Fireball in a Sawmill, or Grain Silo


Advice

Grand Lodge

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Pathfinder Adventure Path, Rulebook Subscriber

Soooooooo, last night while running Rise of the Runelords a player decided that using a fireball in what would be traditionally a highly combustable environment was "a good idea."

I made up something on the fly that felt right, and while it didn't immediately kill anyone, the subsequent slow burning building, with fight going on inside claimed two lives (okay so the confusion spell helped as well.)

Just wondering how others would have ruled the equivalent of a spark in a grain silo? How much damage would you roll?


BOOM!!!

GM rolls a D20, informs group they have [result of D20] rounds to escape before collapse makes escape impossible and burning to death imminent.

Everyone inside the environment takes 1D6 fire damage per turn after the initial explosion. The initial explosion deals 2D6 nonlethal bludgeoning damage, Reflex save for half.

Or that's how I would handle it, at least.


In Return to the Temple of Elemental Evil (3.5), the Mill (area 28) in Hommlet had this this note:

28. Mill wrote:

Fire!

If a fire of significant size (more than a torch flame) starts in the mill, a cumulative 20% chance exists per round the fire burns (01–20 on d% the first round, then 01–40 the second, and so on) that the flour dust in the air ignites. This results in a huge explosion that deals 2d4 damage to everyone in the mill (no saving throw allowed). Damage to the building itself in such an event is significant—it burns to the ground eventually unless action is taken. Extinguishing the fire requires at least three people working with buckets for 10 minutes (luckily, the buckets are close to the river).

Naturally, it is taking about a constant fire that is left ignited, but I believe anything that would ignite a significant portion of flour dust (such as fireball) all at once is implied to just flat out trigger an explosion. (Since anything bigger than a torch left burning is pretty much guaranteed to do it within 30 seconds.)

The 2d4 fire damage (no save) isn't a lot of damage, but they make it clear that the fire rapidly combusts the flour dust throughout the whole area doing widespread damage and starting a fire.
Obviously, different size mills might be different, but I figured I would reference this anyway, not as any official ruling, but merely something you can use to make your own call.


I would treat it as a hazard with it's damage determined by the challenge rating (which you would need to decide).

One example is:

Quote:

Deadly Gas (Desert, Marsh)

In a marsh, pockets of flammable gas can build up under the surface before violently erupting, throwing rocks, mud, and debris in all directions with startling force. In a desert, toxic fumes from a natural vent, old mine, or magical disaster might leak into the air, poisoning or mutating nearby creatures.

In a marsh, PCs can attempt a DC 15 Perception check to notice the smell and swelling before it erupts. The eruption deals 2d6 points of bludgeoning damage in a 20-foot radius, or 4d6 points of fire damage if the area contains open flame.

In a desert, PCs can attempt a DC 15 Perception check to notice the fumes and get out of their path before coming to harm. Otherwise, they must succeed at a DC 15 Fortitude save or take 1d4 points of Constitution damage and be nauseated for 10 minutes.

I thought there was a CR chart with recommended saves and damage for hazards, but I can't find it.

Maybe someone else can chime in with that info.


I'd make everyone in the area need to save vs. the effect that caused the fire (they all take the Fireball damage, or Reflex for half). From there, borrowing from the hot environment rules, they'd need to make increasingly higher Fort saves every X rounds or take nonlethal damage from the residual heat. As they fail saves, they might start taking on conditions to reflect the lingering oxygen burning away, leaving them with less and less air to breath (maybe Fatigued, then Staggered, then Nauseated, then Disabled, then Unconscious). Meanwhile, I could place a few pockets of spreading infernos, having them expand an additional 5' each round. Starting your turn in, or moving through an inferno would deal Z fire damage. After the inferno had spread far enough, I could start randomly rolling for sections of the ceiling to start falling (or if they're not on the ground floor, for sections of floor to collapse). Reflex saves to move out of the area of falling material or take damage, and maybe be pinned. That's when the cage of angry bears breaks open and And that's how I'd run a scenario where someone sets off a Fireball in a sawmill.

