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LAPD blast containment truck fails, seventeen people injured
6

LAPD blast containment truck fails, seventeen people injured

RE: LAPD blast containment truck fails, seventeen people injured

I'm with the government and I'm here to help you.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

It wasn't fireworks there was military grade HE in that which produces colossal amounts more gas and faster.

Although to be honest I do wonder why they are using a contained method of disposal which is always going to cause issues.

And it doesn't matter what EOD are doing in the UK there is no way people would be able to get that close.

If it was stable enough to put it in that contraption then they could have moved it in a bed of sand bags to some pit built sandbags up and done a controlled det on it with the blast focused upwards.

And this is something the UK EOD have been doing in NI since the 60's

RE: LAPD blast containment truck fails, seventeen people injured

Doh!

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
Documentation for this sphere device would be interesting to find I estimate this accident will cost Los Angeles $20 million.

https://youtu.be/ndV12FoPESo

RE: LAPD blast containment truck fails, seventeen people injured

It seem quite a bizarre idea. I am presuming that its a local concept.

We don't let the police screw around with stuff like that in the UK.

Here are some container tests of fire works

https://youtu.be/S1QTeAogtko

RE: LAPD blast containment truck fails, seventeen people injured

It says in the report 10 pounds of HE which was "far less than its safety rating", whatever that means. That sounds like quite a lot ( 5kg). I wonder if they meant 10 ounces....

But it's a completely stupid thing to do.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: LAPD blast containment truck fails, seventeen people injured

I had assumed the blast truck was for safely transporting explosives (or suspect devices) to a range where they could be detonated. I didn't realise the idea was to offer a "doorstep" service! Quite mad.

RE: LAPD blast containment truck fails, seventeen people injured


250 kbar 6MJ/KG is what C4 can put out.



RE: LAPD blast containment truck fails, seventeen people injured

Quote (WLIW article)

...arrested on suspicion of possessing a destructive device...

Suspicion :)

I like fireworks and all, but 5000 lbs? Crazy.

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

RE: LAPD blast containment truck fails, seventeen people injured

Who the heck detonates explosives in a residential area, bomb disposal containment unit or not?

Obviously it wasn't 10 lbs or it was not the type of explosives they thought it was.

RE: LAPD blast containment truck fails, seventeen people injured

Not completely related to this post, but my high school chemistry teacher from the early 90's was involved in a similar situation. He had been fired from his teaching position, so he started manufacturing fireworks in his garage. A small fire and explosion resulted in the bomb squad being dispatched and a good section of town being evacuated. I have no idea as to the quantities, but he would provide the town the fireworks for the annual in dependence day celebration, as well as selling them to local kids for their own displays.

RE: LAPD blast containment truck fails, seventeen people injured

I question the idea that transporting is safer than detonating. A vehicle designed for transport must be able to survive an accident and a subsequent detonation, rather than just detonation. I'm with the OP, they likely missed a critical step. RTFM.

RE: LAPD blast containment truck fails, seventeen people injured

Not really, they drive real slow and have a police escort. Either way, the risk of accidental detonation during transport is always lower than intentionally detonating on site.

RE: LAPD blast containment truck fails, seventeen people injured

"We are trained professionals. DON"T try this at home!"

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

RE: LAPD blast containment truck fails, seventeen people injured

Now that was funny rofl

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: LAPD blast containment truck fails, seventeen people injured

Hehehehehehe...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

I wonder if they left a vent closed or somthing.

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
These total containment vessels are highly engineered devices.

What is interesting is the LAPD may have been using a single use protocol on this "controlled" detonation, which means the vessel would have had to be replaced regardless.

RE: LAPD blast containment truck fails, seventeen people injured

My guess- there's a rating for X lbs of pipe-bomb (pipe with smokeless powder) or something like that and they got something a little more energetic than the normal home-made bomb.
Here's how to open a container: https://www.youtube.com/watch?v=du5H1AtdZYc
Note that when the box fails, it doesn't just fail a little bit.

RE: LAPD blast containment truck fails, seventeen people injured

It looks like the door failed. The vessel rocket propelled itself forward in to the cab of the truck.



As for th quantity of explosives, it appears these units are rated for 25lbs of TNT.

RE: LAPD blast containment truck fails, seventeen people injured

C4 is 1.34 tnt equivalent.

Semtex is 1.25

RE: LAPD blast containment truck fails, seventeen people injured

The chamber uses a system similar to o a v-band clamp to hold the door on. There are two relatively small threaded rods that pull the clamp halves together. All of that assembly is missing in the picture. I would be interested to see if the vessel can verify proper setting of the clamping system (limit switch). If not, there may have been some movement of the door to cause an impact which broke the clamping system off.

RE: LAPD blast containment truck fails, seventeen people injured

If this is accurate, the charge in the bomb truck should have been within limits, or perhaps a bit over (they might not have a scale on site, so the weight might be an estimate).

Quote (https://www.mercurynews.com/2021/07/01/large-firew...)

The blast happened in the area of East 27th Street near San Pedro Street at 7:36 p.m., according to LAPD Chief Michel Moore during a news conference Wednesday evening.

The explosion occurred while the LAPD’s bomb squad was attempting to dispose of a cache of illegal fireworks that were discovered earlier in the day, Moore said. Police seized more than 5,000 pounds of illegal fireworks in the same area and took one person into custody. . . .

Moore said that there were less than 10 pounds of total charge inside of the containment vehicle, which was rated to handle up to 15 pounds of total charge.

RE: LAPD blast containment truck fails, seventeen people injured

Oop's back to the drawing board ...

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: LAPD blast containment truck fails, seventeen people injured

Don't know why they didn't just soak it in a dumpster in water which would have rendered the black powder useless and removed the instigator for the plastic.

Depending what form the sodium and the lithium was in you might have got a bit of heat reaction but by that point the black powder would be dead and wouldn't fire which would just leave the plastic which could then be taken to a burn pit.

RE: LAPD blast containment truck fails, seventeen people injured

This is the SE version on a car trailer.



It has a rotational lock.





And it can open as little or as much as needed, usually not more than to get what ever they are putting in there in.



It also have a cradle, of fabrics in there so the explosives lay in the cradle so it can't bump around when driving.



When this is used they always takes it away and detonate it at a secure location.

With really small objects they can detonate them where there at, if they deem it secure, as they did here in Umeå ones

https://www.svt.se/nyheter/lokalt/vasterbotten/bom...

BR A

RE: LAPD blast containment truck fails, seventeen people injured

Hmmm,

These things look very much like pig trap doors / quick opening enclosures found on many pipelines, pressure vessels etc.

