Use this page as a quick reference when checking 3/4 inch Schedule 40S stainless steel pipe for piping layouts, material takeoffs, fabrication, and drafting. The reference combines NPS and DN terminology with outside diameter, inside diameter, wall thickness, weight, and a downloadable DWG resource.
Before using the dimensions for a project, confirm the required material specification, joining method, service conditions, and applicable project standards. The schedule identifies a dimensional wall-thickness designation; it does not by itself establish allowable pressure, temperature limits, corrosion performance, or structural adequacy.
Schedule 40S Pipe 3/4 Inch (DN20) is a stainless steel pipe size commonly used in industrial piping systems that require corrosion resistance, dependable wall thickness, and reliable flow capacity. This pipe size is often used in process plants, utility systems, water treatment projects, 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.
3/4 Inch Schedule 40S Pipe Dimensions
- Pipe Schedule: 40S
- Nominal Pipe Size: 3/4 Inch
- DN Size: DN20
- Outside Diameter (OD): 26.7 mm
- Inside Diameter (ID): 20.96 mm
- Wall Thickness: 2.87 mm
- Pipe Weight: 1.69 kg/m
- Pipe Weight Including Water: 2.03 kg/m
- Standard: ANSI/ASME B36.19
Schedule 40S Pipe 3/4 Inch Dimension Table
| Pipe Schedule | NPS (Inch) | DN (mm) | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| 40S | 3/4 | 20 | 26.7 | 20.96 | 2.87 | 1.69 |
What Is 3/4 Inch Schedule 40S Pipe?
A 3/4 inch Schedule 40S pipe is a stainless steel pipe with a nominal size of 3/4 inch and a wall thickness defined by the 40S schedule. For this size, the outside diameter is fixed at 26.7 mm, while the inside diameter is 20.96 mm based on a wall thickness of 2.87 mm.
The letter S in 40S is commonly used for stainless steel pipe dimensions under ASME B36.19. This designation is widely used by engineers, fabricators, and procurement teams when selecting stainless steel piping for industrial service.
Where Is Schedule 40S Pipe 3/4 Inch Used?
This pipe size is commonly used in systems that need both good flow capacity and the corrosion resistance of stainless steel. Typical applications include:
- Process piping in industrial plants
- Water treatment and utility systems
- Food and beverage piping lines
- Chemical service piping
- Stainless steel branch and service lines
Why Pipe Dimensions Matter
Accurate 3/4 inch Schedule 40S pipe dimensions are important for piping layout, fabrication, support design, transport planning, and material takeoff. Engineers and designers often check OD, ID, wall thickness, and weight before selecting flanges, fittings, supports, and installation methods.
The outside diameter is important for matching clamps, flanges, and pipe supports. The inside diameter helps estimate flow area and system capacity. The wall thickness is important for specification compliance and mechanical strength, while the pipe weight per meter is useful for structural loading, support design, and handling calculations.
3/4 Inch Schedule 40S Pipe Weight Information
The nominal weight of this pipe size is 1.69 kg/m. When filled with water, the combined weight becomes approximately 2.03 kg/m. This information is useful for lifting plans, support design, and pipe rack load calculations in industrial projects.
Difference Between NPS 3/4 and DN20
NPS 3/4 is the inch-based nominal pipe size, while DN20 is the metric designation used in 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 3/4 inch Schedule 40S pipe dimensions, DN20 Schedule 40S pipe dimensions, 3/4 inch stainless steel pipe weight, DN20 pipe dimensions, or DN20 sch 40s pipe dimensions.
Conclusion
Schedule 40S Pipe 3/4 Inch (DN20) has an outside diameter of 26.7 mm, an inside diameter of 20.96 mm, a wall thickness of 2.87 mm, and a weight of 1.69 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 3/4 inch Schedule 40S pipe dimensions and DN20 pipe dimensions in one place.
How to Use This Pipe Reference
Start with the nominal designation when searching drawings, specifications, or supplier documents. NPS 3/4 and DN20 are alternate naming conventions for the same nominal pipe size, while the schedule identifies the stainless steel dimensional series used for the reference.
For layout and connection checks, use the listed outside diameter when coordinating supports, clamps, sleeves, and fitting interfaces. The listed inside diameter is useful for preliminary flow-area reviews, but final hydraulic calculations should also account for the piping system, fittings, valves, surface condition, and design assumptions.
For fabrication and installation planning, review wall thickness and unit weight together with the selected material and joining process. The water-filled weight is especially relevant when considering temporary handling, support reactions, and operating loads. These values should be coordinated with the project piping specification and verified by the responsible engineer.
Related Pipe and Piping References
Readers comparing this size with other options may also benefit from the site’s pipe schedule references, stainless steel pipe dimensions, pipe fitting dimensions, and flange dimension tables. For drafting workflows, the downloadable Schedule 40S Pipe 3/4 Inch (DN20) DWG can support layout coordination, but the drawing should be checked against the project model and connection details before fabrication.
Frequently Asked Questions
What is the outside diameter of 3/4 inch Schedule 40S pipe?
The listed outside diameter is 26.7 mm.
What is the inside diameter of DN20 Schedule 40S pipe?
The listed inside diameter is 20.96 mm. The reference also lists a wall thickness of 2.87 mm.
Are NPS 3/4 and DN20 the same pipe size?
They are alternate nominal designations for the same pipe size: NPS uses the inch-based system, while DN uses the metric designation.
What is the listed weight of this pipe?
The listed pipe weight is 1.69 kg/m. The listed weight including water is 2.03 kg/m.
Does Schedule 40S determine the pipe material grade?
No. Schedule 40S identifies a stainless steel pipe dimensional designation, but the material grade, product specification, corrosion suitability, and design requirements must be confirmed separately.
Can the DWG file be used directly for fabrication?
The DWG is a drafting reference for coordination and layout. Confirm dimensions, tolerances, connection details, material requirements, and project-specific revisions before releasing fabrication information.