You have no clue what you´re talking about. Make an explosion using a few kg of flour first, but NOT standing nearby.
Ezz is talking about a BIG amount here.
And if what you claim is true, then please explain how FAE bombs work since some of the fuels they use have roughly similar energy content and properties? And then explain why dust explosions are considered the same sort of explosion? And then why it would not be fatal when FAE is considered the most deadly weapons on a weight basis, only excepting nukes.
Yeah sure. Go ahead and use a hundred kg of flour to make an explosion from. I´m afraid i wont be attending your funeral though. Hell, try to get an optimal explosion from even just ONE kg of flour.
I have already admitted that I have only done small scale dust fires - however, I thought I was clear about the difference between an uncontained fire and an actual explosion?
You can get a very nasty explosion with quite small amounts of dust if you enclose it in something; then the shockwave can indeed have the effect you think is warranted on anything else within the container, or anything on the outside from schrapnel effects.
A fire, on the other hand, is not an explosion. If you use the +5 damage I suggested, the average person will be wounded, some lightly but most medium or heavy. Burns also carry a much higher rate of infection afterwards than stab wounds, so many people caught within such a fire will die without modern medical treatment or magical aid.
Please don't misconstrue what I wrote originally about fires vs explosions; and there is no need to use an unpleasant tone.
The thing is, even without confinement you re still getting positive feedback - the temperature and pressure of the burn front increases as it moves through the cloud so it burns faster and hotter and accelerates. It's not a detonation but it is an explosion and if it's big enough you will get effects like supersonic shockwaves and flash ignition and a fireball that can vapourise flesh.
You dont seem to know what you´re talking about in that regard. That was kinda the problem.
And a dust explosion is called explosion because it IS an explosion.
I was excessively nice relative to what degree of realism your claims had. I´ve MADE dust EXPLOSIONS myself, and i know damn well the difference between explosion and burning.
Want to see what a modern FAE bomb does? youtube.com/watch?v=GmRASCHJe2Q
Notice how the fireball barely touches the house and still completely obliterates it?
And i might add that the amount of fuel used isn´t too far from what Ezz was talking about here.
Except deployed with magic, it can be given an even greater area spread instead of spherical which means the blast wave is even stronger horisontally.
So the above vid is roughly what you could expect from the OP suggestion.
Those are completely open-air EXPLOSIONS. Flour, coal and sawdust react with explosions if ignited close to optimally. They burn if they´re ignited at sub-optimal conditions.
Watch the videos posted. Notice the very nasty explosions that are completely NOT enclosed and realise that you´re making claims not in accordance with reality.
Sometimes one can misunderstand someone else's point - in your first reply to my statements, Direwolf, (and I appreciate that I would struggle far more than you do when using another language) had you simply said that 'you won't get a fire, you'll get an actual explosion every time' (or words to that effect), I wouldn't have implied that you didn't know the difference between them yourself. [As a bit of a nit-picker myself, I could quibble about whether a bomb that is enclosed in a metal casing when dropped from a plane counts as an 'open-air explosion', but I won't. ]
So, sorry about that: You are correct about what happens when scaling this up.
I have done a little bit of further research youtube.com/watch?v=iIkk0D2tUU8 might be more relevant to everyone's understanding since it features actual flour. Even when the flour isn't dispersed, being tightly packed in sub-optimal conditions, it STILL causes a lot of damage - far more than I would have expected. It looks like we don't need to worry about getting the conditions exactly perfect...so, no finesse roll necessary?
Now, to get this back on topic, what level guidelines should we use for how much damage?
Hmm... in this video the explosion is caused by the firecracker, not by the flour. In fact, despite quite a bit of looking, I could not found one single video on the internet showing a flour bomb explosion. I've watched many attempts ... but the majority just think they got the explosion, and it's just either the firecracker used for ignition or a baloon container popping (a few smarter folks realize that they are simply not getting it).
Now, it seems pretty easy to get flour to burn -- say, just like alcohol would -- but no explosion. Also, the fires seem pretty tame -- they look impressive, but if you look closely very little around gets scorched or catches fire.
