Pumping Calculations - Basic Mathematics for Water and Wastewater Operators - page 209

■ Example 14.29
Problem: A pump is pumping against a total head of 48 ft. If 860 gpm are to be
pumped, what is the horsepower requirement?

Solution:

Flow (gpm)Head (ft)
3960

× 860 gpm ×

960

48 ft

whp = = = 10.42 hp

3

■ Example 14.30
Problem: A pump is delivering a flow 840 gpm against a total head of 33.8 ft. What
is the water horsepower?

Solution:

Flow (gpm)Head (ft)
3960

× 840 gpm × 33.8 f t

whp = = = 7.17 hp

3960

■ Example 14.31
Problem: What is the water horsepower of a pump that is producing 1555 gpm
against a head of 66 ft?

Solution:

Flow (gpm)Head (ft)
3960

× 1555 gpm ×

3960

66 ft

whp = = = 25.9 hp

■ Example 14.32
Problem: If a pump delivers 380 gpm of water against a total head of 90 ft, and the
pump has an efficiency of 85%, what horsepower must be supplied to the pump?

Solution:

Flow (gpm)Head (ft)
3960

× 380 gpm × 90 ft

bhp = = = 10.16hp

× Pump efficienc y 3960 × 0.85

■ Example 14.33
Problem: If a pump is to deliver 460 gpm of water against a total head of 85 ft, and
the pump has an efficiency of 70%, what horsepower must be supplied to the pump?

Solution:

Flow (gpm)Head (ft)
3960

× 460 gpm × 85 ft

bhp = = = 14.11 hp

× Pump efficienc y 3960 × 0.70