Use this reference when checking NPS 18 Schedule 100 pipe dimensions for piping layouts, material takeoffs, fabrication documents, and engineering estimates. The table separates the nominal designation from the actual outside diameter, wall thickness, inside diameter, and unit weight so each value can be applied correctly.
For related design work, compare this page with the site’s pipe schedule references, NPS-to-DN terminology guide, pipe weight resources, and steel pipe CAD/DWG library. Always confirm the applicable material specification, manufacturing requirements, and project design basis before using dimensional data for procurement or final engineering.
Schedule 100 pipe 18 inch (DN450) is a heavy-wall steel pipe size commonly used in piping design, fabrication, drafting, and engineering estimation work. This page provides the standard dimensions, wall thickness, inside diameter, and weight per meter for NPS 18 Schedule 100 pipe based on ASME B36.10.
18 Inch Schedule 100 Pipe Dimensions
- Nominal Pipe Size (NPS): 18 inch
- Diameter Nominal (DN): DN450
- Outside Diameter (OD): 457 mm
- Wall Thickness: 29.36 mm
- Inside Diameter (ID): 398.28 mm
- Pipe Weight: 309.64 kg/m
- Pipe Weight Filled With Water: 434.16 kg/m
- Reference Standard: ASME B36.10
Schedule 100 Pipe 18 Inch Data Table
| Pipe Size | DN | OD (mm) | Wall Thickness (mm) | ID (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 18 inch | 450 | 457 | 29.36 | 398.28 | 309.64 |
What Does Schedule 100 Mean?
Schedule 100 refers to a heavier wall thickness series than lighter schedules such as Schedule 10 or Schedule 40. For the same nominal pipe size, the outside diameter remains fixed while the wall thickness increases according to the schedule. A thicker wall reduces the inside diameter and significantly increases pipe weight.
Typical Uses of 18 Inch Schedule 100 Pipe
NPS 18 Schedule 100 pipe is commonly referenced for heavy-duty industrial piping systems where higher wall thickness is required. It may be used in process piping, plant utility systems, fabrication work, structural loading checks, and engineering applications where pipe strength and wall thickness are more critical than maximum flow area.
Why Pipe Weight Matters
Pipe weight per meter is essential for transport planning, lifting studies, support design, structural loading, fabrication estimates, and installation planning. For an 18 inch Schedule 100 pipe, the heavy wall thickness creates a much higher installed weight than lighter schedules, so accurate weight data is important for engineering and construction work.
18 Inch Schedule 100 Pipe Calculation Notes
The listed weight is based on standard steel pipe dimensions using the outside diameter and wall thickness of the pipe. Actual product weight may vary slightly depending on manufacturing tolerance, material specification, and supplier standard.
Frequently Asked Questions
What is the outside diameter of 18 inch Schedule 100 pipe?
The outside diameter is 457 mm.
What is the wall thickness of DN450 Schedule 100 pipe?
The wall thickness is 29.36 mm.
What is the inside diameter of NPS 18 Schedule 100 pipe?
The inside diameter is 398.28 mm.
How much does 18 inch Schedule 100 pipe weigh?
The approximate weight is 309.64 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 100 pipe 18 inch (DN450) has an outside diameter of 457 mm, wall thickness of 29.36 mm, inside diameter of 398.28 mm, and a weight of 309.64 kg/m. It is a useful reference for piping design, fabrication, estimating, and heavy-duty industrial engineering work.
How to Use This Pipe Reference
The dimensional list and data table are useful for different checking tasks. Use the outside diameter when coordinating pipe with fittings, clamps, supports, sleeves, and layout clearances. Use the inside diameter when reviewing flow passage, lining space, or internal clearance. The wall thickness is relevant to fabrication details, corrosion allowance reviews, weight estimates, and design checks.
Nominal Size and Actual Diameter
NPS and DN are identification systems rather than direct measurements of the pipe bore. The actual dimensions must therefore be taken from the stated OD, wall thickness, and ID values rather than inferred from the nominal size alone. This distinction is especially important when coordinating large-bore pipe with flanges, reducers, valves, and structural supports.
Using the Weight Information
The dry pipe weight supports estimating, transport planning, lifting studies, support reactions, and structural load checks. The water-filled figure represents a different planning condition and should not be treated as the dry shipping weight. Site-specific contents, insulation, coatings, fittings, and attachments may require additional review.
Drafting and CAD Coordination
The downloadable DWG can help establish a starting geometry for layouts and detailing. Before issuing a drawing, check the project units, connection details, fitting dimensions, flange requirements, and any applicable fabrication tolerances. A generic dimensional reference should not replace approved vendor or project documents.
Related Reference Topics
- Compare this entry with the site’s pipe schedules and dimensions references.
- Use the pipe fittings and flange dimensions resources when coordinating connected components.
- Review piping terminology for NPS, DN, OD, ID, and schedule definitions.
- Browse the CAD/DWG pipe library for related drafting resources.
Additional Questions About 18 Inch Schedule 100 Pipe
Is the nominal pipe size the same as the measured outside diameter?
No. The nominal size is a designation used to identify the pipe size. For design coordination, use the listed outside diameter and other dimensional values rather than assuming the nominal size is a direct measurement.
Why are both dry and water-filled weights shown?
They describe different planning conditions. The dry weight is useful for handling and material estimates, while the water-filled value helps illustrate a loaded condition for support and structural reviews.
Can this table be used as a procurement specification?
No. It is a dimensional reference. Procurement should also identify the required material specification, manufacturing requirements, testing, end preparation, coatings, and project-specific acceptance criteria.
What should be checked before using the DWG file?
Confirm the drawing units, scale, layer conventions, connection geometry, and project-specific component details. The CAD file should be reviewed against approved design documents before it is used for fabrication or construction.