U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
FDA Prime Connection

M-a-57 - Use of Aux. High Pres. Water Pumps on Gra. "A" Dairy Farms
 
 
DHEW/PHS/FDA/BF/TE/DFT
 
                              200 "C" Street, SW
                              Washington, DC  20204
 
                              M-a-57
 
                              October 24, 1975
                              Revised August 17, 1979
 
 
TO:       All Regional Food and Drug Directors
          Attn:  Regional Milk Specialists
 
FROM:     Chief, Dairy and Lipid Products Branch (HFF-415)
 
SUBJECT:  Use of Auxiliary High Pressure Water Pumps on Grade "A"
          Dairy Farms
 
 
We have had recent requests regarding the use of auxiliary water
pumps to increase water pressure in milk houses, dairy barns and
milking parlors.  These pumps increase the water pressure and
permit easier cleaning of floors, walls stantions, stalls and the
exterior surfaces of equipment.  However, they can create a
negative pressure in the water supply system because of their
capability to pump at a faster rate than water can be supplied if
not properly installed and operated.
 
When a negative pressure exists in the water supply system there is
a possibility for contamination to enter the water system due to
backsiphonage.  This is considered a violation of Item 8r of the
1965 Grade "A" Pasteurized Milk Ordinance, 1978 Edition
 
An auxiliary high pressure water pump may be used if it is
protected in one of the following ways:
 
1.   The auxiliary pump may be supplied by a separate surge tank
     that is isolated from the main water supply system by an air
     gap.
 
2.   The auxiliary pump may be supplied by a separate water source
     that is not connected to the water supply system supplying
     water to the milk house.
 
3.   An effective low pressure cut-off switch may be installed on
     the suction side and immediately upstream from the pump.  This
     switch must deactivate the pump when the pressure on the
     suction or feed line drops below 10 pounds per square inch.
 
4.   The installation of any other device or means that will
     satisfactorily prevent a negative pressure on the water supply
     system and subsequent contamination of the water supply
     system.
 
Copies of this memorandum are enclosed for distribution to the
State milk control agencies and to State Milk Officers in your
Region.
 
 
                                        Eugene T. McGarrahan