Glass Furnace Flame, Sklarna Nizbor, Nizbor, Bohemia (CZ), 2008

Operating at temperatures in excess of 1600 degrees Celsius, these furnaces have a limited life span. I've forgotten what the typical lifespan is at Nizbor, but I do remember being told that it's only a few years, and during that time the furnaces can't be shut down, as they'll clog with glass. Therefore, every few years, this furnace assembly has to be completely replaced, usually due to corrosion, according to what I've read. A definitive source on glass furnaces would be nice to clean up this posting, as I've been unable to find a suitable one on the web.