This reference page is intended for engineers, designers, estimators, drafters, and fabricators checking 18 inch Schedule 10 pipe dimensions. Use the dimensional data below when coordinating pipe layouts, preparing material takeoffs, reviewing fabrication drawings, or selecting a starting point for a CAD model.
For related sizing work, compare this entry with the site’s pipe schedule reference and pipe dimensions resources. Those references can help distinguish nominal pipe size, outside diameter, wall thickness, and inside diameter when reviewing adjacent pipe sizes or schedules.
Schedule 10 pipe 18 inch (DN450) is a large-diameter steel pipe size commonly used as a reference in piping design, fabrication, drafting, and estimation work. This page provides the standard dimensions, wall thickness, inside diameter, and weight per meter for NPS 18 Schedule 10 pipe based on ASME B36.10.
18 Inch Schedule 10 Pipe Dimensions
- Nominal Pipe Size (NPS): 18 inch
- Diameter Nominal (DN): DN450
- Outside Diameter (OD): 457 mm
- Wall Thickness: 6.35 mm
- Inside Diameter (ID): 444.3 mm
- Pipe Weight: 70.57 kg/m
- Pipe Weight Filled With Water: 225.53 kg/m
- Reference Standard: ASME B36.10
Schedule 10 Pipe 18 Inch Data Table
| Pipe Size | DN | OD (mm) | Wall Thickness (mm) | ID (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 18 inch | 450 | 457 | 6.35 | 444.3 | 70.57 |
What Does Schedule 10 Mean?
Schedule 10 refers to the wall thickness series of the pipe. For the same nominal pipe size, the outside diameter remains fixed while the wall thickness changes depending on the schedule. A thicker wall generally increases pipe weight and reduces the inside diameter.
Typical Uses of 18 Inch Schedule 10 Pipe
NPS 18 Schedule 10 pipe is commonly used where large flow capacity is needed with relatively lighter wall thickness than heavier schedules. It may be used in water transfer lines, utility systems, low-pressure process piping, drainage applications, and general plant layout or fabrication reference work.
Why Pipe Weight Matters
Pipe weight per meter is important for transport planning, support design, structural loading, fabrication estimates, and lifting calculations. In large-diameter piping systems, total line weight can significantly affect support spacing, installation methods, and project cost.
18 Inch Schedule 10 Pipe Calculation Notes
The listed weight is based on standard steel pipe dimension data using the outside diameter and wall thickness of the pipe. Actual product weight may vary slightly depending on manufacturing tolerance, material grade, and supplier standard.
Frequently Asked Questions
What is the outside diameter of 18 inch Schedule 10 pipe?
The outside diameter is 457 mm.
What is the wall thickness of DN450 Schedule 10 pipe?
The wall thickness is 6.35 mm.
What is the inside diameter of NPS 18 Schedule 10 pipe?
The inside diameter is 444.3 mm.
How much does 18 inch Schedule 10 pipe weigh?
The approximate weight is 70.57 kg/m.
Which standard covers this pipe size?
This dimension data is based on ASME B36.10 for welded and seamless wrought steel pipe.
Conclusion
Schedule 10 pipe 18 inch (DN450) has an outside diameter of 457 mm, wall thickness of 6.35 mm, inside diameter of 444.3 mm, and a weight of 70.57 kg/m. It is a useful reference for piping design, drafting, estimating, and fabrication work.
How to Use This Pipe Reference
The values on this page describe the pipe geometry and listed mass for the NPS 18, DN450 Schedule 10 entry. The nominal size is a designation used for identification; it should not be treated as a direct measurement of the pipe’s outside or inside diameter. For layout and fit-up work, use the stated outside diameter, wall thickness, and inside diameter rather than relying on the nominal size alone.
Schedule is a wall-thickness designation within a nominal pipe size. When comparing schedules for the same size, the outside diameter generally remains the controlling envelope while the wall thickness and available internal passage change. This makes schedule comparisons useful during pipe layout, pipe support planning, and interference checking.
Weight and Project Coordination
The listed pipe weight is useful for material estimates, handling plans, support reactions, and preliminary loading reviews. The water-filled figure provides an additional reference for systems where the pipe may contain water. Final support, lifting, and structural decisions should use the project specification, actual purchased material, operating contents, insulation, valves, fittings, and other attached components as applicable.
Using the DWG Reference
The downloadable DWG can support drafting and coordination workflows. Before using it in a fabrication or construction drawing, confirm units, layer conventions, insertion scale, connection details, end preparation, and project-specific tolerances. A dimension reference is not a substitute for the applicable purchase specification or a verified fabrication drawing.
Related Piping References
- Pipe fittings reference for connecting components and layout terminology.
- Flange dimensions and terminology for flange selection and drawing coordination.
- Piping terminology guide for NPS, DN, OD, ID, and schedule definitions.
- CAD and DWG resources for using downloadable piping geometry in design documentation.
Additional Reference Questions
Is the nominal size the same as the measured inside diameter?
No. NPS and DN are identification designations. The actual outside diameter, wall thickness, and inside diameter are the dimensions to use for modeling, clearance checks, and hydraulic or mechanical review.
Does Schedule 10 alone establish a pipe pressure rating?
No. Pressure capability depends on more than schedule. Material, temperature, manufacturing requirements, weld or seamless construction, design code, corrosion allowance, joints, and project specifications may all affect the engineering assessment.
Can the listed weight be used as the final installed line weight?
It should be treated as a pipe-only reference. An installed line may also include contents, fittings, flanges, valves, insulation, supports, coatings, and other items. Confirm the complete load case before final support or structural design.
Why should the DWG be checked before it is issued?
Downloaded CAD content may require verification of units, scale, layers, orientation, and connection details. Review it against the dimensional table and the project’s drawing standards before incorporating it into controlled design documents.