I can't find what pressure they think these things should be rated to but at the size of the units seen, those closure yokes actually look rather weedy. Add in the shock element of all this and their issue is that you need them to be already quite highly stressed simply to seal the door via the wedge shaped closure halves. Then add on the internal pressure.

There are much better design IMHO, which use a moveable element to engage a large forged ring and hence it is then the shear strength of the ring to hold it in place.

But they really should be taking a leaf out of large gun doors which usually use some sort of key and turn action.

My suspicion looking at a few of these is that either the ring was over tightened too many times and the ring started to fail at the high stress concentration or that someone has started small, gradually increased this in size and scaled up without realising that some of the forces go up as a square of the size.

That is one big door - I reckon 36" or maybe even 42" and in internal shock pressure of what 250/300 bar? or 3,500 to 4500 psi. At 42" that a force on the door of 5 million lbs or 2,250 tonnes and that's non shock load. That clamp is way undersized and a poor design. Too many sharp corners and not thick enough.

They want something more like this.... which is a gun barrel by the way and not a pig trap.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: LAPD blast containment truck fails, seventeen people injured

That swedish one is much much better as the forces trying to pull it apart are direct contact forces / shear forces on those keys on the ring.

Clamps are just not as good as you have bending forces on the U shaped ring which concentrate in the top of the U. Add i the cat that people will over tighten them or need to generate force on the screwe which is then multiplied several time by the shallow angle inside the clamp and Bang - it fails.

It would be great if they could find the parts of the clamp, but I guess the manufacturers won't wont this to get out into the wild....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: LAPD blast containment truck fails, seventeen people injured

We use a thing called a pig stick for that sort of stuff. Its official name is a disrupter.

Its classed as a fire arm but its basically a tube filled with water with a explosive charge to squirt it when fired.

The basic ones are free floating and you set them up with what ever is around and then tie a rope or something onto them because they go whizzing off in the opposite direction when you fire them. Then its a swine trying to find them afterwards. It kills the electrics if it is a device. And as 99% of the time suspect bags are false alarms it means they can be in and out and no fuss or damage.

When you start using point charges there is usually a lot of collateral damage mainly windows and you run the risk of the charge triggering the main explosive charge.

RE: LAPD blast containment truck fails, seventeen people injured

Yes I can see that, that metod is better.
The SE national bomb squad, actually managed to blow up the a parking garage to a polis building in a controlled blasting. haha lol
Luckily no one got hurt.



Quote:

One of the police's storage buildings in the garrison area in Linköping was completely destroyed during the night until Tuesday in a detonation.

At four on Monday afternoon, the evacuation of the Garrison area in Linköping began after the police found explosive dough in the saddle of a moped, according to information to Aftonbladet.
The explosive dough must also have been covered with nails.

The moped was with the police in the room for stolen gods and was just to be returned to the owner when the discovery was made. 170 people were evacuated and a total of about 3,000 people were affected in the immediate area.

The national bomb squad was called in and at midnight a loud bang was heard over parts of Linköping.
That was when the bomb squad carried out what would be a controlled explosion of the object.

But something went wrong and the explosion became more powerful than the police had thought.
Pictures from the scene show one of the police buildings that has been completely destroyed.

- It probably did not go quite as one had hoped while it was such a passing heavy detonation.
At the same time, they had taken this into account, which is why the area was evacuated, says police spokesman Erik Terneborn.
.

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

Our boss in our Sapper unit was felix high threat Northern island trained. There is a remit that all Royal Engineers are trained with basic battle field EOD.

Our boss had been doing for it over 5 years in NI and then got his commission and sent on his way to a normal unit. But due to his qualification level and experience he used to keep a lot of the kit with him.

He also had the contacts and skill set to have access to a hellva lot of bang with very little restrictions where he could train with it.

So basically every time we went on exercise there was always some sort of bomb scare which we would need to deal with. He also used to get roped into any callouts in London and they had multiple shouts on going. But because he knew them all, if they needed heavy plant and labour they would just give him a call and he would send us lot out. It was good fun so there was no shortage of volunteers for his on call list. But we would take it there and hand it over to the real team and then take it back when they were finished.

If you want to see what a UK EOD unit is like have a google for bluestone42 its pretty accurate in my experience.





RE: LAPD blast containment truck fails, seventeen people injured

The first hit I got was this.
https://www.youtube.com/watch?v=gewUQ8SGulU
I wouldn't be surprised if this one is accurate too. winky smile

I hade a similar experience when I was working at the regiment, but then the rolls where reversed, I think my boss set me up for prank. lol

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
Fancy British Rolex wearing bomb techs know better.

https://youtu.be/U9pG1Om_Mpw

As others have mentioned, I too would only want to use a rotating breach lock type door, or at least a door that is mounted inside sphere. The LAPD design optimized robotic and remote loading.

RE: LAPD blast containment truck fails, seventeen people injured

Some pictures for review.







I think this is the weakest link if the hatch for som reason isn't properly seal tight and pressure pushes the looking halves apart that threaded rod isn't going to cut it.



BR A

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

RE: LAPD blast containment truck fails, seventeen people injured

Yep that's series two.

I prefer series 1

The whole setup seems like an accident waiting to happen to be honest.


The royal navy hardly ever defuse they always blow in situ they also have collosal manuals on all munitions. There are still teams combing the beaches in the UK finding stuff. Alot of them are 2nd 3rd generation Poles after ww2. Felix used to be part of the Royal Logistics Corps made up of Ammunition technicians but there was ways and means round that technicality. It deals with the high threat IED type stuff. Sappers RAF and Navy just deal with munitions

RE: LAPD blast containment truck fails, seventeen people injured

Anna,

It seems to be a bit of a Swedish expression "We thought it would go well".....

Looks like they blew the aerial off the roof as well!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: LAPD blast containment truck fails, seventeen people injured

Yes lol
I think the expression has a slightly other meaning then the English translation but it is pretty close.
I think that the reason that this expression pops up so often, is that in Sweden most people is not afraid to admit that something has gone wrong or is done wrong.
In most situations there are no konsekvens, just a possibility to make something better.
And if no one got badly hurt or died, it is easy to admit that something went wrong and you didn't have as good control or insight as you thought you hade.

Quote:

The police report themselves
The police also state that they will review their routines when it comes to handing out seized items.
At the same time, the police have reported the incident to the Swedish Work Environment Authority and to the Police Authority's Special Investigations, which SR first reported.

- It is of course serious and due to that we have to work on reviewing our routines, says John Andåker acting local police area manager in Linköping to the radio channel.

Quote:

The police department for special investigations has written off a report of misconduct regarding the handling of the bomb that exploded on a moped in Linköping.

