"I melt the door with my breath"

[Ranting Fool]

One of my players is a half dragon and often says things along the lines of "I could just melt through the door with my breath" (which there are rolls for since I can work out how much damage he does to the door it's easy) but he also says stuff like "I take time to char the bodies and turn them into ash" so now I need to figure out (Hopefully with the help of someone a little bored and a lot smarter then me) exactly how HOT a half dragons breath is and how much damage it would do to a corpse/how long to turn it into ash.:smallbiggrin:

[HighWater]

Question 1:
Are you sure it really matters? If not, Rule of Cool (err Hot).


from this link (http://science.howstuffworks.com/cremation1.htm)(at 593 degrees Celcius):

An average human body takes from two to three hours to burn completely and will produce an average of 3 to 9 pounds (1.4 to 4.1 kilograms) of ash.


Lower temperatures will take longer (obviously). The above applies to full cremation...

[Ranting Fool]

:smallbiggrin: Thanks, a few hours is nice and vague. He was telling me how it should only quick it should be and my response was "Have you ever tried to cook a turkey, it takes HOURS :smalltongue:"

[Bronk]

Well, first of all... did this half dragon take all the relevant feats so that it can use its breath weapon more than once per day?

After that, treat all your dead turkeys as objects, give them some hit points and whatever relevant hardness you want, and he can damage it all he wants, remembering that fire only does one half damage to objects, and that half is further reduced by hardness.

So, maybe a regular turkey would have 2 hp to kill it, but its body as a whole might have 10 or 20 representing a pile of tasty meat (leather has 5 hp per inch of thickness and 2 hardness for comparison).

Perhaps a half dragon turkey would have some some of that leathery hardness added in as well...

[Abd al-Azrad]

You could certainly char organic material pretty quickly, yes. But to my knowledge, people tend to die from a combination of shock and oxygen deprivation when trapped in a fire. Being reduced to a pile of ash takes an awful lot more than just killing someone.

I was going to link the cremation info, but HighWater already did so.

[nedz]

Allowing him to do it quickly would cheapen a certain sixth level spell — which can do this in a round.

[Segev]

The biggest decision you have to make is whether you wish to fluff it such that he can use his breath weapon so freely. This isn't just a matter of "he's breaking the rules;" it's possible that he can use lesser versions of his breath weapon to cosmetic or even minor real effect that is not generally spelled out in the mechanics of the game, but can only pull off the full-on damaging cone 1/day.

What do you want to allow him to do, and will it either give him an inordinate advantage compared to what other PCs can do at this ECL, or step on other PCs' toes? (Specifically, other PCs in the party, not hypothetical other PCs that might possibly join the party in the future.)

[Psyren]

Allowing him to do it quickly would cheapen a certain sixth level spell — which can do this in a round.

Assuming you mean disintegrate, that's not a direct comparison though - disintegrate literally transmutes you into ashes/powder, rather than cooking you. If he had disintegrating breath (similar to Bahamut's) it would do the same thing.

[Bronk]

Allowing him to do it quickly would cheapen a certain sixth level spell — which can do this in a round.

Disintegrate? I think that would just leave a bit of dust...

I think that in the case of the door from the original post melting would make sense thematically, but the only rules I can find about damaging an object say that once it gets down to zero HP, it is 'destroyed'. It also says that it can no longer be fixed with the relevant craft skill, for a metal door that would mean... what? Some of the metal vaporized and there isn't enough left in the puddle on the floor to make a new one?

Maybe you could say that he just melted it enough to get through, but not super cleanly like disintegrate would have done. If they ask, the metal was a cool alloy or pure iron or whatnot, but now the leftovers are a terrible mess mixed in with sand other crud that could burn them if they touch it.

[Telonius]

From Wikipedia's article on crematories (http://en.wikipedia.org/wiki/Crematory):


A human body usually contains a negative caloric value, meaning that energy is required to combust it. This is a result of the high water content; all water must be vaporized which requires a very large amount of thermal energy.

A 68 kg (150 lbs) body which contains 65% water will require 100 MJ of thermal energy before any combustion will take place. 100 MJ is approximately equivalent to 32 m3 (105 ft3) of natural gas, or 3 liters of fuel oil (0.8 US gallons). Additional energy is necessary to make up for the heat capacity ("preheating") of the furnace, fuel burned for emissions control, and heat losses through the insulation and in the flue gases.

