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A

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B

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C

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D

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E

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F

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G

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H

head
The amount of atmospheric pressure on a fluid is measured in either PSI (pounds per square inch) or feet of head. Head is measured as the equivalent height of a water column; in other words, if a water tower serves your home and the tower is full to a point exactly 100' above your faucet, there will be 100' of head available (less a small amount that is lost to friction). This amount is convertible to PSI.

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I

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J

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K

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L

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M

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N

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O

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P

psi
pounds per square inch

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Q

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R

residual pressure
The amount of pressure (usually measured in psi) that is expected at the point of discharge. This value is the pump's discharge pressure, minus static head losses and friction losses in the pipe.

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S

static head
The amount of elevation between where you pump from and where you pump to. On a suction-lift pump, static suction head is the difference in elevation between the centerline of pump suction and the water level. On a pressure-booster station, the static head is the difference between the elevation of the pump station at the centerline of discharge and the point of the station's final discharge.

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T

TDH
Total Dynamic Head (TDH) is the amount of pressure that a pump must overcome when in operation. This is the sum of static heads and friction losses on the suction and discharge sides.

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U

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V

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W

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X

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Y

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Z

last revised 10.24.2005