- Flow area
- 0.191 in² (123 mm²)
In NPS 3/8 this wall thickness is also designated Standard (STD). 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 3/8
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Schedule | Wall thickness | Inside diameter | Weight, empty | Water (US gal/ft) |
|---|---|---|---|---|
| Sch 5 | 0.0491.24 mm | 0.57714.66 mm | 0.330.49 kg/m | 0.014 |
| Sch 10 | 0.0651.65 mm | 0.54513.84 mm | 0.420.63 kg/m | 0.012 |
| Sch 40 this page | 0.0912.31 mm | 0.49312.52 mm | 0.570.84 kg/m | 0.010 |
| STD | 0.0912.31 mm | 0.49312.52 mm | 0.570.84 kg/m | 0.010 |
| Sch 80 | 0.1263.20 mm | 0.42310.74 mm | 0.741.10 kg/m | 0.007 |
| XS | 0.1263.20 mm | 0.42310.74 mm | 0.741.10 kg/m | 0.007 |
Weight is plain-end carbon steel, w = 10.6802 × t × (OD − t) lb/ft.
Common questions
What is the inside diameter of NPS 3/8 schedule 40 pipe?
0.493 in (12.5 mm). The outside diameter is fixed at 0.675 in (17.1 mm) by ASME B36.10M, and the 0.091 in (2.3 mm) wall takes 0.182 in off it — 0.091 in from each side — leaving that bore.
How much does NPS 3/8 schedule 40 pipe weigh?
0.57 lb/ft (0.84 kg/m) empty, as plain-end carbon steel. Full of water it comes to 0.65 lb/ft (0.97 kg/m), because the bore holds 0.010 US gallons per foot. One short ton of this pipe is about 3524 ft.
Does NPS 3/8 schedule 40 pipe use special flanges or fittings?
No. Flanges and buttweld fittings are dimensioned from NPS, so NPS 3/8 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 0.493 in (12.5 mm) to match.