When installing an air gap to protect a food-prep sink drain, what minimum vertical distance is generally required?

解析

An air gap must be at least twice the diameter of the water supply inlet, and in no case less than one inch, measured vertically between the outlet and the flood rim of the receiving fixture. The Food Code does set a numeric minimum, so a merely visible gap is not enough, a quarter inch is well under the one-inch floor, and distance from the floor or wall is irrelevant — the measurement that matters is the vertical space above the flood rim. Too small a gap can allow back-siphonage of contaminated water.