German term (edited): Abgaszügen

Another possibility.

Here's a reference from a description of the "Anaconda Smelter Stack" in Montana:

"The smelter had a large network of ***exhaust flues*** from the furnaces that all fed a main flue. The main flue carried the combined smelter exhaust gases a half-mile up the hill to the stack. The flue system and stack combined to provide a natural draft to carry the smelter exhaust gases, and it was claimed to be capable of handling three to four million cubic feet per minute of gas.["

Source: http://en.wikipedia.org/wiki/Anaconda_Smelter_Stack

Now THAT'S what I call a chimney!