NPS 20 Pipe Dimensions
Outside diameter 20.000 in (508.0 mm) — fixed across every schedule. 13 wall thicknesses from ASME B36.10M, with bore, plain-end weight and flow area for each.
- Nominal size
- NPS 20
- Metric designator
- DN 500
- Outside diameter
- 20.000 in (508.0 mm)
- Schedules listed
- 13
- Standard weight wall
- 0.375 in (9.5 mm)
- Extra strong wall
- 0.500 in (12.7 mm)
Every schedule in NPS 20
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 | 0.1884.78 mm | 19.624498.45 mm | 39.7859.20 kg/m | 302.46 | 15.712 |
| Sch 10 | 0.2185.54 mm | 19.564496.93 mm | 46.0668.54 kg/m | 300.61 | 15.616 |
| Sch 20 | 0.3759.52 mm | 19.250488.95 mm | 78.60116.97 kg/m | 291.04 | 15.119 |
| Sch 30 | 0.50012.70 mm | 19.000482.60 mm | 104.13154.97 kg/m | 283.53 | 14.729 |
| Sch 40 | 0.59415.09 mm | 18.812477.82 mm | 123.11183.21 kg/m | 277.95 | 14.439 |
| STD | 0.3759.52 mm | 19.250488.95 mm | 78.60116.97 kg/m | 291.04 | 15.119 |
| Sch 60 | 0.81220.62 mm | 18.376466.75 mm | 166.40247.64 kg/m | 265.21 | 13.777 |
| Sch 80 | 1.03126.19 mm | 17.938455.63 mm | 208.87310.84 kg/m | 252.72 | 13.128 |
| XS | 0.50012.70 mm | 19.000482.60 mm | 104.13154.97 kg/m | 283.53 | 14.729 |
| Sch 100 | 1.28132.54 mm | 17.438442.93 mm | 256.10381.12 kg/m | 238.83 | 12.407 |
| Sch 120 | 1.50038.10 mm | 17.000431.80 mm | 296.38441.05 kg/m | 226.98 | 11.791 |
| Sch 140 | 1.75044.45 mm | 16.500419.10 mm | 341.10507.61 kg/m | 213.82 | 11.108 |
| Sch 160 | 1.96950.01 mm | 16.062407.97 mm | 379.18564.28 kg/m | 202.62 | 10.526 |
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 20 in this size. Extra strong equals Schedule 30.
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 20 pipe?
NPS 20 pipe has an outside diameter of 20.000 in (508.0 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 20 schedule 40 pipe weigh?
123.11 lb/ft (183.21 kg/m) as plain-end carbon steel, on a wall thickness of 0.594 in (15.1 mm).
What is the metric equivalent of NPS 20?
DN 500. DN is a dimensionless designator, not a measurement — DN 500 pipe does not measure 500 mm anywhere. Its actual outside diameter is 508.0 mm.