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Axe
I'm a bit iffy on how much dammage explosives can do. I have a runner who is an insane ex-militayr type (ex as in killed 2 officers and escaped to another country) who has a seperate lifestyle just to store his CXII. Last session we left off with him planning to blow up a medium sized apartment building (!!) and I was wondering just how much explosives he will need.
Luke Hardison
IMO, taking down buildings and things are best handled in roleplaying, especially if he's damaging a building and not dealing damage to individuals or vehicles. Make up a 'base amount' of C12 (I'd say 16kg per floor is a good starting place) and have him roll Demolitions. Divide the base amount by the number of successes to see how much it actually takes him. Alternately, make him split his successes between base time and base compound amount.
Herald of Verjigorm
Make him find each and every major support. Make him set up enough explosives on each one to knock it down. Make sure he is told repeatedly that if the explosions go off in the wrong sequence, there will be a 5 in 6 chance of it falling in his direction. Make him roll demolitions for each support.

For each support he will need a sum of damage code and successes (on a demo test vs. 2) equal to no less than triple the barrier rating of the support. (well, that should reduce the barrier rating by 4, which I think would be enough to let gravity do the rest)

If you choose to use the "1 meter hole" basis to determine if the support breaks, he'll only need to surpass the barrier rating on each support.
Johnson
Imploding or exploding. There are two different techniques. Someone with demolitions would blow up any thing, but to take down a building there are many factor to put into consideration.

He could go down to the lower basements and plant enough C12 to blow up the supporting pillars.

This would be a lengthy process.
Here is a good site to peruse


http://www.controlled-demolition.com/
Backgammon
Once again, a nice "HELLO" at the folks of Homeland Security biggrin.gif
Chance359
Do you think they even pay attention anymore?
Austere Emancipator
They have to. Otherwise we might start talking about stuff like how the president is car-bombed or how to kill the most people with 30 rounds with an AK and they wouldn't know to elevate the Nationwide Threat Level.
hobgoblin
personaly the only problem with explosives (as in the nongrenade type) is the rule that all explosives should work against double the barrier rateing.

while this makes sense for grenades and so on that are mostly shrapnel i think that for the commersial to c-12 stuff that rule should have a special disregard. atleast then one stick put on the surface of a glass panel can have a chance of breaking it.

but i just recalled that i belive i watched something over on discovery when someone did put some explosives (think it may have been det cord) onto a sheet of some material or other and detonated it. the surface mostly didnt get a scratch as it was easyer for the force to travel out into the air then try to get thru the surface. but afterwards he but a bag filled with water on top of the explosive stuff and again detonated and that time the surface was penetrated. something about the water deflecting the force of the explosive towards the sheet rather then letting it escape into the air around.
Austere Emancipator
QUOTE (hobgoblin)
atleast then one stick put on the surface of a glass panel can have a chance of breaking it.

Yup, this is a great place to start fixing SR explosives. The next would be the weird Blast ratings, but that was beaten to death here less than 2 weeks ago, and has been discussed so many times before it's probably better to let anyone interested just read those threads.

Then you could introduce some way to make Demolitions significant with larger amounts of explosives, or any amount of powerful explosives. Like adding 25% (or 20%, or 10%) to the Power of the explosive charge per success on the Demolitions test instead of +1 Power. Then you could make the lower-end explosives more powerful, so that the difference between "Commercial", C-4 and C-12 is less than the utterly ridiculous quadruple progression (IRL, C-4 is about 1.2-1.3 x as powerful as TNT).

Then, your explosive rules would be pretty dang sweet, far more realistic, far more believable, and simpler to boot.

Directing the blast, as with stacking any heavy crap on top of the explosive to blast through something on the other side, does make a huge difference in effect. This is why the Demolitions check must remain key to penetrating thick and hard stuff with small amounts of explosives.
Herald of Verjigorm
QUOTE (hobgoblin)
personaly the only problem with explosives (as in the nongrenade type) is the rule that all explosives should work against double the barrier rateing.

