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Schedule 40 Pipe Dimensions
Schedule 40 Pipe Dimensions: Thickness in Inches and MM
Schedule 40 Pipe Dimensions are among the most commonly referenced specifications in the piping industry. Whether you're an engineer, contractor, fabricator, or procurement professional, understanding Schedule 40 pipe sizes is essential for selecting the right piping system for industrial and commercial applications.
Schedule 40 (Sch 40) pipes are manufactured with standardized wall thicknesses while maintaining a fixed outside diameter (OD) for each nominal pipe size (NPS). This standardization ensures compatibility with fittings, flanges, valves and other piping components across various industries.
A complete Schedule 40 pipe dimensions chart, including outside diameter (OD), wall thickness in inches and millimeters, inside diameter (ID) and approximate weight. Whether you're searching for Schedule 40 pipe thickness in mm, Schedule 40 pipe dimensions in inches, or Sch 40 stainless steel pipe dimensions, this guide provides reliable technical information based on ASME B36.10M and ASME B36.19M standards.
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What Is Schedule 40 Pipe?
Schedule 40 (Sch 40) is a standardized pipe wall thickness classification. It specifies the wall thickness of a pipe for a given nominal pipe size rather than its actual diameter.
| Governing Standards |
ASME B36.10M – Carbon Steel Pipe Dimensions ASME B36.19M – Stainless Steel Pipe Dimensions |
|---|
Many people assume Schedule 40 refers to the pipe diameter, but this is incorrect. The schedule only indicates the wall thickness.
| Parameter | Description |
|---|---|
| Outside Diameter (OD) | Remains constant. |
| Wall Thickness (WT) | Varies according to the schedule. |
| Inside Diameter (ID) | Changes depending on the wall thickness. |
| Pressure Capacity | Increases as wall thickness increases. |
Why Schedule 40 Pipe Is Popular
Schedule 40 is the most widely used pipe schedule because it offers an excellent balance between strength, durability, flow capacity, and cost. It is suitable for a broad range of industrial and commercial piping systems.
Its advantages include:
- Standardized dimensions
- Excellent mechanical strength
- Good pressure resistance
- High flow efficiency
- Easy fabrication and welding
- Worldwide availability
- Cost-effective installation
- Compatibility with standard fittings and flanges
Schedule 40 Pipe Dimensions Chart
| Nominal Pipe Size (NPS) |
Outside Diameter (OD) | Wall Thickness (WT) | Inside Diameter (ID) (in) |
Approx. Weight (lb/ft) |
||
|---|---|---|---|---|---|---|
| in | mm | in | mm | |||
| 1/2" | 0.840 | 21.34 | 0.109 | 2.77 | 0.622 | 0.85 |
| 3/4" | 1.050 | 26.67 | 0.113 | 2.87 | 0.824 | 1.13 |
| 1" | 1.315 | 33.40 | 0.133 | 3.38 | 1.049 | 1.68 |
| 1-1/4" | 1.660 | 42.16 | 0.140 | 3.56 | 1.380 | 2.27 |
| 1-1/2" | 1.900 | 48.26 | 0.145 | 3.68 | 1.610 | 2.72 |
| 2" | 2.375 | 60.33 | 0.154 | 3.91 | 2.067 | 3.66 |
| 2-1/2" | 2.875 | 73.03 | 0.203 | 5.16 | 2.469 | 5.79 |
| 3" | 3.500 | 88.90 | 0.216 | 5.49 | 3.068 | 7.58 |
| 4" | 4.500 | 114.30 | 0.237 | 6.02 | 4.026 | 10.79 |
| 5" | 5.563 | 141.30 | 0.258 | 6.55 | 5.047 | 14.62 |
| 6" | 6.625 | 168.28 | 0.280 | 7.11 | 6.065 | 18.97 |
| 8" | 8.625 | 219.08 | 0.322 | 8.18 | 7.981 | 28.55 |
| 10" | 10.750 | 273.05 | 0.365 | 9.27 | 10.020 | 40.48 |
| 12" | 12.750 | 323.85 | 0.406 | 10.31 | 11.938 | 53.52 |
How to Read a Schedule 40 Pipe Dimensions Chart
A Schedule 40 pipe dimensions chart contains several measurements that help engineers and buyers choose the correct pipe.
| Term | Description |
|---|---|
| Nominal Pipe Size (NPS) | The standard trade name of the pipe rather than its actual diameter. |
| Outside Diameter (OD) | The actual external diameter of the pipe. The OD remains the same regardless of the schedule. |
| Wall Thickness (WT) | The thickness of the pipe wall, which determines the pipe's pressure-handling capability. |
| Inside Diameter (ID) | The internal diameter available for fluid flow. It is calculated by subtracting twice the wall thickness from the outside diameter. |
| Approximate Weight | The estimated weight per foot, useful for transportation, structural design, and installation planning. |
Schedule 40 Pipe Thickness Chart
Schedule 40 pipe wall thickness is commonly specified in both imperial and metric units. Imperial dimensions remain the industry standard for engineering drawings, fabrication, and piping specifications, while metric measurements are widely used in international projects.
