Understanding Pipe Schedules: Schedule 10 vs 40 vs 80 Explained

Published on 7 October, 2025

In selecting the correct pipes for a plant-based project, the most crucial technical specification to grasp is the pipe schedule. It decides on the pipe wall thickness, which in turn influences the pressure it can hold, how long it will last, and where it would be suitable to use.

 

Most engineers and purchasing departments encounter designations such as Schedule 10, Schedule 40, and Schedule 80 — but what exactly do these refer to? Let's dissect it in a simple manner.

 

What is "Pipe Schedule"?

 

Pipe schedule is the thickness of the pipe wall when compared to the diameter. It is a specification by the American Society of Mechanical Engineers (ASME) under ASME B36.10 and ASME B36.19.

As the schedule number gets higher, the wall of the pipe gets thicker, and the pipe can sustain more pressure.

For instance, a Schedule 80 pipe of a particular size has a thicker wall than a Schedule 40 pipe, and Schedule 10 is thinner for applications in lighter duty.

 

Why Pipe Wall Thickness Matters?

 

Wall thickness impacts the following important factors:

 

1. Pressure rating: Thicker walls translate to higher internal pressure handling capacity.

2. Flow rate: A slightly decreased inner diameter with more massive walls decreases flow volume.

3. Weight: More weighty schedules are heavier and impact installation and price.

4. Durability: Greater schedules hold up more against wear, temperature fluctuations, and mechanical stress.

 

Comparison of Pipe Schedules

 

Parameters	Schedule 10	Schedule 40	Schedule 80
Wall Thickness	Thin	Medium	Thick
Pressure Capacity	Low-pressure systems	Standard pressure systems	High-pressure systems
Weight	Light	Moderate	Heavy
Flow Efficiency	Excellent	Good	Slightly Reduced
Common Applications	HVAC, water lines, decorative use	Plumbing, oil and gas, general industry	Steam lines, chemical and power plants
Material Availability	Stainless Steel, Carbon Steel	Carbon Steel, Stainless Steel, Alloy Steel	Stainless Steel, Alloy Steel, Duplex Steel

 

The following is a simplified chart comparing the three most prevalent schedules applied in commercial and industrial purposes:

 

Consider an example.

If you are planning to design a water supply system for a residential complex, Schedule 10 or Schedule 40 stainless steel pipes would be suitable because of their corrosion protection and average strength. But for an industrial steam line or chemical plant, Schedule 80 pipes are preferred since they can sustain higher temperatures and internal pressure without deforming or bursting. In the same way, Schedule 10 pipes are commonly used for low-pressure applications, like exhaust systems, drainage, or decorative structural frames, wherein high strength is not essential.

 

Selecting the Appropriate Pipe Schedule

 

In order to choose the proper pipe schedule, you should take into account:

 

1. Operating Pressure and Temperature: Thicker walls are needed for higher conditions.

2. Type of Fluid: Corrosive or dense fluids require heavier materials and schedules.

3. Material of Pipe: Stainless steel, carbon steel, or duplex grades will have varying limits.

4. Budget and Weight Limitations: Schedules rise with both weight and cost.

 

At Online Fittings, we produce and provide stainless steel, carbon steel, and alloy steel pipes in various schedules, from Schedule 5 to Schedule 160, all certified and tested to international standards.

 

Typical Schedule and Material Combinations

 

Schedule 10: Stainless Steel 304, 316L (for decorative purposes, food-grade, and HVAC applications)

Schedule 40: Carbon Steel ASTM A106 Gr B, Stainless Steel 316L (for industrial flow lines)

Schedule 80: Alloy Steel P22, Duplex 2205 (for chemical plants and high-pressure steam)

Related read: Why are SS 410 and SS 420 tubes and pipes the Backbone of Industrial Machinery