Difference Between Schedule 40 and Schedule 80 Pipe

UNIASEN Carbon Steel Pipe Manufacturer-schedule 40 vs 80 steel pipe


Schedule 40 and 80 steel pipes are two common choices when buying industrial pipes. They look the same, but there are substantial distinctions between them that you should know about before you buy.

This article will explain the differences between Schedule Pipe 40 and Schedule 80 steel pipe, their advantages, disadvantages, and applications.

What Is The Nominal Pipe Size?

The inside diameter of a pipe is known as the NPS or nominal pipe size. It’s an indication to distinguish between different kinds of pipes. The internal diameters of pipes are not specified by measurement but rather by a number. However, it works with pipes only up to 12 inches in diameter. Pipes with an outer diameter of 14 inches or more need special handling.

When discussing Schedule 40 pipes, the significance of NPS cannot be emphasized enough. It acts as a crucial factor in classifying and differentiating these pipes based on their nominal sizes. The term “Schedule 40” denotes a specific range of Nominal Pipe Size (NPS) values, measuring the pipe’s wall thickness.

The NPS values that the Schedule 40 pipe’s diameters can accommodate vary from 1/8 inch to 36 inches. There is no change in the nominal pipe size for Schedule 80 pipes, even when the wall thickness varies. The uniformity covers an extensive range of NPS values extending from 1/8 to 36 inches.

What Is Pipe Schedule?

A pipe schedule does not correspond to a specific measurement. The value is derived from a formula based on the wall’s thickness. Many pipes have the same outer diameters. However, they vary in schedule numbers, which signify distinct wall thicknesses. A Pipe Schedule Chart that compares the schedule number and nominal pipe size.

So, it’s recommended to find the most precise dimensions. Combining nominal pipe size and the pipe schedule allows you to determine and choose pipes for your applications. You must also consider factors such as pressure structural stability and flow rates.

What Is The Difference Between Schedule 40 And Schedule 80 Steep Pipes?

The primary differentiating factors between schedule 40 pipe and schedule 80 pipe lie in weight, inner diameter, and wall thickness. The actual numbers will vary based on the nominal pipe size. Furthermore, an enormous number of pipe schedule numbers is available. Considering these factors, you must review a pipe schedule table to carefully determine the appropriate pipe size. Let’s dive into detail:

NPS, Inner and Outer Diameter

Nominal Pipe Size (NPS) measurements are indistinguishable between Sch 40 and Sch 80 pipes of identical size. The pipe’s outer diameter (OD), denoted as NPS, remains the same across both schedule types. However, the crucial distinction between Sch 40 and Sch 80 is its inner diameter (ID). Sch 80 pipes have more durable interior sections than Sch 40 pipes, resulting in a lesser inner diameter.

The additional material utilized in the Sch 80 piping increases the internal sidewall thickness. A minor reduction in fluid flow rate may result from the Sch 80 pipelines’ reduced inner diameter. For applications involving pressurized liquids, Sch 80 pipelines are suitable for their sturdier walls. It gives improved safety and durability.

Thickness of Wall

Schedule 80 pipes have a more substantial wall thickness than Schedule 40, despite having the same nominal pipe size (NPS). With their enhanced wall thickness, Schedule 80 pipes have better resistance to heavier loads and higher pressures and

Schedule 40 Pipe Wall Thickness

Following are the wall thicknesses of schedule 40 steel pipe:

  • 1/4″ -0.088
  • 1⁄2″ -0.109
  • 3/4″ -0.113
  • 1″ – 0.133
  • 5″-0.145
  • 2″ – 0.154
  • 5″ – 0.258
  • 10″ – 0.365

Schedule 80 Pipe Wall Thickness

Following are the wall thickness of schedule 80 steel pipe:

  • 1/4″ – 0.119
  • 1⁄2″ -0.147
  • 3/4″ – 0.154
  • 1″ – 0.179
  • 5″ -0.200
  • 2″ – 0.218
  • 5″ – 0.375
  • 10″ – 0.500

Durability and Strength:

Schedule 40 pipes find extensive application in a variety of common operational conditions. However, their capacity to withstand vigorous pressure may not be on a level with that of Schedule 80 pipes. The durability and extended lifespan of Schedule 80 pipes can be attributed to their substantial wall thickness. Both Schedule 40 and Schedule 80 pipes are used across a wide range of applications. Each offers distinct advantages in their respective uses. Gaining a comprehensive understanding of the various sizes and weights of pipes is crucial. It enables individuals to make sound choices when selecting the appropriate option to meet their specific requirements.

