A horizontal water supply pipe has a length of 2000 m and a diameter of 150 mm. The pipe is connected to an open tank at one end where the elevation of water is 4 m, and at the other end there is a quick-opening valve. Determine the time it will take for the ?ow to reach 99% of the ?nal steady-state velocity if the valve is initially closed and then suddenly opened at t ¼ 0. Assume incompressible water and inelastic piping. Let f ¼ 0.030 and K ¼ 0.2 once the valve is opened.