Quite right 212man, A330/340 says 'Avoid Icing Conditions' if and anti-icing system goes down due to a primary system failure (usually to do with bleed air availability). There are no duplex systems on our (modern) fw. The difference is on the NS and other areas (before the Canadians scream) is the length of exposure. Usually we pass through the icing pretty quickly in an Airbus, the biggest icing accumulation I have ever seen was on that weird toadstool nailed to the side of a Super Puma (or Tiger in case there are more sensitive souls out there).
TOD