R309-545-15. Venting  


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  •   Drinking water storage tanks shall be vented. The air venting capacity shall exceed the water inflow and the water outflow of the tank. Overflows shall not be considered or used as vents. Vents provided on drinking water storage tanks shall:

      (1) Inverted Vent.

      Be downturned a minimum of 2 inches below any opening and shielded to prevent the entrance of contaminants.

      (2) Open Venting.

      On buried structures, the end of the vent discharge shall be a minimum of 24 inches above the earthen covering.

      (3) Blockage.

      Be located and sized to avoid blockage during winter conditions.

      (4) Screen.

      Be fitted with No. 14 mesh or finer non-corrodible screen.

      (5) Screen Protector.

      Vents that are 6-inch diameter or greater shall be fitted with additional heavy gage screen or substantial covering, which will protect the No. 14 mesh screen against vandalism or damage.