What term describes the flow that is available from a hydrant at the designated residual pressure?

The term that describes the flow available from a hydrant at the designated residual pressure is "Rated Capacity." This concept is crucial in fire protection engineering as it indicates the maximum flow rate that can be delivered by a system while maintaining an adequate residual pressure, which is essential for ensuring that firefighting operations can be effectively carried out.

Rated Capacity takes into account various factors such as pipe sizing, the condition of the hydrant, and the hydraulic conditions of the system at the specified pressure. Knowing the Rated Capacity helps engineers and firefighters understand how much water will be accessible during an emergency, allowing for better planning and response strategies.

In contrast, hydraulic calculations involve the process used to determine the flow and pressure conditions throughout a system but do not specify the actual available flow at a hydrant's given pressure. System working pressure refers to the operating pressure of the system under regular conditions, while a hydrostatic test is a method used to check for leaks and the integrity of the piping system by applying pressure beyond normal operating conditions. These latter terms do not directly define the flow capability of a hydrant at a specific pressure level.