The best CPVC pipes are the ones with the right dimensions for the application. Yet there is quite a bit of confusion about PVC pipe measurements. This isn’t helped by the fact that CPVC pipe comes in nominal pipe sizes (NPS) and CTS (copper tube sizes) though it isn’t made of copper. Let’s look at some of the most common measurements of PVC pipes. We’ll also share a few facts about these sizes of PVC pipe you may not have known.
Schedule 40 Pipe
Schedule 40 pipe refers to a set of dimensions, not a single one. For example, Schedule 40 PVC pipe can have a nominal pipe size of 0.75 inches or 1.5 inches. A 0.75 inch nominal pipe size will have an outer diameter of 1.050 inches, inner diameter of 0.824 inches and weight per foot of 0.226. Its rigid pipe PSI rating is generally around 600. One inch diameter nominal pipe size will have an outer diameter of 1.315 inches, inner diameter of 1.049 inches and nominal weight per foot of 0.333. A 1.5 inch nominal pipe size will have an outer diameter of 1.90 inches, inside diameter of 1.610 inches and weight per foot of 0.537. Schedule 40 pipe is found in diameters as narrow as 0.125 inches and in increments of eighths of an inch until you hit half an inch. Then the pipe diameters increase in quarter inch increments. Once you hit 1.5 inches, the next sizes are 2.0 inches and 2.5 inches. The next pipe sizes are in one inch increments. You can find 3, 4, 6, 8, 10 and 12 inch Schedule 40 pipe. Depending on the manufacturer, 14, 16, 18, 20 and 24 Schedule 40 pipe can be found. Schedule 80 pipe is found for these same nominal pipe sizes, too, though the actual dimensions vary.
Schedule 80 Pipe
Schedule 80 pipe has on average a greater wall thickness, resulting in a higher rigid pipe PSI. For 0.75 inch nominal diameter Schedule 80 pipe, the inside diameter would be 0.546 inches with a wall thickness of
0.147 inches. That’s an ID nearly 0.10 inches narrower than Schedule 40 pipe. Yet its rigid pipe PSI rating is 850. In the case of a 1.5 inch nominal pipe size, the inner diameter is actually 1.5 inches while the wall thickness is 0.20 inches. The PSI rating for these pipes is a little under 500 PSI, while the Schedule 40 pipe is rated for just over 300 PSI. For 1 inch Schedule 80 pipe, the internal diameter is 0.957 inches while the pipe thickness is 0.179 inches. Note that these measurements are not absolute. The internal diameter and wall thickness can vary by a few tenths of a percent, though higher quality production lines keep this variation to a minimum. Outer diameter, though, tends to be more uniform.
Class 200 Pipe
Class 200 pipe is rarely required, but it exists because sometimes these are the best CPVC pipes for the job. You can’t find these pipes in nominal sizes below half an inch in diameter. The smallest inside diameter Class 200 pipes you can find are 0.716 inches, while the wall thickness is 0.062 inches. Their PSI rating is around 200 PSI. Class 200 pipe is rarely found wider than 4 inch nominal pipe sizes. Many people don’t even know this class or schedule of pipe even exists.