Schedule 40 Pipe Thickness in mm: Full Dimensions & Weight Chart

What is Schedule 40 Steel Pipe?

Schedule 40 (SCH 40) is the most commonly used standard wall thickness grade for carbon steel pipes, defined by ASME/ANSI B36.10. It offers a balanced combination of strength, weight, and cost-effectiveness, making it the default choice for a wide range of low to medium pressure applications. This guide provides complete dimensional data, weight calculations, and practical selection tips to help you specify SCH 40 pipes for your project.

SCH 40 covers almost all pipe sizes from NPS 1/8 to NPS 24. In common steel pipe wall thickness classes (such as Sch 5S, 10, 20, 40, 80, 160, XXS), the wall thickness increases with the Sch number. Sch 40 is thicker than Sch 10/20, with a higher pressure resistance; but thinner than Sch 80/160, with a lower pressure resistance. It strikes a good balance between mechanical strength, weight, and cost.

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Size Characteristics:

a. For all Sch 40 pipes, the outer diameter is fixed. For example, NPS 2 pipes, whether Sch 40 or Sch 80, have the same outer diameter of 60.3 mm (2.375 inches). This is specified by the standard.

b. Because the outer diameter is fixed, increasing the wall thickness will result in a smaller inner diameter. Therefore, the inner diameter of a Sch 40 pipe is smaller than that of a Sch 10 pipe, but larger than that of a Sch 80 pipe. The wall thickness of a Sch 80 pipe is always greater than that of a Sch 40 pipe of the same size.

Pipe Sch 40 Chart: Dimensions, Weight & Pipe Wall Thickness

The following is a reference table of nominal dimensions, outer diameter, wall thickness (mm), and weight data for SCH 40 carbon steel pipes, compiled according to ASME/ANSI B36.10 standard. It covers sizes ranging from 1/8" to 24" (DN6 to DN600).

Note: 

● This dimensional table applies to both seamless and welded steel pipes (such as ASTM A53/A106).
● The above data applies to carbon steel, alloy steel, and stainless steel pipes. The outer diameter (OD) is fixed; as the Schedule number (wall thickness series) increases, the wall thickness increases, and the inner diameter (ID) decreases accordingly.

● Nominal vs. Actual: The outer diameter and wall thickness in the table are standard values. Actual manufactured pipes have permissible dimensional tolerances (e.g., wall thickness tolerance is approximately ±12.5%). For accurate strength calculations, the minimum measured wall thickness must be used.

● Weight Calculation: The theoretical weight per meter can be calculated using the formula: Weight (kg/m) = [OD (mm) - Wall Thickness (mm)] × Wall Thickness (mm) × 0.02466.

📥 [Download Complete Pipe Weight Chart (SCH 40 & SCH 80 Combined PDF)]
(Covers sizes 1/2" to 48". Available in seamless and welded manufacturing options upon request.)

Quick Reference for Common Sizes:

● 2 inch SCH 40 pipe thickness: 3.91 mm (OD: 60.3 mm)
● 4 inch SCH 40 pipe thickness: 6.02 mm (OD: 114.3 mm)
● 6 inch SCH 40 pipe thickness: 7.11 mm (OD: 168.3 mm)
● 8 inch SCH 40 pipe thickness: 8.18 mm (OD: 219.1 mm)
● 10 inch SCH 40 pipe thickness: 9.27 mm (OD: 273.0 mm)

For all other sizes, please refer to the complete chart above.

Common Uses & Selection Tips for Schedule 40 Pipe

Understanding the common applications and key selection factors for SCH 40 pipe helps ensure you choose the right material and specifications for your project.

Common Applications of SCH 40 Steel Pipes:

1. Low-pressure fluid transportation
● Tap water, gas (ASTM A53 Sch 40 galvanized pipe).
● Chemical media (such as ASTM A106 Sch 40 seamless pipe).

2. Buildings and structures
● Scaffolding (but must comply with structural standards, such as EN 39).
● Air conditioning and ventilation ducts (thin-wall Sch 5/10 is more commonly used).

3. Machinery and equipment
● Low-pressure pipelines in hydraulic systems (high pressure requires Sch 80 or above).

● Food industry (stainless steel 304 Sch 40S).

Key Selection Notes:

1. Pressure matching
Calculate the design pressure to ensure that the pressure bearing capacity of Sch 40 is sufficient (safety factor needs to be considered).

