How is the nominal diameter of a pipe design commonly referred to?

The nominal diameter of a pipe design is commonly referred to as "Diameter." This terminology simply identifies the size of the pipe, which is essential for various applications in plumbing. The nominal diameter provides a standardized measurement that is used for specifying pipe sizes, thus helping to ensure compatibility with fittings, valves, and other components in a plumbing system.

In the context of plumbing and piping, the nominal diameter is critical as it allows for proper flow calculations and helps avoid issues related to pressure loss and blockages. Understanding the nominal diameter is foundational for anyone involved in plumbing design, installation, and inspection.

The other terms mentioned do not pertain to describing the size of a pipe. "Developed Length" pertains to the total length of pipe modifications and bends in a system layout. "Drain" refers to the part of a plumbing system that carries wastewater away, and "Cross Connection" involves a connection between a potable water supply and a non-potable source that may lead to contamination, which is unrelated to pipe diameter.