I believe Giantslayer had an encounter where you needed to save people from a burning building (including needing to make saves or passing out from the heat/lack of oxygen), but I don't think it included calculating initial damage from a blanketed explosion.


There is a scenario that has this type of hazard and the danger of fire sources. But I cannot remember which one.


If I hadn't done anything to call attention to the dangers of fire in the area, and no one had picked up on it, I wouldn't add anything. I'm not fond of 'gotcha' GMing, and this isn't necessarily something a player, even on versed in the rules is necessarily going to expect. The game doesn't have any built in dust explosion rules after all. Of course causing the area to begin burning is a different thing than causing an explosion and that would be perfectly fair in any event.

If I wanted it to be a hazard I'd have made sure to mention it in some way and built rules based on how hazardous I wanted it to be. Several of the examples above are fine, even though different, depending on what you felt would be appropriate for your game and the situation.


Well looking at the aftermath of different dust explosions I'd think they do quite a bit of damage you want something vaguely realistic. I don't think it's any more 'gotcha' than if your players are standing in a big puddle of oil throwing fire around. Of course if its something you allow to happen in your games your players will use it e.g. minor creation for flour (or just buy it) gust of wind and a fireball and that evil baron's keep is coming down/apart.


Pathfinder Maps Subscriber

Depends on the oil. I know a fire fighting instructor who likes to stand in a pan of diesel fuel and drop lit matches to freak out newbie students. Then later (when he's NOT standing in it) he lights it.


I have three things to say that will hopefully help on the decision you make:

1. Fireball has this little nugget at the end of it's spell description:
"The fireball sets fire to combustibles and damages objects in the area. It can melt metals with low melting points, such as lead, gold, copper, silver, and bronze. If the damage caused to an interposing barrier shatters or breaks through it, the fireball may continue beyond the barrier if the area permits; otherwise it stops at the barrier just as any other spell effect does."
Emphasis mine. Depending on what is above the PC's, this will heavily influence the way I'd rule the effects. If the ceiling is within the blast radius (20ft or less high) and does enough damage, things might start falling on them/into the room. If that is several tons of corn or whatever, you might go into the natural hazzard/buried alive rules. Alternatively, if it is "just" some furniture, I'd roll a % miss chance to see where it lands and apply falling damage to the PC.

2. I believe Skull and Shackles added the note that fireball can start fires on ships (which are obviously made of wood more often than not in this game). I'd see if you can find out what that AP said about starting fires and see if that helps.

3. Including environmental effects to fireball (IME this is commonly ignored, but the spell certainly includes rules for it) can set a dangerous precedent. If your PC casts it regularly, I would evaluate the extra effects it would cause in every environment you prepare for as the GM. Then make sure your rulings are as consistent as possible and make sure that the PC's are aware of your thought process moving forward with regards to the spell and the environment. This may alter the game dramatically depending on the environments the AP puts the PC's through.


Pizza Lord wrote:

In Return to the Temple of Elemental Evil (3.5), the Mill (area 28) in Hommlet had this this note:

28. Mill wrote:

Fire!

If a fire of significant size (more than a torch flame) starts in the mill, a cumulative 20% chance exists per round the fire burns (01–20 on d% the first round, then 01–40 the second, and so on) that the flour dust in the air ignites. This results in a huge explosion that deals 2d4 damage to everyone in the mill (no saving throw allowed). Damage to the building itself in such an event is significant—it burns to the ground eventually unless action is taken. Extinguishing the fire requires at least three people working with buckets for 10 minutes (luckily, the buckets are close to the river).

You cannot put out a burning building by throwing pails of water at it. -- It's one of the worst tropes ever. (Do your part to end this trope by never letting this work as a GM.)

If any part of building reaches "flash over", the entire thing is history unless you have magic, or high-tech fire-fighting equipment. The fire will build in intensity until it is literally too hot to be anywhere near, let alone have a remote chance of putting out with pathetically puny pail amounts.

And your god will not help you if it's windy.

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