I am working a valve closure problem down stream of water pumps. The problem is with water hammer when the valves close too quickly. I am using Perrys chemical engineers hand book section 6-44 for the hydraulic transients section but need to know how to account for changing diameters of pipe between the valve that is closing and the pump. Also the plant is saying that the water hammer traveled to the suction of the pump, is this possible while the pump is running? I have a text book on the method of charachteristics, does this extremely complicated method become nessicary any time you introduce a convoluded piping configuration between the valve and the pressure source? I guess technically all I care about is the distance from the closing valve to the area in question which would be the piping upstream of the pump and the upstream tank.