Water Source
 
Determine the depth of water at piping entry location.  In ponds, use low water level, if known, to ensure operation during droughts.  A minimum of two feet of water over the pipe is necessary to avoid cavitation for conventional installations

A floating, non-vortexing intake installation eliminates these requirements, as noted in Dry Hydrant Standards Code 432.  The USDA Natural Resources Conservation Service can assist in design and water source certification.

See Illustration C  -- Slotted Intake

 
Pump Lift
 
Lift in excess of 15 feet should be avoided.  The lift is calculated from the centerline of pump to the expected drought elevation of the water source.
 
Accessibility
 
Dry Hydrants site conditions to consider:
  • All weather access available or can be developed
  • The Dry Hydrant is reasonably close to the water source to minimize the length of the suction line.
  • A maximum grade of 8 percent with a minimum of 12 feet road width -- the Fire Department using the site should participate in this planning.
Location
 
A location map showing the exact site of the hydrant furnished to the local Fire Department (911 address suggested.

A letter of approval to use the site obtained from the landowner, filed at the local Fire Department

A. B.
Illustration A shows an installation of a conventional Dry Hydrant using 45 degree elbows.  Installation B shows installation with 90 degree elbows.
   

Illustration D shows hydrant head approximately 2 feet above ground - and also 10 feet from road surface.  Should be more than 20 feet when more than one pumper is to use the hydrant.

Other designs and practice standards for Dry Hydrants Code 432 may be obtained from USDA Natural Resources Conservation Services (NRCS Alabama -- August 1999)

   
 

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