The Cool Aunt 2021-01-18

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AnotherFairportfan
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Re: The Cool Aunt 2021-01-18

Post by AnotherFairportfan »

FreeFlier wrote: Thu Jan 21, 2021 12:06 am It actually doesn't make that much difference . . . AN is bad enough on its own.

There have been enough large-scale disasters in the last hundred years to show that . . . Texas City, Brest, St Nazaire, Oppua, West (TX) . . .

I don't count Halifax NS, Black Tom NJ, or Roseburg OR because conventional explosives were involved in those.

--FreeFlier
...Beirut...

====================

A friend of a friend worked as a Federal inspector {i forget exactly which agency} and he was involved with grain elevator explosions now and then.
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

Atomic wrote: Thu Jan 21, 2021 12:46 amThere was a sugar company whose factory occupied two very large, tall buildings, each about aircraft hangar size, connected by an underground conveyor belt. The belt transported raw sugar from the processing building to the bagging building. Needless to say, there was sugar powder everywhere, and careful people made sure the conveyor tunnel was well ventilated. Then one day, various food safety types demanded the conveyor be covered in it's tunnel. Something about spider webs and other critters that might get into the mix. Yessir, right-0, three bags full -- the belt was covered, and life went on.

Alas, one of the bearings on the belt needed attention sooner than expected and got hot. Very hot. Ignition hot! And that lovely form fitting belt cover (which wasn't ventilated the way the outer tunnel was) made a lovely concentrated fuel-air bomb with blew out the walls is both lovely buildings at either end. Think of a double ended carbide cannon. Boom! Many injuries, big fire.
I was witness to a sander-dust explosion under similar conditions . . . the big drum sander had a drum unwrap and flail the steel sandpaper retainers around inside a steel compartment full of dry wood dust suspended in air . . . oh the sparks!

The dust in the sander ignited, explosively . . . it propagated into the dust collection system . . . whereupon we discovered that the water supply to the high-speed fire suppression system had been turned off for maintenance, and only the minor feed turned back on . . . the explosion rolled downstream through the low-pressure system, into the high-pressure system, and on downstream through the cyclones into the baghouse, where it blew the blowout panels off the baghouse with an almighty THOOMP! (Fortunately, I'd recently been to the restroom.)

The fire suppression system for the baghouse went off at that point, which stopped the explosion and fire, but shut that whole side of the plant down while they cleaned out the wet dust and replaced all the wet-dust-caked filter bags in the baghouse.

At least it didn't get into the big dry-and store bin . . . that time. (The last time it had, it took a week to get the fire out and another to get the bin back into action.)
AnotherFairportfan wrote: Thu Jan 21, 2021 1:18 am
FreeFlier wrote: Thu Jan 21, 2021 12:06 amIt actually doesn't make that much difference . . . AN is bad enough on its own.

There have been enough large-scale disasters in the last hundred years to show that . . . Texas City, Brest, St Nazaire, Oppua, West (TX) . . .

I don't count Halifax NS, Black Tom NJ, or Roseburg OR because conventional explosives were involved in those.
...Beirut.... . . .
Yes.

--FreeFlier
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Re: The Cool Aunt 2021-01-18

Post by Opus the Poet »

I see I'm not the only one who gets "visits" when there is an unexplained explosion in the area. I didn't get a "visit" after West, there was already enough easily visible stupidity to absolve me of that one. But as crippled as I am now I don't get many visits unless the explosion is in a handicapped-accessible location. In fact I can't remember the last time I had a "visit".
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Re: The Cool Aunt 2021-01-18

Post by jwhouk »

No one mentioning Beirut?
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Re: The Cool Aunt 2021-01-18

Post by lake_wrangler »

jwhouk wrote: Thu Jan 21, 2021 6:26 am No one mentioning Beirut?
Third post above yours, which was then replied to in the second post above yours... You must have just glossed over it.
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Re: The Cool Aunt 2021-01-18

Post by Warrl »

There's a reason why old-fashioned powder houses, if they couldn't reasonably be put waytheheckoverthere, had very sturdy walls plus the outside of the door would face a separate but similarly sturdy wall, but the flimsiest roofs they could manage and still keep the rain and snow out...
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Re: The Cool Aunt 2021-01-18

Post by AnotherFairportfan »

Warrl wrote: Thu Jan 21, 2021 2:49 pm There's a reason why old-fashioned powder houses, if they couldn't reasonably be put waytheheckoverthere, had very sturdy walls plus the outside of the door would face a separate but similarly sturdy wall, but the flimsiest roofs they could manage and still keep the rain and snow out...
Yeps. I seem to recall seeing an illustration of an early duPont facility...

