# 18 inch Sch 10S pipe dimensions & weight

> 18" Sch 10S pipe (DN 450): OD 457.0 mm, wall 4.78 mm, ID 447.44 mm, weight 53.31 kg/m, water capacity and approximate pressure rating.

Source: https://pipingsupplyjournal.com/18-inch-schedule-10s-pipe.html  
Publisher: Piping Supply Journal (Piping Supply Journal Editorial Team) · Published 2026-11-03 · Updated 2026-11-04

18 inch Sch 10S pipe (DN 450) — dimensions, weight and capacity per ASME B36.19M.

Nominal size| 18" (DN 450)  
---|---  
Schedule| Sch 10S  
Outside diameter| 457.0 mm (17.992 in)  
Wall thickness| 4.78 mm (0.188 in)  
Inside diameter| 447.44 mm (17.616 in)  
Weight — carbon steel| 53.31 kg/m · 35.82 lb/ft  
Weight — SS 304 / SS 316| 53.85 / 54.19 kg/m  
6 m length (CS)| 319.9 kg  
20 ft length (CS)| 325.0 kg  
Flow area| 1572.39 cm²  
Water capacity| 157.239 L/m  
Outer surface (painting)| 1.4357 m²/m  
Approx. max. working pressure*| 21 bar (308 psi) — A312 TP316L  
  
*Approximate ASME B31.3 straight-pipe rating at ≤ 38 °C for seamless A312 TP316L (S = 115.0 MPa, E = 1, 12.5% mill tolerance, no corrosion allowance). Use the [wall thickness calculator](https://pipingsupplyjournal.com/pipe-wall-thickness-calculator.html) for your own design conditions.

Other schedules for 18": [Sch 40](https://pipingsupplyjournal.com/18-inch-schedule-40-pipe.html) · [Sch 80](https://pipingsupplyjournal.com/18-inch-schedule-80-pipe.html) · [Sch 160](https://pipingsupplyjournal.com/18-inch-schedule-160-pipe.html) · [all 18" schedules](https://pipingsupplyjournal.com/18-inch-pipe-dimensions.html)

## Frequently asked questions

What is the ID of 18 inch Sch 10S pipe?

447.44 mm (17.616 in), with OD 457.0 mm and wall 4.78 mm.

What is the weight of 18 inch Sch 10S pipe?

53.31 kg/m (35.82 lb/ft) in carbon steel; 319.9 kg per 6 m length.

What pressure can 18 inch Sch 10S pipe take?

Roughly 21 bar at ambient for seamless A312 TP316L under ASME B31.3 with no corrosion allowance; actual rating depends on material, temperature and code.

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Data is for reference; verify against the current edition of the governing standard. Quotations: https://pipingsupplyjournal.com/get-quote.html