What does the term "schedule" refer to in pipe specifications?

In pipe specifications, the term "schedule" specifically refers to the wall thickness of the pipe. The schedule number is a standardized designation that indicates how thick the walls of a pipe are relative to its diameter. As the schedule number increases, so does the wall thickness, which in turn affects the pipe's pressure rating and overall strength.

For instance, common schedule numbers include Schedule 40 and Schedule 80, with Schedule 80 having a thicker wall compared to Schedule 40 for the same nominal diameter of pipe. This information is crucial for pipefitters as it helps them select the appropriate pipe for different applications involving varying pressures and stresses. Understanding the relationship between schedule and wall thickness allows professionals to make informed decisions regarding materials and installation practices that ensure safety and compliance with industry standards.