As a result, cremators are most often heated by burners fueled by natural gas. LPG (propane/butane) or fuel oil may be used where natural gas is not available. These burners can range in power from 150 kW (0.5 MMBTU/h) to over 400 kW (1.5 MMBTU/h).

...

The time to carry out a cremation can vary from 70 minutes to approximately 200 minutes. Cremators used to run on timers (some still do) and one would have to determine the weight of the body therefore calculating how long the body has to be cremated for and set the timers accordingly. Other types of cremators merely have a start and a stop function for the cremation, displayed on the user interface. The end of the cremation must be judged by the operator who in turn stops the cremation process.

A recent XKCD what-if (http://what-if.xkcd.com/115/) may be relevant to your interests.

[aleucard]

Disintegrate? I think that would just leave a bit of dust...

I think that in the case of the door from the original post melting would make sense thematically, but the only rules I can find about damaging an object say that once it gets down to zero HP, it is 'destroyed'. It also says that it can no longer be fixed with the relevant craft skill, for a metal door that would mean... what? Some of the metal vaporized and there isn't enough left in the puddle on the floor to make a new one?

I interpret Destroyed in this context to mean that the original object was trashed so badly that you're not so much repairing it as making a new one with some spare parts and raw/worked material strewn about.

On the subject of turning corpses into clouds of ash, using object rules sounds about right. If they're newly dead, take the normal HP of an average member of that race at that age (ignoring class levels, or treating them as rolls of 1), add 10, add whatever DR and Resistances/Immunities they had, and ad-lib what total destruction means from the damage dealt. If they've been out for long enough to get rigor mortis, add Hardness 5 or so and treat as an object, with no other changes (DR counts as hardness that stacks). If the corpse sat long enough to start rotting, remove the Hardness and DR (since rigor mortis no longer applies), and add 1 damage/day or so from it.

[Troacctid]

Fire does 1/4 damage to most objects, so he probably can't melt through a door.

[Twilightwyrm]

:smallbiggrin: Thanks, a few hours is nice and vague. He was telling me how it should only quick it should be and my response was "Have you ever tried to cook a turkey, it takes HOURS :smalltongue:"

That's because ovens in general are not designed as incinerators. The flames from a Half-Dragon's breath are going to be more hotter than the temperature inside an oven. A flamethrower (assuming we take the DMG Flamer as an equivalent weapon) ejects flames burning at 2,200 F (1,200 C). If we were to apply the pseudoscience of D&D equivalency for a moment*, the Flamer deals 3d6 (average 11 damage) damage for a roughly equal time of exposure as a breath weapon, so given the breath weapon deals 6d8 (average 27) damage, we can imagine that said breath weapon is reaching temperatures of 5400-5864 F (2982-3240 C). So that
The question is, is he trying to reduce these things to ash/a pool of molten slag on the floor, or is he just trying to char the remains/melt a hole in some door? (Why you have so many metal doors is another matter) If the former, then yes, it could take an hour or more (more due to the difficulty in reducing bone to ash than anything else) of sustained fire. If the former, it would be more like 5-10 minutes for the body. I'm unsure for the door.

*Do not attempt to extrapolate based upon this. Not taking into account sticky nature of flamethrower fuel, different consistency of flamethrower flame vs. breath weapon flame, etc.

[aleucard]

Fire does 1/4 damage to most objects, so he probably can't melt through a door.

Given enough time, as long as he is able to do at least 1 HP damage in a single hit, he will melt it eventually. It's just a matter of figuring out how many shots would be needed.

[Troacctid]

Given enough time, as long as he is able to do at least 1 HP damage in a single hit, he will melt it eventually. It's just a matter of figuring out how many shots would be needed.

Well, iron has a hardness of 10, so he'd have to roll 44 damage to knock down 1 of its HP. With a standard half-dragon 6d8 breath weapon, it's technically possible to do as much as 2 damage to it...once per day...if you roll the maximum possible damage. A commoner with 8 strength and a greataxe could bash through it faster than that.

Edit: Unless it's a wooden door, in which case fire should ignore its hardness and do full damage. But in that case it's more "burning down" than "melting through."

