Question for firefighters

Iggmoe · Jul 17, 2007

Hi! I'm currently writing a scene where several characters are trapped on board a ship (it's actually a crashed spaceship, but for all intents and purposes we should treat it as a maritime vessel, except for the fact that it's airtight . . . and is sitting on the ground).

My scenario is this:
-- There are several fires on board in unseen locations, generating a tremendous amount of smoke.

-- Everyone is equipped with self-contained breathing gear, so smoke inhalation would not be a problem.

-- The characters may abandon the ship if everything gets terribly out of hand, but it is their intent to stay on board and try to save the ship if they can.

My question is:
Is it feasible to leave all the hatches closed in the hope that since the vessel is (presumably) airtight, the lack of oxygen would eventually starve the fires? Or will heat eventually kill the crew before this happens?

What would you do if you were in this situation? Would you blow the hatches anyway just in case you really do need to abandon ship? (Since the ship is sitting on the ground in an earthlike atmosphere, vacuum would not come into play, but blowing the hatches might give the fires more oxygen to feed on.)

Any and all input, comments, and thoughts appreciated even if you're not a firefighter!

Vanatru · Jul 18, 2007

I"m not a firefighter, nor do I play one on TV..........but I wouldn't just let the fires burn themselves out. They might have the ability to cause damage till they run out of fuel or flammable items and structually weaken the vessel.

Is there a way to expunge/force out the air from within the ship? If so, I'd do that.

Of course, in true Hollywood fashion, the characters would have to fight there way through the burning sections to the one tiny little value situated way on the other side.

Iggmoe · Jul 18, 2007

My first draft had them blowing the hatches anyway and flooding the compartments with Halon or something. Unless someone has another professional opinion, I think by the time the fires smother themselves out, a lot of critical damage would have already been done.

. . . or I could be wrong. Still waiting to hear any other thoughts!

jclarkdawe · Jul 18, 2007

I was a firefighter, but who you're really looking for is someone in damage control in either the Navy or Coast Guard. Fighting a fire in an enclosed environment like a ship or spaceship is very specialized. That being said, here's how I'd go about it.

1. Self-contained breathing apparatus is time limited. Depending on the design, the most you're going to get is about one hour. Realistically I'd be planning on 15 to 30 minutes, depending upon design.

2. I'd seal all internal hatches to prevent fire spread, but this was probably done prior to the crash.

3. First priority would be removal of injured and non-essential personal.

4. Next priority is assessment of in what compartments is there a fire (sensors would show this ideally, otherwise, someone goes around feeling doors -- if they're hot, there is probably a fire on the other side). This would begin to tell me where the problems are. Until you can find it, you can't put it out.

5. Next priority would be assessing the ventilation system. Can the compartments that are on fire be isolated?

6. Next priority would be determining what resources I have available. Can the compartments be flooded? What do I have for equipment? For a spaceship, water would probably not be used, but what chemical extinguishers are available?

7. Next priority would be venting non-fire compartments to remove smoke.

Remember that the damage control officer would have thought all of this through beforehand and have battle plans already prepared.

At the point, depending on everything I discovered would be how I'd plan on dealing with the situation. This entire assessment would be fast. For a structure fire, I'd have it planned out from the time the building came into sight (calling extra alarms) to a walk around the building. Five minutes max.

Leaving the fires going until they burn out depends on a bunch of variables. Major concern I'd have with that on a spaceship is losing structural strength in the steel (heat is what caused the collapse of the World Trade Centers).

If you need more information, please feel free to PM me.

Jim Clark-Dawe

Mr. Fix · Jul 18, 2007

Where there's smoke, someones on break...

I am not a firefighter, but I grew up in a fire family (Dad & Bro were/are FF) and I did pick up a few things.

I think Jclarkdawe has some excellent point to use. But a simple answer may be;

If you open a hatch you are feeding the fire with fresh O2 - think explosive backdraft. So keeping the hatches closed is the best option. if the heat gets too great, then the occupants will have no choice but to blow the hatches and escape.

P.S. I joined the Army and learned how to start fires, not put them out, just in case anyone was wondering.

Iggmoe · Jul 18, 2007

Thanks, everybody, for all the input!

Jim, you've raised excellent points. That definitely sounds like what my characters ought to be doing, and I'll be sure to do some more research now that I have a rough idea where to start looking. Thanks!

jclarkdawe · Jul 19, 2007

Additional thoughts on fighting a fire on a spaceship:

1. I'm not sure any sci-fi writer has really dealt with the issue. I'm wondering if NASA has any thoughts on this. However, I'm not sure anyone has come up with a multiple compartment spaceship yet.

2. The Navy's approach involves lots of water. Obviously, not an approach for a spaceship. To give you an example, to open a compartment such as Mr. Fix describes would involve ventilation (if possible) and a water curtain. I can't imagine how you'd do it on a spaceship. I don't know if you can get the same type of protection from extinguishers that you get from a water curtain.

