For a single-outlet Fire Department Connection (FDC) to be acceptable, it must be piped to what size riser or smaller?

The requirement that a single-outlet Fire Department Connection (FDC) must be piped to a 3-inch riser or smaller stems from standards governing fire suppression systems. Specifically, the National Fire Protection Association (NFPA) outlines guidelines regarding the sizing and installation of FDCs to ensure that they can provide adequate water flow for firefighting operations without creating pressure or hydraulic issues.

A 3-inch riser is typically sufficient to handle the expected flow rates required for firefighting purposes while maintaining positive pressure and proper functioning of the system. Larger risers could potentially introduce complications in terms of flow management and pressure balance, which is why local codes often limit the size to 3 inches or smaller for a single-outlet connection.

This understanding is particularly important for sprinkler fitters, as proper installation and adherence to the size requirement ensures that FDCs provide the necessary support to fire suppression efforts efficiently and safely. The specific selection of a 3-inch size aligns with both safety practices and operational effectiveness, making it the correct choice in this context.