Of course, the “P” in PVF stands for pipe, those long round things with the hole down the middle! Learning a little bit more about the pipes that connect to your valves will help you as a valve professional.
First, we need to understand how pipe is sized. Pipe is measured by utilizing a dimensionless number known as nominal pipe size or “NPS”. These sizes run from ¼ inch to above 72 inches. If you take a caliper to a 1 inch NPS pipe you will be surprised to see that it is not 1 inch in diameter, rather, it is actually 1.315 inches in diameter. This oversize dimensioning applies to pipe through NPS 12 inches. For diameters 14 inches and above, the NPS is the actual outside diameter. When it comes to dimensions, pipe should not be confused with tubing. Tubing size is equal to its outside diameter.