This reference brings together the key dimensional and weight information for Schedule 40S pipe 3 1/2 inch (DN90). Use the table below when checking a piping layout, preparing a material takeoff, coordinating fittings, or reviewing a fabrication drawing.
For related design work, compare this page with the site’s references for pipe schedules, pipe fittings, and pipe flanges. The accompanying DWG resource can also support drafting and layout coordination, but connection details should be checked against the project specification and selected components.
Schedule 40S Pipe 3 1/2 Inch (DN90) 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 1/2 Inch Schedule 40S Pipe Dimensions
- Pipe Schedule: 40S
- Nominal Pipe Size: 3 1/2 Inch
- DN Size: DN90
- Outside Diameter (OD): 101.6 mm
- Inside Diameter (ID): 90.12 mm
- Wall Thickness: 5.74 mm
- Pipe Weight: 13.57 kg/m
- Pipe Weight Including Water: 19.94 kg/m
- Standard: ANSI/ASME B36.19
Schedule 40S Pipe 3 1/2 Inch Dimension Table
| Pipe Schedule | NPS (Inch) | DN (mm) | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| 40S | 3 1/2 | 90 | 101.6 | 90.12 | 5.74 | 13.57 |
What Is 3 1/2 Inch Schedule 40S Pipe?
A 3 1/2 inch Schedule 40S pipe is a stainless steel pipe with a nominal size of 3 1/2 inches and a wall thickness defined by the 40S schedule. For this size, the outside diameter is fixed at 101.6 mm, while the inside diameter is 90.12 mm based on a wall thickness of 5.74 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 1/2 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 header systems
Why Pipe Dimensions Matter
Accurate 3 1/2 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 1/2 Inch Schedule 40S Pipe Weight Information
The nominal weight of this pipe size is 13.57 kg/m. When filled with water, the combined weight becomes approximately 19.94 kg/m. This information is useful for lifting plans, support design, and pipe rack load calculations in industrial projects.
Difference Between NPS 3 1/2 and DN90
NPS 3 1/2 is the inch-based nominal pipe size, while DN90 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 1/2 inch Schedule 40S pipe dimensions, DN90 Schedule 40S pipe dimensions, 3 1/2 inch stainless steel pipe weight, DN90 pipe dimensions, or DN90 sch 40s pipe dimensions.
Conclusion
Schedule 40S Pipe 3 1/2 Inch (DN90) has an outside diameter of 101.6 mm, an inside diameter of 90.12 mm, a wall thickness of 5.74 mm, and a weight of 13.57 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 1/2 inch Schedule 40S pipe dimensions and DN90 pipe dimensions in one place.
How to Use This Schedule 40S Pipe Reference
Start with the nominal designation used on the drawing or purchase description, then confirm the corresponding outside diameter, inside diameter, wall thickness, and mass values in the source table. Nominal pipe size is a designation rather than a direct measurement of the pipe’s outside or inside diameter.
The outside diameter is especially useful when coordinating supports, clamps, sleeves, and fittings. The inside diameter is a dimensional reference for flow-area checks, while wall thickness and pipe mass support fabrication, handling, and preliminary load coordination. Final design checks should also account for the piping material specification, manufacturing tolerances, joining method, service conditions, and applicable project requirements.
Coordination With Fittings and Flanges
Pipe size and schedule should be confirmed together when selecting elbows, tees, reducers, couplings, flanges, and other components. A matching nominal size alone does not establish complete compatibility: the component standard, connection type, pressure class, material, and facing details must also agree with the piping specification.
For broader coordination, link this page to the site’s stainless steel pipe reference and related pipe dimension resources. These supporting pages can help readers move from a single size lookup to material selection, fitting identification, and drawing review.
Using the DWG File
The downloadable DWG is useful for preliminary drafting, layout development, and reference geometry. Before issuing a drawing or fabricating from it, verify units, layer conventions, connection details, and the project’s approved dimensional data. A CAD block should be treated as a reference aid rather than a substitute for the governing piping specification.
Frequently Asked Questions
What does Schedule 40S mean?
Schedule 40S is the stainless steel pipe schedule designation used with the dimensional reference provided on this page. It identifies a defined wall-thickness series for the listed nominal pipe size; it does not, by itself, specify the complete material grade or service rating.
Are NPS 3 1/2 and DN90 the same pipe size?
They are different designation systems for the same nominal pipe size shown in the source content. Always confirm the actual dimensions and component compatibility rather than relying on the nominal label alone.
Which dimensions should be checked before ordering fittings?
Check the nominal size, schedule, outside diameter, wall thickness, connection type, material specification, and the fitting or flange standard. The mating component must be compatible with the complete piping specification.
Can the inside diameter be used directly for a flow calculation?
The listed inside diameter is useful for preliminary flow-area review. Final hydraulic calculations should use the approved design data and account for the actual pipe condition, fittings, valves, roughness assumptions, and project requirements.
Can I use the DWG file for fabrication?
The DWG is intended as a drafting and reference resource. Confirm its units and geometry against the approved project documents before using it for fabrication or construction.