Question about container mass damage

[samduke]

okay so we had a RL 5E group and an artificer with the ability to turn container item into a bag of holding - by raw it seems that it counts as a bag of holding for al reasonable purposes.

for this purpose the artificer uses a common backpack 2 gp

bag of holding roughly 2 feet in diameter at the mouth and 4 feet deep or about 8 cu ft

next our intrepid artificer goes and fills this bag with lantern oil which has the rule if lit causes a flat 5 fire damge per flask a flask is 1 pint

8 pints to the gallon - 8 Oil (flask) 8 sp

7.48 >60<gallons per cu ft >479 pints < at 5 points fire per flask = 2,394 fire damage

for the low price of about 50 gp

now the conversation at hand
That's not how something covered in oil works.
Each thing covered in oil takes 5/round.
Fully covered maybe 10/round
So all you be doing is covering a large area with all of the oil. It would burn, not blow up

Question for you the playgrounders - is either correct and how would you rule this?

[Crgaston]

The second position is correct. Not an explosive. Oil needs oxygen to burn, so only the surface directly exposed to the air would burn if you lit the oil while it was still in the backpack.

Now, if you could figure out some way to vaporize the oil...

[samduke]

The second position is correct. Not an explosive. Oil needs oxygen to burn, so only the surface directly exposed to the air would burn if you lit the oil while it was still in the backpack.

Now, if you could figure out some way to vaporize the oil...

toss a burning match into said bag of holding and catapult - maybe a bit like the spell fireball at that point purhapes

[Mr Adventurer]

Things from the same source explicitly don't stack so it doesn't matter how much burning oil is on you, it's always 5 damage?

[samduke]

Things from the same source explicitly don't stack so it doesn't matter how much burning oil is on you, it's always 5 damage?

can you reference book and page where this is stated.

[JNAProductions]

I'd rather not bring real-world physics into this.

Instead, I'd ask for an Intelligence check (with proficiency if your PC has a background as an engineer or something like that) with the following results:

10-...........You don't get anything really usable, just a big ol' container of oil.
11-18.......You can get a minor explosion going, dealing 3d6 damage in a 10' radius. Dex save of DC 13 to halve the damage.
19-25.......You get a decent explosive, dealing 6d6 in a 20' radius. Dex save of DC 16 to halve the damage.
26+..........You get something even better than a Fireball, 30' radius and 10d6 damage. DC 19 to halve the damage.

Of course, acquiring that much oil is difficult. I'd also charge a small surcharge (something along the vein of 5-10 GP) for a containment mechanism to move it properly, unless you wanted to just leave it as a landmine or something.

Finally, any of the explosions will wreck the bag. You'll need to re-enchant a new container with Holding.

[samduke]

yes the artificer would need to buy a new backpack and send time to re-enchant it.. and real world physics aside, in a vain effort to find rules on the subject of multiple oils stack the"party" could not find any - thus the question to mr answer for a book and page stating Things from the same source explicitly don't stack - as that only applies to bonuses like enhancement, luck, sacred, profane - ect... nothing there about flat damage fire

[JNAProductions]

yes the artificer would need to buy a new backpack and send time to re-enchant it.. and real world physics aside, in a vain effort to find rules on the subject of multiple oils stack the"party" could not find any - thus the question to mr answer for a book and page stating Things from the same source explicitly don't stack - as that only applies to bonuses like enhancement, luck, sacred, profane - ect... nothing there about flat damage fire

That’s a 3.5 rule you’re referencing. Profane, luck, competence... not 5E things.

Effects from the same source don’t stack, and (dis)advantage doesn’t stack. That’s about it.

Moreover, even if the RAW is that you deal 2,000+ damage, what your DM rules is far more important.

[Samayu]

I agree that the damage is flat. But that fire is going to spread really far! Now depending on what other things catch on fire, damage may increase over time. Being inside a burning building, for example, will deal much more damage.

[Joe the Rat]

Parallel to a dynamite and daggers proposal, if you are trying to set the whole pack off, and somehow manage get all the oil going, how long would it take for that oil to burn a "rupture," and spill the goods into astral space?

[furby076]

In what section of DMG or PHB is the stacking rule labeled? If it's magic section id say it doesn't apply since oil is not magic. Also, id say stacking rules don't apply because we shouldn't be thinking about this as some ## of individual flasks of oil, but think of it as one massive flask (keg) of oil.

So, what would a keg of oil do? I agree on the surface contact issue, so you wouldn't get thousands of point of damage. That amount of oil would cause a huge spill, so it would be a large radius. So, I would say:
5 ft radius of impact take the most amount of damage (they are fully coated in oil) and are burning for 1d4+1 rounds. Someone (other than person on fire) must help put out the fire for 2 rounds, or the burning victim must be doused with water
5 ft radius of first group gets rushed with oil (knee high) so half as much damage and are burning for 2 rounds. 1 Action can be spent to put out the fire
10 ft radius of second group take 2x normal oil flask damage and follow normal oil flask fire rules

Considering what it needs to set this up (buy backpack, all of the oil, enchant the bag), then light the bag on fire and hurl it at targets. A fireball spell is much easier to cast and is free.