page 119, the double barrier rating is evaded by setting up the explosives specifically to damage the wall and you get to add successes on a TN 2 demolitions test to the power of the explosive.
Austere Emancipator
The point being that someone without Demolitions skill, or without the inclination to use it, won't manage to break a standard window pane with a full kilogram of TNT -- only slightly damage it. Without Demolitions, you need ~1.8kg of TNT to break through a window. I think you'll agree that's not very reasonable.
Herald of Verjigorm
No, because to set up the kg you would need to roll intelligence against a 6. If you fail to get any successes, you blow up, if you get a single success, it shatters the glass.
Mr. Woodchuck
remember comercial explosives are only fully effective in a 1m radius, and degrade power from there. so if you want to take down an entire building you will need explosive on most of the support colums as each colum will be to far away to to be hit with charges from other colums. Also the demolitions skill will alow the player to set the charges, but architecture, structural engineering, or electronics checks may have to be made to plan out the removal of an entie building with minimal time and equiptment. Have your player start with the basic you can blow up 1m of building per success on all of your checks, base time 1hour. Even if yor player has 10dice to demolitions it will cost him a whole load of time and money to demolish a building.
Austere Emancipator
QUOTE (Herald of Verjigorm)
No, because to set up the kg you would need to roll intelligence against a 6. If you fail to get any successes, you blow up, if you get a single success, it shatters the glass.


Bob: INT 3 character with no Demolitions skill. Let's give Bob 1kg of TNT with attached blasting cap and fuse set up and ready (rules-wise, attached Timer with a particular time, 30 seconds, already set) -- all it takes is to place the explosive and light the fuse/press the button.

If Bob wants to use this TNT to break open a window during a run, would you force the player to roll his 3 INT dice, making the TNT blow up in his face if he doesn't get a single 6?

The rules in question are quite explicit about using Demolitions to place the explosive being optional. They go "If a character uses Demolitions Skill to place explosive charges, [blah blah]". Always requiring the Demolitions roll is very much a house rule, and a rather silly one at that. Most human beings, even if they've never handled explosives before, given such a ready-made explosive charge would be capable of placing it on a window sill, or taping it right on the window pane, and lighting the fuse/pressing a button.

In my games, the majority of explosives use is of this exact type: characters with little or no Demolitions skill use explosive charges which have been set up in advance (complete "bombs"). IRL, that sort of thing is nearly impossible to fuck up -- you're as likely to shoot yourself accidentally.
RangerJoe
In making a complete "bomb" device, someone (PC, NPC, whatever) has used a demolitions or a demolitions B/R skill. If Bob were to try and make a "bomb" of his own, I would require him to roll those 3 int dice, and learn the hard way that you should read a book/get military training/surf the net before attempting to use explosives.
GrinderTheTroll
Don't have the SR3 handy atm, but there are 3 specific page references to Demolitions about 1) Damage, 2) Blast radius and 3) The skill, IIRC.

I'll update this thread once I get a hold of my BBB.
Austere Emancipator
QUOTE (RangerJoe)
In making a complete "bomb" device, someone (PC, NPC, whatever) has used a demolitions or a demolitions B/R skill. If Bob were to try and make a "bomb" of his own, I would require him to roll those 3 int dice, and learn the hard way that you should read a book/get military training/surf the net before attempting to use explosives.

Yeah, you absolutely should have at least Demolitions-1 before building a bomb (though fucking that up can be pretty hard, too, as long as you're not trying to make it hard to defuse and aren't going for any delicate stuff). But the Demolitions (no Demo B/R) test performed when creating the device doesn't count when considering the effects of the explosion, only the successes from the "placement" test do.

The latter test is optional, and currently makes it almost really damn hard for people without the Demolitions skill to use explosive charges to get anything done.

Apart from the no-Demolitions skill characters, there's also collateral damage that could really use a no-doubled-BR-vs-explosives rule. Canonically, if you're blowing up a wall 1 meter away from a window, you can do it with 7kg of TNT without breaking the glass. You could use 18kg of TNT to crack a safe embedded in a normal concrete wall in a house without risking a hole in the wall. Etc etc.
Axe
Thanks for the input guys. This is gonna be a lot harder than he thought it would be biggrin.gif
Johnson
Well 18 KG of any explosive is a little excessive to take out a strong room door.

But there again the are different ratings of strong room doors. and 18kg of any explosive use wrong would not help.

Going back to the Building story and with what is mentioned about the explosive.

In order to get an explosive to work well you have to get the explosive in to a controlled enviroment.

packing TNT around a supporting structure and detonating it is going to get you minimal damage to supporting strucure. No contolled enviroment.

Now take the same TNT and drill holes into the the supporting structure and place the TNT sticks in to the holes and then detonated it. Controlled enviroment.

Your results are going to be better.

Now if you take the Hamburger effect, that exlosive is going kick some A##.

Game machanics: 1 KG TNT

1 Uncontrolled enviroment. wall takes say 16D -1/M no rebounds from direct exlosive. Well lets hope it drops the support.

2 controlled enviroment. 16D now with a 50mm Dia hole well Lets work it out.

1000mm = 1m
50mm dia = 20 rebounds in a meter.

for power 16 to deminish 16 Meters x 20 rebounds a meter

okay I hope my maths works here.
20 x 16 = 320D before first power level is used.
20 x 15 = 300D before second power level used.
I will stop there. as by now the wall would well and trully be toast. but it is not going to effect the other reinforced pillars.