- No preliminary investigation has been initiated against police employees as a result. It has been written off, says Mats Ericsson at the Public Prosecutor's Office for special investigations.

It was the police in Linköping who submitted the report on Tuesday.

- There was no crime by the police to investigate that emerged from the documents that came to me, says Ericsson.

- It mostly looks like an accident.

The moped containing explosives was seized by the police and in the explosion that was triggered when the bomb guard was working on the object, one of the police buildings was destroyed.

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

I was wondering about have they managed to make a controlled blast. ponder
Radio remote seems out of the question and wire.
I would have guessed a timer set device.

But here is a wire, so how do they get it inside without a hole somewhere?



/A

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

RE: LAPD blast containment truck fails, seventeen people injured

Maybe they should have bought a Dynasafe instead winky smile
Didn't know it was Swedish made actually.

It loos like the LA one is a NABCO 64-GT-SCS.

Dose not say anything about how you trigger a explosion inside the NABCO.

The Sweidish Dynasafe you can buy a add on heating system capable of raising the temperature of the loading tray to approximately 662°F, causing explosives to burn or detonate.

/A


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

RE: LAPD blast containment truck fails, seventeen people injured

Well lots of speculation going on here, so I'll add my own:

The LAPD vessel was a proven design, but obviously, something went amiss.

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

RE: LAPD blast containment truck fails, seventeen people injured

At least from tugboats pictures I think it looks lik, the hatch was blow open and as you sade the explosion was quit "uniform" symmetric in the beginning.
And the blast compartment "bowl" was pushed forward as a bullet then twisted, in some video you can see that the blast fire changes to left looking from the front at the end of the explosion.
I think it is the hatch opening you see here from tugs picture.



/A

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

RE: LAPD blast containment truck fails, seventeen people injured

That would be very unlikely unless the unit was used often for years, with no lubrication nor maintenance.

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

RE: LAPD blast containment truck fails, seventeen people injured

This was sort of the proverbial "An immovable force meets an immovable object" scenario.

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: LAPD blast containment truck fails, seventeen people injured

The truck is super clean in that picture but the topp and bottom off the hatch frame isn't.
There are also rubber sealings, they are to prevent gas leakage.
But it looks like there has been leakages from earlier explosions.



BR A

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

RE: LAPD blast containment truck fails, seventeen people injured

That could just be poor clean-up after the last use.

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: LAPD blast containment truck fails, seventeen people injured

Found...

https://www.nbclosangeles.com/news/local/lapd-to-p...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

I don't think the seal is particularly important in this design. Dik's post alludes to the lid being found in tact some distance away so this is looking like a failure of the clamping system that retains the lid.

RE: LAPD blast containment truck fails, seventeen people injured

Not knowing anything about it... that would be my kind of guess... I had no idea the 'projectile' could travel like that...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

Quote (JohnRBaker)

That could just be poor clean-up after the last use.
Well that is my point, why polish the whole truck and everything else up for this show off, but leave that if it was possible to clean it off. ponder

Quote (Tug.)

I don't think the seal is particularly important in this design.
No as I sade it's only there to make it gas-tight when transporting things that can evaporate toxic gases.

Quote (dik)

I had no idea the 'projectile' could travel like that...
Frisbee you know. winky smile
Or maybe it's really a flying saucer.

/A


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

RE: LAPD blast containment truck fails, seventeen people injured







/A

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

RE: LAPD blast containment truck fails, seventeen people injured







It looks as if there could have been some change in the metal structure in this area from earlier blasts.

/A

RE: LAPD blast containment truck fails, seventeen people injured

I am not sure what kind of regulations applies for this blast containers.
At least here on the European side it's seems the normal procedure is to use them for transport and then take things out and blast them in another places.
And if there is a explosion during transportation, at is still safe.
There surely most be some limitations for how many blasts can be done inside this blast containers before they are deemed insecure for use.
At least there should be a X-ray or ultrasound examination after every inside blast or something. ponder
I would like to say that a yearly inspection would not do it, in this case.

At least the SE Dynasafe is rated for "Number of Repeated Detonations" usually 10 there is some that can only take 1 but then we are talking 20kg TNT.
Abd the smaller one 5 and 8 kg (TNT) seems to be made only for transport.

Best Regards A

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

RE: LAPD blast containment truck fails, seventeen people injured

NABCO Model-64 GT-SCS:

• Rated for unlimited detonations of 6.8 kg/ 15 lbs. Military C-4
• Rated for one-time detonation of 11 kg /26 lbs. TNT

15lb= 6.803885kg, 26lb= 11.79340kg

https://store.mssdefence.com/home/1293-nabco-nabco...

Dynasafe

DYNASEALR X10
Explosive Rating (DDESB Approved) 5 kg / 11 lbs. TNT-eq
Number of Repeated Detonations 10
Maximum One-Time Detonation 15 kg / 33 lbs. TNT-eq

DYNASEALR X12
Explosive Rating (DDESB Approved) 8 kg/ 17.64 lbs. TNT-eq
Number of Repeated Detonations 10
Maximum One-Time Detonation 20 kg/ 44 lbs. TNT-eq

https://dynasafe.com/containment/eod-bomb-squads/d...

It is clear that there is a difference in security thinking here.
The NABCO there you can explode as many 6.8 kg Military C-4 as you like but it can only handle an explosion of 11 kg TNT.
While the SE Dynsafe may only be used 10 times with 5 kg TNT and is only allowed one blast with 15 kg TNT.
It's has 25% security margin on the 5 kg. (6,25 kg/18,75 kg)

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

That clamp type design might look big and strong, but I think it is rather weedy and open to stress concentration, over tightening and you start at a high level of stress in the clamp to clamp it tight then go and add a load more.

We have no idea at the moment how many times that chamber was used?

But shock loading needs a FOS of at least 3 IMHO. There is no way that chamber closure is strong enough for that.

At the root cause, a clamp design is a poor choice of closure mechanism for such a shock loading condition.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: LAPD blast containment truck fails, seventeen people injured

Quote (TugboatEng)

f you think about it, a 24 inch diameter lid with 4500 psi applied to it and travelling 0.010 inch gains some 240,000 ftlbs of energy so a tiny amount of movement can generate tremendous amounts of energy.
I thought about it and I came to the conclusion that one of us has a busted calculator.

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

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
The photos of the truck from the fair are 12 years old. We have no idea of actual vessel history, but at hundreds of thousands dollars each, they are not disposable. LAPD released statements that they did not overload vessel. But they quoted onetime rating, not accumulative... This vessel would require impeccable record keeping...

