Use this page as a quick reference for 1/4 inch Schedule 40S pipe, also identified as DN8. It brings the nominal size, outside diameter, inside diameter, wall thickness, and weight together for piping layout, fabrication, procurement, and drafting work.
The table below is the page’s primary dimensional reference. Use the inch designation when working from NPS-based documents and the DN designation when reviewing metric project documentation. For connected components, compare the listed outside diameter with the applicable fitting, flange, clamp, or valve reference before preparing a fabrication drawing.
Schedule 40S Pipe 1/4 Inch (DN8) is a stainless steel pipe size commonly used in industrial piping systems that require corrosion resistance, dependable wall thickness, and compact pipe dimensions. This pipe size is often used in instrumentation lines, utility piping, light process systems, 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.
1/4 Inch Schedule 40S Pipe Dimensions
- Pipe Schedule: 40S
- Nominal Pipe Size: 1/4 Inch
- DN Size: DN8
- Outside Diameter (OD): 13.7 mm
- Inside Diameter (ID): 9.22 mm
- Wall Thickness: 2.24 mm
- Pipe Weight: 0.63 kg/m
- Pipe Weight Including Water: 0.69 kg/m
- Standard: ANSI/ASME B36.19
Schedule 40S Pipe 1/4 Inch Dimension Table
| Pipe Schedule | NPS (Inch) | DN (mm) | OD (mm) | ID (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| 40S | 1/4 | 8 | 13.7 | 9.22 | 2.24 | 0.63 |
What Is 1/4 Inch Schedule 40S Pipe?
A 1/4 inch Schedule 40S pipe is a stainless steel pipe with a nominal size of 1/4 inch and a wall thickness defined by the 40S schedule. For this size, the outside diameter is fixed at 13.7 mm, while the inside diameter is 9.22 mm based on a wall thickness of 2.24 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 compact industrial service and instrumentation applications.
Where Is Schedule 40S Pipe 1/4 Inch Used?
This pipe size is commonly used in systems that need corrosion resistance together with small and compact stainless steel piping. Typical applications include:
- Instrumentation and impulse piping
- Small utility and service lines
- Water and chemical service piping
- Food and beverage stainless piping
- Compact branch and connection lines
Why Pipe Dimensions Matter
Accurate 1/4 inch Schedule 40S pipe dimensions are important for piping layout, fabrication, support selection, connection planning, and material takeoff. Engineers and designers often check OD, ID, wall thickness, and weight before selecting fittings, supports, and installation methods.
The outside diameter is important for matching clamps, fittings, and supports. The inside diameter helps estimate flow area and service capacity. The wall thickness is important for mechanical strength and specification compliance, while the pipe weight per meter is useful for handling and light support planning.
1/4 Inch Schedule 40S Pipe Weight Information
The nominal weight of this pipe size is 0.63 kg/m. When filled with water, the combined weight becomes approximately 0.69 kg/m. This information is useful for fabrication work, installation planning, and small support calculations.
Difference Between NPS 1/4 and DN8
NPS 1/4 is the inch-based nominal pipe size, while DN8 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 1/4 inch Schedule 40S pipe dimensions, DN8 Schedule 40S pipe dimensions, 1/4 inch stainless steel pipe weight, DN8 pipe dimensions, or DN8 sch 40s pipe dimensions.
Conclusion
Schedule 40S Pipe 1/4 Inch (DN8) has an outside diameter of 13.7 mm, an inside diameter of 9.22 mm, a wall thickness of 2.24 mm, and a weight of 0.63 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 1/4 inch Schedule 40S pipe dimensions and DN8 pipe dimensions in one place.
How to Use This Schedule 40S Pipe Reference
For this pipe size, the nominal designation identifies the standard pipe size rather than directly stating the measured outside diameter. The dimensional entries should therefore be read together: outside diameter supports connection and layout checks, inside diameter helps describe the available bore, and wall thickness identifies the pipe section shown in the reference.
The weight entries serve different purposes. The pipe weight is useful for material takeoff, handling, and preliminary support planning. The water-filled weight provides a separate reference for a pipe containing water. Final support, stress, pressure, and service evaluations require the complete project specification and engineering review.
Drafting and procurement checks
- Use both NPS 1/4 and DN8 when cross-referencing drawings, purchase descriptions, and equipment documentation.
- Confirm that connected fittings and components use the same dimensional system and stainless steel pipe reference.
- Do not select a material grade, pressure class, joining method, or design allowance from the schedule designation alone.
- For CAD work, pair the dimensional reference with the applicable fitting, flange, and pipe-support pages in the site reference library.
Readers comparing this size with other pipe sections may also benefit from the site’s related pipe schedule dimensions, stainless steel pipe weight, pipe fittings, flange dimensions, and CAD/DWG pipe reference resources. Those related references help maintain consistent terminology between design drawings, bills of material, and fabrication documentation.
Frequently Asked Questions
What is the outside diameter of 1/4 inch Schedule 40S pipe?
The listed outside diameter is 13.7 mm.
What is the inside diameter of DN8 Schedule 40S pipe?
The listed inside diameter is 9.22 mm.
What is the wall thickness?
The listed wall thickness is 2.24 mm for the 1/4 inch Schedule 40S reference shown on this page.
Are NPS 1/4 and DN8 the same pipe size?
They are two nominal designations for the same referenced pipe size: NPS 1/4 uses the inch-based system, while DN8 uses the metric designation.
What is the pipe weight?
The listed pipe weight is 0.63 kg/m. The page also lists the combined pipe-and-water weight as 0.69 kg/m.
Does Schedule 40S by itself define the complete design requirement?
No. The schedule identifies the dimensional pipe reference. Material grade, joining details, pressure and temperature requirements, corrosion considerations, supports, and other project criteria must be checked separately.