This reference provides the dimensional data, weight information, and practical selection context for Schedule 80 Pipe 3 1/2 Inch (DN90). Use the table for checking drawings, estimating support loads, coordinating fittings, and comparing the pipe with other schedules or nominal sizes.
The dimensional values on this page describe the pipe section itself. Project selection also depends on material specification, joining method, service fluid, temperature, pressure, corrosion allowance, and the governing design requirements. Treat the listed dimensions as reference data and confirm the complete purchasing and design specification before fabrication or installation.
Schedule 80 Pipe 3 1/2 Inch (DN90) is a heavy wall steel pipe commonly used in industrial piping systems that require higher strength and thicker pipe walls than lighter schedules. This pipe size is based on ANSI/ASME B36.10 and is widely used in process piping, utility systems, water treatment plants, and mechanical services. For this size, the standard data shows an outside diameter of 101.6 mm, an inside diameter of 85.44 mm, a wall thickness of 8.08 mm, and a pipe weight of 18.64 kg/m.
Schedule 80 Pipe 3 1/2 Inch (DN90) Dimensions
- Pipe Standard: ANSI/ASME B36.10
- Nominal Pipe Size: 3 1/2 inch
- DN Size: DN90
- Outside Diameter (OD): 101.6 mm
- Inside Diameter (ID): 85.44 mm
- Wall Thickness: 8.08 mm
- Pipe Weight: 18.64 kg/m
- Pipe Weight Including Water: 24.37 kg/m
What Is Schedule 80 Pipe?
Schedule 80 refers to a pipe wall thickness classification. For the same nominal pipe size, a Schedule 80 pipe has a thicker wall and a smaller inside diameter than lower schedule pipes. This makes it a practical choice for systems that need additional pipe strength, durability, and long-term service performance.
Why 3 1/2 Inch DN90 Pipe Dimensions Matter
Knowing the exact dimensions of a 3 1/2 inch Schedule 80 pipe is important for piping design, fabrication, and installation. The outside diameter helps with flange matching, clamps, and supports. The inside diameter affects flow area and system capacity. The wall thickness is important for strength and service conditions, while the pipe weight per meter is useful for transport, lifting plans, and structural support calculations.
Common Uses of Schedule 80 Pipe 3 1/2 Inch (DN90)
This pipe size is often used in industrial and commercial piping systems such as:
- Water treatment and utility piping
- Process and plant piping systems
- Oil and gas applications
- Pump stations and mechanical services
- Heavy-duty industrial pipe networks
3 1/2 Inch Schedule 80 Pipe Data Table
| NPS | DN | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 3 1/2 inch | 90 | 101.6 | 85.44 | 8.08 | 18.64 |
Additional Information for Engineers and Buyers
Before selecting this pipe size, it is also important to review the material grade, end type, design pressure, corrosion allowance, operating temperature, and project code requirements. While Schedule 80 defines the dimensional wall category, the final pipe selection should always match the actual service condition and engineering specification.
Note: NPS means nominal pipe size in inches, while DN means diameter nominal in millimeters. These are standard reference sizes used for pipe identification.
How to Use This Schedule 80 Pipe Reference
Start with the nominal designation when searching catalogs, drawings, and bills of materials. NPS identifies the nominal inch-based pipe size, while DN is the metric nominal designation. Neither designation should be treated as a direct measurement of the pipe bore.
Checking dimensions during design and drafting
Use the outside diameter when coordinating external interfaces such as clamps, supports, sleeves, branch connections, and flange-related components. Use the inside diameter when reviewing flow passages, instrument connections, internal clearances, and transitions to other components. The wall thickness helps confirm the section shown in a drawing and supports fabrication and inspection discussions.
Understanding weight information
The listed pipe weight per unit length is useful for preliminary material takeoffs, handling plans, lifting discussions, and support-layout reviews. The value that includes water represents a different loading condition from the bare-pipe weight. Actual installed loads may also include fittings, valves, insulation, lining, contents, supports, and other attached equipment, so final support design requires a complete system load assessment.
Schedule selection is not a complete design specification
Schedule identifies a wall-thickness category for a nominal pipe size; it does not by itself identify the material grade, corrosion resistance, allowable pressure, operating temperature, end preparation, or joining method. Confirm those items against the project specification and applicable engineering requirements. A thicker wall can reduce the available internal passage compared with a lighter schedule, so both external fit-up and internal performance should be reviewed.
Using the CAD resource
The downloadable DWG can support layout and drafting work, but users should verify units, drawing scale, layer conventions, connection details, and project-specific tolerances before incorporating the file into issued documents. The dimensional table on this page remains the reference for the listed pipe data.
Frequently Asked Questions
What does Schedule 80 mean for this pipe?
Schedule 80 identifies the pipe wall-thickness category for the stated nominal size. It is not a material grade and should not be used alone to determine allowable pressure or service suitability.
Are 3 1/2 inch and DN90 the same designation?
They are the inch-based nominal designation and metric nominal designation used to identify this pipe size. The actual outside and inside dimensions are the values listed in the reference data, not simply the nominal labels.
Which dimension is most important for fitting coordination?
The outside diameter is generally the key pipe dimension for external fit-up with clamps, supports, sleeves, and related components. Connection compatibility must still be checked against the selected fittings, flanges, end preparation, and project specifications.
Can the listed pipe weight be used for support design?
It can provide a reference for preliminary load estimates. Final support design should also account for contents, fittings, valves, insulation, attached equipment, dynamic effects, and the applicable structural requirements.
What should be checked before ordering this pipe?
Confirm the material grade, manufacturing and dimensional requirements, end type, corrosion allowance, operating conditions, joining method, inspection requirements, and project code or specification. Schedule alone does not define the complete order description.