"The Teens' PCs set fire to the dungeon!" Topic

Teen Library D&D:
They are looking through a large bin of coal, when attacked by giant beetles living in the bin. The wizard ignites a fflask of oil and tosses it in the bin. The coal, of course, catches fire. They flee the room, leaving it burning.

So, now what? The chamber is very large 30'x100', all stone, but has wooden doors about 40' from the coal bin. The chamber is open on one end to another large area, so the room has ventilation, meaning the oxygen won't run out, though there's no real draw source, especially into the bin. The coal is absolutely pure; anthracite wishes it could be this pure. Say there's about 500 lbs in the bin, somewhat loosely stored.
I know coal burns at around 3500 F. The stone is granite. Aside from the doors, there's nothing else flammable in the room. An ore cart made of iron is located about 80' from the bin.

How long would the coal likely burn? With a limited draw, would it burn itself out quickly, or would the whole pile go up? What will happen to the doors and the ore cart, if anything? What about the granite?

Right now the PCs are in another part of the dungeon, well away from the fire (good for them), but what will they find when they get back? Would the chamber be safe to even re-enter?

The smoke, at least, flows into a very large chamber with high vaulted ceilings (about 20') with shafts that allow the smoke/CO to escape the dungeon.

Wait… Would pure coal produce visible smoke?

With the luck my characters had, if I were playing, the coal would burn long enough and hot enough to block any escape via that room when the Big Bad starts chasing the party down…

If you want to know about coal fires check this out.
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Fortunately, it's not a coal mine. It's just a big stone-walled bin filled with coal.

Wouldn't it rather quickly start filling the air with Carbon monoxide? No matter the purity, when burned Coal, which after all is carbon, will produce a rather deadly gas. It's just me but I think that would be more deadly than the fire. Assuming you are going for realism that is.

First of all this is D&D which is fantasy adventure, not a science adventure RPG. The coal behaves exactly the way you say and not any other way.

(If you make it science-based then you have to argue with the players about what the effects of setting coal on fire are, and there are more of them than of you so one of them will have better facts than you and you'll look like a jerk making wrong rulings and retracting them.)

Decide what lesson should be taught then dictate circumstances accordingly. Dice rolls only for direct player action.

If the players should feel impunity to start large fires and leave them burning, then nothing happens except when they come back in the future it will be all burned out and black. And you'll all joke about it. And it will happen again.

If you feel that is irresponsible behavior then the non-chaotic and/or non-evil characters should be suffering whatever conscience twinges are appropriate, and possibly checking to change alignment.

If you want to burn up the coal and be done with it and just have a token effect on the players so they remember actions have consequences, then have the air start to get sucked out of the dungeon and make them crawl out to the entrance on their hands and knees coughing. Be sure to have plausible reasons why the dungeon doesn't de-populate, or on all their future dungeon delves they'll bring a couple carts of coal.

All in all, CL, that was not particularly helpful and came across as rather condescending. But perhaps that was not your intent. In any case, I am not one of those who believes that "it's fantasy, anything can happen." While yes, one can imagine anything, nevertheless if one wishes to create a believable and consistent fantasy world, one should try for a level of underlying realism as well as a consistent approach to those workings that are fantastic in nature. Coal is not fantastic in nature, and personally I think a realistic result of the fire would actually add to the overall story experience. I asked here about coal fires because I've found TMP to be an eclectic group with a broad knowledge and experience base who might be able to help me craft a realistic result to the situation described. If you have such knowledge, I would be happy to receive it.

Back to the question at hand:

So far, I've discovered that coal burns at roughly 3500 deg F, and granite melts at around 2200 deg F.
The bin itself is a simply a 9' x 10' niche dug into granite, with other (empty) niches dug in on either side, with granite walls 1' thick between them.
So is it seem reasonable to assume that the floor, walls and potentially ceiling (about 7' high, and thus about 4' above the fire) might begin to crack and flow at some point, with the resulting slag covering the coal? That would cut off oxygen and smother the fire, I would think, but the heat would still take some time to cool. I think a cave-in in the immediate vicinity also makes sense. This, too, should quench the fire. The tremor would probably also be felt and heard throughout the complex (which would be a great freak-out moment for the group).
Thoughts?