From all the failed attempts I've seen on the internet, I'm starting to believe that Direwolf's initial post was basically correct. Getting a "flashy" fire is fairly easy, getting an explosion is pretty hard unless you use a sealed container. However, it's not clear how things would scale up; the total energy of the explosion is proportional to the mass, and thus to the volume of the flour, while the surface over which the shockwave is distributed is only proportional to the square of the cubic root of said mass (and volume). So it may well be it's just an issue of critical mass: it certainly seems hard to get an explosion with a cup of flour, but maybe a few tons of flour in a big cloud could produce a very nasty boom. Still too little information.
I used to work at a plant that burned coal so we had to watch training videos on dust explosions.
The initial explosion caused by airborne dust isn't actually that dangerous by itself. It's called a primary dust explosion and it's fairly low pressure. A lot of times they just blow the roof off or a wall out, without hurting a thing inside the building. Of course collapsing walls and flying roofs are bad.
The real danger comes if the powder has accumulated on surfaces or in piles. If it has then the pressure wave will sweep it up and create a firestorm, this is called a secondary explosion. That's when the real fatalities happen.
I believe the flour and rocket engine bomb is more closely simulating a secondary explosion.
Please do your research better. A FAE bomb casing is discarded before the bomb explodes as by then it´s no longer relevant. The fuel in the casing is blasted into the air around it, that´s what makes the initial "cloud" part in the vid with the demolished house, the cloud is then ignited. There is nothing what so ever containing the fuel cloud, ergo it´s an open air explosion. If you tried igniting the fuel inside the casing, you simply cant make it explode because it lacks an oxidizer and has less than a billionth of the surface area needed to explode.
This is actually another bonus for FAE munitions, because the casing has no other strength requirements than being able to hold the fuel and other parts inside it until it´s expended.
And i might also add that the reason the fuel in FAE is such complex stuff is simply because the munition is very poor at causing optimal dispersion of the cloud, so fuel that is more lenient to poor dispersion is needed.
Magic has no such restrictions.
Yeah. Now, consider this, the vid above uses 3kg. I got almost the same explosion from using ~0.1kg at near optimal dispersion. I would guess 0.2kg should equal that explosion without problem. So at the very least they´re doing the boom at a 10-1 inefficiency because of the lousy dispersion.
Necessary to get full damage, or you end up with half or maybe just fire damage or something.
Ezz is talking several hundred kg of flour/dust so... Potentially, ridiculously much.
And this is where guidelines kinda break down and cry, because you only need to add a few Magnitudes for size to this to start looking at mushroom cloud level devastation. You actually start getting similar effects on a minor scale already with Ezz current spell. Fireball-shockwave-reverse shockwave... Everything but the radiation.
Anyway, for the sake of not blasting game balance into a complete wreck, starting out in the +30 damage area or thereabouts is probably a good idea. Or maybe +25 with a successful finesse roll and +10 without or something.
Ezz, as soon as you make something explode, it generally burns too fast to ignite most things.
While i agree that the explosion is clearly suboptimal, the resulting fireball IS an explosion and IS mostly caused by the flour. We dont know how big the firecracker used for dispersal is, but we DO know that black powder or anything else the rocket may have used does NOT cause a fireball style explosions of ANY kind.
What they´re doing is basically a lazy guys dust explosion, just enough dispersion to cause an explosion, but a very poor one.
Essentially yes. If you create enough fuel, even a poor explosion can be massively powerful.
Exactly, and that is because that´s what it´s supposed to look like. Or, optimally like in this case you skip past the primary explosion and replace it with something that causes better dispersed fuel because the primary will cause a cloud of fuel to end up with very uneven distribution.
DW... What I tried to explain is that game mechanics are only an abstraction and the same thing may be very, very different. It also isn't linear: Compare the damage of a man with the damage from a giant... It doesn't scale. 100 times the mass (+6 size) sometimes just means +12 damage (+12 str), for exemple.
To compare, a direct hit by full force lightning does +35 damage. Lava damage has been estimated, too (IIRC, something like +40, although I may be wrong). Do you really think a Dust floor explosion is, at the minimum, equivalent to having lightning strike the entirety of the area? Or having it dropped in a volcano?
Sometimes, an area of effect weapon will destroy buildings that are way more sturdy than any person, but there'll still be survivors. Because they'll be sent flying instead of enduring the brunt of the explosion, because they'll be too close to the ground... Like, at tchernobyl, people survived in places where buildings were flattened.
