How do different modes of fire/acid damage stack and how they should by your opinion?

[jpreem]

I got myself thinking on alchemist fire acid and other such stuff. By RAW they seem to be just weapons that to an x amount of x energy damage on hit. ( secondary damage later on for some). But how many wials of alchemist fire in same round could you chuck on somebody for new damage still to come. There should be some limit - you know when someone is fully covered in burning stuff it shouldnt matter for a damage in round if taht someone is covered even more - the burning might last longer for sure.
Same question about lamp oil. Or standing in a binfire :D
I guess that alchemist fire vials are quite small so i coudl imagine that you could chuck a small number of them in a round and still do damage.

[KillianHawkeye]

For reference, total immersion in acid deals 10d6 damage per round. Total immersion in lava deals 20d6 damage per round. I suppose anybody taking less than that amount of damage isn't completely covered.

[panaikhan]

For alchemical stuff, I would run with the 10D6 max.
Lava is a special case I think - not only is is hot, it is heavy - to be immersed would imply pressure as well as heat (unless lava is hotter than alchemical fire)

[jpreem]

For reference, total immersion in acid deals 10d6 damage per round. Total immersion in lava deals 20d6 damage per round. I suppose anybody taking less than that amount of damage isn't completely covered.

Thats a good idea to put it. 10d6 sounds reasonable. It means you can throw ~ 10-12 alchemist fires or acids per round on someone before that someone is fully covered. 10-12 attacks of this kind is more than enough for most parties (where everybody is not build for making crazy iteractive attacks with thrown weapons :D)and it will keep away stuff like - "I'lll drop my portable hole full of alchemist fire on BBEG for over 9000 damage."