What is the O.D (outside diameter) of a 20" nominal pipe size?

In plumbing and piping systems, nominal pipe size (NPS) is a standardized designation used to categorize pipe dimensions. For a 20-inch nominal pipe size, the corresponding outside diameter (O.D.) is standardized at approximately 24 inches. This standardization allows for some variation in wall thickness and internal diameter based on the specific type of pipe being used (like schedule 40 or schedule 80), but the outside diameter remains consistent.

It's important to note that the nominal size does not represent the actual exterior measurement of the pipe. Instead, it serves as a standardized reference for pipe fittings and connectivity. Thus, in the case of a 20-inch nominal pipe, the O.D. is more accurately aligned with measurement standards determined by organizations like the American National Standards Institute (ANSI).

The correct knowledge concerning nominal sizes and their actual dimensions is crucial for piping applications to ensure proper fit and function in installations. Understanding these specifics aids pipefitters in selecting the right pipe and fittings for their work.