If you drop a FAE on a town (everyone takes +x damage), and if you have every single of its inhabitants take a bullet in the head (everyone takes +y damage), when will you have more deaths? I'd bet on the FAE leaving more survivors. Yet, no bullet ever dropped a building, so, by your reasonning, the FAE should do more damage, thus have way more deaths.
Similarly, a given earthquake will, say, do +20 damage to buildings. Will it really do +20 damage to every living thing in here?
=> Sometimes, just converting real-world knowledge, scaling damage up (especially linearly) and applying it to everything is not the solution, you have to work differently and simplify, and abstrate. And use narrative.
There's nothing wrong in saying "x will happen to buildings, y to people". IIRC, there are already spells with this kind of description.
After reading 4 pages discussing (mostly irrelevant) real world dust explosions (which I think I understand as very dangerous but rather tricky to get "right") I'm left wondering how the very different physics of Mythic Europe would influence this?
Would we get any vacuum that should be filled by lots of air suddenly rushing in?
Would we get a shock wave at all? (After all there is nothing keeping the wave moving after the momentary spell ends, and you need something to keep moving in ME...)
How does dust behave and disperse and ignite?
In My Saga I would solve this based on keeping it simple and consistent:
I would say that since it looks like a fire ball, burns like a fire ball, hurts like a fire ball, just scale it after Creo Ignem. Let it damage like an Ignem spell two magnitudes smaller, and give one freebie magnitude for the need of a suitable source of ignition. So make it like Creo Ignem, add one magnitude and require it to be ignited. The rest is cosmetic.
In reality, lightning strikes tends to leave a much greater part of victims alive than anyone at or close to ground zero in dust explosions.
Outside of whoever actually got hit by a lightning strike, people nearby might get shocked or got hearing damaged, or in a severe case get injured if they´re close. So, normally lightning only really goes "full force" against someone at ground zero, whoever is actually directly hit. So the only way you can make a valid direct comparison is with people who are inside the dust explosion. And unless it´s a tiny little thing, or they have ridiculously much luck, people inside that volume are dead.
Dont forget, what Ezz was talking about was a HUGE amount of fuel for the explosion. So much that it should probably create an explosion similar in power to that vid i posted, the one which makes splinters out of a house that isn´t even inside the explosion itself. At this kind of size of explosion, anyone within the explosion dies unless they´re 100% protected both from shock. If they´re somehow resistant to the dual shockwaves, they may very well survive the fire part, since it by itself isnt very damaging.
Putting someone into a volcano or placing it inside a huge explosion? Unless it has protection against the effect, it´s screwed either way.
Well yes, that is exactly why FAE munitions are oh so liked by military today. If used on an area, there are no survivors in the area of explosion unless they have hard cover. If a tank has a hatch open and a FAE detonates close enough to it, no more tank crew.
Surprisingly many people have survived a bullet through the head. Surviving inside the explosion of a FAE barely ever happens. I haven´t heard of ANY time it´s happened actually. And this is with FAE with just a few kg of fuel.
Oh i know that. It´s just that people keep gravely underestimating this kind of explosions. And again, dont forget that what i´m mainly talking about is the kind of scale which Ezz spell provides. A small or tiny dust explosion can leave plenty survivors if it´s not inside buildings. But as soon as you start looking at several kg of fuel, anyone actually inside the explosion is taking seriously massive damage. And Ezz spell is talking about hundreds of kg of fuel.
Personally if i had to choose, i would take getting hit by lightning anytime rather than stand in the middle of a big dust explosion. Survival chances are astronomically higher and the difference in permanent damage even if surviving both is like night and day.
Can we allow it to influence it at all? Even though serious ones very extremely rare, dust explosions were still a well known risk and anyone who had looked into it knew fairly well what happened even if they may not know the exact mechanics of it.
The shockwave is over before the spell ends anyway. A dust explosion is protracted compared to other explosions, it´s still an event that happens counted in milliseconds.
The shockwave part is also known at the time even if not so well explained or understood.
Like the above, when it happened it was also observed that there was a "reverse shockwave" as splinters from a mill could end up hundreds of meters away from the explosion, while others could be embedded into the ground towards the center of explosion.
Hmm... That makes it a bit odd since you must use another spell to create the fuel, He(flour, sawdust) or Te (coaldust), and as noted above, even if not understood, shockwaves were observed and noted.
I would say use whatever damagetype you would use against a character getting crushed, since that by far causes the greater part of the damage.