Weight Capacity and Pressure:

Because the walls of Schedule 80 pipes are thicker, they handle more weight and pressure than Schedule 40 pipes. A Schedule 80 pipe is better for carrying heavy chemicals or fluids at high pressure. Schedule 80 pipes are used in applications where the pipe is damaged by heavy vehicles or exposed to extreme conditions. They last longer and are less likely to be damaged.


Schedule 40 and Schedule 80 pipes are usually easy to distinguish by their color. Schedule 40 pipes are white, while Schedule 80 pipes are gray. The color change can help find out which Schedule is for the plumbing. It is crucial to ensure that not all manufacturers use this color scheme. That’s why you should always check the specifications written on the fitting and pipes.

Although the color of the pipes helps to differentiate, however, there are also other ways to determine the difference between schedule 80 pipe and schedule 40 pipe. Before installing the pipes, check the Schedule to ensure it works for the required applications.

Flow Rate and Pressure Drops:

The pressure drop and flow rates are two more important aspects of making steel pipe decisions. The thinner walls of Schedule 40 pipes make their pressure drop less than those of Schedule 80 pipes. It also means that they have a higher flow rate. This makes them perfect for low-pressure watering systems and other places where the flow rate is essential. Schedule 80 lines, on the other hand, have a higher pressure drop and a smaller flow rate. This makes them better for high-pressure, pumps, and water transfer systems.


Schedule 40 pipes are often used in light commercial and residential settings. These are used for;

  • heating systems
  • water and gas lines
  • sewage systems.

In industries that need to handle high-pressure and significant loads. These are oil and gas pipelines, chemical transportation, and power plants; Schedule 80 pipes are perfect. If you know the differences between Schedule 40 and 80 pipes, you choose the right one for your task. This will save you time and money while ensuring the installation is safe and long-lasting.


Using the same material for both the scheduled pipes makes installation no different from using separate materials.

According to the ASTM standard, all schedules of pipes with the same NPS must have the same outer diameter. Because each pipe schedule has its standard fittings and joining techniques, connecting pipes of various schedules is possible.

The plumbing system must be installed correctly and promptly to ensure its safety and effectiveness.

The pipes must be adequately cleaned and prepared. Appropriate fittings and connections must be used, and the pipes must be properly aligned and supported.

Pipes of the same material may be installed in either the Schedule 40 or the Schedule 80 orientation.

Therefore, the process is essentially the same. Pipes with varying schedules are linked together using standard fittings and techniques if the installation is followed and ASTM applies.


When it comes to industrial plumbing, the price is significant. Because their walls are smaller, Schedule 40 pipes cost less than Schedule 80.

Ensuring their strength, longevity, and resistance to high pressure and large loads is essential. So, Schedule 80 pipes need additional materials, manufacturing processes, and quality inspections.

Schedule 40 pipes may be a better choice if the price is your primary concern.

Schedule 40 Vs 80: Which Is Stronger?

There are primarily two varieties of pipes: schedule 40 and schedule 80. Each has advantages, but which one is stronger?

Schedule 40 pipe consists of thinner pipes compared to schedule 80. As a result, it is lighter, more cost-effective, and less durable.

However, Schedule 80 consists of robust pipes and is more powerful; regardless, it is more expensive and weighty.

Typically, schedule 80 pipe is better when strength and durability are required. However, if you are looking for a lightweight and cost-effective option, schedule 40 pipe might be more suitable.


In conclusion, you must carefully choose the steel pipe that is used in your applications. Both Schedule 40 pipe and Schedule 80 pipe are extensively used in manufacturing and other commercial settings.

Schedule 40 pipes are excellent for light commercial and domestic use. It has thin walls, minimal pressure drop, and a high flow rate.

Schedule 80 pipes are ideal for industry use due to thicker walls and significant pressure. You choose your unique project by knowing the distinctions between Schedule 40 pipe and Schedule 80 pipe. This will bring safety, reliability, and longevity to your installation.

If you don’t know how to choose, please contact UNIASEN experts to help you online.