3. Spaceships involve a lot of electrical fixtures. As well as putting out the fire, you want to minimize damage. Using a lot of chemicals has the potential of causing short-circuits. If you put out a fire, but spray a lot of chemicals around which screws up all your electronics, you're just as screwed as if you let the fire keep burning.

4. I'd think about pumping in carbon dioxide gas into the compartment. The other possibility is dumping the compartment to space, and creating a vacuum. My problem with dumping the compartment is I'm not sure what consequences (i.e., problems) a vacuum would create. And obviously, that wouldn't work in your situation.

5. Damage control officer would have thought this all through before hand. Problem for a damage control officer is when things go wrong. For example, he goes to pump in carbon dioxide and the pump doesn't work.

Best of luck,

Jim Clark-Dawe

Pike · Jul 19, 2007

Hey gang.

I just saw this thread and thought I'd add a few ideas. I'm not a fire fighter but work as the fire and disaster coordinator for the senior comminity I work for. There have been some excellent points brought up but there might be others, such as:

Are any of the electronics on fire? If they still have power going to them they'll continue to burn often after they've been doused. The power provides fuel to the fire.

What damage has the ship taken? You may have already written in an automated fire suppresion system and ventilation ducts that seal up as well but how much damage have they sustained.

Also, is there any haul breaches? That would screw up most systems and ops from sustaining and preventing continued damage.

You mentioned Halon and for the life of me, I can't recall if it does damage to electrical systems or not. I thought I heard that somewhere but could be wrong.

Hope my input adds fuel to your fire.

Pike

Plot Device · Jul 19, 2007

I believe in the TV show Battlestar Galactica, they vent the afflicted compartments out into the vacuum of space to suffocated the fire.

And I also believe the Navy has very rigid protocols for how to handle fires onboard submerged submarines. One of the dangers I have been told about in a submarine fire is that oxygen is technically a flamable gas. What we breathe every day is NOT pure oxygen but a mix of oxygen and nitrogen, more heavilly skewed toward nitrogen. But on a sub, it's compressed oxygen, and very dangerous.

I recently saw a submarine movie on the Sci-Fi channel where one whole compartment suffered a flash fire. The whole room was engulfed in flame and everyone inside was killed instantly. When the rescue crew opened the door, the fire was already out and every surface area in the room was eerilly scorched and charred completely black. Many human bodies lay around, stiff and black and singed down to their skeletons.

jclarkdawe · Jul 19, 2007

Plot Device said:
I believe in the TV show Battlestar Galactica, they vent the afflicted compartments out into the vacuum of space to suffocated the fire.

And I also believe the Navy has very rigid protocols for how to handle fires onboard submerged submarines. One of the dangers I have been told about in a submarine fire is that oxygen is technically a flamable gas. What we breathe every day is NOT pure oxygen but a mix of oxygen and nitrogen, more heavilly skewed toward nitrogen. But on a sub, it's compressed oxygen, and very dangerous.

I recently saw a submarine movie on the Sci-Fi channel where one whole compartment suffered a flash fire. The whole room was engulfed in flame and everyone inside was killed instantly. When the rescue crew opened the door, the fire was already out and every surface area in the room was eerilly scorched and charred completely black. Many human bodies lay around, stiff and black and singed down to their skeletons.

I should have mentioned throwing the circuit breakers. One of the first things the damage control officer would do is pull the power.

Oxygen is not "technically" highly flammable, it is. In it's compressed state, it is very dangerous to handle, and is essentially explosive.

The sci-fi movie situation has happened on spacecraft. Before the Apollo program launched the first one, NASA had a flash fire in the capsule. At the time, NASA was using an oxygen rich environment. One spark, and that's all she wrote.

Flashovers happen in lots of fires. Basically, the fire gets going, uses up all of the available oxygen, and then smolders. Air gets really hot (over 1,000 degrees F.). Suddenly a window breaks/melts from the heat, allowing air (with oxygen) into this superheated environment. Fire burns very quickly through the entire area from all the superheated carbon molocules floating in the air. Can scorch the entire house in seconds, then go out. Very strange to see the first couple of times.

Jim Clark-Dawe

Iggmoe · Jul 19, 2007

Thanks for all your suggestions!

Jim and Plot, you bring up an excellent point about compressed oxygen. A spaceship will almost certainly have lots and lots of it, especially if it remains underway for months at a time, which means having a fire on board is actually a much more dangerous situation than I first thought . . . it's actually really scary. Unless, of course, the oxygen is generated from inert materials like the electrolysis of water or something (hmmm, I'll have to look into how this is currently done on the ISS).

Here's the slightly more detailed scenario I've envisoned so far:
1.) Immediately after the crash, almost all power to the ship is cut off because the generator room suffers a great amount of damage. The fire starts in the generator room, which seems like a logical place for a fire to start.