What on can do to strengthen the walls is add reinforced walls and metal reinforced to gether make the use of more explosives.

Hope this will help
Austere Emancipator
QUOTE (Johnson)
Game machanics: 1 KG TNT

1 Uncontrolled enviroment. wall takes say 16D -1/M no rebounds from direct exlosive. Well lets hope it drops the support.

If you're using canon Damage Codes and Blast Ratings, that should be 3D -3/m. In the UE-case, that won't even scratch anything but light wood-and-paper interior walls (and won't break windows, as previously mentioned). The CE-case (portrayed in SR by the Demolitions placement test) could pump that up to 8D if you've got Demolitions-6, which will blow a 0.5meter hole in a basic concrete wall.

Playing around with loads of rebounds is certainly fun, though.
Necro Tech
Just a quick question, why is he trying to blow up said building? If it is for illegal means, start from the basement, add gasoline and flour or bring O2 cannisters into the basement first, let them disperse and then blow the place up. Its much faster to destroy a building when you don't care what happens to it or its surroundings. Trying to "drop" a building safely requires a small company.
lokugh
QUOTE (Austere Emancipator)
They have to. Otherwise we might start talking about stuff like how the president is car-bombed or how to kill the most people with 30 rounds with an AK and they wouldn't know to elevate the Nationwide Threat Level.

The President isn't carbombed. The President uses ritual dragon magic to suicide to save the world from an invasion of demons from Beyond. Wonder what that would do to the Terror Threat Level? Do they have an Ultraviolet level? Or, actually, an Infrared level (since they seem to be descending the spectrum).
Kagetenshi
O2 doesn't explode, it just helps things burn really well.

~J
Clyde
I think that's what the gasoline and flour are for. He's talking about a cheap fuel air bomb, which will rip it up in any enclosed space. . .
Kagetenshi
That would work, but the or suggested to me he meant just oxygen.

~J
Puck Wildhorse, M.D.
You’ve been hired to destroy a building. There are several ways it can be done, but I’m going to discuss only two of them: the legal way and the illegal way.

The legal way: You and a small team of engineers and technicians walk thru the facility and get a first hand view of what has to be done. You go back to your office and review the construction plans (blue-prints and as-built’s) calculating the forces that hold the building up. All of these calculations (and believe me, there are a lot of them) taken together will form a model of the building. Usually this will be a computer model, since all those variables become nearly impossible to juggle on paper. This mathematical model will show all of the forces that act on the building. In order for a structure to remain standing, all of the forces must balance out and the sum of the forces will equal zero. Anyone who has ever taken an engineering course in Statics could do this, in theory at least.

Using this model, you could then start changing things (i.e., what would happen if this supporting column were to be removed?) You build a new model in which events happen in a certain order (i.e., this column is removed and the structure shifts in this direction; three seconds later, this beam is removed and the structure responds like this; and so on.). Basically, you are changing the model so that the sum of the forces no longer equals zero. If you do this correctly, your math is good and you have properly sacrificed a goat to the gods of engineering, the structure will move in the direction you want it to, and go the distance you want it to go. Anyone who has ever taken an engineering course in Dynamics could do this, in theory.

It is entirely possible for a structure to move and then reach a new state of equilibrium. Basically, the building moves but doesn’t fall. Think Leaning Tower of Pisa (although that was an entirely different engineering fuck-up). That would be very embarrassing and potentially very dangerous because the building could then respond to different forces (a sudden gust of wind or a falling pile of dragon poo) in unpredictable ways.

Assuming that you and the other engineers agree that the math is good, you will probably have to get approval from the state, county and/or city governments to perform the actual demolition. Notice that you haven’t touched any explosives yet and you’ve probably put in about a month’s worth of skull sweat. Getting approval could take quite a while as different agencies have different regulations, environmental impact reports, licenses and other hoops to jump through. Knocking down a building in the middle of BFE is a lot easier than doing it in a downtown area.

One thing I didn’t mention above is that while creating your model, you’ll probably be making a lot of assumptions to simplify the math. Assumptions like: the building will be empty of people, furniture and carpet; the heavy AC unit on the roof will be removed; the windows will be removed; sections of water pipe, gas pipe and electrical conduit will be taken out; certain internal (non-load bearing) walls may be removed; certain load bearing members may be weakened or removed entirely; all of the doors and door frames will be removed; signage (especially neon signs) are taken down; light bulbs (especially fluorescent lights) are removed, etc. So after you get approval, you and a demo crew will pretty much gut the building. A lot of that stuff is reusable and no one wants to clean up broken glass.

