What is the maximum distance for the last support hanger on a fire sprinkler branch of a 1-1/4" nominal pipe size from the end?

The maximum distance for the last support hanger on a fire sprinkler branch for a 1-1/4" nominal pipe size is indeed 48 inches from the end of the pipe. This requirement is usually established by the codes and standards governing fire protection systems, such as NFPA 13.

Support hangers play a crucial role in maintaining the structural integrity of the piping system. They prevent sagging, ensure proper alignment, and minimize the risk of damage due to the weight of the water inside the pipe, along with other potential forces acting upon it. By specifying a maximum distance between hangers, codes ensure that the piping system remains stable and functional throughout its service life.

For a 1-1/4" nominal pipe, the 48-inch spacing helps ensure that adequate support is provided without being excessively spaced, which could lead to issues such as sagging or misalignment that can compromise the system's performance. This standard aligns with best practices in plumbing and fire protection engineering, reinforcing the importance of correct installation and support for effective fire safety measures.