How does a controlled explosion work?
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Just curious as I've always wondered this - when there is a suspicious package/vehicle (like the one reported today at Gatwick) and a controlled explosion is carried out - how does that work? How does it not make any real bomb go off?
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Anyone else? :P
1 Bury the bomb and detonate it while everyone stays well back.
2 pack the bomb inder a ton of sandbags and do as above.
3 drop the bomb in deep water and explode, following the above advice about standing well back.
I'm sure there are others too.
I seem to remember a special lorry with a reinforced box on the back that the explosives could be placed in and detonated.
How is a controlled explosion carried out?
That sort of thing is for when you want the full force of a bomb or other explosive to go off - just in a controlled environment...
In bomb disposal terms - they roll up the "chariot" remote control robot - see the top pic here http://en.wikipedia.org/wiki/Bomb_disposal_robot - which is "armed" with a stunted shotgun thing that fires a big half-inch lead ball, a lot like an old musket round...guided by camera on the chariot...and the impact is supposed to blast the IED physically apart - splitting any primer charge from the main charge, smashing any circuitry, ripping wires apart etc.
Fired at very short range, such a heavy impact will look to a camera seeing it from distance like a small explosion...and a primer charge on an IED or car bomb CAN go off - but that's what they want - it to go off WITHOUT setting off the rest of any larger device
(the half-inch "ball" ammunition is actually in the form of a shotgun cartridge...and it wasn't unknown in NI for those rounds to get into the hands of UDR or RUC personnel who just happened to have shotguns at home...:D)
Thanks - sounds risky and huge respect to those who undertake this!
Thanks for all replies - would like to quote more but don't know how to 'multi quote' - still learning (you can see why I struggle with science)
Controlled explosion: they are trying to mechanically disrupt the explosive charge, by blasting it into small pieces. The chemical reaction that would have been the explosion doesn't then occur, minimising the damage and making the device safe.
What I'd like someone to explain to me is why this isn't always an option, and why we still need people laboriously making devices safe, at great personal risk, even when they are in the middle of a dirt track...
Some explosive devices are SO simple that "disrupting" them by blowing them apart doesn't work well; some are so complicated, with multiple fuzing systems etc, and antihandling/tremblor devices that any attempt to manually defuse or disrupt by controlled explosion actually triggers the back up fuzing system and blows the bomb anyway!
Some devices - like car/van bombs, are so well-hidden inside panelwork etc.that you can't see where the best option for disrupting the device is;some are composed of so many separate bags of enriched fertiliser that one controlled explosion wouldn't be enough to defuse/disrupt it!
And some - like....ahem...pressure cooker bombs - might have all or enough of their internal workings and components inside a hardened case that it affords the bomb some protection against a controlled explosion.
Also - controlled explosions are a RISK; there's no guarantee that a controlled explosion WON'T set off a full IED....so sometimes it's simply easier and safer to send in the guy in the armoured oversuit...
Er...what you mean is that it explodes...or preferably not, or not fully!...at the decision of the bomb disposal team, not the terrorist
It's all semantics.
There's a world of real difference between a "citybuster" van bomb going off and levelling a city block or two...the only difference being between the terrorists or their timing devices set it off or the bomb disposal team...
...and a "controlled explosion" designed to REDUCE the destructive capacity of the IED.
Vans stuffed full of fertiliser, supposedly "viable", or possibly a dud, and we're all to believe we were in gravest peril. If it helps you feel safer then by all means, but it's just security spin to me.
Look left...what do you see? The word "Belfast"...
I'm old enough to have lived throyugh the NI Troubles...and old enough to have worked for a year in the NI Forensic Science lab at the height of them....as well as sat in a cinema as the outside wall blew in from the no-warningcar bomb outside...
Even if I hadn't experienced and lived through the things I have -I'd know that the landscape of the city and towns I knew as a kid were changed utterly by those heavyhanded town planners, the Provisional IRA.
The real word, the one we live in, is nothing like your fantasy, shiny, primary colour Lloyds TSB-advert world where everyone has long noses and pet alligators, where there's no such thing as no-warning carbombs or exploding rucksacks on buses and underground trains.
The real world is a place where people DO try to kill large numbers of people at random on British streets, and have been doing it since the 1970s (well, earlier actually - the old IRA mounted three-year bombing offensive in the UK beginning in 1938!) AND they don't actually bother telling anyone in advance nowadays that they're going to - no nice polite codeworded phonecalls to newspapers saying "hi this is your local jihadist, I'm calling you from the top deck of a London bus..."...
In THIS world - there is a real and ongoing, long duration threat; and if it reared it's head and nothing was done about it and people killed when there was a chance of saving them...you'd be jumping up and down tomorrow on your soap box demanding to know why not.
I'm quite happy there's such a thing in this world as a "controlled explosion" - it has saved my life on a number of occasions. Nor is the threat "spin" as you put it; in fact, regarding the very real threat as "spin" is pretty damn insulting to all the dead of 7/7 and every other bomb outrage on British streets.
I'm sure their families would wish their loved ones could have been saved by a bomb alert and a controlled explosion...
Yes, because Oceania has always been at war with Eastasia.