Within the framework of our local fire control program, we have come up against the problem of a very high-pressure network. Its configuration is pretty straightforward: a high water tower with a distribution pipe that descends and then rises in height. So, at the lowest point, the pressure is ~ 200 psi, rising to ~ 90 psi at the highest point downstream.
Customers are connected via stabilized pipes tapped onto the distribution network. The fire hydrants are along the main. So some hydrants have a static pressure of ~ 200 psi, and a pressure of 265 gpm above 145 psi, which is a problem compared with the municipal fire department regulations that call for 120 psi of dynamic pressure. There is no way to reduce the pressure in this pipe because it would provoke a drop in pressure on the high point downstream.
Have you encountered this type of problem? If so, what solutions did you come up with and how did you implement them?