Pressure surge is a common phenomenon when a dry deluge system is primed. In the worst case the maximum pressure can reach high values when the remote nozzle is primed. This is because the flow resistance increases and the flow rate decreases instantly when the fluid in the nozzle changes from air to water. The following network has pressure surge problem based on the simulation results. In this document two cost-effective ways are discussed to solve the difficulties.
1 – using a short dry pipe near the most remote nozzle for creating a cushion effect
2 – decreasing pipe size to limit the flow rate when the network is primed