The pipe in Problem 4.40 (/f= 0.02) is 3,049 m (10,000 ft) long and extends from an '...

The pipe in Problem 4.40 (/f= 0.02) is 3,049 m (10,000 ft) long and extends from an ' upper reservoir [WSEL = 304.9 m (1,000 ft)] to a lower reservoir [WSEL = 259.1 m (850 ft)]. What water-hammer pressure would develop if a valve in the line near the lower reservoir [Elevation = 253.0 m (830 ft)] was closed based on the following approximate equation

where Hh is the water-hammer pressure head, V is the change in velocity in the pipeline caused by the valve change, Tc is the time for the valve change, and T is 2L/a with the limitation that (T/Tc) cannot exceed 1.0. Compute the minimum time for valve closure, if the allowable stress in the steel pipe is 240,000 kPa (18,000 psi). Note that the total pressure head is Hh plus the static pressure head of 51.9 m (170 ft).