[[quoteright:350:[[Film/TheEmpireStrikesBack http://static.tvtropes.org/pmwiki/pub/images/starwarssteam_7049.jpg]]]]
[[caption-width-right:350:TheChosenOne [[IncrediblyLamePun bringing balance to the Fog]]]]

When a place has more steam present than there should be, you've got ExcessiveSteamSyndrome. Two extremely common versions are steam expulsion during an escape sequence after a self-destruct mechanism is triggered and the other is where space faring vessels demonstrate a tendency to belch steam.

In the case of steam produced during a Self-Destruct sequence, after the SelfDestructMechanism is active, the Hero will need to escape as quickly as possible while The SupervillainLair is collapsing around him and he will be hampered by all the steam that seems to be venting into the main escape corridor. Somehow he manages to dash his way out of the crumbling hive of villainy and burst out of the clouds of steam.

It's all very dramatic, but to be completely honest, no one would hire an architect that made vents dump steam into the main exit, especially when people are trying to escape. It just goes against any semblance of sanity or decent design.

The second common example is in speculative fiction spacecraft, where the spacecraft leak steam apparently as part of regular functionality. These vessels have a tendency to vent dense streams of steam-like gas at every occasion, both outside and in.

When an engineer is confined in the bowels of a ship, he's almost guaranteed to run into a cloud of the stuff. Maybe it's hot, like a steam pipe opening up, maybe it's cold, like a liquid oxygen pipe opening to atmosphere. It's usually dangerous, and always cool-looking on film.

Because SpaceIsAnOcean, this may have started as an homage to classic cinema depicting naval life. On a submarine or steamship, streams of thick steam were ubiquitous. It's an easy and cheap way to make an area look industrial, damaged, dangerous, gritty, or any combination thereof.

On the outside of the ship, ventings usually accompany an atmospheric landing, power-up, lift-off, or other such event. This comes from footage of real spacecraft, which often sever lines and conduits with explosive charges during launch.

See also SelfDestructMechanism. Compare to ImpressivePyrotechnics and MadeOfExplodium. Has nothing to do with fanservice anime that overdo CensorSteam nor addiction to buying far too many games at 20% off on UsefulNotes/{{Steam}}.

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!!'''Examples:'''

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[[folder:Anime and Manga]]
* While not a spaceship, Raising Heart from ''MagicalGirlLyricalNanoha'' usually discharges ''some'' kind of gas after any particularly impressive attack.
** Considering the sheer amounts of energy being thrown around, it's probably coolant, or at least ambient gas that gets superheated by accident. It's apparently a design feature, since the vents have caps that pop off to let it happen.
** Not just RH; Bardiche and really, most other Intelligent Devices, Storage Devices and Armed Devices do this. Especially with a cartridge system. This kind of supports the theory that Magi-Link Cartridges generate a lot of waste heat, if not for the AI system decompiling the [[VancianMagic Magic As Programs]] attacks in split-seconds and then cooling down in-between. In other words, [[FridgeBrilliance AI split-second overclocking in weapon forms]].
*** It even gets supported by the side materials: Nanoha mentions her new Raising Heart Exelion jury-rigged with a cartridge system is a total maintenance nightmare.
* Brought to the logical extreme by LeijiMatsumoto in ''Manga/GalaxyExpress999'': the titular CoolTrain is a spaceship that looks like a train pulled by a [[http://en.wikipedia.org/wiki/JNR_Class_C62 C62 steam locomotive]], smoke included. Justified out of universe by AuthorAppeal and in-universe by RuleOfCool (Maetel quickly points out it was built with that look because people preferred it to more modern-looking space trains).
* Steamboy. This trope is present throughout pretty much the whole movie, especially so in the second half with the Steam Castle. Of course, when you're talking about a colossal structure that runs entirely on steam power, large quantities of the stuff are to be expected, right?
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[[folder:Film]]
* The ''Franchise/{{Alien}}'' films and their spin-offs feature tons of steam blasts from leaky pipes, perfect for [[CatScare cheap scares]] when fighting xenomorph infestations.
** Subverted a bit in ''Film/{{Alien}}'' when a steam burst that is annoying Ripley is actually shown to be under the control of another crew member.
*** Though he doesn't realize it until after she leaves. "Son of a bitch." *STEAM!*
** Justified after Ripley sets the SelfDestructMechanism, which involves turning off the cooling units of the ship's reactor. The ship's systems are automatically venting in an effort to cool itself.
*** The same can also be said of, though not on a spaceship, the converter on LBV-426 towards the end of ''Film/{{Aliens}}'' when she goes to look for Newt. Notice those pipes she passes that are glowing a dull red, yeah, that's the coolant pipes trying to compensate a reactor that's about to pop. The light you see on the bottom floors is the residual radiation of the core...neat sound effect too!
*** ''Partly'' justified, since there are surely better places for the coolant system to try and dump excess heat than into crew spaces. (It's interesting that in ''[[Film/TwoThousandOneASpaceOdyssey 2001]]'' the ''Discovery'' was originally going to have radiator fins jutting out from the engine block; they were dropped from the design to avoid people asking why the ship needed wings).
* And how can anyone forget the scenes in ''Franchise/StarWars'', where Darth Vader walks dramatically through steam exhausts that for some reason are set around the ship's main entrance. Made even weirder, though more {{Badass}}, in the [[Franchise/StarWarsExpandedUniverse novelizations]], which claim that the steam is burning hot and that normal people won't exit until it's evaporated. This is actually {{lampshade|Hanging}}d as a security feature to prevent assaults or sabotage when docking.
** The ''Millennium Falcon'' also vents steam/coolant/whatever after setting down on the Cloud City landing platform on Bespin. Nobody tries to walk through it.
* In the ''Film/StarTrek'' reboot movie, when ''Enterprise'' is getting sucked into a black hole near the end and they're running the warp engines at maximum power, Scotty is running around in Engineering trying to hold the ship together. A pipe cracks overhead and steam comes venting out.
* In ''Film/TheFifthElement'', the airlock of the Mondoshawans' ship hisses steam and drips condensation when it first opens up at the Egyptian temple.

