LAPD blast containment truck fails, seventeen people injured 6

[jrs87]

https://www.dailymail.co.uk/news/ar...illegal-fireworks-LA-goes-terribly-wrong.html

Someone did not read the manual.

 

[SnTMan]

From the patent:

3-lbs TNT—totally sealed system, repeatable detonations. The UTCV 10 will require decontamination and maintenance, but no repairs.

15-lbs TNT—repeatable detonations with venting. Minor repairs may be required which include mechanical components, ports 68, and flanges (at the yoke 16, door 14, and body 12).

Can't find any discussion of the venting arrangement.

Perhaps the vessel was inadvertently not vented for this detonation?

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[RedSnake]

I might as well confess that I have been drinking a Gunnpowder IPA so I will not take any responsibility of any wrong calculations or other strange claims.

Well in that video LAPD using this truck from 2015 if you look at the pictures at the end when the looking halves are closed between 12 and 3 a clock the looking halves are not fully closed you can still see quite a lot of the flange.
And there is also smoke where it comes from, not sure.

Since the looking device is attached as tug sade to the fram and this bowl is supposed to be removed for emptying and cleaning.
What secures it in it's right place?
If it isn't properly centered the looking will not go inte to place properly or enough.

This vessel would require impeccable record keeping..

Why the manufakturer says you can blast thing within the limits as often as you like it is just when going for the big blast you need to know but then you need to replace it.
But if you are not sure of what you are putting in there, how would you then know whit which force the blast will have or had

BR A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[stevenal]

I see that red and green indications are used in some of the photos above. I understand red/green color blindness is the most common. But why depend on the latching mechanism for containment? If the door were to open inward instead of outward, the latch could be very simple. Think of the door on an airplane or compression chamber.

 

[TugboatEng]

I think an important point of consideration is the dual modes of operation, vented and unvented. If LAPD detonated 10lbs of explosives thinking they were in the vented mode that could certainly have caused the failure.

 

[RedSnake]

Well I think if you are the one opening and closing it you would know even if you are colorblind.
Since it rotates.
And I am not sure how common colorblind Explosiv Experts are.
I am just joking.
It is a good point it should have been supplemented with a symbol of a open and closed padlock.

The reason why, at least in Dynasafes case is it isn't made for blasting things inside, it's made for transport.
So it would bee much harder to pick things out of it if the hatch open inward and it would be a safety risk if the explosives inside would be nocked about when opening the hatch.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[IRstuff]

Colorblind, "do I cut the grey or greyer wire?"

The new (old) video shows something interesting, which what should happen to the overpressure; one might think that some leakiness of the seal makes it safer than a fully hermetic seal. In the latter case, you would have no idea when the overpressure has dropped sufficiently to safely open the chamber, but if it's leaky, then overpressure is automatically relieved.

One other interesting thing is the "countercharge," which seems to make sense; they detonate their own charge to deflagrate the suspect explosive.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[TugboatEng]

Welp, looks like it was just good old incompetence.

https://www.sfgate.com/news/article/Chief-Bomb-squad-caused-Los-Angeles-fireworks-16324832.php

Investigators estimate 42 lbs of explosives were loaded. Officers thought they had loaded 16.5 lbs. The chamber has a 15 lb reusable rating and a 1 shot 25lb rating. Odd that the officers thought 16.5 was still acceptable as I would think that would still require condemning the chamber.

I won't comment on other statements made in the article

 

[jrs87]

https://abc7news.com/la-fireworks-explosion-lapd-bomb-squad-south-los-angeles/10897683/

The video is informative.

 

[Cool_Controls]

16.5 lbs is larger than 15 lbs even for extremely large values of 15

 

[MintJulep]

16.5 lbs is larger than 15 lbs even for extremely large values of 15

True.

But how does 16.5 pounds of unknown homemade explosive compare to 15 or 25 pounds of C4?

 

[jrs87]

The counter-charge is probably what pushed it over the edge. Source: Keith Moon.

 

[Cool_Controls]

RE factor for C-4 is 1.37, so I guess you could safely dispose of 10.9 lbs of C-4 in LAPDs truck.

 

[waross]

How do you evaluate candidates for the bomb squad?
Take the smartest guys who were dumb enough to apply for the squad.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[AusG]

So the crew had to perform (or chose to perform) a triple estimate: the weight of the objects' explosive content as flash powder from a guess at the overall weight, and then estimate the conversion of that to TNT equivalent for the 15lb rating. A systematic error in the first two (0.5 oz to 1.37 oz * 280 devices) and the thing is doomed anyway but assumptions of explosive efficiency of homemade firework vs powder and then TNT added further uncertainty. Any errors * 280 is the problem. 16.5 regular lbs being 15 LAPD lbs is a headscratcher all on its own.

I'm not sure that adding a Captain to the process helps: brass just makes more shrapnel.

 

[TugboatEng]

I think the officers were so poorly trained or so ignorant that they did not understand that 15 lbs was the MAX reusable load and that 15.1 to 25 lbs condemns the shell. I really hope they didn't think that it was any use over 25 lbs that condemned the shell. The worst part is that out of the number involved, not one raised a red flag. 5 officers are suspended.

 

[Spartan5]

The bomb technicians — without using a scale, as is allowed by Los Angeles police procedures to avoid additional handling of the unstable devices — estimated the weight of the homemade explosives and a counter-charge to be about 16.5 pounds (7.5 kilograms) in a standard flash powder measurement. That measurement is not the same as an item's physical weight and is instead calculated as a TNT equivalent because explosives have different concentrations and therefore have varying “explosive weights."

They arrived at 16.5 pounds by estimating that the smaller explosives — there were 280 of them — each weighed about a half an ounce (14 grams) in that standard measurement. The bomb technicians estimated that the 44 larger explosives — which were about the size of a soda can with a fuse — had about 1.5 ounces (42.5 grams) worth of flash powder.

Federal authorities who weighed the remains after the blast calculated that the weight was actually more than 42 pounds (19 kilograms) in the standard measurement. The smaller explosives were actually 1.37 ounces (38.9 grams) and the larger ones were about 5 ounces (142 grams).

The detonation chamber's maximum capacity is 15 pounds (6.8 kilograms) for multiple uses or 25 pounds (11 kilograms) for a single use, Moore said. The LAPD has not publicly identified the manufacturer of the detonation chamber, despite repeated requests.

It’s too bad I don’t teach. There’s the makings of one hell of a story problem right there.

 

[waross]

This is not rocket science.

You got that right!

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Alistair_Heaton]

i suspect they had been running it overloaded before and got away with it.

And this time there was a hefty dose of plastic HE in there as well.

Don't have a clue what courses they have to go through.

UK its BDO course 1-3 which are about 2 weeks each and then they go and do the job for a bit as a BDO's bitch, Then there is a load of tech subjects of various lengths. Then the high threats course which apparently is an utter swine and high failure rate.

Then they are fully qualified it takes about 5 years start to finish to get fully qualified.

There mess is amusing. You basically have to defuse something to be able to buy a beer and the devices to get in get changed every week.

 

[TugboatEng]

If we can define a rocket as a self oxidized reaction motor I'd say that the scientists if LAPD built themselves a self oxidized reaction motor. Luckily it only had a 15 foot range.