At the Boiler House were exhaust steam vents to the atmosphere from a pipe above the roof line is usually fitted a Steam Exhaust Head. This fitting is for exhaust steam from equipment, such as steam pumps and small engines that are not connected to a condenser.
The Exhaust Head does several things: It muffles the steam sound and it also separates left over condensation (water) as so not to spray like rain over plant grounds. From the Exhaust Head, a small pipe that runs downward (along side of the larger uptake line), carries water to the hot well.
Exhaust Heads are usually made in several cast iron pieces, sometimes they are even made of sheet iron. I know little about them other than seeing them working at a far distance.