Well, I think CL made you come up with your own, reasonable, plan for how to handle it. It is impossible to convey feelings with simple text, so I can't say what CL's intent was. I do, however, feel he was pretty much spot on with his suggestions, at least, until you countered with the melting point of granite…

Regardless, I agree with your ideas, Parzival. The granite, surrounding the burning coal, would, in fact, melt. The idea of it causing a partial cave-in, really satisfies my evil desire, as a DM myself, to let the Players know that there are consequences to their actions. I say go with what you just outlined: the granite melts partially, there is a partial cave-in, and let the Players hear, and feel, the unintended results of their actions. This will surely make them think twice about it.

I like the tie-in to realism: that the coal fire would burn hot enough to melt granite rock. This will re-inforce the notion that science has its applications in fantasy, just as it does in the real-world. The oxygen depletion idea, is not bad, either. There are consequence to their actions. If they get away with doing stupid things in the game, which might kill them in real life, I feel you have done a terrible dis-service to these young people. Let them apply science to your fantasy realm, and let it happen as it should/would, in the real-world. This will encourage them to pursue science, to learn how they can create their own "magic" in the game, using science. Cheers!

I've been consulting others on this, and the science is not so disastrous. 3500 is for a "forced-air furnace" situation, which this is not.. At most it appears the coal would reach around 2000 deg F, and even then only really at the core of the fire, not so much the edge. Granite, despite the melting point, is very effective at diffusing heat, so it wouldn't wouldn't melt in this situation. Now, CO or CO2 poisoning is the hazard, though I suspect my dungeon layout and stated ventilation actually resolves this risk considerably, if not completely.
Perhaps the idea of cracking stone and a partial cave-in still works, but that might be stretching things, rather than actual realism.
Realism might actually be that it burns itself out due to the lack of effective oxygen flow into the bin (there's no effective flue).

At least the party did have to flee, and two had smoke inhalation problems. So they did realize that tossing burning oil on a flammable area is a bad idea…

I apologize for any animosity. I was trying to offer practical advice on running a game. Clearly I failed abysmally since you took my advice to be "it's fantasy, anything can happen".

At least the party did have to flee, and two had smoke inhalation problems. So they did realize that tossing burning oil on a flammable area is a bad idea.

This is actually quite similar to something I suggested, but worth all the more since you came to it on your own. Nice work.

Yeah, I started DMing over thirty years ago. True, it's been a decade or so since I last ran one, but I'm also a scriptwriter and novelist, so I know a teensy bit about plotting and dramatic twists, however weak I am on chemistry and thermodynamics. There was no way I wasn't gonna have *something* bad happen after that burning oil move!
(Just like when a PC strolled into a room without looking up, after I described the place as having "cobwebs hanging from the ceiling like banners." Time for spider surprise… ).

I do think I will go with the cave-in. I'll let things continue on for a bit, let them deal with a few localized surprises, and then, crack, rumble and shake… "What was that?" Oughta be fun.

Smoke tends to draw monsters, unless they have animal intelligence in which case the natural reaction is to flee. Intelligent monsters (if present) usually want to locate what is burning and asses the situation (I.E does this fire pose a threat to the clan, family group, me etc.). If intelligent enough, they're going to want to find out who started the large fire and do something about their pyromaniac tendencies before they destroy the monsters' lair. Just something to think about if you haven't already.

When they return to the room have them discover that the fire destroyed some valuable treasure/magic items that had been hidden in the bottom of the coal bin. They will think twice about doing something like that in the future.

Oh, it did. They just don't know it yet.

What? No comatose "Burning Coal Golem" waiting to be revivified by a nice, hot fire? Which then goes in search of the beings who disturbed its comfy nap.