Here it is - the Brandywine plant {black powder} which suffered an explosion in 1818; it was finally closed in 1921 because of low demand for black powder. Notice the bunkers with heavy walls and sloped roofs facing the river.
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dupont.jpg
dupont.jpg (133.71 KiB) Viewed 11263 times
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========

Hollywood studios have powder storage bunkers {with heavy spring-loaded blowout hatches in the roof}. and professional powdermen.

The pros like to tell apprentices two things:

1. If you're working with primacord, make sure it's laid out exactly how you want it, because you'll play hell stomping it out

and

2. It's not the explosion that kills you, it's when your head hits the hatch on the way out.

{Which reminds me - i need to find a specific few seconds from Rock n Roll High School to post...}
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

Opus the Poet wrote: Thu Jan 21, 2021 3:14 amI see I'm not the only one who gets "visits" when there is an unexplained explosion in the area. I didn't get a "visit" after West, there was already enough easily visible stupidity to absolve me of that one. But as crippled as I am now I don't get many visits unless the explosion is in a handicapped-accessible location. In fact I can't remember the last time I had a "visit".
Mine wasn't a "visit" . . . that happened in a hearing room in the state senate building, because he wanted to confirm what he suspected about the sources of the knowledge that I'd just displayed in testimony.

I just like to mention the time I got questioned by the bomb squad. Sometimes I will explain it without being asked . . . sometimes not.

I've heard about some interesting stories . . . like the guy who found several tons of ancient stolen dynamite concealed in an abandoned boiler . . . or the entire year's supply of 50+ year-old dynamite in the underground magazine at a mine . . . or in an abandoned quarry . . . or found a WWII naval mine washed ashore on a pacific beach . . . or a trawler that trawled up a WWII torpedo . . .

AnotherFairportfan wrote: Thu Jan 21, 2021 9:37 pm . . .
The pros like to tell apprentices two things:
1. If you're working with primacord, make sure it's laid out exactly how you want it, because you'll play hell stomping it out

. . .
. . .

Primacord detonates at 22,000 feet per second . . . I'd like to see someone stomp that out!

--FreeFlier
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Re: The Cool Aunt 2021-01-18

Post by Dave »

Those bunkers look a lot like picture I've seen of rocket-engine test cells... for reasons that should be fairly obvious.

In his book "Ignition!" John Clark writes of one propellant test which went wrong and detonated. It blew the steel lid of the test cell a good fraction of a mile, slicing through a bunch of trees as it went. The cleanup crew were somewhat disturbed...
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

BTW, acetylene gas becomes explosively unstable if pressurized beyond about 20 PSI . . . which is why it's stored by dissolving it into acetone in a porous matrix.

--FreeFlier
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Re: The Cool Aunt 2021-01-18

Post by Atomic »

Note the powder houses in the DuPont image above. They were placed near the river so the flaming debris would have something wet to land in.

Inside the house was a rack with sulpher, saltpeter, and charcoal supplies for a day's work. The worker would take the recipe amount and pour it into a ball mill barrel. The barrel was wooden, and so were the balls which did the mixing. Think of one of those rock polisher jewelry things, except the sand was the gunpowder to be, and the wooden balls thumped around as the barrel turned. Many hundred hand cranks later, the mixture was poured out, sifted, and then into bags. Reload the barrel, lather, rinse repeat.

You worked alone after being trained. No smoking, no lamps, no flame, flint, or sparks of any kind -- otherwise, poof! Then again, if you cranked the barrel too fast, the balls colliding inside might be just be enough for a cap-gun like strike. IIRC one day's work would be nearly 100 pounds of gunpowder. Those were the days, 1800s style!
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Re: The Cool Aunt 2021-01-18

Post by Warrl »

Many hundred hand cranks later, the mixture was poured out, sifted, and then into bags.
The sifting was important. The finer the grind, the faster the explosion, because more exposed surface in proportion to mass... which means the immediate pressure would be higher, from any given amount of powder.

Stage magicians routinely used an extremely fine grind - literally powder - so a very tiny amount of it would make a very showy explosion that actually has very little energy.

But load a sack of that into a cannon, and you'd risk blowing up the cannon.

(In fact, the story has it that the US military in Vietnam did this deliberately - found a Vietcong weapons cache, very quietly and quickly disassembled the ammo so they could grind the explosives finer and reassemble the stuff, and put it back...)
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Re: The Cool Aunt 2021-01-18

Post by AnotherFairportfan »

Remember: Black powder does not explode - it deflagrates {burns rapidly and generates large volumes of gasses}. The flame front in black powder is subsonic; in dynamite and other such it is supersonic..

If it's not confined, it flares. Put a charge of loose black powder and a charge of dynamite or other such explosive of {nominally} equal power on top of identical stone slabs and detonate.

