Reduced Pressure Principle Backflow Prevention Device Assembly Relief Valve Catastrophic Discharge
With a catastrophic failure, gallons of water will discharge from the relief valve. Because of this design characteristic of the RPZ, adequate drainage shall be installed to handle a catastrophic failure to prevent property damage due to flooding. Additional drainage capacity may be required to accommodate a catastrophic relief valve failure. The size of the drain should be based on the manufacture’s discharge rates. Note: These curves represent catastrophic or worst case discharge rates.
The catastrophic relief valve discharge rate for a ¾-inch RPZ with a zone pressure of 60 PSIG is approximately 95 gallons per minute. At this rate, this ¾ inch RPZ would fill a 1,200 cubic foot room in 99 minutes.