| Pipe Size | Wall Thickness (in) | Wall Thickness (mm) |
|---|---|---|
| 1/2" | 0.109 | 2.77 |
| 3/4" | 0.113 | 2.87 |
| 1" | 0.133 | 3.38 |
| 1-1/4" | 0.140 | 3.56 |
| 1-1/2" | 0.145 | 3.68 |
| 2" | 0.154 | 3.91 |
| 2-1/2" | 0.203 | 5.16 |
| 3" | 0.216 | 5.49 |
| 4" | 0.237 | 6.02 |
| 5" | 0.258 | 6.55 |
| 6" | 0.280 | 7.11 |
| 8" | 0.322 | 8.18 |
| 10" | 0.365 | 9.27 |
| 12" | 0.406 | 10.31 |
Understanding Schedule 40 Pipe Sizes
Many users confuse Nominal Pipe Size (NPS) with the actual pipe diameter.
Here's a simple explanation:
| Term | Explanation |
|---|---|
| NPS (Nominal Pipe Size) | Standard trade designation. |
| NB (Nominal Bore) | Metric naming convention used in many countries. |
| OD (Outside Diameter) | Actual external measurement. |
| WT (Wall Thickness) | Thickness of the pipe wall. |
| ID (Inside Diameter) | Flow passage inside the pipe. |
- Nominal Pipe Size: 2"
- Outside Diameter: 60.33 mm
- Wall Thickness: 3.91 mm
- Inside Diameter: 52.50 mm (approx.)
Understanding these values helps ensure compatibility with pipe fittings, flanges, valves, and supports.
Schedule 40 Stainless Steel Pipe Dimensions
Schedule 40 stainless steel pipes are manufactured according to ASME B36.19M and are available in several grades, including:
- Stainless Steel 304
- Stainless Steel 304L
- Stainless Steel 316
- Stainless Steel 316L
- Stainless Steel 321
- Stainless Steel 310
- Stainless Steel 347H
- Duplex Stainless Steel
- Super Duplex Stainless Steel
Advantages of Schedule 40 Pipe
- Standardized international dimensions
- Excellent mechanical strength
- Good pressure handling capability
- Reliable corrosion resistance in stainless steel grades
- Easy welding, threading, and fabrication
- Compatible with standard fittings and flanges
- Cost-effective for general industrial service
- Available in carbon steel, stainless steel, alloy steel, duplex, and nickel alloys
- Suitable for high-volume industrial applications
Applications of Schedule 40 Pipe
- Water distribution systems
- Oil and gas pipelines
- Chemical processing plants
- Petrochemical facilities
- Power generation
- HVAC systems
- Fire protection systems
- Structural fabrication
- Marine engineering
- Food processing
- Pharmaceutical manufacturing
- Paper and pulp industries
- Sugar plants
- Fertilizer plants
- General industrial piping
Frequently Asked Questions
Schedule 40 is a standardized pipe wall thickness designation that specifies the wall thickness for a given nominal pipe size while maintaining a fixed outside diameter.
No. Schedule 40 refers only to the wall thickness. The outside diameter remains constant for each nominal pipe size, while the inside diameter changes depending on the wall thickness.
A 2-inch Schedule 40 pipe has a wall thickness of 0.154 inches (3.91 mm) according to ASME standards.
Carbon steel Schedule 40 pipe dimensions are covered by ASME B36.10M, while stainless steel Schedule 40 pipe dimensions follow ASME B36.19M.
Schedule 40 pipes are suitable for many low- and medium-pressure applications. Higher-pressure systems may require Schedule 80 or heavier wall pipes depending on the operating conditions.
Schedule 40 pipes are commonly manufactured in carbon steel, stainless steel, alloy steel, duplex stainless steel, super duplex stainless steel, and nickel alloy grades.
Schedule 40 pipes are widely used in oil and gas, chemical processing, water treatment, power plants, HVAC systems, pharmaceuticals, food processing, marine engineering, and general industrial piping.
Select the appropriate nominal pipe size based on the required flow rate, operating pressure, wall thickness, and compatibility with fittings, valves, and flanges.
Yes. Schedule 40 dimensions are commonly used for stainless steel pipes manufactured in grades such as SS 304, 304L, 316, 316L, 321, 310, 347H, Duplex, and Super Duplex for industrial applications.
A Schedule 40 pipe dimensions chart provides standardized outside diameter, wall thickness, inside diameter, and approximate weight, helping engineers, fabricators, and buyers select the correct pipe for their applications.