Which term describes the pressure the fire protection system requires to operate as designed?

Which term describes the pressure the fire protection system requires to operate as designed?

• A. Working pressure
• B. System demand pressure
• C. Static pressure
• D. Relief pressure

Answer: (B)

The key idea is the pressure the system must develop while water is flowing to meet the designed demand. This is the system demand pressure: the pressure required at the most hydraulically demanding point (often at the farthest or highest head) when the design flow is being delivered, after accounting for friction losses in piping, elevation changes, and any head losses from devices. Hydraulic calculations determine this value to ensure pumps, pipes, and sprinklers can deliver the intended flow at the correct pressures under fire conditions. Static pressure is the pressure when no water is moving, so it doesn’t reflect the needs during a fire flow. Relief pressure refers to the threshold at which a relief device would open to prevent overpressure, not the system’s required operating pressure. Working pressure is the rated operating pressure of system components, not the pressure needed to meet the design flow.

The key idea is the pressure the system must develop while water is flowing to meet the designed demand. This is the system demand pressure: the pressure required at the most hydraulically demanding point (often at the farthest or highest head) when the design flow is being delivered, after accounting for friction losses in piping, elevation changes, and any head losses from devices. Hydraulic calculations determine this value to ensure pumps, pipes, and sprinklers can deliver the intended flow at the correct pressures under fire conditions.

Static pressure is the pressure when no water is moving, so it doesn’t reflect the needs during a fire flow. Relief pressure refers to the threshold at which a relief device would open to prevent overpressure, not the system’s required operating pressure. Working pressure is the rated operating pressure of system components, not the pressure needed to meet the design flow.