Ventilation system
Ventilation systems, or ventilating systems, were used throughout buildings, starships, starbases, and other facilities, to direct and control the flow of breatheable atmosphere. (; )

Turkana City had a ventilation and recirculation complex in one of its underground levels. ()

In 2268, on stardate 3619.2, the dikironium cloud creature entered the 's ventilation system and subsequently killed one crewman and severely injured another. Captain James T. Kirk, Commander Spock, and Doctor Leonard McCoy then met and decided to drive the creature out of the ventilation system by flooding the system with radioactive waste. ()

Later that year, on stardate 4523.3, tribbles infested Deep Space Station K-7 by moving through the station's ventilation ducts, allowing them access to the station's grain storage area. ()

In 2269, on stardate 4978.5, the crew of the Enterprise became intoxicated by the effects of Harry Mudd's love potion, which was disseminated throughout the ship using the ventilation system. ()

In 2371, on stardate 48846.5 bacterial cultures which Neelix used to create Brill cheese got into 's ventilation system and shut down or infected the ship's gel packs. B'Elanna Torres, Kes, and The Doctor killed the virus by heating the gel packs and raising the ship's temperature by inverting the warp field. ()     

In 2374, on stardate 51425.4 (Day 133 of the Year of Hell), the ventilation system on board the  began to fail – as a result of constant attacks from the Krenim Imperium – which allowed gas from a class 9 nebula to flood one of the last habitable decks on the ship. ()

Later that year, on stardate 51462, The Doctor and the EMH Mark II of the  dispersed neurozine gas throughout the Prometheus using the ventilation system, incapacitating a group of Romulan hijackers. ()

Life support technology
Spacecraft sections