PVC Pipe

A type of plastic used for pipes that carry water and for many other products. PVC is an abbreviation of “polyvinyl chloride.”

Class number for PVC pipe denotes its pressure rating; examples are Class 315, Class 200, Class 160, Class 125, etc. This "pressure class" distinction tells you the pipe is designed to withstand normal pressures of 315 psi, 200 psi, 160 psi, 125 psi, etc. The industry standard is to have a built-in safety factor of 2:1 for pressure surges, so a Class 200 pipe could probably withstand 400 psi water hammer (shock) pressures.

Schedule numbers for PVC pipe denotes the wall thickness; examples are schedule 40 and schedule 80. PVC pipe has standardize schedules from 5 to 160. It is important to note that the OD for all schedules of PVC pipe are the same, only the inside diameter of the pipe change.

In 1927 the American Standard Association replaced the previously used Iron Pipe Sizing (IPS) with Nominal Pipe Sizing (NPS). This North American standard is used on pipes for high or low pressures and temperatures.