Causes of Overpressure and Lower Pressure Range of Booster Pump Systems in Standpipe Installations of Performance-Based High-Rise Buildings

This study analyzed the overpressure issues arising from differences in the design standards of pressurized water supply devices in standpipe systems installed in performance-based high-rise buildings and proposes a minimum lower-limit supply pressure range for fire pump trucks. Nine buildings over 30 stories constructed within the past six years were investigated, and among them, three buildings with similar pressurized water supply device installation heights (72.1∼74.9 m) and nameplate pressure ranges (0.8∼1.2 MPa) were selected for high-rise water discharge experiments and hydraulic calculations. Experimental results showed that, even under the nameplate lower-pressure conditions, discharge pressures ranging from 0.4 to 0.9 MPa were observed at the upper floors, with a maximum friction loss of approximately 10 m on the suction side. These findings suggest that the safety margin of total head should be reduced and motor capacity should be rationally determined in the design of pressurized water supply devices. Furthermore, for field operations, a stepwise water supply method adding 0.1 MPa to the elevation pressure corresponding to the installation floor of the pressurized water supply device is proposed to effectively prevent overpressure on the upper floors.