Ah, the gravity's failed, has it? If gravs are off, you've got more going on than a compartment fire. You've lost power to that system, and there may be additional issues related to whatever caused that failure. Nonetheless, the possibility of higher order emergencies should not keep you from implementing reasonable measures to address lower order emergencies.
Shipboard safety and security
- Thread starter Spartan159
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Ah, the gravity's failed, has it? If gravs are off, you've got more going on than a compartment fire. You've lost power to that system, and there may be additional issues related to whatever caused that failure. Nonetheless, the possibility of higher order emergencies should not keep you from implementing reasonable measures to address lower order emergencies.
So we have ... a big pipe branching to smaller pipes to cover a number of compartments ... and it has a vacuum inside. Sounds like the kind of thing that could be a real headache if it takes damage in battle.
Enoki
SOC-14 1K
It's not that easy. Let's say you have a compartment with 40.5 cubic meters (a stateroom roughly) filled with 1 atmosphere of pressure gas. You are trying to evacuate that to vacuum using a, say 10cm diameter pipe of x length. If this is part of system that dumps into a larger pipe, the pressure will fall the instant the larger pipe is reached and the flow rate will slow.
It's going to take a while to do that, particularly once the pressure gets close to the vacuum. That means you now have to add pump(s) to the system. Big pumps.
Overall, this is going to be a complex piping system costing (in Traveller terms likely tens of thousands of extra credits to the cost of the ship.
It will also be of marginal effectiveness as you'd have to plan ahead on evacuating a compartment for it to work. It could well take the better part of an hour to pump down a large space like a cargo bay.
Gases don't act like liquids. A closed liquid system has constant pressure on the whole system. Gases in an open system like you propose will vary in pressure.
All this for a very complex, added, system that rarely gets used.
Only if the flame front is moving through a burnable mixture of fuel and oxidizer or if there's a draft. Otherwise, you get brief flares until either conduction or radiation transfers the heat...
So went the experiments on the ISS...
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I said repeatedly that it does NOT take it to vacuum, the valves shut off when a manually set pressure is reached. And the master shut off valve is your backup in the case of battle damage breaches the piping system, Military ships however typically pump down prior to entering a planned battle, unplanned ones however...
I just had a chat with a retired submarine man about fire fighting aboard a sub and they DO vent the compartment either overboard or to the ballast tanks. Also they shut down the ventilation systems and yes the temp in the sub rises very quickly to what was described as astronomical levels.
Shutting down the gravity plates would be one of the measures taken to reduce the flow of oxygen into the fire, That's why I said the gravity was off in one of my previous replies. It's not that the gravity system is not working it's that you turned it off to fight the fire.
Shutting down the gravity plates would be one of the measures taken to reduce the flow of oxygen into the fire, That's why I said the gravity was off in one of my previous replies. It's not that the gravity system is not working it's that you turned it off to fight the fire.
Does a rapid depressurization have a cooling effect?
In most but not all gas mixtures...
Atmosphere-6 in this case. :coffeesip:
I'm still not seeing the point. Reducing pressure I understand, since that would tend to reduce the likelihood of smoke spreading through, say, damaged bulkheads, not to mention preventing pressure from heated gasses causing more damage, but that could be accomplished with some modification of the existing ventilation system, and it would only take a moderate reduction in pressure.
What was their stated purpose in venting?
How does zero g affect O2 levels? Smoke won't rise - is that smothering the fire? I'd still avoid that option unless I was pretty certain there was no hope of rescuing occupants - conventional measures should still be sufficient. On the other hand, a merchantman's priorities and challenges may not be the same as a warship's.
Condottiere
SOC-14 5K
Certain sections may have blow out panels, though that's essentially the same as opening up the airlock.
Enoki
SOC-14 1K
It really would make little difference compared to the fire being contained by the bulkheads. If the compartment was airtight then the available oxygen for the fire would be quickly consumed and the fire would extinguish itself for the most part. This would also contain the smoke from the fire, often a bigger problem than the fire itself.
But, the smoke can be cleared with portable equipment and ducting that would be far cheaper and more compact than a complex system of permanently installed piping / ducting.
As for "pump(ing) down prior to a battle, I see little or no reason to do it. The only weapon that can do internal damage to a ship without penetrating the hull first is a meson gun. Everything else puts a big hole in the hull, so compartments hit or damaged will automatically vent to space.
With a meson gun the damage is going to be primarily on the molecular and atomic level. A fire isn't going to be a normal result. Instead the huge burst of radiation embrittles the area hit and irradiates stuff.
So, taking the ship to a vacuum doesn't seem very necessary.
I gathered that Bad Things happen to soft squishy sophonts when there is a sudden pressure imbalance, such as when a laser pokes a hole in the compartment and it's not already depressurized.
Enoki
SOC-14 1K
Only if you weren't already in a pressure suit or vac suit. Then its sort of a meh thing...
After all, we can see what happens when an aircraft depressurizes at altitude. They even did that on Mythbusters.
https://www.youtube.com/watch?v=4yG2h1aDB6k
After all, the differential pressure would only be 15 psi at most, and possibly less.
And if he comes in with dead passengers and the rest telling horror stories about passengers abandoned to their fate, he's likely to have problems finding new passengers. Unlike the warship, the merchantman has to weigh risks against profits, and word of mouth can make or break him.
Not to mention, I take it that as limited as Imperial law seems to be, the captain of a merchant is responsible for passengers under his care. This goes along with the assumption that there are standards and some kind of certification involved with promotions in the merchant service.
A captain who comes in with dead passengers is going to need to answer to an investigation. He may end up not being a captain anymore. He may spend the rest of his life running a cheap Startown dive, with SOC 4....
If your compartment is already in vacuum and it takes a hit you will not have any problems like sudden gusts of wind slamming you onto sharp pointy torn bulkheads. Shock waves are not conducted by vacuum so you do not have overpressure injuries. Yes a 250 MW laser pulse will cause explosions, but there is not an explosion like an explosive filled shell produces, it's more like what happens when a squish round hits, a bunch of armor bits fly away from the inner surface. (The KE to do this comes from the laser vaporizing some amount of armor from the surface.)
