Schedule 40 and Schedule 80

"Schedule 40" and "Schedule 80" refer to reference charts published by the American National Standards Institute (ANSI).

When speaking about seamless pipe, the different schedules refer to the size, thickness and maximum pressure of the pipe.

What is the difference between Schedule 40 vs Schedule 80?

The major difference between schedule 40 and schedule 80 pipe is the wall thickness, inside diameter, and their weight. Schedule 80 will have a greater wall thickness, a smaller inside diameter and a higher weight than Schedule 40 pipe at a given nominal pipe size. Of course, all of these numbers will vary based on the nominal pipe size. There are also many other pipe schedule numbers as well. For these reasons, it is important to also reference a pipe schedule table to ensure that the proper pipe size is being selected.

Schedule 40 pipe has thinner walls, so it is best for applications involving relatively low water pressure. Schedule 80 pipe has thicker walls and is able to withstand higher PSI (pounds per square inch). This makes it ideal for industrial and chemical applications.

Smaller schedule pipe tends to be less expensive than larger schedule pipe. Depending on the volume and pressure of material that needs to be moved with the pipe, the different schedules offer a choice in the cost of materials used. If a low-pressure drainage line is being installed, a Schedule 40 seamless pipe would be adequate and more cost effective than a Schedule 120 seamless pipe.