Pipe Schedule Explained – How to Choose the Right Thickness

When selecting pipes for any industrial project — boiler, refinery, chemical plant, HVAC system, petroleum line, or construction — the most confusing term is:

👉 What is Pipe Schedule (SCH)?
👉 Is SCH 40 thicker than SCH 20?
👉 Should I use SCH 80, SCH 160, or XXS for high pressure?

The wrong schedule = leakage, bursting, failure, or wasted money. This blog explains everything in simple English so any engineer, buyer, or beginner can easily choose the correct pipe thickness.

What Is Pipe Schedule?

Pipe Schedule = Wall Thickness of a Pipe.
Higher the schedule → thicker the pipe wall → higher pressure capacity.

Examples

SCH 40 = Standard wall
SCH 80 = Thick wall
SCH 160 = Extra thick
XXS = Extremely heavy wall

It ensures the pipe can safely handle internal pressure without bursting.

Why Pipe Schedule Matters

✔ Prevents leakage
✔ Handles higher pressure
✔ Ensures safety
✔ Avoids pipe burst
✔ Maintains compliance (ASME, ASTM)

Choosing the wrong schedule can damage equipment and cause expensive downtime.

Common Pipe Schedules Used in Industry

SCH 10 → Thin wall, low pressure
SCH 20 → Light pressure
SCH 40 (STD) → Standard
SCH 80 (Extra Strong) → High pressure
SCH 160 → Very high pressure
XXS (Double Extra Strong) → Extreme duty

Pipe Schedule vs Thickness – Example

NPS (inches)	SCH 40 (mm)	SCH 80 (mm)	SCH 160 (mm)
1"	3.38	4.55	6.35
2"	3.91	5.54	8.74
4"	6.02	8.56	13.49

Higher schedule = thicker pipe.

How to Choose the Right Schedule?

Low Pressure Applications

Use: SCH 10 / SCH 20
For: Water lines, Firefighting, HVAC

Medium Pressure Applications

Use: SCH 40 (STD)
For: Chemical lines, Utility pipelines, Structural use

High Pressure Applications

Use: SCH 80 / SCH 160
For: Steam lines, Oil & gas, High temperature systems

Extreme Pressure Applications

Use: XXS
For: Boiler tubes, Petrochemical reactors, High pressure steam

Seamless vs Welded – Which Is Better for High Schedule?

Seamless Pipes: Best for SCH 80, SCH 160, XXS → High pressure.
Welded Pipes: Good for SCH 10, 20, 40 → Medium pressure.

Rule: High schedule → Higher stress → Seamless is safer.

Applications of Different Schedules

✔ SCH 10 → Food, pharma, low pressure
✔ SCH 40 → Oil, chemical, utility lines
✔ SCH 80 → Steam, refinery, high temperature
✔ SCH 160 → Pressure vessels, offshore
✔ XXS → Boilers, reactors, severe duty

Conclusion

Pipe schedule may look confusing, but understanding it ensures:

✔ Safer installation
✔ Higher performance
✔ Longer service life
✔ No leakage or failure

Always choose the schedule based on pressure, temperature, and fluid type — and when unsure, Moksh Tubes can help with technical guidance.

FAQ's

Is SCH 40 thick?

Yes — it is standard wall thickness.

Which is thicker — SCH 40 or SCH 80?

SCH 80 is thicker.

Do high-pressure lines require seamless pipes?

Yes — ideally seamless SCH 80+.

What is XXS?

Double Extra Strong → extremely thick wall.