A centrifugal firewater pump is operating to pressurize a fire main.
The pump takes suction from a vented water storage tank.
A fire hose connected to the fire main is being used to suppress an elevated fire.
Given:
- The eye of the pump impeller is located 30 feet below the tank water level.
- The pump has a design shutoff head of 120 feet.
- The required net positive suction head (NPSH) for the pump is 15 feet.
- The tank water temperature is 60°F.
At which one of the following elevations above the eye of the pump impeller will the fire hose spray nozzle first be unable to provide flow?
(Disregard all sources of head loss.)
A. 106 feet
B. 121 feet
C. 136 feet
D. 151 feet
Show Answer
Answer: D
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