The end to center of a long radius return bend is how many times the NPS?

The end to center measurement of a long radius return bend is designed to provide a smooth transition for the flow within the piping system, minimizing turbulence and pressure losses. For a long radius bend, the radius is typically defined as being three times the nominal pipe size (NPS). Therefore, the end to center distance, which effectively measures how far the center of the pipe travels from the start to the end of the bend, is also equivalent to three times the NPS.

This measurement is crucial for ensuring that the plumbing system maintains optimal flow characteristics and is compliant with engineering standards. In contrast, a short radius bend would have a different measurement, typically being one and a half times the NPS. This distinction clarifies why understanding the geometry of the piping system is essential for maintaining efficiency and performance in pipe fitting applications. Thus, the correct answer reflects the standard practice in the industry regarding long radius return bends.