On the stained flange at 6 and 12 o'clock, you can observe two clean rings in the stain. This indicates perhaps the hatch is rotating against the flange during detonation. (Note I do not mean the hatch is spinning against flange, think Challenger solid rocket case rotation of joint.) Or perhaps the rings are from vibration when the whole thing rings like a bell? Note they occur where the clamp is discontinuous.

RE: LAPD blast containment truck fails, seventeen people injured

(OP)


The black material on the I.D. of the flange opening looks a little stained as well. Refer to high resolution flickr photo.

RE: LAPD blast containment truck fails, seventeen people injured

Ignore my energy comment. I may have been drinking beer riding in the back of a ski boat when I did the "calculation". I used a product in place of a quotient.

RE: LAPD blast containment truck fails, seventeen people injured

I wounder what the remains of the clamp look like.
I agree the location where the clamp halfs join is a location where strain (and possibly bending) could be important.

The following is speculation.
Possible failure modes could include:
  • Explosive quantity was misjudged
  • Service life limits were not observed
  • Clamp was not tight.
  • Door flexed enough that it's OD became smaller than the ID of the clamp.
  • Clamp failed in bending
  • Clamp failed by brittle fracture
  • Probably a bunch more, as impulse shock on the inside face of the vessel can translate into a shockwave traveling radially through the steel shell, behavior is going to be dramatically different from steady state loading.

RE: LAPD blast containment truck fails, seventeen people injured

Another problematic design feature I see is that the mechanism that supports and operates the clamps is not actually attached to the vessel but to the frame instead. Any movement of the vessel would add additional stress to the clamps.

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
Video of LAPD using this truck from 2015

https://youtu.be/ynC_lbETep4

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
See Figure 4 in patent PDF above. Clear areas in stained flange are simply the result of O-Ring seal.

RE: LAPD blast containment truck fails, seventeen people injured

I would be very interested to know the details of the last use of the containment vessel for s substantial blast.
There may have been previous damage to the clamp ring.

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

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
Gases got past O-rings, pressurized unvented yoke, detached it? Corner stresses in yoke caused cracks to develop? Yoke and/or cover did not fully seat? Could a nylon strap from inside the vessel been draping over the flange when the cover was closed? Does operator pressure test vessel to confirm seal before detonation and/or transport is authorized?

RE: LAPD blast containment truck fails, seventeen people injured

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

RE: LAPD blast containment truck fails, seventeen people injured

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.

Quote (jrs87)

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 ponder

BR A


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

RE: LAPD blast containment truck fails, seventeen people injured

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

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

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. ponder
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

RE: LAPD blast containment truck fails, seventeen people injured

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
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RE: LAPD blast containment truck fails, seventeen people injured

Welp, looks like it was just good old incompetence.

https://www.sfgate.com/news/article/Chief-Bomb-squ...

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 🙄

RE: LAPD blast containment truck fails, seventeen people injured

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

RE: LAPD blast containment truck fails, seventeen people injured

Quote (Cool Controls)

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?

RE: LAPD blast containment truck fails, seventeen people injured

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

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

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!

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

Quote:

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.

RE: LAPD blast containment truck fails, seventeen people injured

This is not rocket science.

You got that right!

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

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

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.

RE: LAPD blast containment truck fails, seventeen people injured

The 500 lb lid was found several blocks away... range was a little more...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

Rocket scientists and cannoneers? Get these guys a defense contract. They have done the impossible by developing an improvised rocket device as well as a barrel-less cannon.

RE: LAPD blast containment truck fails, seventeen people injured

Quote (From the SFGate article)

The LAPD has not publicly identified the manufacturer of the detonation chamber, despite repeated requests.

At least in this thread I think we came to the conclusion that there could only be one manufacturer of this particular model of blast chamber.
Even if we don't know the exact model and the data about how many times you can blast a certain amount before you need to scrape it seems to vary between different places.
It seems strange that the LAPD will not give out that information unless they are looking for a subcontractor for certain parts. ponder

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

https://www.yahoo.com/news/los-angeles-bomb-squad-...

"Bomb technicians estimated the weight of the explosives to be 16.5 pounds. without using a scale, Moore said. The vessel is designed to take, at most, 25 pounds for a single-use and 15 pounds for multiple uses. An investigation by The Bureau of Alcohol, Tobacco, Firearms and Explosives National Response Team found that the actual weight of the explosives was over 42 pounds."

RE: LAPD blast containment truck fails, seventeen people injured

There goes your factor of safety...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

My first thought was that it makes no sense to guess to the limit when they could take more time and do multiple explosions. My next thought was that this happened on the holiday weekend so they rushed it to get home. But, checking the date again it was a few days too early for that excuse.

RE: LAPD blast containment truck fails, seventeen people injured

You would think that those guys, if anyone, would know what they were dealing with.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

At least we now know that there wasn't a problem with the containment vessel, there was just a problem with people using it! When you put a lot more explosives in the device that it was designed to contain it's bound to cause problems! I'm surprised that the device itself doesn't have some way of weighing the devices put inside of it but it probably will after this experience!

RE: LAPD blast containment truck fails, seventeen people injured

definately no one on the team had this mantra

“when you can measure what
you are speaking about, …
you know something about it;
but when you cannot measure it, …
your knowledge is of a meagre
and unsatisfactory kind…” Lord Kelvin 1883

But in their defense, taking a "bomb" apart so you can measure just the explosive would not be a job anyone would like

erring on the "safe" side should be a golden tule

RE: LAPD blast containment truck fails, seventeen people injured

I do wonder if confining the material made it worse.

How bad would it have been if they'd tossed the stuff in a Weber, doused it with kerosene, and tossed a match.

True, a populated area may not be the best place for such an experiment. But I'll also bet you could've sold tickets.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

Some explosives detonate by heat, others percussion. A fire is not a one size fits all solution here. I'm sure the counter charges are expensive. Department was probably trying to save money.

RE: LAPD blast containment truck fails, seventeen people injured

The explosives don't have to detonate by heat, if they just burn up, that's okay too.
Call out one of those pier-drilling rigs, dig a shaft 50' deep, shovel everything in, sell tickets, throw in the gasoline and the match.

RE: LAPD blast containment truck fails, seventeen people injured

I want to know what they blew up the other 42 times.

RE: LAPD blast containment truck fails, seventeen people injured

Unattended luggage from the airport.

RE: LAPD blast containment truck fails, seventeen people injured

It seems to me that a factor 2 is not adequate for such a catastrophic possibility. There's at least a 50% difference in detonation pressure amongst various explosives such as PETN and Semtex, so one would think that the safety margin would need to be more like 4x or higher, to account for explosive variability, errors in weighing, potential errors/defects in operation/construction.

