18 inch Sch 80 pipe dimensions & weight
18 inch Sch 80 pipe (DN 450) — dimensions, weight and capacity per ASME B36.10M.
| Nominal size | 18" (DN 450) |
| Schedule | Sch 80 |
| Outside diameter | 457.0 mm (17.992 in) |
| Wall thickness | 23.83 mm (0.938 in) |
| Inside diameter | 409.34 mm (16.116 in) |
| Weight — carbon steel | 254.55 kg/m · 171.06 lb/ft |
| Weight — SS 304 / SS 316 | 257.14 / 258.77 kg/m |
| 6 m length (CS) | 1527.3 kg |
| 20 ft length (CS) | 1551.7 kg |
| Flow area | 1316.01 cm² |
| Water capacity | 131.601 L/m |
| Outer surface (painting) | 1.4357 m²/m |
| Approx. max. working pressure* | 131 bar (1,894 psi) — A106 Gr B |
*Approximate ASME B31.3 straight-pipe rating at ≤ 38 °C for seamless A106 Gr B (S = 137.9 MPa, E = 1, 12.5% mill tolerance, no corrosion allowance). Use the wall thickness calculator for your own design conditions.
Other schedules for 18": Sch 10S · Sch 40 · Sch 160 · all 18" schedules
Frequently asked questions
What is the ID of 18 inch Sch 80 pipe?
409.34 mm (16.116 in), with OD 457.0 mm and wall 23.83 mm.
What is the weight of 18 inch Sch 80 pipe?
254.55 kg/m (171.06 lb/ft) in carbon steel; 1527.3 kg per 6 m length.
What pressure can 18 inch Sch 80 pipe take?
Roughly 131 bar at ambient for seamless A106 Gr B under ASME B31.3 with no corrosion allowance; actual rating depends on material, temperature and code.
Last updated 2026-11-02