Which of the pipes listed would have the thickest wall?

In the context of pipe wall thickness, the schedule rating indicates the pipe's wall thickness relative to its diameter. As the schedule number increases, the wall thickness of the pipe also increases.

Schedule 20, for instance, has the thinnest walls among the options presented. When moving to Schedule 40, the wall thickness increases, providing more strength and durability for the pipe's use. Schedule 80 continues this trend, offering even thicker walls than Schedule 40, which is ideal for applications that require higher pressure ratings.

Schedule 120, on the other hand, is designed for even more demanding applications where maximum strength is necessary. It has the thickest wall among all listed options, allowing it to withstand greater pressures and harsher environments. This makes it suitable for heavy-duty applications in various industries, highlighting its superiority in wall thickness when compared to Schedule 20, 40, and 80.