What is the maximum size of a riser that can be supplied by a single outer fire department connection?

The correct answer is based on the guidelines established for fire department connections (FDCs) and the design of standpipe systems. A single outer fire department connection should be able to supply a riser that is no greater than 3 inches in diameter. This limitation is in place to ensure that firefighters can effectively connect their equipment and deliver the necessary water flow without complications that could arise from larger pipe sizes.

A 3-inch riser is optimal for providing sufficient pressure and flow, while also being manageable in terms of accessibility and compatibility with large hoses used by fire departments. Larger sizes could complicate connections and may not provide the desired pressure drop that might occur with increased diameter.

Understanding these specifications is crucial for maintaining effective fire protection systems and ensuring that they meet the requirements outlined in NFPA regulations.