What is the maximum length of pipe allowed before a larger nominal pipe size must be used in a test header connection?

The correct answer indicates that, for a test header connection, the maximum length of pipe allowed before transitioning to a larger nominal pipe size is 15 feet. This standard is established to ensure that the system maintains adequate flow and pressure. When piping runs exceed a specific length, it is essential to increase the diameter to avoid excessive friction loss and to maintain the performance characteristics required for fire protection systems.

In fire protection systems, maintaining pressure and flow is crucial for effective operation. If the pipe is too long for its diameter, it can impede the flow of water, resulting in insufficient pressure at the end of the run. By requiring that a larger nominal pipe size be used after 15 feet, building codes and standards help prevent these issues, ensuring the reliability and effectiveness of the fire suppression system.

This requirement serves to optimize the functionality of the sprinkler system, facilitating proper distribution of water during an emergency situation.