What is the recommended transfer valve setting for pumps used in a relay operation or master stream?

In a relay operation or when utilizing a master stream, the recommended transfer valve setting for fire pumps is the parallel (volume) setting. This setting optimizes the pump's output for maximum water flow, which is critical in relay operations where water must be moved efficiently over long distances. The parallel setting allows the pump to deliver a higher volume of water without increasing the pressure, ensuring that sufficient water is available at the end of the line for effective firefighting.

In situations where a master stream is employed, the increased demand for water necessitates this setting, as it helps in maintaining adequate flow rates while reducing the potential for pressure loss that could compromise the operation. Using the parallel setting ensures that the firefighting efforts are not hindered by low water supply, a crucial factor when responding to large-scale incidents.

The other options, such as bypass and single pressure settings, do not provide the volume output necessary for relay operations and master stream applications, as they are designed for different operational needs. Each of these options serves specific functions but falls short when the objective is to maximize flow for extensive firefighting operations.