I recently read about an oil rig accident where the workers who were put into a pressure chamber over a course of a few months (about 9 atmospheres) to deal with decompression sickness were decompressed instantly when one of the workers accidentally opened the entrance to the chamber, which killed most of them and severly injured the remaining. At risk of sounding unsympathetic, I'd like to know if such a system would be able to keep supernatural inmates in a prison, killing them if they managed to escape.

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    $\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$
    – Community Bot
    Commented Oct 13, 2022 at 4:02
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    $\begingroup$ That obviously depends on the supernatural beings, and that's your choice. You can say that the only way to safely store them is to pressurize them. $\endgroup$
    – Nepene Nep
    Commented Oct 13, 2022 at 9:09
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    $\begingroup$ As others have said, we need more information on your supernatural inmates and how they are "supernatural" to know if this would work. For example, looking at superheroes: this would not work for Superman, but would likely work to contain Spiderman. $\endgroup$
    – kuhl
    Commented Oct 13, 2022 at 13:11
  • $\begingroup$ This idea was used in Grrl Power. $\endgroup$ Commented Oct 13, 2022 at 17:54
  • $\begingroup$ For the people interested about the accident: history.howstuffworks.com/historical-events/… $\endgroup$ Commented Oct 13, 2022 at 21:32

3 Answers 3


In the same way you cannot drown a fish but only a land animal, a high pressure chamber works well as mean of containment only if the contained subject is likely to be harmed by sudden decompression.

If your supernatural being is prone to suffer from decompression sickness, it can work.

If your supernatural being is immune to decompression sickness, you are just giving them a nice suit where they can rest for some time.

  • $\begingroup$ I doubt there is a species that can handle rapid decompression easily. Even fish need gentle decompression to avoid problems: xray-mag.com/content/fish-need-decompress-too $\endgroup$
    – Matthias
    Commented Oct 13, 2022 at 12:53
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    $\begingroup$ @Matthias, but fishes are not supernatural $\endgroup$
    – L.Dutch
    Commented Oct 13, 2022 at 12:54
  • $\begingroup$ @L.Dutch, not yet they aren’t $\endgroup$ Commented Oct 13, 2022 at 13:18
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    $\begingroup$ @Matthias ghosts are supernatural and I highly doubt they are vulnerable to pressure. Off the top of my head, I doubt many demons or angels or rakshasa or a kelpie or a flame elemental or a hooloovoo (if you consider it supernatural) would care, either. $\endgroup$
    – VLAZ
    Commented Oct 13, 2022 at 14:06
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    $\begingroup$ @Vesper Depending on what stories you take as true, a kelpie might be an immortal fae horse-thing. Being corporeal, is unlikely to trump immortality and general fae nature which according to which stories you take (again) is just "basically limited by plot". Rashasa might be similar. Yet again, depending on which stories you take. They might also be little more than just weird humans but they might actually just be spirits, as well. But overall, the point is that without any idea what means to be "supernatural" there is no actual useful discussion to be had here. The term is too unclear. $\endgroup$
    – VLAZ
    Commented Oct 13, 2022 at 15:10

It will be expensive to maintain. You will need to pressurize and depressurize all objects passing to and from the chamber (food and waste) which takes time and energy, and air filtration will have to be more sophisticated than a simple vent, naturally. But if there is a need for it (and assuming the being it is imprisoning is vulnerable to decompression) it can be done.

You will need to monitor the pressure in the chamber at all times; if the prisoner finds a way to prick a tiny hole in the chamber wall the pressure will slowly equalize and they will be able to escape. This will take some time though.

This is one of the best means available for imprisoning someone with free teleportation abilities and no other notable powers.

