Use this page as a quick reference when a drawing, material takeoff, or procurement document identifies stainless steel pipe as NPS 20, DN500, or Schedule 40S. The table provides the dimensional and weight data needed to coordinate large-bore piping with fittings, flanges, supports, and layout drawings.
For related design work, compare this entry with the site’s references for stainless steel pipe schedules, pipe flange dimensions, pipe fittings, and pipe support design. Those references help explain how the listed pipe dimensions interact with adjoining components without confusing nominal size with the measured pipe diameter.
Schedule 40S Pipe 20 Inch (DN500) is a stainless steel pipe size commonly used in industrial piping systems that require corrosion resistance, reliable wall thickness, and large flow capacity. This pipe size is widely used in process plants, utility lines, water treatment systems, and stainless steel fabrication work.
This dimension data is based on ANSI/ASME B36.19, which is the standard commonly used for stainless steel pipe dimensions.
20 Inch Schedule 40S Pipe Dimensions
- Pipe Schedule: 40S
- Nominal Pipe Size: 20 Inch
- DN Size: DN500
- Outside Diameter (OD): 508 mm
- Inside Diameter (ID): 488.94 mm
- Wall Thickness: 9.53 mm
- Pipe Weight: 117.15 kg/m
- Pipe Weight Including Water: 304.81 kg/m
- Standard: ANSI/ASME B36.19
Schedule 40S Pipe 20 Inch Dimension Table
| Pipe Schedule | NPS (Inch) | DN (mm) | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| 40S | 20 | 500 | 508 | 488.94 | 9.53 | 117.15 |
What Is 20 Inch Schedule 40S Pipe?
A 20 inch Schedule 40S pipe is a stainless steel pipe with a nominal size of 20 inches and a wall thickness defined by the 40S schedule. For this size, the outside diameter is fixed at 508 mm, while the inside diameter is 488.94 mm based on a wall thickness of 9.53 mm.
The letter S in 40S is typically used for stainless steel pipe dimensions under ASME B36.19. This designation is commonly used by engineers, fabricators, and procurement teams when selecting stainless steel piping for industrial applications.
Where Is Schedule 40S Pipe 20 Inch Used?
This pipe size is commonly used in projects that require a strong balance between flow capacity and stainless steel corrosion resistance. Typical applications include:
- Process piping in industrial plants
- Water treatment and utility systems
- Food and beverage piping lines
- Chemical service piping
- Large stainless steel header systems
Why Pipe Dimensions Matter
Accurate 20 inch Schedule 40S pipe dimensions are important for piping layout, fabrication, support design, transport planning, and material takeoff. Designers and engineers often check the pipe OD, ID, thickness, and weight before selecting supports, fittings, flanges, and installation methods.
The outside diameter is important for matching clamps, flanges, and pipe supports. The inside diameter helps estimate flow capacity and internal area. The wall thickness is a key factor for strength and specification compliance, while the pipe weight per meter is useful for structural loading and lifting calculations.
20 Inch Schedule 40S Pipe Weight Information
The nominal weight of this pipe size is 117.15 kg/m. When filled with water, the combined weight becomes approximately 304.81 kg/m. This additional information is useful for support design, equipment handling, and pipe rack load planning in real projects.
Difference Between NPS 20 and DN500
NPS 20 is the inch-based nominal pipe size, while DN500 is the metric designation used in many international drawings and specifications. Both terms refer to the same nominal pipe size, and users may search by either inch or DN format depending on project standards.
Common Search Terms for This Pipe Size
Users may also search for this pipe using related keywords such as 20 inch Schedule 40S pipe dimensions, DN500 Schedule 40S pipe dimensions, 20 inch stainless steel pipe weight, DN500 pipe dimensions, or DN500 sch 40s pipe dimensions.
Conclusion
Schedule 40S Pipe 20 Inch (DN500) has an outside diameter of 508 mm, an inside diameter of 488.94 mm, a wall thickness of 9.53 mm, and a weight of 117.15 kg/m. It is a useful stainless steel pipe reference size for design, drafting, fabrication, and procurement work.
This page provides a quick reference for engineers, drafters, fabricators, and buyers who need reliable 20 inch Schedule 40S pipe dimensions and DN500 pipe dimensions in one place.
How to Read This 20 Inch Schedule 40S Pipe Reference
NPS 20 and DN500 are nominal designations used to identify the same pipe size in different measurement conventions. They are not, by themselves, a substitute for checking the listed outside diameter when coordinating clamps, supports, flanges, sleeves, or opening details.
The schedule designation identifies a standardized stainless steel pipe wall category. It should be read together with the pipe material specification, manufacturing requirements, corrosion conditions, joining method, and project design code. A schedule designation alone does not establish a complete pressure rating or confirm that the pipe is appropriate for a particular service.
Using the Dimensions in Design and Drafting
- Use the outside diameter when coordinating external interfaces such as supports, clamps, insulation clearances, and flange or fitting connections.
- Use the inside diameter when reviewing flow-area assumptions, internal clearances, and connection transitions.
- Use the wall thickness when checking fabrication details, end preparation, corrosion allowances, and specification requirements.
- Use the listed pipe weight for preliminary material handling and support-load coordination, subject to project-specific load combinations and engineering review.
- Use the water-filled weight only for cases where the line contents and operating condition match the stated basis; other fluids will produce different operating loads.
Coordination Checks Before Procurement
Before ordering material, confirm the required stainless steel grade, product form, end condition, length, surface requirements, testing, certification, and governing project specification. Also verify that connected flanges, elbows, tees, valves, gaskets, and bolt details use compatible dimensional and pressure-class requirements.
For CAD work, the accompanying DWG resource can support layout and drafting workflows, but the drawing should be checked against the project’s approved piping specification and the dimensions shown in this reference. Field fabrication should rely on approved drawings and qualified engineering review rather than a catalog value alone.
Frequently Asked Questions
What does 40S mean for this pipe?
40S is the stainless steel pipe schedule designation used with the dimensional reference identified on this page. It describes the standardized wall category for the listed nominal size; it does not identify the stainless steel grade or provide a complete design-pressure rating.
Are NPS 20 and DN500 the same pipe size?
Yes. NPS 20 is the inch-based nominal designation, while DN500 is the metric designation used for the same nominal pipe size. The actual dimensional values should still be taken from the applicable table and project specification.
Which dimension should be used for pipe supports?
The outside diameter is the primary dimensional reference for supports, clamps, and other external interfaces. Support spacing, load capacity, restraint requirements, insulation, and operating conditions require a separate project-specific engineering check.
Can the listed pipe weight be used for pipe-rack design?
It can serve as a reference for preliminary coordination, material takeoff, and handling discussions. Final pipe-rack design should also consider contents, insulation, valves and fittings, test conditions, thermal effects, seismic or wind effects, and the governing design criteria.
Does Schedule 40S identify the stainless steel material grade?
No. The schedule identifies the dimensional wall category. The material grade, corrosion performance, welding requirements, and inspection requirements must come from the project specification or material standard.