I don't know how accurately the bomb squad can assess the actual explosive, i.e., 25 lb of PETN vs. 25 lb of Semtex

Also, there's literature on how the detonation velocity, which is dependent on detonation pressure, is a function of the amount/density of explosive https://www.osti.gov/servlets/purl/5560850
https://aip.scitation.org/doi/pdf/10.1063/1.504498... seems to say there's at least around a factor of 2 in detonation pressure between various explosives.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: LAPD blast containment truck fails, seventeen people injured

That is something I have been thinking about what is the most "explosiv" material per gram is it TNT or Military C-4.
Both TNT and Military C-4 is used as a measurement of what the container can take.
But what is that the most explosive thing per gram that someone can be put tougher when making explosivs. ponder

And even if they only X-rayed the cans and made a estimate, it hade been safer to assume it was the maximum amount that could be put in them, that where the weight.

Quote (SFGate)

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 larger ones sade they were about 5 ounces (142 grams).

In SE a soda can is 33 cl if you fill it up with flash powder 5 parts potassium nitrate, to 3 parts aluminum powder, to 2 parts sulfur
The potassium nitrate and sulfur aprox (2gram/cm3) = 46,2 gram aluminum powder aprox (1 g/cm3) = 9,9 grams.
The powder or can would weighed around 56,1 grams.

So there is some miscalculation on someone's part or maybe your soda cans are not 33 cl.
Or it wasn't potassium nitrate, aluminum powder, sulfur flash powder.

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

I think the whole thing is run incorrectly. If you have a pile of things to blow up why would you not blow up a single one to take it's measure. Look at the pressure wave data generated and looking at some chart that pukes out TNT equivalence. Then there is zero explosive percentage estimation, zero weighing, and zero guessing of TNT equivalence. A small device would probably exclude the need for any kind of detailed inspection of the chamber post detonation.

That process would dump out, "You can depose of 12 devices at a time".

Keith Cress
kcress - http://www.flaminsystems.com

RE: LAPD blast containment truck fails, seventeen people injured

to be honest even with my extreme low level knowledge of such things i can't understand why you would want to blow fireworks anyway.

They are mostly powder.

The easiest way of dealing with powder is to soak it with water which then kills the saltpeter and for ever more its useless. The biggest issue when I was involved in doing that was the waste water afterwards had to be disposed of because the water board didn't want such a huge amount of salty water screwing up the sewage system.

RE: LAPD blast containment truck fails, seventeen people injured

I think calling the expolosive "fireworks" is to misinformation the facts possible militarty (terorist) grade high explosives were mixed with possible proffesional grade fireworks

RE: LAPD blast containment truck fails, seventeen people injured

yes but if the fireworks are useless there is no initiator for the HE which is pretty harmless then. You can throw it on a fire and it won't go bang. You can even eat it if you want.

RE: LAPD blast containment truck fails, seventeen people injured

I guess the answer is if you have a hammer, you treat everything as a nail. If you have a box to safely blow stuff up, you put stuff in the box.

Operators are rarely like engineers with a curious mind, but people who want to get the job done, and in this case return the neighbourhood to the residents.

RE: LAPD blast containment truck fails, seventeen people injured

aye but you don't hit a picture frame pin with a sledge hammer

RE: LAPD blast containment truck fails, seventeen people injured

I would still like to know what is considered to be the volym of a soda can in the US ponder

BR A

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

RE: LAPD blast containment truck fails, seventeen people injured

Your typical 'soda can' (where I grew-up we called them 'pop cans') in the US is 12 fluid ounces or 355 mL.

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: LAPD blast containment truck fails, seventeen people injured

Okey Tanks John.

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

RE: LAPD blast containment truck fails, seventeen people injured

In war zones they put some plastic in them and then fill them up with nuts and metal cutting in animal poo. Then use a drop hammer to fire a bullet percussion into the plastic which is triggered by a trip wire.

RE: LAPD blast containment truck fails, seventeen people injured

In the first article cited by the OP

Quote:

However, 'improvised explosives' also were found that were too dangerous to move.

He described them as 40 home-made devices the size of Coca-Cola cans with simple fuses and 200 smaller but similar devices.

These IEDs were the ones being disposed of. The article claims 5000 pounds of fireworks, which obviously were not exploded in the containment vessel.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: LAPD blast containment truck fails, seventeen people injured

For that... they need a whole bunch of trucks.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

I presume the guy they arrested is looking at a very long time in prison?

RE: LAPD blast containment truck fails, seventeen people injured

Must admit the burns and disposals of bulk the BDO's always did a test shot first with one or two then if that was fine doubled it until it got bum twitching.

But then again they never had anything as fancy as that contraption.

And they had us grunts to shift sand bags which they crafted into a pit which apparently was a special shape to focus the blast upwards.

RE: LAPD blast containment truck fails, seventeen people injured

I showed this link and photos to a Thai police friend who was until very recently in command of the Northern region SWAT team, had to get my wife to translate a couple of the finer points into Thai and in turn translate a few questions back to me, his reaction was, a look of amazement, a shake of the head and x*"#*" in Thai.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: LAPD blast containment truck fails, seventeen people injured

Quote (I presume the guy they arrested is looking at a very long time in prison?)


how about those that actually did the damage; is he responsible for that?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

Quote (dik)

how about those that actually did the damage; is he responsible for that?
It can (and has in the past) be argued in court that he is responsible... he created a dangerous situation by making the bombs, and the fact that someone else screwed up and made the situation worse doesn't necessarily absolve the original situation creator.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: LAPD blast containment truck fails, seventeen people injured

On the other hand may gross incompetence rise to the level of criminal negligence?
Not expecting that charge to ever be laid.

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

RE: LAPD blast containment truck fails, seventeen people injured

If the police had been following proper protocol, I think it might make sense to hold the "owner" additionally responsible.

But they were not.

You might as well try adding charges for when a cop shoots himself while reholstering his weapon after arresting someone. Would a jury go for it?

Qualified immunity protects cops when they are attempting to do what a reasonable person would do, but turn out to be wrong. For this to apply, a reasonable person would have to have put 45 pounds of explosives in a container not designed for it, after being instructed not to. It would probably be argued that they THOUGHT they were not exceeding the weight limit.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

I would be pretty surprised if someone doesn't have an order-of-magnitude rough feel for what 42 pounds feels like compared to 15...

Dan - Owner
http://www.Hi-TecDesigns.com

RE: LAPD blast containment truck fails, seventeen people injured

Not shore they actually got it that wrong, there is something not adding up here.

