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JoGrix
08-12-2012, 12:15 PM
I have a question about a plot point,

A man who works for a pool maintenance company hides an IED in a bucket with a label for a pool chemical and hides it in a shed of a private home where pool chemicals are stored. If this is a house on stilts and the shed is below the house itself, how much damage would the house see during the explosion.

If there are people in the house, say, at the other end of the house, how likely are they to survive? If there are people in a pool about ten feet from the shed, would they survive? How about standing around twenty feet from the shed, but not in the pool?

(Also, how much flour would need to be present to destroy a single story, thousand to twelve hundred square foot home, if it's stored in the attached garage?)

My next mystery novel features a bomb maker/arsonist terrorizing the town before he's found out by my MC. The flour-bomb he pulled off twenty years ago, but the pool chemical bomb happens early in the novel as a sort of 'anniversary gift' to the families of the victims.

heyjude
08-12-2012, 02:46 PM
:hi: Jo, and welcome to AW! I'm going to port this question off to Story Research and Experts, where you'll get more eyes on it.

I don't know enough about bombs to even try to answer your question, but I'm guessing a lot will depend on what kind of explosives you're using. Do you want the house to survive? Probably there's a way to wing anything with some tweaking.

WriteKnight
08-12-2012, 08:30 PM
You'll need to specify the container size. Something like a five gallon bucket? Or a fifty-five gallon drum?

ExpertNovice
08-12-2012, 08:56 PM
JoGrix,

First, let me establish some street cred: 10 years active duty military. There are episodic articles on my website about creating realistic military environments (http://josephzieja.com), and you've just given me an idea for a new topic.

So, there are five basic ways that an explosion causes damage: blast, fragmentation, fire, cratering, and penetration. All of these things depend on multiple physical factors, and all (except fire) are pretty predictable.

It's going to depend on the amount of explosives in the bucket and the composition of the shed. In all likelihood, a small bucket of chemicals wouldn't create enough blast force to collapse both the shed and the house, or kill anyone nearby, because, honestly, a bucket of explosives isn't very much. IEDs in the desert that are buried don't kill anyone that doesn't roll directly over it, and IEDs in the open market only kill a lot of people because there's open air through which the fragmentation can move.

In short, putting the bomb in the shed is going to severely limit the kill radius. I would anticipate that almost nobody would die from the blast because of the shielding of the shed walls, but if you could frag out the shed it might be able to kill some folks standing very close. If the shed is made out of siding, it probably won't work. If it's made out of a wood that splinters nicely, you'll get some frag. Mostly, it's just going to scare the piss out of anyone in the house and ruin the inside of the shed.

Does this help? Feel free to follow up.

Jamesaritchie
08-12-2012, 09:00 PM
If I get your meaning, the explosive is in a bucket. For such a bomb to do extensive damage in such a situation, you would need an explosive much stronger than anything you can whip up at home without specialized knowledge, and when you do make it, it will be one of the conventional explosives.

You aren't going to destroy anything with a flour bomb unless you have a truckload of flour, and just the right conditions for exploding it.

A much better bet, and an easy to make bet, is to use a fertilizer bomb. You can also make thermite at home very easily, and thermite grenades aren't all that much tougher.

People also underestimate the power of properly made flash powder, which is also easy to make at home.

If the house is on stilts, your best bet is to blow the stilts, causing the house to collapse. Couple this with thermite, and the house will be gone quickly.

But any explosion depends on type of explosive, amount of explosive, type of structure your want to destroy, and knowledge of where to place the explosive.

ExpertNovice
08-12-2012, 11:24 PM
If the house is on stilts, your best bet is to blow the stilts, causing the house to collapse. Couple this with thermite, and the house will be gone quickly.



This. I wasn't sure what your desired intent was, otherwise I would have suggested the same thing.

JoGrix
08-13-2012, 02:11 AM
Thank you, all of you. Now I am reworking that particular plot point. There are two explosions, one already happened and caused a huge fire. The other one happens early on in the book to give my character the motovation to find the guy who is doing it.

This leads to new questions (and more questions, and more questions), but now that I have a new point of research I'll see what I can put together. Then I'll have more questions, I'm sure. Although that shed, definitely older, weather worn wood, repurpused for the pool supplies, less than a mile off the ocean.

Especially thanks, Expert Novice. That was exactly the answer I needed (not necessarily that I wanted... I wanted fire and mayham) to make more story actually work.

