Beirut explosion

Via MSN:

A large cache of explosive material seized by the government years ago was stored where the explosions occurred, according to top Lebanese officials — specifically ammonium nitrate…

The cache was estimated to be 2,750 tons. Boomershoot uses about 1 ton each year. Timothy McVeigh used (IIRC) about 2.5 tons in the Oklahoma City bombing.

This is the best video I’ve seen so far:

Incredible tragedy. I’m sure the death toll will rise for many days. And of course the property damage will be horrendous as well.

As Boomershooter Aaron M. said in email:

Check out that white in that explosion. Remind you of something? They are now saying it was something like 2000 tons of ammonium nitrate. It looks correct for that.

I agree. The white “smoke” is probably the water vapor from the ammonium nitrate decomposition.*

* NH4NO3 –> N2 + 2H2O + 1/2 O2

26 thoughts on “Beirut explosion

  1. There are bad days, and then there are BAD days. May those who didn’t make it rest in peace, and whose who did find peace.

    On the more technical side, looking at it closely, there appear to be smaller pops and spurts of flame, like small fireworks or something in the fire, just before it goes up. As AN will just burn (vigorously) if it catches on fire, it looks like they had the bad luck to also have something else exploding to initiate the AN detonation (assuming that initial reports are correct, which for once isn’t too unreasonable.)

  2. I find it interesting that there were two stories floating in my feeds:
    1) It was 2.7Ktons of AN that went up when some fireworks (firecrackers) initiated the explosion
    2) There was a weapons factory there and that the weapons factory went up.

    Regardless, that is one big arse explosion. I was more impressed with the people that were so close filming. We see this everywhere today. “Oh look, a firefight between the cops and the bad guys, lets see if we can get a better angle by putting ourselves in the line of fire.”

    Is there really enough fuel to go with that oxidizer? The ratio is 94% AN and 6% fuel ( #2 fuel oil). That would be 172 TONS of fuel to make it go big boom.

    Or is it that they were freaking lucky and most of the AN just burned with no boom because not enough fuel?

    • Under the right conditions it can detonate without fuel. It produces excess oxygen under these circumstances, so the explosion isn’t as powerful as it could be. The 6% fuel is to utilize that oxygen.

    • The Texas City article speaks of a combination of extreme heat and pressure. That doesn’t seem to apply here. My vague memory is that it takes a size 10 blasting cap to set off AN — i.e., it’s hard to do. The notion of a terrorist armory or bomb factory being the trigger seems plausible though I don’t know if it comes with any evidence right now. Fireworks, not so clear, I don’t know how a slow explosive like black powder would act as a primer for AN.
      Does a fire, without a pressure vessel, make a plausible trigger for an AN explosion?

      • No. Back in the day I was a MOS 12C, a sub-category of combat engineer. One of the things we trained on was demolitions. A standard 40lb cratering charge was a cylinder with 10 lb of TNT in the middle, and 15 lb of AN on either end. We’d use a 1lb block on TNT tied to the middle with det-cord, and a blasting cap to initiate the TNT block. So it was blasting cap —> 1lb TNT+det-cord —-> 10 lb TNT —–> AN.

        At Boomershoot, we have to get the mix just right or a high-velocity rifle-round won’t set it off. No, it’s not easy to detonate.

  3. one of my staff members was watching the video yesterday; When I first saw it my brain’s reaction was: “footage from Bikini Atoll nuclear testing”.

    Very tragic; that could have some very long term consequences, I’m hearing today 95% of their grain stores were destroyed. (although they expect they’ll still have enough flour to avoid famine.)

    • Red Fuming Nitric Acid gives off red smoke, and is commonly used as an oxidizer in military rockets.

  4. Okay- with our .gov’s penchant for overreacting to Everything sensational- is there a scenario where this might make it more difficult for civilians to obtain these materials in the future?
    Could this threaten Boomershoot?

  5. Regarding what Aaron was referring to, the “white in the explosion”, I don’t think that is chemical.

    The explosion happened on the Mediterranean coast. