What is the unsupported length on the end of branch lines from the last hanger location for 1¼" pipe?

The correct answer of 4 feet for the unsupported length on the end of branch lines from the last hanger location for 1¼" pipe is based on established industry standards and safety regulations regarding the installation of piping systems. It ensures that the pipe is adequately supported to prevent sagging or potential damage over time, which is crucial for maintaining the integrity of the fire protection system.

In this context, branch lines must have specific lengths for unsupported spans to reduce strain and to allow for thermal expansion and contraction without compromising the system’s effectiveness. The 4-foot length is a balance between allowing for efficient layout and ensuring structural support, mitigating the risk of pipe failure or leakage due to inadequate support.

Understanding this regulation is essential for anyone working with sprinkler systems, as it directly impacts the safety and reliability of fire protection installations. Proper support prevents unnecessary stress on joints and fittings, which can lead to malfunction in emergency situations.