ExpertNovice
08-13-2012, 05:12 AM
Glad I could help!

If you want fire and mayhem, try setting gasoline on fire or (as was suggested) try a fertilizer bomb. Perhaps your character stores lawnmower fuel (a lot of it) in his shed. That might blow the shed out enough to catch the stilts on fire if you wanted.

JoGrix
08-13-2012, 05:52 AM
I am trying to figure out the first one; the explosion that happened twenty years ago. I know that it was a dry spring, the explosion caused a great deal of fire damage to the whole neighborhood, and that it was in the middle of a teen party from which there were no survivors (including the MC's older sister).

I also know that the explosion itself was an accident, the firebug set the fire to scare the teenagers (he was a bullied loner wanting to get his own back against the popular kids). I'm thinking some combo of a molotov cocktail, water heater, household chemicals and those landscape supplies.

The stories are set on a fictional island off the Texas coast just south of Matagorda Bay (south of Houston, north of Corpus Christi) so I'm trying to keep things realistic

The second was a deliberate explosion, less damaging but very scary for the attendees of the teen pool/birthday party going on at the time. (Same guy, did it as an 'anniversary gift' for the MC to mark the twenty years from the last explosion)

blacbird
08-13-2012, 06:11 AM
I hate to post this, but it's pretty much public knowledge since Timothy McVeigh blew up the Murrah Federal Building in Oklahoma City back in 1995: Ammonium nitrate fertilizier and fuel oil, or some similarly flammable petroleum distillate. Anders Breivik in Norway concocted a similar bomb, using his cover as a "farmer" for the legal purchase of the fertilizer, which he never used to fertilize anything. Nitrates are famously unstable explosive compounds (potassium nitrate is a major component of gunpowder), and ammonium nitrate is by far the most widely available one in quantity.

And, yes, as suggested, if it's on stilts, you don't need to blow the house to smithereens. Just take out the supports, like blowing up a bridge.

caw

debirlfan
08-13-2012, 09:59 AM
There was a real-life case not long ago where someone at a Frat type party threw a keg of beer into a fire and it exploded killing someone - I don't know if you could use something like that. Of course, if it's a teen party, there could always be a box of fireworks around....

blacbird
08-13-2012, 10:13 AM
For further historical evidence, the worst industrial accident in U.S. history was the 1947 explosion involving two freighter ships full of ammonium nitrate in the harbor of Texas City, Texas. 500+ people were killed, some of them up to a mile from the explosions. NH4NO3 is very scary stuff. But you can grow hellacious good corn and soybeans with it, long as you don't set it on fire.

caw

JoGrix
08-13-2012, 10:15 AM
Well, the first one, as I said, was an accident based on supplies already there (it's a garage attached to a one story home, not on stilts)

The second house is on stilts, but I don't think my firebug/bomb maker is going to get lucky twice. Especially when destroying the house isn't the point. It's the explosion and the panic that's the point.

Fireworks does sound interesting. There was a video of some pool chemicals that shouldn't be mixed that made me think of fireworks.

I need to think on fireworks.... Thanks for that idea debirlfan!

(The firebug later goes on to threaten the local school, ferry, courthouse and a few other places to ensure that the FBI don't get involved, so he clearly has something going on. He may or may not blow up the ferry to prove he's willing and able too.)

Snick
08-13-2012, 05:48 PM
Propane would be excellent for the first exp[losion. There was a party with a gas grill. The tank was damaged such that it leaked. When the grill was turned on everything went bang. A five gallon propane tank can estroy buildings and knocke out windows all down the street. Everyone in the garage could expect serious injury, at least.

For the second bomb put the shed close enough to the house that a small blast will destroy more than one stilt, and the house will come tumbling down. Pool chemicals could work nicely. There was a warehouse fire some years ago in which pool chemicals caught fire. the fire continued for a long time, and the firefighters had trouble with it, because they couldn't get close because of the fumes. Possible homemade explosive to use would be nitrocellulose, nitroglicerine, some things that are used as cartridge primers, and the propane tank thing might be a good idea, because it would harken back to the earlier fire; it would also be good for blowing up a stilt or two.

Xelebes
08-13-2012, 07:55 PM
Half-full propane tank beside a strut would do the trick. If not, the propane tank will likely shoot and if it hits anybody. . .

Snick
08-13-2012, 08:27 PM
Half-full propane tank beside a strut would do the trick. If not, the propane tank will likely shoot and if it hits anybody. . .

