System Head Curve

System Head Curve

To Calculate a System Head Curve several points must be chosen to calculate friction losses on both the suction and discharge sides of the pump at various flow rates. The static suction head/lift and the static discharge head remain constant.

Using the example on the previous page for <--Calculating TDH for a flooded suction application plot the friction losses for 50, 90 and 100 GPM as follows:

Suction Side

Flow
Rate

GPM
Total
Equivalent

Length

of Pipe
Friction
Loss/100'

of Pipe
Friction
Loss
Total
Static

Head
Suction
Head

50 26.3 1.38 0.36 10 9.67

90 26.3 4.08 1.07 10 8.93

100 26.3 4.96 1.30 10 8.7

Discharge Side

Flow
Rate

GPM
Total
Equivalent

Length of

Pipe
Friction
Loss/100'

of Pipe
Friction
Loss
Total
Static

Head
Discharge
Head

50 202.3 9.9 20.03 50 70.03

90 202.3 29.4 59.5 50 109.5

100 202.3 35.8 72.4 50 122.4

Total Dynamic Head(TDH) at 50 GPM = 70.03' - 9.67' = 60.36'

Total Dynamic Head(TDH) at 90 GPM = 109.5' - 8.93' = 100.6'

Total Dynamic Head(TDH) at 100 GPM= 122.4' - 8.70' = 113.7'