Ahydronic system is proposed for a 20-story building, with the chilled water pump located on the lowest floor and makeup water at the top floor. each story is 15 ft (4.6 m), and the makeup water pressure is 15 psi (103 kpa). the main air handlers are located on the top floor, and a variety of terminal units on each floor. the total piping friction loss is 60 ft of head (179 kpa). what is the static head of the chilled water system at the pump while turned off? 75 psi (517 kpa) a. b. 115 psi (793 kpa) c. 145 psi (1000 kpa)