[Baroknik]

That's because ovens in general are not designed as incinerators. The flames from a Half-Dragon's breath are going to be more hotter than the temperature inside an oven. A flamethrower (assuming we take the DMG Flamer as an equivalent weapon) ejects flames burning at 2,200 F (1,200 C). If we were to apply the pseudoscience of D&D equivalency for a moment*, the Flamer deals 3d6 (average 11 damage) damage for a roughly equal time of exposure as a breath weapon, so given the breath weapon deals 6d8 (average 27) damage, we can imagine that said breath weapon is reaching temperatures of 5400-5864 F (2982-3240 C). So that
The question is, is he trying to reduce these things to ash/a pool of molten slag on the floor, or is he just trying to char the remains/melt a hole in some door? (Why you have so many metal doors is another matter) If the former, then yes, it could take an hour or more (more due to the difficulty in reducing bone to ash than anything else) of sustained fire. If the former, it would be more like 5-10 minutes for the body. I'm unsure for the door.

*Do not attempt to extrapolate based upon this. Not taking into account sticky nature of flamethrower fuel, different consistency of flamethrower flame vs. breath weapon flame, etc.

Under that theory, a fireball gives off 5x as much heat (about 7.4k Kelvin) as a flamer in an instantaneous amount of time and still does 0 damage to any object even with the explosive decompression that would follow.

Also, when I did the math, the breath weapon was around 3.6k Kelvin using average dice rolls.

Edit: as a reference, the surface if the sun is about 5.8k Kelvin and is hot enough to atomize pretty much anything passing through it. Heat doesn't work the same in D&D or else fireball would be a more effective disintegration than disinintegrate.

[Feint's End]

Don't mesh physics and d&d ... never a good idea.

In general I think your half dragon won't be able to melt through a door or burn a body to Ashes. He has a 1/day breath weapon which doesn't do enough damage to do either of those.

Of course you can always apply the rule of cool but from a logical point of view it makes no sense (well ... as far as somebody can say logical in this context).

[dascarletm]

Probably best not to use a linear scale of damage to temperature if you want to go down that road.

[Fax Celestis]

Under that theory, a fireball gives off 5x as much heat (about 7.4k Kelvin) as a flamer in an instantaneous amount of time and still does 0 damage to any object even with the explosive decompression that would follow.

...why do you think fireball doesn't damage objects?


A fireball spell is an explosion of flame that detonates with a low roar and deals 1d6 points of fire damage per caster level (maximum 10d6) to every creature within the area. Unattended objects also take this damage. The explosion creates almost no pressure.

You point your finger and determine the range (distance and height) at which the fireball is to burst. A glowing, pea-sized bead streaks from the pointing digit and, unless it impacts upon a material body or solid barrier prior to attaining the prescribed range, blossoms into the fireball at that point. (An early impact results in an early detonation.) If you attempt to send the bead through a narrow passage, such as through an arrow slit, you must “hit” the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.

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.

Melting points:
Gold: 1948F
Lead: 621.5F
Copper: 1984F
Silver: 1763F
Bronze: 1742F

It's pretty safe to assume that fireball's1 heat is ~2000F (~1093C, ~1366K). Wooden objects are combustibles, so if you fireball a wooden door, it's going to catch on fire and take an additional d6 per round until someone puts it out. A wooden door is Hardness 5, 10-20HP (http://www.d20srd.org/srd/exploration.htm) (depending on quality), so being lit on fire (http://www.d20srd.org/srd/environment.htm#catchingOnFire) will deal it ((1d6)/2)-5, or no damage ever.2

1A donation has been made to the Society for the Preservation of Catgirls in apology for this post.
2To the Dysfunctions thread!

[Greenish]

Fire ignoring a wooden object's hardness probably falls under "Vulnerability to Certain Attacks".

[Bronk]

ooden objects are combustibles, so if you fireball a wooden door, it's going to catch on fire and take an additional d6 per round until someone puts it out. A wooden door is Hardness 5, 10-20HP (http://www.d20srd.org/srd/exploration.htm) (depending on quality), so being lit on fire (http://www.d20srd.org/srd/environment.htm#catchingOnFire) will deal it ((1d6)/2)-5, or no damage ever.2


Hah! Why would anyone ever put up torches in dungeons if you could just light all your doors on fire? That's great!

Wait... so every torch is an everburning torch as long as the wood it's made of is one inch thick! That does explain torches in dungeons!