Quote (SFGate)

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 larger ones sade they were about 5 ounces (142 grams).

If the soda cans was the size JohnRBaker suggests 12 fluid ounces or 355 mL.
And the flash powder was 5 parts potassium nitrate, to 3 parts aluminum powder, to 2 parts sulfur
The cans would have contained approximately 49,7 gram potassium nitrate and sulfur approx. (2gram/cm3)
and 10,65 grams aluminum powder approx. (1 g/cm3).
Totally the cans would have contained around 60,35 grams of flash powder fully filled up.
That's more then 42,5 gr as was calculated by the people on site but it is definitely much less then the federal authorities calculation of 142 gr.

So either there wasn't flash powder in the cans, but something else, or the they use flash powder as a term for anything that can go bom!

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

I understand that there is a conversion factor involved and the value are equivalent weights rather than actual weights.

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

RE: LAPD blast containment truck fails, seventeen people injured

Quote (RedSnake (Electrical))

there is something not adding up here.
cl = centiliter?

Then 1 cl = 10 cm^3

Your calculations were otherwise correct for the density of that mix. Keep in mind powder contains some air. It's typically 1-1.3 g / cm3 for blasting powders, 1.57 for C4.

I'm not sure how the bomb techs miscalculated by 3x after x-raying. It's possible x-ray was inconclusive and they overestimated the skill of the fireworks maker. Generally home-made/low-quality devices would be suspected to contain more functional material at the cost of safety & quality material. They knew the devices were leaking...

It also might reflect poorly on rigid police protocols if they could not take advantage of detonating a small sample to estimate yield.

RE: LAPD blast containment truck fails, seventeen people injured

"Federal authorities who weighed the larger ones sade they were about 5 ounces (142 grams)."

That says the federal authorities weighed the larger ones, not calculated. So the larger ones weighed about 5 oz, and that's 141.75g, or 140g for a bit less false precision. Somewhere between 100-200g, anyway. Probably not pure flash powder.

RE: LAPD blast containment truck fails, seventeen people injured

The elephant in the room is that they knowingly put 16.5 lbs in which is still over the rated capacity. Me thinks the party was mathematically lacking. That is all.

15 lbs is the max reusable shot and you know they were planning to reuse the vessel because there were enough explosives left over for the feds to analyze and estimate the actual load.

RE: LAPD blast containment truck fails, seventeen people injured

Using the word "knowingly" might be a little generous.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

The responsible party said they put 16.5 lbs in, intentionally. They didn't know it was actually 42 lbs. Both measures exceeded the rating. It's as if they didn't know 16.5 lbs was greater than 15 lbs. With that bit of knowledge, I would be extremely surprised if they were able to do the multiplication to calculate the total charge.

RE: LAPD blast containment truck fails, seventeen people injured

Quote (SFGate)

The bomb technicians — 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."

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.

2014 https://www.dhs.gov/sites/default/files/publicatio...
TNT equivalent 2014


https://store.mssdefence.com/home/1293-nabco-nabco...


The detonation chamber's maximum capacity is 15 pounds (6.8 kilograms) of what. ponder
Here it says 15 lbs. MIL-C4

Since everything is recalculated in TNT equivalent it should have sade it could take multiple blasts of 19.4 lbs. (8,8 kg) TNT.
(8,8 x 4,6)/6,8 = 5,95MJ (Military C-4 (5,9 - 6,7 MJ/kg))

Energy density
TNT 4,6 MJ/kg
Military C-4 5.9 - 6,7 MJ/kg
Flash powder 9,2 MJ/kg

And one blast of 26 lbs. (11,8 kg) TNT equivalent.

Not sure the people on site got the 15 lbs. vs 16,5 lbs. wrong, it might have been Chief Moore that hadn't read the specs properly.

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

Why have a TNT rating for one value and C4 for another? I think your first link is correct and your second in error. Interesting that flash powder has a higher energy density than commercial explosives.

RE: LAPD blast containment truck fails, seventeen people injured

Well if the first link is correct then it would have been okey to put in 19.4 lbs. (8,8 kg) TNT equivalent.

And if so they are both correct as it is the same value in MJ
19,4 lbs. TNT 8,8 x 4,6 = 40,48 MJ
15 lbs. MIL-C4 6,8 x 5,95 = 40,46 MJ

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

Tug its to do with the amount of gas produced.

Explosives its a combination of speed of detonation, pressure front, temperature and a few other factors.

Flash powder takes up colossal volume, is relatively slow and produces lower pressure. So even though its got a higher energy yield it produces less of a bang with a lot of it being turned into heat slowly which lowers the pressure front......


This is going back 30 years now so distant memory of a lecture standing soaked on a pissing wet day in wales on Sennybridge ranges.

RE: LAPD blast containment truck fails, seventeen people injured

Red, the patent calls out 15 lbs TNT.

Quote:

The design charge weights for the present invention are:
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).
26-lbs TNT—one-time event with venting. Major repairs may be required to all components of the system. However, the system will retain structural integrity during the event.

https://patents.google.com/patent/US20090044690 (same as posted earlier)


I think the manufacturer's description is poorly worded. It should state that it is rated for one time use at charges over 15 lbs and up to 26 lbs. I think the description isn't sufficient for non-engineer types.

RE: LAPD blast containment truck fails, seventeen people injured

Yes I remembered seeing some different values here, but then the Total Containment Vessels Market Survey Report
done by Space and Naval Warfare Systems Center Atlantic in 2014 for Homeland Security isn't correct.
And they claim they took the values from NABCOs homepage.
/A

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

RE: LAPD blast containment truck fails, seventeen people injured

They use factorisation with the TNT as the base line for loadings for some things.

But it doesn't really work in some situations.

You can cut metal with C4 with a sausage half the width of your finger with a bit of copper wire under it. It just won't work with TNT or powder using the same factorisation adjustments to amount. You will just get a big bang and smoke and the tank track will just be sitting there saying screw you buddy.

HE is actually good fun stuff to use and its very handy to do quick jobs. Much less hassle than using a cutting torch

RE: LAPD blast containment truck fails, seventeen people injured

More fun then snail dynamit I suppose. lol

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

yep and less dangerous than real dynamite. There is pretty much no restrictions on HE mil explosives in how you carry it and naked flames etc. So you can just stick in in your Bergan and use it as required its relatively light. Dynamite/TNT comes in big metal boxes and you have to set up no flame zones around it and there is a heap of storage restrictions as well.

RE: LAPD blast containment truck fails, seventeen people injured

Considering the patent is in pounds and the market survey report is in kilograms and we now know the people that surround these chambers are bad at math, I'd wager that there was an error in conversion to get the metric number.