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[[folder:Literature]]
* In TheAmtrakWars books the [[MilitaryMashupMachine Wagon Trains]] do vent steam; it's used as a close-range defense system, and capable of blasting the flesh right off your bones.
* The Soviet officers in the novel ''Literature/TheHuntForRedOctober'' mention a cook who tried cleaning his pots and pans with steam from the primary coolant loop (read: ''radioactive'' steam) for the ship's reactor and ended up killing himself and irradiating the entire engine compartment. "At least he cleaned his pans though. They should be safe to use after several hundred years."
** Not so much a joke as it might seem. The same story, minus irradiating the engine compartment, is related in ''Crash Dive,'' edited by Larry Bond. In the vignette, ''Accident on K-219,'' a crewman of the K-219 recalls this story involving an unsuspecting cook aboard the Soviet icebreaker ''Lenin'' who did, in fact, use steam from the reactor coolant system to clean his pans. The vignette was composed with the input of former Soviet captain Igor Kurdin, so it may well have happened.[[note]]Or he may have fallen victim to urban legends, too.[[/note]]
** Any reactor design that allows for a cook to have access to the primary cooling loop to clean his pans was a [[ThisIsGonnaSuck Bad One.]]
* ''Chasm City'' features a space station that is cooled by pumping ice through pipes, turning to steam in the process before being ejected into space; this is justified, as the station's heat radiators were broken off by space debris.
* Jerry Pournelle and Larry Niven's alien invasion story ''Literature/{{Footfall}}'' includes a spaceship with an Orion-class nuclear engine that is indeed cooled by and powered by steam.
* Larry Niven's Smoke Ring setting includes rockets that travel inside the Smoke Ring, on jets of live steam. It is unpleasant if they malfunction. [[spoiler: The novel Smoke Ring has such a malfunction in an early scene. One victim has the misfortune to not be killed immediately when engulfed by live steam from the exploding ship. There is a brief mention of one of the already-known characters trying to catch the victim as she goes by, grabbing her ankle...and the flesh coming off in the would-be rescuer's hand.]]
* Possibly exaggerated in a story by Brazilian author Creator/LuisFernandoVerissimo, where an InsufficientlyAdvancedAlien race built a wood-powered spaceship, with chimney and such, when they were trying to build a nautical ship instead.
* In the StarWarsExpandedUniverse, leaky starfreighters can release korfaise gas, which looks like steam, into the engine room. This is a bad thing, because korfaise is toxic.
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[[folder:Live Action TV]]
* ''Franchise/StarTrek'', all incarnations, most notably in ''Voyager'''s landing sequence.
** Klingon ships seem especially prone to this as well.
* ''Series/{{Thunderbirds}}'' made extensive use of steam, smoke, and zero-thrust rocket motors to depict takeoffs and landings in miniature. Rockets in flight were filmed inverted, so the smoke would rise ''away'' from the rocket instead of climbing after it.
* In the ''Series/MysteryScienceTheater3000'' episode ''The Phantom Planet'', Tom Servo explains this: "Look, there's the problem, their dryer's leaking."
* Several ships in ''Series/{{Farscape}}'' had this, especially when they were malfunctioning. One particularly bad-ass sequence that was used in the opening had John and D'Argo walking in slow-motion through a steaming corridor. Near the end of Season 3, an imploding space-ship has steam going off all over, leading to some prime horror, as one strikes [[spoiler:an old childhood friend of Aeryn's, who is just about to shoot her, and ''burns the flesh off her face.'']]
* In ''Series/StargateUniverse'', for some as of yet unexplained reason, there are [[strike:steam]] [=CO2=] vents on the floor of the gate room of the ''Destiny''. They fire every time the wormhole closes.
* The original ''Series/{{Battlestar Galactica|Classic}}'' pilot does this. Starbuck and Cassiopeia are seen kissing in the hangar bay, while Starbuck's other love interest catches them by surveillance camera. Cue the push of a "Steam Vent" button.
** The pilot of the [[Series/BattlestarGalacticaReimagined re-imagined version]] had Ragnar Station. Justified, as [[RidiculouslyHumanRobot Leoben]] had just ripped a steam pipe. The rest of the station wasn't really steamy at all.
* ''Series/BabylonFive'' had steam vents occasionally, notably in "Grey 17 Is Missing", where Garibaldi used a broken steam pipe to build an improvised gun.