The powder will flare and go "Floomp!" and scorch the stone. The dynamite will go "BANG!" and {most likely} crack it.
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

There isn't actually a flame front as such in high explosives . . . there's a pressure wave that passes through the explosive, tipping it over the edge into detonation. This is why high explosives must be initiated with a blasting cap, not a flame . . . most high explosives will simply burn if ignited. (Though they will usually evolve noxious fumes in burning.) Excess or damaged high explosives are frequently/usually destroyed by burning, though there is a risk of accidental detonation, especially with deteriorated explosives.

Black powder burns at the approximately same rate whether confined or unconfined, whereas smokeless smallarms propellant (also called "gunpowder") will simply burn in a few seconds, usually with a clear yellow flame, when unconfined. Sufficiently strong confinement, OTOH, can tip smokeless propellant over the edge into detonation. (Double- and triple-base propellants are especially prone to detonation if used injudiciously.)

Black powder is usually destroyed by immersion in large amounts of water, whereas smokeless is either reprocessed or burned. (Water does little to smokeless powder or high explosives.)

Explosion is an imprecise term . . . it applies to deflagration, detonation, mechanical explosion (such as a bursting flywheel), Fuel-Air Explosions (FAE) such as gasoline vapor, flour, and coal dust, and to Boiling Liquid Vapor Explosions (BLVEs) such as boilers, water heaters, and propane tanks . . . among other things.

--FreeFlier
(edit: spelling)
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Re: The Cool Aunt 2021-01-18

Post by AnotherFairportfan »

THAT'S what i was trying to recall!

BLEVE

It was a BLEVE in Mississippi {near Laurel?} that threw railroad-car wheelsets something like half-a-mile.

Have you ever looked at a wheelset?
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Re: The Cool Aunt 2021-01-18

Post by Atomic »

Isn't it amazing how much Bud knows about explosives and related topics! No wonder she's the Cool Aunt.
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

AnotherFairportfan wrote: Sat Jan 23, 2021 2:49 amTHAT'S what i was trying to recall!

BLEVE

It was a BLEVE in Mississippi {near Laurel?} that threw railroad-car wheelsets something like half-a-mile.

Have you ever looked at a wheelset?
Yes.

At Texas City, a two-ton anchor from the Grandcamp was thrown more than 1.6 miles (2.4km) and a multi=ton propeller from the Highflier landed more than a mile 1.5km) inland, while windows in Galveston, ten miles/15km away, were shattered.

--FreeFlier
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Re: The Cool Aunt 2021-01-18

Post by Atomic »

BLVE - Boiling Liquid Vapor Explosion

As a weather guy, we learned the vapor:liquid ratio for water (and almost every other liquid) is 1000:1

That quart (4 cups) of 300F pressurized water is a cubic yard of steam. (OK -- 1 Liter = 1 cubic Meter. Sue me.) Those Star Trek phasers? A human water vapor cloud would be the size of a hot air balloon, not including the blast wave. That's why steam heater explosions can knock down a whole apartment building -- it takes out the first few floors and the rest collapses down into the basement. Likewise ship boilers in naval battles.

Some bright guy set up a steam engine collision as an event in 1896. The crowd of onlookers paid for tickets and filled the stands, safely(?) placed 200 yards away, along with up to 40,000 people "nearby".

Ooops!
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Re: The Cool Aunt 2021-01-18

Post by FreeFlier »

I think the name has been changed from BLVE to BLEVE . . . not sure why.


And dad told about a story he'd gotten from a EOD man out of Vancouver Barracks (Vancouver, Washington, USA) about an abandoned boiler that nearly exploded . . . despite not having steam up in many years . . .

There was an abandoned boiler sitting in a field, and the property owner was developing the property, and sold the boiler for scrap . . . the scrap man came out and went to cut the smokebox off the front of the boiler, but for some reason, cut the nuts off the cleanout door instead . . . swung the door open, and it was brown trousers time! The smokebox was full of cases of dynamite, with white crystals all over everything!

Knowing what he was looking at, he shut the torch off and walked away to call the bomb squad.

Bomb squad called EOD, and the EOD man (who told dad about it) evacuated the area, moved the scrapper's truck away, and then very carefully piled a lot of dry wood around the boiler, and lit it on fire . . . once the fire burned out, they inspected the boiler carefully to make sure combustion was complete (they may have burned it again, I'm not sure) then cut the smokebox off for the scrapper to prove it was safe.

It turned out that the dynamite had been stolen years or decades before, and had apparently spent that time sitting there exuding nitroglycerine.

--FreeFlier
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Re: The Cool Aunt 2021-01-18

Post by Atomic »

Ah, nothing like aged hot toasted sweaty dynamite. Sop up the nitroglycerine and filter the fullers earth, and you're in the recycling business!
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