Concept art
The final destination for the line of deceased at the Vale Street Ironworks, the Furnace Hall is where the Thief-Taker General oversees the disposal of Gloom victims by cremation...after ensuring that nothing of value goes to waste, of course.
The chamber itself is rather large, though it contains only a single furnace in the center of the room. During Chapter 2, this is where the Thief-Taker retrieves Cornelius' Ring from its owner's stomach, before heading off to stash the trinket in the Supervisor's Office.
A list of orders on the nearby wall details the disposal process. A room in the back contains the Diamond Circle ring.