2. Material selection
Corrosive environment → Select stainless steel Sch 40 (ASTM A312) [View Stainless Steel SCH 40S Pipe Dimensions Chart] or galvanized carbon steel (ASTM A53).
High temperature environment → Select ASTM A106 Sch 40 (temperature resistance ≤350℃).

3. Economic efficiency

Sch 40 is the most cost-effective general choice, but Sch 80/160 is required for ultra-high pressure scenarios.  [Compare SCH 40 vs SCH 80 for your specific pressure requirements].

Surface Treatment & Customization Options

To meet diverse project requirements, HSCO provides value-added services for SCH 40 pipes:

● Surface Treatments: Hot-dip galvanizing (ASTM A53), 3PE/FBE anti-corrosion coatings, or black painting.
● End Finishes: Plain ends (for welding), threaded ends (NPT/BSP), or grooved ends.
● Custom Lengths: Standard lengths (5.8m/6m/12m) or cut-to-length as per your drawing.

FAQs

Q1. What is the thickness of Schedule 40 pipe?

The thickness depends on the nominal size (NPS). For example, a 6-inch pipe is 7.11 mm, while a 8-inch pipe is 8.18 mm. Please refer to the complete chart above for all sizes.

Q2. How much does Schedule 40 pipe weigh?
The weight depends on the pipe's size, material, and length. You can calculate it using the formula:

Weight per meter (kg/m) = [OD (mm) - Wall Thickness (mm)] × Wall Thickness (mm) × 0.02466

For example, a 2" SCH 40 carbon steel pipe (OD: 60.3mm, wall: 3.91mm) weighs approximately:
(60.3 - 3.91) × 3.91 × 0.02466 ≈ 5.44 kg/m

Use the table above to find the weight for other sizes. For an exact quote, please provide your required size, material, and length.

Q3. What is the pressure rating of Schedule 40 pipe?
The pressure rating of Schedule 40 pipe varies, depending on size, material, and temperature. At room temperature, the pressure rating of carbon steel Schedule 40 pipe ranges from approximately 700 psi to 2,200 psi (4.8 to 15.2 MPa), with smaller diameter pipes offering higher pressure ratings. ▶ Learn more about the [Pressure Rating Chart for Schedule 40 Steel Pipe].

Q4. Is SCH 40 seamless or welded, and can it be threaded?
A: SCH 40 can be either seamless (ASTM A106) or welded (ASTM A53). Both types can be threaded. However, because its wall is moderate, threading is generally recommended for sizes below 8 inches to ensure joint strength. For larger sizes, welding or flanges are preferred.

Q5. What lengths and end finishes are available for SCH 40 pipe?
A: We offer standard lengths (e.g., 5.8m, 6m, 11.8m, 12m) and custom cut-to-length services to reduce waste for your project. Available end finishes include plain ends (for welding), threaded ends (NPT/BSP), and grooved ends. Contact us with your specific drawing or requirement.

Q6. SCH 40 vs. SCH 80: What are the differences?
The key difference is wall thickness. SCH 80 is typically 30% to 100% thicker than SCH 40 for the same pipe size, making it significantly stronger, heavier, and able to withstand higher pressures. ▶ For a full comparison table covering all sizes, weight, cost, and application guidelines, please see [Schedule 40 vs. Schedule 80: Full Selection Guide].

Q7. Where is Schedule 40 pipe used?
Due to its economical and versatile nature, Schedule 40 pipe is widely used in:

● Building water supply and drainage systems
● Low-pressure fluid transport (water, air, oil)
● Heating, ventilation, and air conditioning (HVAC) systems
● Structural support and scaffolding

Need SCH 40 Carbon Steel Pipe for Your Project?

Hunan Standard Steel Co., Ltd (HSCO) is a trusted direct manufacturer, offering high-quality Sch 40 carbon steel pipe in sizes up to 24" with wall thicknesses up to 17.48mm. 

Get a Quick Quote or Technical Support:
▶ Email us: sales@hu-steel.com 

(Please include your required size, grade, and quantity for priority handling)

▶ WhatsApp:+86 13874851830

Our experienced team will respond within 24 hours with detailed specifications and competitive pricing.

Related topics

●  Schedule 80 Carbon Steel Pipe Thickness

●  SCH 40 Black Carbon Steel Pipe

●  SCH 40 vs SCH 40S Pipe Selection Guide – Carbon Steel vs Stainless Steel

●  ASME B36.10 / B36.19 Steel Pipe Dimensions & Sizes Chart