  • $\begingroup$ Monitoring will surely be in place for such a thing as pressurized chamber, and should a leak occur, alarm will sound. And if you want to contain someone whose escape will be at least expensive and at most disastrous, why don't you worry about expensive storage made to contain them? PS: leaks still happen in normal pressurized stuff, so re-inflation systems are in order, thus even if the prisoner would make a leak, the pressure won't fade, at least as easily. $\endgroup$
    – Vesper
    Commented Oct 13, 2022 at 11:32
  • $\begingroup$ Well, there may be cheaper ways of containing them, like keeping them sedated or just killing them. Imprisonment through this method is a big investment so you need to have a good reason for wanting them alive and conscious despite them being presumably dangerous. $\endgroup$ Commented Oct 13, 2022 at 11:43
  • $\begingroup$ @Vesper: Of course, but it could open the possibility for an interesting plot, if the prisoner finds a way to disable the pressurization system and trick the alarm system. $\endgroup$
    – Michael
    Commented Oct 13, 2022 at 13:10
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    $\begingroup$ This kind of storage could be very simple and fairly cheap to operate if the pressure chamber is managed like a pressurized airplane - have one thing pumping fresh air in all the time which serves as vent, HVAC, etc. which can be a pretty simple air cycle machine, and separately have a controlled leak in the chamber which opens and closes to maintain a target pressure. This kind of system can even be fully mechanical except for whatever turns the input pump. $\endgroup$
    – nexus_2006
    Commented Oct 13, 2022 at 14:32
  • $\begingroup$ Interesting point about containing a teleporter! It could also contain creatures that have capabilities that could punch through a normal prison. $\endgroup$ Commented Oct 14, 2022 at 4:20

It would work about as well as other concept prisons for supernatural beings in Marvel comic books, such as The Raft, The Fridge, and The Quantum Realm. And by "about as well" I mean "cool concept art but utterly infeasible".

The reason for the infeasibility is logistics. Unless your prisoner is an immortal being in solitary for life who doesn't eat, a prison is not an isolated environment; it's part of a system that interacts with the outside world via guards, doctors, food services, sewage, lawyers, and courts. And while lawyers can courts could be handled over video, food, discipline, and medical care require direct physical interaction with the prisoners. Which is pretty impractical if it requires service staff to undergo hours or days of compression and decompression. And the less said about sewage removal, the better; this is a major recurring issue on submarines.

Marvel comics address this somewhat; in the comic books the superintelligent robot Ultron was originally created to be prison guards for one of these interdimensional supervillian prisons since human staff were impractical. You would be facing the same necessity. Not sure what you'd do about the sewage, though.

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    $\begingroup$ The only part of the answer that requires exact direct interation here is medical care. Discipline? Why? They are locked in, the chamber is pressurized so whatever they do inside can only harm them. Food? An air lock the size of a microwave can handle food issues. Toilet? Vacuum-based system would do perfectly, depressed on the other end. But since OP is talking about some kind of super-people, they usually don't require medical aid until killed, or at least injured to unconscious, the latter condition could even be maintained until putting them under pressure. $\endgroup$
    – Vesper
    Commented Oct 13, 2022 at 7:43
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    $\begingroup$ Presumably medical and service staff would be able to wear some sort of pressurised suit to avoid the need for compression and decompression. $\endgroup$
    – NotThatGuy
    Commented Oct 13, 2022 at 12:57
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    $\begingroup$ @NotThatGuy depressurized, unless you want them to stay under pressure all the time. Or pressurized and they stay in it all the time even when they're not giving medical care? Bonus: A suit that keeps loads of pressure in or out kinda inherently has to be rigid, since the pressure is going to push it to the extreme of its flexibility all the time. Try giving medical care inside a blown-up balloon. Doesn't work. $\endgroup$ Commented Oct 13, 2022 at 13:05
  • $\begingroup$ @NotThatGuy You can't make a mobile suit that can stand up to that much external pressure. Most medical care isn't going to be a problem, anyway--doctors do little that couldn't be done with a bit of instrumentation and a robotic manipulator. Dental care is actually going to be the bigger headache. $\endgroup$ Commented Oct 14, 2022 at 4:23
  • $\begingroup$ OP has neither posited solitary confinement for his prisoners, nor that their supernatural characteristics include immunity to illness. If prisoners are together, then disciplinary issues occur. $\endgroup$
    – FuzzyChef
    Commented Oct 14, 2022 at 18:05

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