* In the ''Series/DoctorWho [[Series/DoctorWhoConfidential Confidential]]'' episode for "The Impossible Planet" it's commented by the producer that practically every shot has steam rising from somewhere.
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[[folder:Tabletop Games]]
* ''TabletopGame/{{Warhammer 40000}}'' has Stanley Steamer Spaceships and Stanley Steamer ''tanks''. Sometimes justified in the latter case; the primary STC tank of the Imperium is of extremely basic design, so much so that the things can be adapted to run on 'actual steam engines''. This is quite a popular option on less developed worlds; after all, a steam engine can be made to run on just about anything you can reliably light on fire.
* Justified for ''TabletopGame/{{Space 1889}}'' where ships use solar boilers to power their "aether propellers" between planets. The boilers, which consist of a large parabolic mirror and a boiler on a turntable vent their safety valves directly into the engine room on a space ship, in order to preserve as much water as possible from being lost.
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[[folder:Video Games]]
* The mining barges from ''VideoGame/EVEOnline'' discharge smoke and flames from ports on their flanks. [[AvertedTrope Averted]], since it is most likely the barge ejecting the excess material from extracting the ore.
** Do remember that these exhaust pipes are always venting, even when docked in a station.
* In the ''VideoGame/{{Fallout 3}}'' add-on ''Mothership Zeta'', the featured ship has an area called 'steamworks' which is mostly filled with steam releasing pipes (there's also several "cryo chamber" areas with leaking coolant and evaporation).
* The [[GhostShip USG Ishimura]] in ''VideoGame/DeadSpace'' and the Sprawl ''VideoGame/DeadSpace2'' both have this in places. Particularly as the Ishimura is a mining ship, the industrial sectors of it are noisy and clanky, with steam and other evidence of heavy processing machinery going on. Both games of course have a rush of visually obstructing gasses when in a room undergoing a change in air pressure, such as an airlock or [[ContinuousDecompression a window being blown out]].
* ''BraveFencerMusashi'' has lots of pipes seemingly designed to pump hot steam into areas where you need to be.
* In the intro level for ''Super VideoGame/{{Metroid}}'', Samus needs to escape a space station, while avoiding gushes of steam coming out from practically everywhere. If you get hit by the steam, you lose precious time to escape.
** Happens again during the escape from planet Zebes, only the steam's escaping ''from the ground'' itself.
* ''VideoGame/RemnantsOfSkystone'' has steam vents as obstacles, despite their supposedly having been untended for [[EternalEngine nearly two hundred years]], often acting just to make you schlep all the way around to try a particularly tricky threading-the-needle series of spikes and nasties.
** The Aeronaut class has a jetpack, which blasts one skyward on a pillar of steam. Their "blasters" also work by weaponizing this.
* This is often used in the ''Franchise/SonicTheHedgehog'' games.
* Present in ''VideoGame/BioShock1'' to show damage and decay in many of the stages, especially present in Hephaestus.
* The "Flush Coolant" command in most ''VideoGame/MechWarrior'' video games resulted in a greenish cloud of gas forming underneath your mech as your reactor quickly cooled. Sadly not present in Mechwarrior Online.
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[[folder:Western Animation]]
* ''WesternAnimation/TeenTitans'', though that was when the Titans were TrappedInTVLand. All other interstellar ships were steam-free.
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[[folder:Real Life]]
* TruthInTelevision: During [[http://www.wired.com/science/discoveries/magazine/16-03/ff_seacowboys the righting of the Cougar Ace]], the salvage team had to climb down part of the rear deck -- which was being periodically blasted by plumes of -110 degree carbon dioxide.
** Given that it was cold gas, that likely counts more as a inversion.
* During the Apollo 13 disaster, the crew could see vapors venting from their damaged spacecraft. Of course, the Apollo spacecraft wasn't ''supposed'' to do this once it was out of the atmosphere; Jim Lovell has said that the last thing any Commander ever wants to see is his ship "bleeding".
