Gunpowder Barrel damage?

[Emperor Valerian]

How much damage would an explosion of a barrel of gunpowder inflict on characters? Say, an 80 pound barrel? 1d6 per ten pounds? Would it be incremented by distance away from the explosion?

I asking because my players have had bad luck with fire recently, and there's a chance in the next session things could go kaboom.

 

[andargor]

From the Modern SRD, 1 pound of dynamite explodes in a 5 ft. radius for 2d6 concussion damage. Reflex DC 15 for half.

Andargor

 

[andargor]

More details about greater quantities:

Dynamite
Perhaps one of the most common and straightforward explosives, dynamite is very stable under normal conditions. A stick of dynamite requires a fuse or detonator to set it off. Additional sticks can be set off at the same time if they are within the burst radius of the first stick, increasing the damage and burst radius of the explosion. Each additional stick increases the damage by +1d6 (maximum 10d6) and the burst radius by 5 feet (maximum 20 feet).
It’s possible to wire together several sticks of dynamite for even greater explosive effect. Doing so requires a Demolitions check (DC 10 + 1 per stick). If the character succeeds on the check, the damage or the burst radius of the explosion increases by 50% (the character’s choice).
Dynamite is sold in boxes of 12 sticks. It is considered to be a simple explosive for the purpose of using a Craft (chemical) check to manufacture it.
To set off dynamite using a fuse, the fuse must first be lit, requiring a move action (and a lighter or other source of flame). The amount of time until the dynamite explodes depends on the length of the fuse—a fuse can be cut short enough for the dynamite to detonate in the same round (allowing it to be used much like a grenade), or long enough to take several minutes to detonate. Cutting the fuse to the appropriate length requires a move action.

Andargor

 

[Macbrea]

So given that bit of information and the information on traps:



Fireball Trap: CR 5; magic device; touch trigger; automatic reset; spell effect (fireball, 8th-level wizard, 8d6 fire, DC 14 Reflex save half damage); Search DC 28; Disable Device DC 28. Cost: 12,000 gp, 960 XP.



So...


Exploding barrel trap: CR 5; Mechanical Device, Special Trigger; Delay 1d3-1 rounds; No reset; Elemental Effect (8d6 fire, 10ft radius), DC 15 reflex save for half damage, Search DC 28, Disable device DC 28. Can result from rolling a 1 on a cannon.

 

[Emperor Valerian]

Hmm... that sounds okay. The reason why I'm asking is that next session the players are going to be storming a ship whose hold is filled with gunpowder. I don't think the party cleric will be tossing around fire magic, but if the ship does catch alight, I wanted something concrete I could point to. (Yes, you did jump in the water, but you're still x feet away from the ship, so there's some problems for you.)

 

[Macbrea]

8d6 fire damage isn't too far out of line for an explosion in DnD. To give you an idea of amount of heat damage that can be taken from a source we will take a quick look at lava.

Lava or magma deals 2d6 points of damage per round of exposure, except in the case of total immersion (such as when a character falls into the crater of an active volcano), which deals 20d6 points of damage per round.

I would assume alot of the explosive force will be pushing the people away from it. The detonation of a ship with 8d6 damage to everyone will kill most npcs outright. The players will be thrown into the sea. Yes, this does allow the rogue to possibly survive without a scratch, but remember this is pretty much a story about heros. Not people easily killed by small items.

 

[andargor]

Well, gunpowder in barrels is probably less effective than dynamite, so you could cut the equivalent quantity by half (I think).

So 80 pounds of gunpowder = 40 pounds of dynamite. That's a lot...

But what you could do is say that it is in fact a chain reaction of multiple explosions. So, if they are in the water, some explosions on the far side of the ship wouldn't reach them. The dynamite text indicates that 12d6 is the max (for 11 sticks, 2d6 + (min(10d6,1d6/stick))), so you could have a bunch of 20 ft. radius explosions (or 30 ft. if you take the "sticks tied together" approach).

Depending on the level of the characters, you could have only one or several bursts affect them. There doesn't seem to be guidelines for damage dropping off with range: you get hit or not.

Andargor