Use this reference when you need a concise dimensional check for 1 inch Schedule 10 pipe, also identified as NPS 1 and DN25. The page separates nominal size from measured pipe geometry so designers, drafters, fabricators, and estimators can select the correct value for each task.
For layout and connection work, the outside diameter is generally the key value for fittings, clamps, and clearances, while the inside diameter is more relevant to flow-path checks. Wall thickness and mass are useful for fabrication, support planning, material takeoffs, and handling estimates. Always coordinate this dimensional reference with the project specification, material requirements, joining method, and applicable design checks.
Schedule 10 pipe 1 inch (DN25) is a standard steel pipe size commonly used in piping design, fabrication, drafting, and estimation work. This page provides the standard dimensions, wall thickness, inside diameter, and weight per meter for NPS 1 Schedule 10 pipe based on ASME B36.10.
1 Inch Schedule 10 Pipe Dimensions
- Nominal Pipe Size (NPS): 1 inch
- Diameter Nominal (DN): DN25
- Outside Diameter (OD): 33.4 mm
- Wall Thickness: 2.77 mm
- Inside Diameter (ID): 27.86 mm
- Pipe Weight: 2.09 kg/m
- Pipe Weight Filled With Water: 2.69 kg/m
- Reference Standard: ASME B36.10
Schedule 10 Pipe 1 Inch Data Table
| Pipe Size | DN | OD (mm) | Wall Thickness (mm) | ID (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 1 inch | 25 | 33.4 | 2.77 | 27.86 | 2.09 |
What Does Schedule 10 Mean?
Schedule 10 refers to the wall thickness series of the pipe. For the same nominal pipe size, the outside diameter remains fixed while the wall thickness changes depending on the schedule. A thicker wall generally increases pipe weight and reduces the inside diameter.
Typical Uses of 1 Inch Schedule 10 Pipe
NPS 1 Schedule 10 pipe is commonly used in utility systems, water lines, low-pressure process piping, drainage applications, and general fabrication work where a lighter wall thickness is suitable. It is also a practical reference size for material takeoff, support planning, and piping layout.
Why Pipe Weight Matters
Pipe weight per meter is important for transport planning, support design, structural loading, fabrication estimates, and lifting calculations. Even in smaller piping systems, installed weight can affect support spacing, handling methods, and project cost.
1 Inch Schedule 10 Pipe Calculation Notes
The listed weight is based on standard steel pipe dimension data using the outside diameter and wall thickness of the pipe. Actual product weight may vary slightly depending on manufacturing tolerance, material grade, and supplier standard.
Frequently Asked Questions
What is the outside diameter of 1 inch Schedule 10 pipe?
The outside diameter is 33.4 mm.
What is the wall thickness of DN25 Schedule 10 pipe?
The wall thickness is 2.77 mm.
What is the inside diameter of NPS 1 Schedule 10 pipe?
The inside diameter is 27.86 mm.
How much does 1 inch Schedule 10 pipe weigh?
The approximate weight is 2.09 kg/m.
Which standard covers this pipe size?
This dimension data is based on ASME B36.10 for welded and seamless wrought steel pipe.
Conclusion
Schedule 10 pipe 1 inch (DN25) has an outside diameter of 33.4 mm, wall thickness of 2.77 mm, inside diameter of 27.86 mm, and a weight of 2.09 kg/m. It is a useful reference for piping design, drafting, estimating, and fabrication work.
How to Read This 1 Inch Schedule 10 Pipe Reference
NPS 1 is a nominal designation rather than a direct statement of the measured outside diameter. The source data identifies the corresponding metric designation as DN25 and provides the actual outside diameter, wall thickness, and inside diameter for this schedule.
Schedule describes a wall-thickness series within a nominal pipe size. It should not be treated by itself as a complete pressure rating. Pressure capability depends on factors such as material, temperature, manufacturing condition, corrosion allowance, joining details, and the governing design code. Confirm those requirements before selecting pipe for a service application.
Using the Dimensions in Drawings and Takeoffs
- Use the outside diameter when checking interface dimensions, pipe supports, clamps, sleeves, and fitting connections.
- Use the inside diameter when preparing preliminary flow-area or clearance checks; final hydraulic calculations should follow the project method and account for the actual system.
- Use wall thickness when coordinating fabrication details, weld preparations, corrosion allowances, and material specifications.
- Use the listed weight per meter for preliminary quantity, transport, lifting, and support-load estimates. Add any contents, insulation, valves, fittings, or other attached components separately when evaluating installed weight.
This page is also a useful companion reference for related PipeSTD topics, including pipe schedules, NPS and DN terminology, fitting dimensions, flange references, and pipe CAD/DWG resources. Link those subjects from this page where they support the reader’s next design or drafting task.
Checks Before Using the Data
Confirm that the selected product is steel pipe covered by the stated reference, and check the supplier’s dimensional and mass tolerances before fabrication or procurement. The listed water-filled mass is a reference value for the pipe and water together; project calculations may also need to include fittings, contents other than water, coatings, insulation, and attached equipment.
Additional Questions About 1 Inch Schedule 10 Pipe
Is 1 inch pipe the same as DN25 pipe?
In this reference, NPS 1 corresponds to the nominal metric designation DN25. The nominal designation should not be confused with the measured outside or inside diameter.
Which dimension should I use for a pipe layout?
Use the outside diameter for external clearances, supports, sleeves, and connection coordination. Use the inside diameter when the task concerns the internal flow path. Check the applicable fitting or component drawing when coordinating a connection.
Does Schedule 10 alone define the pipe pressure rating?
No. Schedule identifies the wall-thickness series, but an allowable pressure assessment also depends on the material, temperature, design code, manufacturing details, and other project conditions.
Can the listed pipe weight be used as the complete installed load?
No. The listed pipe weight is a pipe reference value. Installed-load checks may need to include the contents, fittings, valves, insulation, coatings, supports, and other connected items.
Why can supplier weight differ from the listed value?
Published or delivered mass can vary because of manufacturing tolerances, material details, finishing, and supplier conventions. Use the manufacturer’s certified data for procurement and final project calculations.