This reference provides a practical overview of Schedule 80 Pipe 3/4 Inch (DN20) for engineers, designers, buyers, fabricators, and piping drafters. The page brings together the dimensional terminology used to identify the pipe, the key values in the reference table, and selection considerations that should be checked before the pipe is specified or ordered.
Use the dimensions for early layout, takeoff, support coordination, and fitting or flange review. For detailed work, compare the project specification with the applicable material, manufacturing, joining, and inspection requirements. The downloadable DWG file can also support drafting workflows, but CAD geometry should be checked against the approved project data before fabrication.
Schedule 80 Pipe 3/4 Inch (DN20) 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 26.7 mm, an inside diameter of 18.88 mm, a wall thickness of 3.91 mm, and a pipe weight of 2.2 kg/m.
Schedule 80 Pipe 3/4 Inch (DN20) Dimensions
- Pipe Standard: ANSI/ASME B36.10
- Nominal Pipe Size: 3/4 inch
- DN Size: DN20
- Outside Diameter (OD): 26.7 mm
- Inside Diameter (ID): 18.88 mm
- Wall Thickness: 3.91 mm
- Pipe Weight: 2.2 kg/m
- Pipe Weight Including Water: 2.47 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 3/4 Inch DN20 Pipe Dimensions Matter
Knowing the exact dimensions of a 3/4 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 3/4 Inch (DN20)
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
3/4 Inch Schedule 80 Pipe Data Table
| NPS | DN | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 3/4 inch | 20 | 26.7 | 18.88 | 3.91 | 2.2 |
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 Read This Schedule 80 Pipe Reference
The nominal designation identifies the pipe size for industry communication; it is not a direct statement of the measured outside or inside diameter. That is why the table should be read using the listed OD, ID, and wall thickness when coordinating pipe with fittings, supports, clamps, sleeves, valves, and other components.
Schedule is a wall-thickness classification within a nominal pipe size. It should not be treated as a complete description of pipe performance. Material grade, manufacturing specification, corrosion allowance, temperature, pressure, joining method, and project design code can all affect whether a particular pipe is appropriate for service. Final selection requires review by the responsible piping or mechanical engineer.
Using the Dimensions in Design and Drafting
- Outside diameter: Use this value when checking external clearances, supports, clamps, sleeves, and connections that locate around the pipe.
- Inside diameter: Use this value when assessing the available flow passage and coordinating internal clearances.
- Wall thickness: Use it for dimensional coordination and specification review; it does not by itself establish allowable pressure or service life.
- Weight: Use the listed mass data during material takeoff, handling planning, and preliminary support coordination. Include fittings, valves, insulation, contents, and other imposed loads where applicable.
Useful Related References
Readers comparing this item with other products may also benefit from the site’s references on pipe schedules, NPS and DN terminology, pipe fittings, flange dimensions, and piping CAD/DWG resources. These topics help connect a straight-pipe dimension reference with the components and drafting conventions used in a complete piping system.
Checks Before Ordering or Fabrication
- Confirm that the nominal designation and schedule match the project line list or material requisition.
- Verify the required material grade, end preparation, coating, and inspection requirements.
- Check that connected fittings, flanges, valves, and supports use compatible dimensional references.
- Review operating conditions, corrosion allowance, and applicable project codes with the responsible engineer.
- Confirm that the downloaded drawing represents the intended item and is suitable for the current revision of the project.
Frequently Asked Questions
What does Schedule 80 mean for this pipe?
Schedule 80 identifies a comparatively thicker wall category for the nominal pipe size. The schedule helps communicate dimensional configuration, but it does not alone define the pipe material, allowable pressure, or suitability for a particular service.
Are NPS and DN interchangeable descriptions?
NPS and DN are nominal identification systems used for pipe sizing. They help users communicate the intended size, while the actual outside diameter, inside diameter, and wall thickness should be taken from the applicable reference data.
Why are both outside and inside diameters important?
The outside diameter is important for external fit-up, supports, clamps, and clearances. The inside diameter relates to the flow passage and internal coordination. Both values should be considered when checking a piping arrangement.
Does the listed pipe weight include the contents of the pipe?
The dry pipe weight and the value identified as pipe weight including water are separate reference items in the source data. Actual design loads may also include fittings, valves, insulation, supports, and the specified process fluid.
Can the DWG file be used directly for fabrication?
The DWG is a drafting reference and should be checked against the approved project documents, revision status, units, connection details, and applicable specifications before it is used for fabrication or construction.