This commercial water system is to be sized for a flushometer valve water closet and urinals as well as the other fixtures as shown. The dotted line represents the hot water supply piping. What minimum size is required at “E” (the cold water supply just ahead of the water heater)?

This commercial water system is to be sized for a flushometer valve water closet and urinals as well as the other fixtures as shown. The dotted line represents the hot water supply piping. What minimum size is required at “E” (the cold water supply just ahead of the water heater)?