RE: LAPD blast containment truck fails, seventeen people injured

Yes I have been thinking about that too but it would have been less then twice the amount and not three.
And there should be programs or ready made tables for this, I would think.

And Í wonder what "in a standard flash powder measurement" stands for?

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

bad at math... reminds me of the Gimli Glider...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

How did they weigh what was put in the unit? Sorry if that's already been answered before.

Precision guess work based on information provided by those of questionable knowledge

RE: LAPD blast containment truck fails, seventeen people injured

Quote (Demented)

How did they weigh what was put in the unit? Sorry if that's already been answered before.
Your tag line answers that question quite well.

Quote (Answer)

Precision guess work based on information provided by those of questionable knowledge

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

RE: LAPD blast containment truck fails, seventeen people injured

They X-rayed one, two, some, all ponder and made a estimate idea and then recalculated it some way to TNT equivalents.bomb

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

Do we know what the specs of the X-ray device?
They measure through the side of the can, bottom of the can, through the open mouth? You'll get inaccurate readings of Al content if your calibration is off or you're too far away and you measure through the can.

Edit:
I've x-rayed my fair share of metals with XRF guns. You can get wildly different results if you use it incorrectly. So much so you could easily be lead to think the firework maker sucked and filled cans with mostly Al powder and not enough oxidizer, therefore putting more cans in than they should have. This could be simply failure to RTFM of the testing equipment.
I bet those bomb guys looked over every inch of that container before using it each time.

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
https://patents.google.com/patent/US8621973B2/en?q...

Quote from above patent (Read the entire patent please, this is for a competing device) >

A principal disadvantage of these prior art devices is that they are necessarily large and bulky because they rely for blast containment on a large internal chamber volume enclosed by a relatively thin spherical chamber body, often of aluminum. While providing greater physical volume can better contain and suppress a controlled detonation, it also requires a larger chamber opening. Such a large opening, while facilitating the loading of a threat device, necessarily results in a greatly increased door surface area. Thus the total separation force from a given internal explosion pressure are equally increased. When combined with relatively weak construction materials and unreliable door-sealing mechanisms, these prior art devices can become unreliable or even dangerous from a safety standpoint. Because of the stresses and deformation that necessarily accompany a detonation of any size (10 lb or TNT or more), certain of these aluminum-body spherical chambers are believed to be one-shot tools at best.



RE: LAPD blast containment truck fails, seventeen people injured

Aluminum?

I'd go with styrofoam, with a heavy coating of enamel paint, inside and out, for added strength.

To secure the door, I'd use top quality twine, tied with a DOUBLE knot.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
One side of the clamping yoke can be seen in this still frame.




Half of clamp under tree

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
Someone help me. Are these the soda can sized devices? They do not look home-made or improvised to me.



Source: https://youtu.be/0HmmVgjOQfw

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
The other side of the clamp was captured by the roof of the overturned car.

RE: LAPD blast containment truck fails, seventeen people injured

If those are homemade, then I am the queen of France.
https://youtu.be/0HmmVgjOQfw?t=143

So, how many boxes did they fit in there?

Precision guess work based on information provided by those of questionable knowledge

RE: LAPD blast containment truck fails, seventeen people injured



I too am surprised to see a safety cap on an improvised explosive.

It does appear the door came off sideways and impacted the overturned car as the car is nearly cut in half through the b pillar. I'm sure the lid was deflected upwards and onwards by the car. I have seen the same thing happen with a bowling ball fires from an oxygen cylinder with 4 ounces of Pyrodex behind it.

RE: LAPD blast containment truck fails, seventeen people injured

I think that's half the lock--two halve sliding open sideways--normally?

And I think the door flew WAY over to somebody's house.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

(OP)
spsalso,

I think you are correct. The hatch (without its hinge) flew blocks, struck a house and ended up in the yard. One half of the yoke clamp with the threaded rods still attached ended up under the tree as depicted. The other half hit the over turned car. The hatch/door did no strike the car.

RE: LAPD blast containment truck fails, seventeen people injured

Over 50 years back they were doing experiments in explosive welding at the UofM. I was't involved with it at all, but they had a large sphere about 15' or 20' dia and they were using CIL sheet explosive for the welding. The sphere was sealed, and I'm pretty sure a partial vacuum was created to minimise the effects of the blast. They were just using small 'chunks' of the sheet explosive, about 3"x6"; it was about 3/16" thick if memory serves.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

Quote:

They do not look home-made or improvised to me.

I expect that they labeled them as "improvised" because they had no markings and no manufacturing information. Doesn't mean they weren't "manufactured;" there were lots of garage shops in Iraq and Afghanistan that could crank out explosively formed projectiles (EFPs) that were both professional looking and effective.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: LAPD blast containment truck fails, seventeen people injured

Quote (IRstuff)


there were lots of garage shops in Iraq and Afghanistan that could crank out explosively formed projectiles (EFPs) that were both professional looking and effective.


It's not right to discount the many other professionals throughout the world,beyond Iraq and Afghanistan, that can do this kind of work. I think it's important to acknowledge that the world is full of people who are competent to assemble explosive devices.

Except, perhaps, the LAPD. Not that they WOULD, of course.....


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

Quote:

world is full of people who are competent to assemble explosive devices.

Except, perhaps, the LAPD. Not that they WOULD, of course.....
They don't seem to be competent to even disassemble explosive devices. grin

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

RE: LAPD blast containment truck fails, seventeen people injured

Cover your ass. Always label as IED so that when something goes wrong you can blame the unpredictable nature of IED. The evidence destroys itself in either case so nobody will know.

RE: LAPD blast containment truck fails, seventeen people injured

Are there ISO standards for IED's?

Might be time to write a proposal and kick it upstairs (did I get that right?). GOTTA bring the EU in on this!

We CANNOT have any fly-by-night group building these without conforming to international standards.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

Aye get the European commission on it.

No IDE parts can be used from main land UK for future IRA or unionist terrorism if they are smuggled in with chilled meat products.



RE: LAPD blast containment truck fails, seventeen people injured

There was a story of some sappers blowing some rocks and tree stump out down in a valley in Germany.

Bang ground goes up and suddenly they is loads of water appearing.

A muffled crump is heard at the top of the hill as a water tower tank implodes after 20 mins.

Hey boss I though you said we were blowing stuff up today not killing things by giving it a blow job.

The qmsi didn't even look at him... Start running son back to camp and don't stop until I find you. If you get there before us start coming back.

