18 inch Sch 40 pipe dimensions & weight
18 inch Sch 40 pipe (DN 450) — dimensions, weight and capacity per ASME B36.10M.
| Nominal size | 18" (DN 450) |
| Schedule | Sch 40 |
| Outside diameter | 457.0 mm (17.992 in) |
| Wall thickness | 14.27 mm (0.562 in) |
| Inside diameter | 428.46 mm (16.869 in) |
| Weight — carbon steel | 155.80 kg/m · 104.70 lb/ft |
| Weight — SS 304 / SS 316 | 157.39 / 158.38 kg/m |
| 6 m length (CS) | 934.8 kg |
| 20 ft length (CS) | 949.8 kg |
| Flow area | 1441.82 cm² |
| Water capacity | 144.182 L/m |
| Outer surface (painting) | 1.4357 m²/m |
| Approx. max. working pressure* | 77 bar (1,117 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 80 · Sch 160 · all 18" schedules
Frequently asked questions
What is the ID of 18 inch Sch 40 pipe?
428.46 mm (16.869 in), with OD 457.0 mm and wall 14.27 mm.
What is the weight of 18 inch Sch 40 pipe?
155.80 kg/m (104.70 lb/ft) in carbon steel; 934.8 kg per 6 m length.
What pressure can 18 inch Sch 40 pipe take?
Roughly 77 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