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  1. #1
    Join Date
    Dec 2009
    Posts
    1,268
    Country: United States

    Default Vault Construction Details

    With the Hatton Garden burglary still in the news I started thinking about vault construction details, so I thought I'd start a new thread to discuss this. I don't intend to discuss how to break in, only how make to improvements.

    At Hatton Garden and other burglaries the tool du jour seems to be the diamond-tipped core drill. Two ideas come to mind to thwart such an attack, or at least to slow it down. Aside from basic construction methods (high strength concrete, lots of rebar, possibly some deflector plates or hard steel bits thrown in), one idea is to mix into the concrete some sort of hard and sticky substance in the hope of seizing the core drill to stop it and to make extraction difficult. Capsules of something in between tree sap and amber come to mind. Also capsules of a fast setting epoxy but they need to be stable for at least the expected life of the building if not beyond. If used in great abundance they might impact the strength of the concrete, and after pouring, they might tend to float up in the concrete. I consider this an interesting but iffy idea that would require lots of experimentation.

    Another anti-diamond-core-drill possibility is to mix in tungsten carbide cutting bits as used in machining. There are likely tons of broken/dulled inserts generated every day. Is there any sort of recycling being done? These could possibly be obtained in large quantities. Though diamond is harder than tungsten carbide, it might still slow down a drill significantly. This would require a fair amount of experimentation to determine the utility.

    Most of today's high strength concrete is probably fairly resistant to the good old jackhammer. Plus it's slow and noisy and gets bogged down when the rebar is hit. But a friend suggested that mixing in a little bit of carbon fiber might make concrete more resistant. When a jackhammer breaks free a bit of the concrete at the surface it just likely falls away but with carbon fiber it might tend more to just stay in place, requiring extra work to break the fibers. I'm not too convinced but it's an interesting idea.

    Any other thoughts, even if they aren't very economical or practical?

  2. #2
    Join Date
    Dec 2009
    Posts
    1,268
    Country: United States

    Default

    Some types of rebar are epoxy coated, normally for corrosion resistance (not an expected issue for vaults). It might be possible to mix in a small amount of industrial diamond dust ("junk" diamond, even by industrial standards, if there is such a thing) into the epoxy. Alternatively, give the rebar a light coating of diamond then apply the epoxy or other coating to hold it in place until the concrete is poured. This might slow down a core drill enough to be useful. But it might also be excessively expensive in quantities that would do any good.

  3. #3
    Join Date
    Sep 2007
    Location
    Aberdeenshire
    Posts
    417
    Country: Great Britain

    Default Strongroom Construction.

    Quote Originally Posted by wylk View Post
    Some types of rebar are epoxy coated, normally for corrosion resistance (not an expected issue for vaults). It might be possible to mix in a small amount of industrial diamond dust ("junk" diamond, even by industrial standards, if there is such a thing) into the epoxy. Alternatively, give the rebar a light coating of diamond then apply the epoxy or other coating to hold it in place until the concrete is poured. This might slow down a core drill enough to be useful. But it might also be excessively expensive in quantities that would do any good.

    Some interesting ideas there wylk.

    To add to these could be the method used successfully by Tann in their modular panels for demountable strongrooms way back in time.

    They managed to achieve equivalent resistance times to 12" reinforced concrete in their 4" panels against the 100mm diamond core drill by the use of small (approx. 2mm.) ball bearings within the mix. The test results showed that as the dia.tube penetrated the concrete the balls began to accumulate around the cutting head groove causing some segments to break off causing the drill to seize.

  4. #4
    Join Date
    Aug 2013
    Posts
    1,454
    Country: Wales

    Default

    Interesting subject wylk. I think a lot of the potential solutions would also be governed by balancing the mix ratios, without 'over-filling' the concrete with too much solids or additives.
    In the same way the balance is critical using steel reinforcements, spiral, mattresses, rebar etc it all has to be right in order to prevent oversteeling of the concrete.

    The carbon fibre idea is one I've pondered over for a long time. Can't help thinking that it might have a lot of potential uses for safe and vault protection, I'm surprised that we don't hear more mention of it, especially with German manufacturers like Stacke.