RE: LAPD blast containment truck fails, seventeen people injured

For the lid flying of look at post 4 Jul 21 07:40

smile
Well at least the Canadians seems to have this under control.
If you want to find European specialist's go to Malta, there is a fire display home manufacturer i in almost every garage. ponder

https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/file...

Quote:

F.2 - Display Fireworks
The default NEQ of display fireworks that have been classified 1.3G for transportation is 75% of gross mass.
For display fireworks containing flash powder* that have been classified 1.1G for transportation (i.e. salute aerial shells), the NEEQ (TNT equivalency) must be used.
The NEEQ in this situation is 70% of NEQ.
The NEQ would be 75% of gross mass.
Otherwise, the NEEQ (TNT equivalency) for all other display fireworks classified
1.1G for transportation (i.e. shells with diameter size > 155mm) is 50% of NEQ.
Again, the NEQ would be 75% of gross mass.

Quote (Auri)

It's typically 1-1.3 g / cm3 for blasting powders

So (355 ml x 1,3 gram/cm3 x 0,75)/2 = 173 gram TNT ekvivalens.

Quote:

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).

/A


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

RE: LAPD blast containment truck fails, seventeen people injured

Quote (spsalso)

Are there ISO standards for IED's?
I guess you could refer to ISO 25947-3:2017. lol
ISO 25947-3:2017
Fireworks — Categories 1, 2 and 3 — Part 3: Minimum labelling requirements

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

The difference in tone between the stories is remarkable. In California news, fireworks are "unstable" and "IED". In rural America, fireworks "deteriorate" and get "removed".

RE: LAPD blast containment truck fails, seventeen people injured

I remember the gender reveal party and the 80 lbs of Tannerite (sp?) recently... can't ever have too much fun... as kids we had a crate of railway torpedoes... lots of fun...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

Some guys get all the luck. We never got railway torpedoes, just the occasional fusee flare.

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

RE: LAPD blast containment truck fails, seventeen people injured

For the railroad illiterate, a railroad "torpedo" is a device that is attached to a railtop. When a locomotive or rolling stock hit it, it explodes so as to make a loud noise. They can be used in multiple.

It is a warning device, not infrequently used to warn of a "difficulty" on the route ahead.


From "The Consolidated Code of Operating Rules" (1959):

"The explosion of two torpedoes is a signal to immediately reduce speed to twenty (20) miles per hour...keeping a close lookout for train or obstruction."


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

and three of them in a row... 'really warns', we found out... we also had a dozen or so fusees... and if you clamp a torpedo on a fusee... it just burns, we found that out too... we were clever kids and still have all our limbs. Only casualty was one kid lost his eyesight from rocket fuel...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured


This is a safer alternative
2 H2O + CaC2 => H2C2 + Ca(OH)2

H2C2 + spark = BANG

RE: LAPD blast containment truck fails, seventeen people injured

Quote (FacEngrPE (Mechanical) 7 Aug 21 10:36)

This is a safer alternative

Not all the Time !
Substituding FFG when one runs out of Bangsite worked OK in the cannon for a few bangs. Running out of fuse taught me a lesson for life.
"If first time, test the components seperatly"

Just seeing the ad gave me a cold chill, the beard hides all the specks embedded

RE: LAPD blast containment truck fails, seventeen people injured

When I was a kid, I used to have a carbide lamp... old miner's lamp... and remember the toy carbide cannons from back then.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

The carbide cannons that I remember were in shops and were connected to acetylene torches.

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

RE: LAPD blast containment truck fails, seventeen people injured

Never had one, nor knew anyone that did... I recall the ads in some magazines... Popular Mechanics, maybe... don't recall...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: LAPD blast containment truck fails, seventeen people injured

On the "Beyond the Press" youtube channel, he's done some acetylene explosions, and I seem to recall hearing there that mixing acetylene and oxygen and then igniting made just an unreasonably loud bang, a lot louder than would be expected from a little gas igniting, as in earsplitting deafening loudness.

RE: LAPD blast containment truck fails, seventeen people injured

Oh it makes a good boom. The deafness in my left ear is partially from acetylene explosions.
I learned the hard way a few years ago, always make sure no one in the shop has PTSD before you start having fun with solo cup cannons.

Precision guess work based on information provided by those of questionable knowledge

RE: LAPD blast containment truck fails, seventeen people injured

You're my kind of people.

But perhaps at a safe distance.


spsalso

RE: LAPD blast containment truck fails, seventeen people injured

You guys and your toys, sigh... cannon

/A

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

RE: LAPD blast containment truck fails, seventeen people injured

A 1/4" NPT pipe about 2 ft long makes a good cannon or machine gun when you insert an oxy-acetylene torch (adjusted to a neutral flame) in one end. If you place a pilot light at the other end it will fire like a machine gun, with the rate of fire determined by the flow rate and length of pipe. If you use a push-button spark igniter instead of a pilot light it fires in semi-auto. It sounds just like a real gun. You can buy commercial versions that are used in movie production, for thousands dollars each.

RE: LAPD blast containment truck fails, seventeen people injured

Carbide Acetylene Gas Generator.

The units that I remember were similar except that rather than the round chamber on top there was a quarter turn valve about 3 inches in diameter that controlled the water flow.
Gas pressure stopped the water flow. As the pressure dropped, the water flow resumed.

Quote (Wiki)

Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi). Most regulators and pressure gauges on equipment report gauge pressure, and the safe limit for acetylene therefore is 101 kPagage, or 15 psig.[
Eventually the water valve would start to leak and the pressure would build up until the generator became a bomb waiting for a trigger.

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

RE: LAPD blast containment truck fails, seventeen people injured

Acetylene cannons used to be pretty common hereabouts as deterrents to birds during the rice harvest.

When I was in high school one showed up at the industrial arts (remember that?) class for some work. Naturally we had to test it. It made quite a racket - small howitzer level noise - and we 'tested' it multiple times.

In today's world, I cannot begin to imagine the impact of such a thing at a school. Back then? Just another day.

They weren't that effective at their intended use. After a few blasts, birds seem to differentiate between the acetylene cannon and a farmer with a shotgun, and go about their business accordingly.

Another interesting bird mitigation technique involved flying a light plane (J-3 Cubs worked well) over the fields to roust the birds. You could tell whose plane was used for this by the dents in the wing's leading edge.

old field guy

RE: LAPD blast containment truck fails, seventeen people injured

I had one of those BIG BANG cannons. I remember being impressed by the design in that you really couldn't screw it up. The enclosed volume and ignition mix couldn't be screwed with enough to exceed the structural limits unless, of course, you used 'other chemicals'. Lost mine in the hedge, found it a couple of decades later.

Keith Cress
kcress - http://www.flaminsystems.com

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