Finally, you wire up the building. We’re not talking one big bomb but rather hundreds of little ones. All of them are wired to a firing computer that will trigger each blast in a precise order. Each charge is probably wired with at least two blasting caps following the simple rule that two is one and one is none. In other words, you want a lot of redundancy. You’ll then probably have another inspection by the state, county and/or city authorities before you can actually trigger the demolition.

You then sacrifice a cow to the gods of engineering, push the button and hope like hell you didn’t fuck up. Total time from beginning to end: 6 weeks to 6 months for a moderately sized structure.


Now the illegal way: You and your team have been hired by a Mr. Johnson to destroy a building. First you discuss what he means by ‘destroy’. Does he mean a big crater with nothing left but ash? Does he mean a gutted building with maybe part of the super-structure standing and a huge pile of debris? Does he mean a mostly intact building that is never the less uninhabitable? The answers would make a big difference as to how the job would be handled.

The easiest thing to do would be arson. Spread around enough flammable material and even concrete will burn. Unfortunately, it’s possible that the fire suppression system will kick in, the fire department will arrive in time to save the building, a mage will do something magical or a huge pile of falling dragon poo will smother the flames. Drat!

Magic could be used. A toxic wave spell, an earthquake spell, an earth-shape spell, a wreck spell or any number of other magical effects could potentially do the job. Unfortunately, magic can be countered and drain on a spell large enough to destroy a building would probably geek the mage. Double drat!

So we turn to explosives. The question is, how does a small team take down a building in one night? Volume, volume, volume. Instead of calculating all of the forces on the structure and creating a mathematical model, you go for sheer overkill. A large enough car bomb in the parking structure (assuming that there is a parking structure under the building) or parked next to the building will do the trick. Crashing a plane into the building also works.

But what if you are limited to what you can conceivable carry on your back? I’d use several small charges that were pre-made and ganged together using det cord. Det cord explodes at something like 20,000 feet per second. If you had a series of structural supports each 100 feet apart, you could detonate them all nearly simultaneously (about 5 milliseconds apart) if you used det cord to tie them all together. Pretty much you’d put charges on every support structure in sight and hope that the weight of the building causes it to collapse.

You could also do what was suggested above and use a small amount of explosives to trigger a larger blast of potentially explosive materials. Compressed oxygen, gasoline, flour, coal dust, even hot cocoa powder, have all been known to explode under the right circumstances. These types of explosives can’t really be used to perform precision blasts. Rather they do their job by sheet concussive force; they literally blow the walls down. In a building with a lot of glass, the glass and most of the concussive force will blow outwards and the inner walls will probably be left standing. Of course the interior of the building will probably be a blasted wreck.

Or you could just hire a dragon to poo on the building. I mean, who wants to work in a building covered in dragon poo?
Kagetenshi
QUOTE (Puck Wildhorse, M.D.)
In order for a structure to remain standing, all of the forces must balance out and the sum of the forces will equal zero.

Not entirely true, as you point out later (Pisa); they just have to balance out roughly enough that the change won't be noticable except over a very long period of time. Of course, for a structure to remain standing indefinitely, you're correct.

~J
Puck Wildhorse, M.D.
The issue with the Leaning Tower of Pisa has more to do with gradually compacting soil than with any structural deficiency. And to the best of my knowledge, the angle of the tower hasn't decreased for many years. In other words, the tower is still leaning the same now as it was 50 years ago.

But I take your point. It is possible that some forces are exerting themselves against a structure, but are too small to measure. Over time (a long time) they could cause a structural failure. More likely though, the forces would be detected and corrected long before failure could occur.
RedmondLarry
QUOTE (Puck Wildhorse @ M.D.,Sep 15 2004, 11:00 AM)
And to the best of my knowledge, the angle of the tower hasn't decreased for many years.  In other words, the tower is still leaning the same now as it was 50 years ago.

Over the last 50 years the lean increased to the point of concern. Additional supports were installed, underground work was done to shore it up, and the lean was reduced. It is an ongoing engineering problem. How to keep the lean enough to bring the tourists, but not so much as to kill them.

Here are records of Tilt Correction: (source)
Lead added to North Side to reduce tilt in 1995: 830 tons
Amount of tilt correction from 1990 - 1999: 25 mm (about 1.0")
Amount of tilt correction from 1999-2001: 43.8 cm (about 17.25")
Recent corrections have brought it back to approximately the lean it had in 1700.
Puck Wildhorse, M.D.
Ah. I stand (er . . . sit) corrected.

I would hate to be the lead engineer working on that project. Screw up and you destroy a national treasure.
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