** Before launch, however, ''all'' Saturn V rockets had plumes of condensed water vapour streaming off them, because the liquid hydrogen ([=LH2=], the fuel for stages 2 and 3) and liquid oxygen (used as oxidiser for all three stages) were so cold. The steaming can be seen in several shots in [[http://www.youtube.com/watch?v=FzCsDVfPQqk this video]].
* As mentioned above, getting hit with a jet of steam in RealLife usually invokes a particularly hideous and gruesome version of the ChunkySalsaRule: it literally cooks you alive like a giant, ambulatory shrimp.
** Very high pressure steam leaks are dangerous in another way - one procedure for finding them involves waving a broom handle around until it's neatly cut by the invisible knife.
*** This is specifically for super-critical water, aka 'live steam'. This is water heated to a temperature above the critical point, where the difference between liquid and gas disappears. It's invisible because it's physically impossible for the water droplets that make normal steam visible to form at such temperatures. This also makes it phenomenally dangerous, since it can cook the flesh right off your bones if it hits you. Potentially before you drop to the floor, since the only reason to use this insanely nasty phase of water is to drive high-speed steam turbines, which means very high pressure as well.
* Water makes an excellent heatsink, as it can absorb remarkable amount of energy in the ice to water and water to steam phase changes. This property makes it exceedingly valuable in a realistic space warship which would cook itself to death otherwise (as [[SpaceIsCold space is not cold in real life]]). Open cycle cooling where coolant is vented into space is useful in some circumstances, but leaking 600 degree steam into engineering or living spaces would only happen in the result of catastrophic damage.
** Or, potentially, [[CombatPragmatist to deal with either mutinying crew or intruders]].
** One proposal is to use what's called a 'flash cube reactor', in which the fuel is uranium hexaflouride contained in a quartz tube, with a movable beryllium neutron mirror outside it that can be moved to surround however much of the reactor vessel is desired, with power increasing as more is covered. The heat produced would be used to boil water, which would then provide steam for a steam rocket, which could easily provide 0.25g of thrust for up to an hour at a time, which is a ''huge'' thrust for very long time for a ship in open space. This is proposed for the battle drive for a space warship, which needs lots of thrust for the short periods of battle (which would tend to end as soon as someone got a telling blow in, since space is a tremendously unforgiving environment).
* Some engineers theorize that [[http://www.space.com/11230-water-powered-spaceship-mars-solar-system.html a solar powered steam-propellant spaceship]] could be used for economical Mars travel, which just goes to show we could easily go full circle and start traversing the solar system in steam ships....
** There also exist multiple concepts for nuclear-powered ships that essentially run on continuous steam explosions or equivalent effects with other molecules. For instance, with a suitable reaction surface, you can produce a similar effect with carbon dioxide to make an engine. What's the use of that? It gives you an exploration ship with a an effectively unlimited cruising range on Mars. When you get done with that, refit it to use water and head for the moons of Jupiter and Saturn.
* Almost all cryogenic systems are deliberately designed to fall into this trope if something goes wrong. Liquid nitrogen or helium systems need pressure relief vales so that if cooling fails or too much heat gets dumped into it, it can boil off safely rather than building up pressure and exploding. As the [[StuffBlowingUp slight problem]] the LHC had when it first started running shows, even this [[FailsafeFailure isn't always enough]].
** A complicating factor in these designs is a phenomenon known as 'quenching'. If you localize the field of a superconducting magnet too much (by, say, dropping a significant mass of magnetic material like a steel hammer onto the casing) it can cause the superconductor coil carrying the current generating the field to abruptly lose superconductivity, resulting in the energy in the current all being rapidly liberated as heat in the coil. The effects of this are pretty dramatic, even if the emergency pressure release works perfectly.
* Sort of [[TruthinTelevision Truth in Television]]. Most of the clouds you see at a rocket launch pad are steam. Super hot exhaust gas would destroy the concrete "flame pits"? Easy solution, spray massive amounts of water at them so all that energy goes into turning it into steam.
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