    Not sure about the diamond dust idea, think dust might act more like a mild polishing abrasive, it'd need to be gritty chips of material like those deposited on coarse files and rasps in order to be most effective.
    The big problem with diamond coating anything for vault walls is you need a lot of it because of the massive surface areas involved.
    I'm sure that if internal reinforcements had an electro-deposited diamond coating it would be highly effective against the core drill, albeit costing more than the rest of the vault put together!

    i think the combined use of hard and soft materials to choke and clog cutting tools is an often overlooked one. I experimented years ago and found that a particularly soft and 'sticky' grade of aluminium alloy 'seeded' with Ball bearings gave reasonable resistance against even the fiercest disc-cutter. Once the disc choked with the soft alloy it became largely ineffective. Perhaps Soft plastic inserts or epoxy resins could be used as a cheap way of achieving similar in a concrete matrix, it all helps to buy that bit of extra time.

    safeman, your mention of Tann's use of ball bearings reminded me of a Tann Bankers I opened years ago, was early 1960s model I think, with chrome trim and two brass 10-lever locks. Think I put one hole through the side into the bolt case and 2 through the front over the locks(4 and a half inch door slab from memory) and can remember clearly both door and body had loads of tiny ball bearings in the mix. Perhaps this was similar to their vault panels idea? Was simple but effective, I wasn't using a core drill but it was tough stuff and frequently chipped the cutting edges of the TC tipped drills. anyway I've lost this a few times now and managed to bring it back so time to go before I lose the entire lot, happy new year everyone :-)

  5. #5
    Join Date
    Feb 2014
    Posts
    157
    Country: Great Britain

    Default

    I realise the below is dated but makes interesting reading. Good old "Rivet Grip" may not survive attacks by modern tools I suspect



    https://dl.dropboxusercontent.com/u/74738260/Rivet-Grip_Steel_1924.pdf

  6. #6
    Join Date
    Sep 2007
    Location
    Aberdeenshire
    Posts
    417
    Country: Great Britain

    Default Security

    Security, not unlike buying a car, is a compromise. In what circumstances will the product be expected to perform to itsí maximum?
    Mass is strength but not necessarily practical. Each component has itís failure point and has to be positioned in the most effective way within the mass to achieve itsí potential.
    The Hatton Garden robbery was successful not because of any failure of the mass or the components.
    As was the case in 1865 - the famous Cornhill Robbery - when the Strongest Holdfast Thief-resisting Milner safe was opened by wedges and levers in 35 minutes, Milnerís were cleared of the failure of their product because it was ruled that the thieves had been permitted free access for such a time without discovery that the product could not have been expected to resist.

    To put things in perspective regarding strongroom protection:

    Test to Skyddstekniska Kommitten Standard.
    500mm. Concrete wall. Manhole. SIS 3000 Specification.
    To make a manhole having minimum dimensions 420 x 320, time required 209.33 minutes. (net working time)
    Tools: Hammers, sledges, punches, chisels, Hilti Hammer Driller, 208, 250, 190 Hilti Drills.
    Concrete 47N with reinforcing grids 12mm and 6mm.
    Attached Thumbnails Attached Thumbnails Capture.JPG  

  7. #7
    Join Date
    Aug 2013
    Posts
    1,454
    Country: Wales

    Default

    That's the thing with vaults and strong rooms, they have for so long been often wrongly portrayed in ways which suggest total resistance against everything, and not for what they really are- a 6 sided enclosure that's simply designed to resist certain attacks for a certain (limited) amount of time.

    As a result they are often looked upon with extremely high expectations, often far more than for which they are intended.

  8. #8
    Join Date
    Nov 2014
    Location
    Kuwait
    Posts
    654
    Country: Kuwait

    Default

    One very good way of beefing things up is to get a supply of the TC bullets from the old APDS anti tank rounds. Use something of the sort to replace some of the aggregate in the concrete mix. Old broken drills, taps, dies, files etc are all old friends too.

  9. #9
    Join Date
    Feb 2014
    Posts
    157
    Country: Great Britain

    Default

    Quote Originally Posted by Chubby View Post
    One very good way of beefing things up is to get a supply of the TC bullets from the old APDS anti tank rounds. Use something of the sort to replace some of the aggregate in the concrete mix. Old broken drills, taps, dies, files etc are all old friends too.
    Would corrosion of files, drills, taps etc that get thown in the mix cause eventual weakening of the concrete ?

  10. #10
    Join Date
    Aug 2013
    Posts
    1,454
    Country: Wales

    Default

    Here's a couple of 1970s Fichet testing pictures showing the random pattern that twisted spiral reinforcement, in this case, Tordbar, presents to the attacker. Highly effective against mech chisel, hammer and oxy-arc:
    Click image for larger version. 

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