[flow factor] The flow factor is the metric equivalent of Flow coefficient. In more practical terms, the flow factor Kv is the rate of flow of cold water in cubic metres per hour at a pressure drop of one kilogram per square centimetre across the valve. where: Kv = flow factor F = Rate of flow (cubic meters per hour). SG = Specific gravity ... Found on http://en.wikipedia.org/wiki/Kv_(flow_factor)