2.) I've read on the internet that Halon 1301 is a gaseous suppression agent commonly used on aircraft because it doesn't leave any residue that damages electronics. It's commonly found in portable firefighting systems and also on automated systems that flood a compartment when fire is detected. However, it's very damaging to the Ozone layer and by law the manufacturing of Halon has been stopped since 1998. But there are still plenty of reserves that people who currently use Halon can use to recharge their systems. In my WIP, the ship is equipped with a Halon release system. And as Pike brought up, it doesn't work because some of the pipes have ruptured during the crash, and the gas doesn't spread throughout the ship.

3.) The first officer orders all internal hatches to be closed immediately after the crash, but half of them don't respond, and the crew has to scour the ship and close them manually.

4.) I'm thinking, due to an act of plot, the Halon system is eventually fixed and they flood the ship. After waiting for to ensure the risk of flashover is minimized, they open the external hatches to vent the smoke. Any idea how long they should wait before opening the external hatches?

Of course, carbon dioxide seems like an alternative to Halon, especially if I can't justify how a spaceship is still using a substance phased out in 1998, or I can invent some alternative chemical. And if I really wanted to ratchet up the tension . . . I can have the fire creep towards several compressed oxygen tanks

.

Iggmoe · Jul 19, 2007

(removed a strange double post)

jclarkdawe · Jul 20, 2007

Iggmoe said:
Thanks for all your suggestions!

Jim and Plot, you bring up an excellent point about compressed oxygen. A spaceship will almost certainly have lots and lots of it, especially if it remains underway for months at a time, which means having a fire on board is actually a much more dangerous situation than I first thought . . . it's actually really scary. Unless, of course, the oxygen is generated from inert materials like the electrolysis of water or something (hmmm, I'll have to look into how this is currently done on the ISS).

I hadn't been thinking about the O2 tank. Arthur Clark used this in a couple of his stories from way back when. I don't know anything about how oxygen is generated.

Here's the slightly more detailed scenario I've envisoned so far:
1.) Immediately after the crash, almost all power to the ship is cut off because the generator room suffers a great amount of damage. The fire starts in the generator room, which seems like a logical place for a fire to start. Generator dying will not kill power. You'd have power from batteries. My guess also is that rather than a generator, spaceships would use solar power, but I don't know. Power would be killed through the circuit barriers.

2.) I've read on the internet that Halon 1301 is a gaseous suppression agent commonly used on aircraft because it doesn't leave any residue that damages electronics. It's commonly found in portable firefighting systems and also on automated systems that flood a compartment when fire is detected. However, it's very damaging to the Ozone layer and by law the manufacturing of Halon has been stopped since 1998. But there are still plenty of reserves that people who currently use Halon can use to recharge their systems. In my WIP, the ship is equipped with a Halon release system. And as Pike brought up, it doesn't work because some of the pipes have ruptured during the crash, and the gas doesn't spread throughout the ship. I don't know what aircraft use for fire suppression. I'd check at your nearest airport. They'll know.

3.) The first officer orders all internal hatches to be closed immediately after the crash, but half of them don't respond, and the crew has to scour the ship and close them manually. Even when it does work, you check manually.

4.) I'm thinking, due to an act of plot, the Halon system is eventually fixed and they flood the ship. After waiting for to ensure the risk of flashover is minimized, they open the external hatches to vent the smoke. Any idea how long they should wait before opening the external hatches? Flashover potential is checked real easily. You take your glove off, put the back of your hand (never the palm) against the door knob (metal conducts heat). If it's hot, you don't open it. In the movie, Backdraft, you see them doing this during the apartment house fire. And you see what happens when a probie fails to do that. As soon as you get some handle on what's going on, you're going to want to get the injured as far away as possible. Definitely would be evacuating injured within five minutes.

Question is whether rescue is available. Can I risk the spacecraft or is it impossible to replace. That determines priorities. Normally saving life is the highest priority, but if the spacecraft is your only way out, then saving it might be higher.

Of course, carbon dioxide seems like an alternative to Halon, especially if I can't justify how a spaceship is still using a substance phased out in 1998, or I can invent some alternative chemical. And if I really wanted to ratchet up the tension . . . I can have the fire creep towards several compressed oxygen tanks . Been done before. I also believe it would be liquefied oxygen, commonly referred to as LOX (if my memory is at all correct).

Best of luck,

Jim Clark-Dawe

jclarkdawe · Jul 20, 2007

You might want to take a look at A Fall of Moondust by Arthur Clarke. Story is about a surface craft on the Moon that is buried in moon dust, which causes short circuits, which cause a fire, which eventually result in the LOX tanks blowing. Dated probably because it's about 50 years old, but might give you some ideas.

Jim Clark-Dawe

Iggmoe · Jul 20, 2007

Thanks for your suggestions. I think I'll go the circuit-breaker route, just like you said -- it definitely makes the crew seem more competent to anticipate the possibility of a fire and make attempts to prevent one from breaking out, even though it eventually happens anyway. And they'll be feeling hatches before they open them, to prevent flashover. Thanks!

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