What Is SCH40 SCH80 Aluminum Pipe? Size, Standards, and Applications Explained
In industrial piping systems, SCH40 and SCH80 aluminum pipes are widely used in fluid transport, power systems, construction, and petrochemical applications.
Unlike standard aluminum tubes, these pipes are not defined by traditional aluminum sizing systems. Instead: they adopt the steel pipe dimension system (NPS + Schedule) to ensure full compatibility with standard piping systems.
In real-world engineering, piping systems are typically designed based on ASME standards, where flanges, valves, and fittings follow unified dimensions.
By using the SCH (Schedule) wall thickness system, aluminum pipes can:
Maintain consistent outside diameter (OD)
Connect directly with standard pipe fittings
Replace steel pipes for weight reduction and corrosion resistance
What Are SCH40 Pipe and SCH80 Pipe?
SCH (Schedule) is a standardized numbering system that defines pipe wall thickness.
Its key principle:
For a given Nominal Pipe Size (NPS):
Outside diameter (OD) remains constant
Wall thickness (WT) increases with schedule number
Inside diameter (ID) decreases accordingly
Example:
NPS 2" aluminum pipe
SCH40 → Wall thickness 3.91 mm
SCH80 → Wall thickness 5.54 mm
Conclusion:
SCH40 = Standard wall thickness (Standard Duty)
SCH80 = Thicker wall (Heavy Duty)
What's the Difference Between SCH40 and SCH80?
The main difference lies in strength and pressure capability:
| Property | SCH40 | SCH80 |
|---|---|---|
| Wall Thickness | Thinner | Thicker |
| Pressure Rating | Medium | Higher |
| Burst Strength | Lower | Higher |
| Impact Resistance | Moderate | Better |
| Fatigue Resistance | Moderate | Improved |
| Weight | Lighter | +25–45% heavier |
In simple terms: SCH80 is stronger and safer, but heavier and more expensive
Aluminum Pipe SCH40 / SCH80 Dimensions (Including ID)
The following dimensions are based on standard piping systems and apply to aluminum pipes interchangeable with steel systems:
| NPS (Inch) | OD (mm) | SCH40 WT (mm) | SCH40 ID (mm) | SCH80 WT (mm) | SCH80 ID (mm) |
|---|---|---|---|---|---|
| 1/2" | 21.34 | 2.77 | 15.80 | 3.73 | 13.88 |
| 3/4" | 26.67 | 2.87 | 20.93 | 3.91 | 18.85 |
| 1" | 33.40 | 3.38 | 26.64 | 4.55 | 24.30 |
| 1-1/4" | 42.16 | 3.56 | 35.04 | 4.85 | 32.46 |
| 1-1/2" | 48.26 | 3.68 | 40.90 | 5.08 | 38.10 |
| 2" | 60.33 | 3.91 | 52.51 | 5.54 | 49.25 |
| 2-1/2" | 73.03 | 5.16 | 62.71 | 7.01 | 59.01 |
| 3" | 88.90 | 5.49 | 77.92 | 7.62 | 73.66 |
| 4" | 114.30 | 6.02 | 102.26 | 8.56 | 97.18 |
| 6" | 168.28 | 7.11 | 154.06 | 10.97 | 146.34 |
| 8" | 219.08 | 8.18 | 202.72 | 12.70 | 193.68 |
| 10" | 273.05 | 9.27 | 254.51 | 15.09 | 242.87 |
Aluminum Pipe SCH40 / SCH80 Weight Chart (kg/m)
Calculated based on aluminum density of approximately 2.70 g/cm³:
| NPS (Inch) | SCH40 (kg/m) | SCH80 (kg/m) |
|---|---|---|
| 1/2" | 0.39 | 0.49 |
| 3/4" | 0.56 | 0.74 |
| 1" | 0.86 | 1.10 |
| 1-1/4" | 1.20 | 1.56 |
| 1-1/2" | 1.50 | 2.00 |
| 2" | 2.20 | 2.98 |
| 2-1/2" | 3.60 | 4.90 |
| 3" | 4.80 | 6.50 |
| 4" | 7.80 | 10.80 |
| 6" | 15.50 | 23.00 |
| 8" | 26.00 | 40.00 |
| 10" | 39.00 | 65.00 |
How to Quickly Calculate the Weight of Aluminum Pipe?
In real procurement and quoting scenarios, you often need to calculate weight for custom lengths or non-standard sizes.
General formula:
W = 0.02466 \times (OD - WT) \times WTW=0.02466×(OD−WT)×WT
Parameters:
W = weight (kg/m)
OD = outside diameter (mm)
WT = wall thickness (mm)
Simple explanation: Weight ≈ Cross-sectional area × Density
Example (NPS 2" SCH40):
OD = 60.33 mm
WT = 3.91 mm
Result: ≈ 2.2 kg/m (matches the table)
Aluminum Alloys Used with SCH Pipe System
| Alloy | Typical Applications |
|---|---|
| 6061-T6 | Pressure pipes, hydraulic systems |
| 6063-T5 | Structural pipes, bus pipes |
| 6101-T63 | High-conductivity bus pipes |
| 5083-H112 | Marine and corrosion-resistant environments |
| 1070 / 1350 | Electrical conductors |
Note:SCH defines wall thickness only; actual pressure performance depends on alloy and temper.
Applications of SCH40 / SCH80 Aluminum Pipes
SCH40 (Standard Duty)
Water and air pipelines
HVAC systems
Medium to low pressure fluid transport
Electrical bus pipes
Structural piping
👉 Features: lightweight and cost-effective
SCH80 (Heavy Duty)
Oil and gas pipelines
Hydraulic systems
Chemical processing lines
Power plant piping
High-pressure compressed air systems
👉 Features: high strength and safety
How to Choose SCH40 vs SCH80?
Choose SCH40 when:
Medium to low pressure
Weight reduction is important
HVAC or cooling systems
Electrical bus pipes
Choose SCH80 when:
Higher pressure conditions
Hydraulic systems
Chemical or corrosive environments
High safety requirements
Conclusion
SCH40 and SCH80 are not native standards for aluminum pipes; rather, they are wall thickness systems adopted from steel pipe standards to ensure compatibility across piping systems. Their primary value lies in providing dimensional consistency, enabling seamless integration with standard fittings and components, and offering different pressure ratings to meet a wide range of application requirements.
6061 / 6063 / 5083 aluminum pipes
Full SCH40 / SCH80 size range
Cut-to-length and custom sizes
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