Also, it only really looks like a fireball if the spread is poor enough for it to burn more than explode.
Either way, it´s your game so i´m suggesting not ordering.
And a flour mill explosions can blow the roof of the a building without harming a single person inside. If there is no significant layer of dust to be picked up by the primary explosion their is no secondary explosion so no firestorm or vacuum. The pressure wave just isn't that strong by itself it more like a single gust of hurricane force wind. Faster burning more energy dense fuels like petroleum products or high nitrogen explosives are a different story. But, even primary coal dust explosions by themselves are not events likely to cause serious injury to people.
Modeling the difference in the game sounds rather complicated. Such is the problem with trying to apply to much real world physics to a game about magic.
Correction, if it never becomes a real explosion, just a primary burn, then the pressure wave is very weak. An optimally ignited explosion, then the pressure wave is extreme.
I'm not sure what you mean. Are you talking about the difference between deflagration and detonation? They are both explosions of a sort with a propagated pressure wave. If the pressure wave travels below the speed of sound it's a deflagration if it goes above it's a detonation. Most dust explosions are deflagrations whether primary or secondary explosions. The materials involved just don't burn that fast. Vapor explosions and some high explosives will detonate at optimum fuel to air mixtures, but flour will not. Don't confuse dust explosions with modern weaponized FAE's.
Additionally optimal fuel air mixtures change with ignition temps and air pressure. Your mixture can't be to fuel rich to ignite with an open flame or spark at standard atmospheric pressure. This limits the power of a primary explosion. A secondary explosion ignited by the heat and pressure wave of the first can be more fuel dense and therefore energy dense. Again as I have said before primary explosions blow doors open, send roofs flying, and maybe knock people around singeing their eyebrows. Secondary explosions create firestorms, blast out masonry walls, buckle concrete floors and kill lots of people.
Even at their most damaging dust fires must be contained in a tight space to be considered explosions. Check out this OSHA document. http://www.osha.gov/dts/shib/shib073105.html
So... When I create my own paramilitary group remind me to hire you all :mrgreen: Lots of people knowing quite a lot of things about explosives here. However, I find the whole discussion quite pointless for Mythic Europe. In Mythic Europe something that blows a house (mill, in this case) to pieces must cause some serious damage. Still "serious damage" is +10 to +20 to me, not +30. +30 is the realm of lava flows.
In that direction at least yes. The huge difference between getting something that burns very fast, which you get from poor dispersal of the fuel, and the very, VERY powerful explosion you get from optimal distribution.
I´ve created such explosions myself, yes it most certainly does. As i noted before in comment to a video posted of a forced flour bomb, i got almost same result from a dl of flour.
You seem to fail to understand that >99% of regular "dust explosions" happen DESPITE measures taken to avoid them, these are utterly lame wannabe´s compared to if you set up an optimised dust explosion.
Except they are actually the same thing. Modern FAE has to use more advanced fuel because dispersal cant be made perfect and for them you still WANT the explosion to happen. So, they need more volatile and selfdispersing fuel that will still ignite at poor fuel/oxygen and surface area ratios.
Both are created from having fuel mix with air in such a way as to maximise burn/surface area of the fuel and to provide the fuel with optimal amounts of oxygen without having any as part of the fuel mix.
And when you cause an optimal dust explosion, you essentially do BOTH at the same time. Which also speeds it up.
Hehe... Well, I probably do belong to the category of people which here are sometimes called MÖP, Militärt Överintresserad Person, ~roughly translated to a person unusually/excessively interested in military stuff. Not to be confused with "mupp", which comes from "Muppets show" and is basically someone very "far out" or makes stupid mistakes or manages to kill any sense of logic or common sense in a large radius on a regular basis... :mrgreen:
Anyway, that big amount of damage is simply because Ezzelino´s spell is talking about HUNDREDS of kg of fuel.
That´s why i posted the vid with the FAE bomb and the house, because you should get an effect similar to that one from Ez spell. And that´s pretty much utter annihilationlevel damage anywhere close to the effect.
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:mrgreen: Lots of people knowing quite a lot of things about explosives here. However, I find the whole discussion quite pointless for Mythic Europe. In Mythic Europe something that blows a house (mill, in this case) to pieces must cause some serious damage. Still "serious damage" is +10 to +20 to me, not +30. +30 is the realm of lava flows.