Schedule 80 Pipe 18 Inch (DN450 mm) is a heavy-wall steel pipe size commonly used in industrial piping systems where higher wall thickness and stronger pressure-related performance are required. This pipe size is referenced from ANSI/ASME B36.10 and is widely used in oil and gas, water treatment, process piping, utility lines, and general mechanical applications. The current page data lists this size with an outside diameter of 457 mm, inside diameter of 409.34 mm, wall thickness of 23.83 mm, and pipe weight of 254.57 kg/m.
In pipe sizing, NPS 18 corresponds to DN450 as a nominal reference size. The schedule number indicates wall thickness. For the same nominal pipe size, a higher schedule generally means a thicker wall and a smaller inside diameter, while the outside diameter remains standardized. This is why Schedule 80 pipe is often selected when additional strength, durability, or corrosion allowance is needed in the design.
Schedule 80 Pipe 18 Inch DN450 Dimensions
- Pipe Standard: ANSI/ASME B36.10
- Nominal Pipe Size: 18 inch
- DN Size: DN450
- Outside Diameter (OD): 457 mm
- Inside Diameter (ID): 409.34 mm
- Wall Thickness: 23.83 mm
- Pipe Weight: 254.57 kg/m
- Pipe Weight Including Water: 386.1 kg/m
What Does Schedule 80 Mean?
Schedule 80 refers to a pipe wall thickness classification. It does not directly describe the outside diameter. In standardized steel pipe systems, the outside diameter stays fixed for a given NPS size, while the wall thickness changes by schedule. Because of this, Schedule 80 pipe provides a thicker wall than lighter schedules and reduces the internal flow diameter compared with lower schedules of the same nominal size.
Where Is 18 Inch DN450 Schedule 80 Pipe Used?
This pipe size is often used in larger industrial systems where mechanical strength and long service life are important. Typical applications include:
- Process piping in factories and plants
- Water transmission and utility piping
- Oil and gas pipeline systems
- Fire protection and heavy-duty service lines
- Pump stations and treatment facilities
Why These Dimensions Matter
Understanding pipe dimensions is important for engineering design, fabrication, and installation. The outside diameter is needed for clamps, supports, and flange compatibility. The inside diameter affects flow capacity and pressure drop. The wall thickness influences strength and allowable service conditions, while the weight per meter is useful for transport planning, structural support design, and lifting calculations.
18 Inch Schedule 80 Pipe Dimension Table
| NPS | DN | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 18 inch | 450 | 457 | 409.34 | 23.83 | 254.57 |
Additional Reference for Designers and Buyers
Before selecting this pipe for a project, engineers usually also review the pipe material specification, end type, corrosion allowance, operating temperature, design pressure, and applicable code requirements. While Schedule 80 gives the dimensional wall category, the final pipe selection should always match the full project specification and service condition.
Note: NPS is the nominal pipe size in inches, while DN is the nominal diameter reference in metric format. These are standardized naming systems used for piping identification and are not always equal to the exact measured internal diameter.