If the first half drained into the garage full of people without anyone noticing, then the explosion would be adequate. If it drained fast, then it could go off before they could do anything. Someone drops something heavy on the valve, and it breaks.

Jamesaritchie
08-13-2012, 08:36 PM
Propane would be excellent for the first exp[losion. There was a party with a gas grill. The tank was damaged such that it leaked. When the grill was turned on everything went bang. A five gallon propane tank can estroy buildings and knocke out windows all down the street. Everyone in the garage could expect serious injury, at least.

For the second bomb put the shed close enough to the house that a small blast will destroy more than one stilt, and the house will come tumbling down. Pool chemicals could work nicely. There was a warehouse fire some years ago in which pool chemicals caught fire. the fire continued for a long time, and the firefighters had trouble with it, because they couldn't get close because of the fumes. Possible homemade explosive to use would be nitrocellulose, nitroglicerine, some things that are used as cartridge primers, and the propane tank thing might be a good idea, because it would harken back to the earlier fire; it would also be good for blowing up a stilt or two.

If you even attempt to make nitroglycerine, the odds of killing yourself are about a thousand times higher than being around to use it on someone else. I can think of a dozen explosives that can be made at home, but only by an expert. A REAL expert.

Nitrocellulose is easy to make in very small amounts, thought even with a tiny amount you need concentrated nitric and sulfuric acids, but making enough to matter takes a ton of space, time, and equipment, that isn't going to go unnoticed.

Propane does make a pretty good explosion, but it isn't easy at all to set up a propane bomb in a way that will work on a random house.

The internet makes homemade explosives look easy, but it's almost never easy or safe, usually requires a LOT of space, time, and equipment. Get this wrong in a novel, and you're dead.

The best homemade explosive is one you don't make, but one you buy or steal. It's turning this explosive into a working bomb that's the tough part, and where many kill themselves.

The Terrorist's Handbook is available free online, and would be a great thing for a mystery novel character to have, but it, too, makes everything sound much easier than it is in reality.

Most who want to blow up a house should keep it simple and buy five pounds of black powder, and five gallons of gasoline. Though I've actually seen flash powder totally destroy a house of this size.

But even when you have the explosive, the hard work is just beginning. You still have to know where to place it, and how to safely explode it at just the right time when you're far, far away.

Snick
08-13-2012, 10:20 PM
If you even attempt to make nitroglycerine, the odds of killing yourself are about a thousand times higher than being around to use it on someone else. I can think of a dozen explosives that can be made at home, but only by an expert. A REAL expert.

Yes, nitroglycerine can be a problem, but it has been in production for more than a hundred years


Nitrocellulose is easy to make in very small amounts, thought even with a tiny amount you need concentrated nitric and sulfuric acids, but making enough to matter takes a ton of space, time, and equipment, that isn't going to go unnoticed.

This is actually easier and safer than many sources make it sound. I suspect that they are trying to keep people from making it.


Propane does make a pretty good explosion, but it isn't easy at all to set up a propane bomb in a way that will work on a random house.

Propane blows up better by accident than by design. That's why I suggested the method that I did; it is how it blows up by accident.


The internet makes homemade explosives look easy, but it's almost never easy or safe, usually requires a LOT of space, time, and equipment. Get this wrong in a novel, and you're dead.

The best homemade explosive is one you don't make, but one you buy or steal. It's turning this explosive into a working bomb that's the tough part, and where many kill themselves.

The Terrorist's Handbook is available free online, and would be a great thing for a mystery novel character to have, but it, too, makes everything sound much easier than it is in reality.

Yes, the books make things sound easy, or they make them sound impossible.


Most who want to blow up a house should keep it simple and buy five pounds of black powder, and five gallons of gasoline. Though I've actually seen flash powder totally destroy a house of this size.

But even when you have the explosive, the hard work is just beginning. You still have to know where to place it, and how to safely explode it at just the right time when you're far, far away.

I still think tht propane would be much easuer, and more reliable, than gasoline and black powder.

Trebor1415
08-13-2012, 11:07 PM
What about plain old commerical grade dynamite as a source for one of the explosions, especially the older one.

Dynamite wasn't always as tightly controlled as it is now. When I was a kid my Grandfather still had some left from use on the farm blowing stumps. (It was a bit old then, and not as stable as it should have been, but he still used it when needed for quite awhile).

Now old dynamite can get unstable, but that might actually work in your favor depending on how you set up your scenario.