text: The stack effect in industrial flue gas stacks is similar to that in buildings, except that it involves hot flue gases having large temperature differences with the ambient outside air. Furthermore, an industrial flue gas stack typically provides little obstruction for the flue gas along its length and is, in fact, normally optimized to enhance the stack effect to reduce fan energy requirements.
  Large temperature differences between the outside air and the flue gases can create a strong stack effect in chimneys for buildings using a fireplace for heating.
  Before the development of large volume fans, mines were ventilated using the stack effect.  A downcast shaft allowed air into the mine.  At the foot of the upcast shaft a furnace was kept continuously burning.  The shaft (commonly several hundred yards deep) behaved like a chimney and air rose through it drawing fresh air down the downcast stack and around the mine.