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Pretty self explanatory. I was wondering if this was ever talked about. Seems like they wouldn't want to dump their water reserves all over a damaged engine, do they use something else? Is it ever named?

I would imagine they just, yknow, close some bulkheads and open some airlocks and vent atmo (and crew) out into space so the fire doesn't have any oxygen to feed it.

chaos0xomega wrote:
I would imagine they just, yknow, close some bulkheads and open some airlocks and vent atmo (and crew) out into space so the fire doesn't have any oxygen to feed it.

Hmm, that certainly fits their MO, however, there is a great deal of ship that is not adjacent to vacuum and not easy to vent.

 Tawnis wrote:

chaos0xomega wrote:
I would imagine they just, yknow, close some bulkheads and open some airlocks and vent atmo (and crew) out into space so the fire doesn't have any oxygen to feed it.

Hmm, that certainly fits their MO, however, there is a great deal of ship that is not adjacent to vacuum and not easy to vent.

In the original BFG rulebook, there is one of these short story boxes. In it the crewmen are trying to start some sort of mobile firefighting pump to quell a deck fire, eventually they manage it with the help of a tech priest that has the right ritual and knows to hit the 'ON' button, and the engine starts to spit 'flame-retardant suffocating foam'. So i guess they use some sort of chemical mix.

Worth noting it may vary from ship to ship, let alone class to class, on account they’re repaired and refitted over the millenia.

So where one Luna Class might have foam, the next might have powder, the next might have water, the next might simply rely on vacuum. It may even vary deck to deck for much the same reasons.

Might also depend on where in the ship you are.

Areas close to the outer hull might be decompressed as the ship goes to action stations, to starve fires, while others might have some sort of suppression foam or a oxygen displacement gas for firefighting. their might also be multiple systems in a given compartment, be it a handheld system to allow the crew to put out small fires, a larger system that plugs into the ships main system for bigger ones, etc.

A lot of these systems would likely write off the crew in that compartment, but a lot of real life, in service-on-ships-now fire supression systems are fatal for the crew as well, so its not exactly a stretch to have a "Needs of the many" approach to this.

theirs also a element of crew discipline and design worked into this: its important that the crew keeps flammable material secured as much as possible, so as to limit the fuel sources a fire might have. things like crew beds, the paperwork, paints, oil and lubes, etc...all need to be stored properly, or at least should be. Given the normal depiction of 40k starships with candles everywhere and such, this might not always be the case.

Depending on the book you read, 40k ship crews can be generational - at least in part, potentially wholly, all living, procreating and dying aboard ship.

So for them, stuff like proper stowage is less a matter of discipline, and more one of upbringing and first nature, as they’ve never known anything different.

If i recall there is mention of fire suppression servitors. So essentially just a cyborg dude with a fire extinguisher.

cody.d. wrote:
If i recall there is mention of fire suppression servitors. So essentially just a cyborg dude with a fire extinguisher.

No no, the Servitor is the fire extinguisher. Gently drape it over the flames, and job is a good’un.


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I suppose there’s also the option to just seal a section, and reverse the air pumps. Even if there’s crew present, I’m guessing they can survive a short period without air longer than a blaze can?

 Mad Doc Grotsnik wrote:


I suppose there’s also the option to just seal a section, and reverse the air pumps. Even if there’s crew present, I’m guessing they can survive a short period without air longer than a blaze can?

Not really. The issue is not the oxygen per se, but both the speed at which you can get it out of the compartment (ie how fast your pumps are) and the fact you need it to be oxygen free for long enough for residual heat to die down (which takes longer in a vacuum, as well, given the lack of convection), or else as soon as oxygen is returned to get a flareup and your back to square one. so once you decompress the room (or dump a oxygen displacing gas like halon or novak into the room), even if the fire is out, you need to wait quite some time before letting oxygenated air back in.

I don;t know the exact effects of decompression on humans, but generally its bad, and without sufficent oxygen, humans are rendered incapable of coherent thought and action in a literal matter of seconds (like maybe 20-30 at most), and death is a matter of minutes. Obviously a void suit would negate that, but lets be honest, the Imperium barely gives most of the crew clothes, no way its given them all void suits.

Like i said, modern, built by western powers ships have fire supression systems that would kill anyone that was unable to escape the compartment. Crew losses are basically inevitable in a major fire, it really does become a "needs of the many" situation where you just have to seal the compartment and let loose the gas, then recover the bodies afterwards.

Yeah, I am pretty sure that Imperial ships will have few qualms about killing crew trapped in fire-stricken compartments. Void suits obviously exist for combat and maintenance purposes, but these are probably only issued to particular teams as required and almost certainly won't be available to the entire crew (especially the low ranking muscle). Damage control teams probably use them though.

Space Marine ships are high-end and mostly crewed by servitors. They are more likely to use equipment that provides fire protection to the crew I would think, so there may be more survivors within compartments.

Reducing oxygen content of the air would probably be the most effective way in an environment as controlled as a space ship. If the concentration drops below about 14% it gets hard for a lot of stuff to burn properly, reducing the heat feedback cycle. Benefit of this is that people are relatively unaffected. You could push it lower with increased effectiveness, but also an increased level of risk to occupants.

It wont work for everything, especially anything that has its own oxidiser present, but it would help prevent fire spread beyond the immediate vicinity of the oxidiser source. Also some materials are just really reactive, so again would burn quite happily in a lower oxygen atmosphere. Quite a lot of stuff might also keep smouldering, but that gives a lot more time to hunt down the fire compared to a happily raging spreading inferno.

It doesn’t tend to get deployed that much currently because you need a really effective seal to keep the atmospheric gas mix at the right level. Buildings are rarely that well sealed, and you need to burn a lot of energy or chemical feedstock to keep backfilling the room with something to displace the oxygen, or whatever clever reverse osmosis systems are used nowadays.




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Also, I’m pretty sure the imperium would be delighted to basically douse everything in that most wonderous of materials, asbestos

Some of the warships I work on have a Halon system that floods a compartment, cooling and suffocating the fire as well anyone who happens to be trapped inside...
Pretty sure that they're looking to replace it as it's an ozone killer and we don't like killing our own guys, but I don't think the Imperium is bothered by such trivialities...

On another note fire on a ship can escalate quickly and needs immediate and aggressive action to deal with, I would imagine any void ship would have a robust and probably automatic fire suppression system...

 Guardling wrote:
Some of the warships I work on have a Halon system that floods a compartment, cooling and suffocating the fire as well anyone who happens to be trapped inside...
Pretty sure that they're looking to replace it as it's an ozone killer and we don't like killing our own guys, but I don't think the Imperium is bothered by such trivialities...

On another note fire on a ship can escalate quickly and needs immediate and aggressive action to deal with, I would imagine any void ship would have a robust and probably automatic fire suppression system...

Fun fact: in germany many military installations and vehicles have halon systems too, but due to environmental laws they're only allowed to be used in actual emergencies, and not in training. So they exist and are supposed to be regularly maintained, but you can't run live drills with them, which is probably a disaster waiting to happen.

On the issue with the Imperium: in the series 'Priest of Mars', there's a huge accident onboard the protagonist's ship, which leads to the accidental firing of a Warlord-class Plasma Annihilator inside the titan holding bays. The ensuing runaway plasma fire causes almost-catastrophic damage on large parts of the ship, and is indeed only halted by venting a lot of the decks, sacrificing the crew in the process.