For piping other than 1-1/4 inch, what is the maximum distance allowed between hangers?

The maximum distance allowed between hangers for piping larger than 1-1/4 inches is based on industry standards, specifically aiming to ensure proper support and prevent sagging or stress on the pipes. The correct answer of 15 feet aligns with these standards because it strikes a balance between providing adequate support while minimizing the overall number of hangers required.

In practice, when piping is spaced too far apart without adequate support, it can lead to issues such as deformation of the pipe, increased risk of leaks at joints, or even failure of the piping system under pressure. Thus, maintaining this spacing ensures a stable installation that can accommodate the thermal expansion and contraction of the pipes, as well as any additional load that might be imposed by the water flow, insulation, or other factors.

The other distances provided, such as 12 feet, 20 feet, and 30 feet, do not meet the requisite standards for this size of piping, either by being too short or too long, which compromises the integrity and functionality of the piping system.