*TM 5-813-1/AFM-88-10, Vol. 1
other modifications in the design. The calculations
should be reviewed when all systems are finally sized.
The well diameter may be oversized to allow for future
installation of a larger pump, but the pump installed
e.
Total dynamic head is the sum of the above.
should not exceed the capacity of the well. This
TDH = 120 + 217 + 37 + 0.25 = 374 ft.
procedure gives sufficient information to specify a water
Calculate the pump horsepower using equation 5-7.
well.
Efficiency can be found in manufacturer's literature.
B-8. Construction details
Since this area is subject to freezing temperatures and
other climatic conditions which would be detrimental to
an exposed pump and motor, a small building should be
erected for protection. The floor of the building should
B-7. Specification preparation
be raised above grade and the foundation extended
Given the above information, the designer can review
below frost depth. A separate room with access only
manufacturer's literature and consult with their
from the outside should be provided for the chlorination
representatives to determine types of pumps and motor
equipment. The well casing should be extended above
drives which are available to meet the operating
the floor approximately 12 inches and concrete placed to
conditions. The calculations can then be refined to
this level for the pump base. Electric power can be
account for actual pump and well characteristics.
provided from the main facility. Some small parts
Although not a function of well design, the engineer may
storage may be provided.
want to oversize the transmission main from the well to
the storage tank to allow for future expansion or make
B-3
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