"Vent" is the official name given to what players typically refer to as a "steam pipe." Vents are part of the family of base items, which also includes things like background earth, graffiti, and maws. As such, they occur in all biomes as a sort of specialized background block.
Vents are a rusty red color and snake up from the very bottom of the world, often branching as they climb. Vents serve as the source of steam power for various engineering items.
On occasion, vent lines near certain dungeons will generate in isolation (meaning they don't reach all the way to the bottom of the map). These vents are still viable sources of power.
How to Obtain
This item cannot be obtained into player inventories.
How to Use
To tap into a vent, you must place a collector over it and then use at least one segment of brass pipe to direct the steam. The center block of the collector must be the block that lies on top of the vent. Once you have the collector positioned, use brass pipe to extend the steam to whatever device you wish.
Note that when a vent line ends, the last segment will appear cut off. Don't place the collector over this last segment, as it doesn't carry steam. Corner and branching segments, however, do carry steam.
Early on in the game, it wasn't possible to excavate steam vents. As a result, when visiting old builds, you'll sometimes see random vents in an otherwise fully excavated area.
It is unclear why vents are called vents, when they are so obviously pipes.