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.

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.