NPS 1 1/4 Pipe Dimensions
Outside diameter 1.660 in (42.2 mm) — fixed across every schedule. 8 wall thicknesses from ASME B36.10M, with bore, plain-end weight and flow area for each.
- Nominal size
- NPS 1 1/4
- Metric designator
- DN 32
- Outside diameter
- 1.660 in (42.2 mm)
- Schedules listed
- 8
- Standard weight wall
- 0.140 in (3.6 mm)
- Extra strong wall
- 0.191 in (4.9 mm)
Every schedule in NPS 1 1/4
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Schedule | Wall thickness | Inside diameter | Weight, empty | Flow area (in²) | Water (US gal/ft) |
|---|---|---|---|---|---|
| Sch 5 | 0.0651.65 mm | 1.53038.86 mm | 1.111.65 kg/m | 1.84 | 0.096 |
| Sch 10 | 0.1092.77 mm | 1.44236.63 mm | 1.812.69 kg/m | 1.63 | 0.085 |
| Sch 40 | 0.1403.56 mm | 1.38035.05 mm | 2.273.38 kg/m | 1.50 | 0.078 |
| STD | 0.1403.56 mm | 1.38035.05 mm | 2.273.38 kg/m | 1.50 | 0.078 |
| Sch 80 | 0.1914.85 mm | 1.27832.46 mm | 3.004.46 kg/m | 1.28 | 0.067 |
| XS | 0.1914.85 mm | 1.27832.46 mm | 3.004.46 kg/m | 1.28 | 0.067 |
| Sch 160 | 0.2506.35 mm | 1.16029.46 mm | 3.765.60 kg/m | 1.06 | 0.055 |
| XXS | 0.3829.70 mm | 0.89622.76 mm | 5.217.76 kg/m | 0.63 | 0.033 |
Weight is calculated for carbon steel as w = 10.6802 × t × (OD − t) lb/ft and is the plain-end weight, excluding coatings, linings and fittings.
Standard weight equals Schedule 40 in this size. Extra strong equals Schedule 80.
This size, schedule by schedule
A page for each combination, with bore, weight, water capacity and the matching flange and fitting data.
This size in a schedule chart
Common questions
What is the outside diameter of NPS 1 1/4 pipe?
NPS 1 1/4 pipe has an outside diameter of 1.660 in (42.2 mm). That outside diameter is fixed: it is identical in every schedule, and only the wall thickness — and therefore the bore — changes from one schedule to the next.
How much does NPS 1 1/4 schedule 40 pipe weigh?
2.27 lb/ft (3.38 kg/m) as plain-end carbon steel, on a wall thickness of 0.140 in (3.6 mm).
What is the metric equivalent of NPS 1 1/4?
DN 32. DN is a dimensionless designator, not a measurement — DN 32 pipe does not measure 32 mm anywhere. Its actual outside diameter is 42.2 mm.