MIL-HDBK-1164
APPENDIX A (Continued)
Metric Field Head Calculation
1. Assume that a pressure gage located on the discharge of a well pump indicates a
pressure of 240 kPa for a discharge of 30 liters per second (Lps). The
corresponding pumping level in the well is 18 m below the elevation of the pressure
gage. The pump column is 200 millimeters (mm) in diameter and extends into the
well 30 m below the pump discharge.
2. The friction loss for 30 Lps of water through a 200-mm pipe, with a friction
coefficient (C) of 100, is 2.5 m divided by 300 m. The equivalent length of a 200-
mm long sweep elbow is 4 m. Thus, the friction loss through the column and
discharge elbow can be calculated as follows:
2.5 m
34 m
= 0.28 m
300 m
For help with head loss calculations, refer to par. 2.1.1.
3. The vertical distance from the well pumping level to the pressure gage was given as
18 m.
4. The pressure at the pressure gage expressed as meters of head equals:
0.1020 m
240 kPa
= 24.5 m
kPa
5. Total field head is the sum of the friction loss, vertical distance, and pressure in ft of
head:
0.28 m + 18 m + 24.5 m = 42.8 m
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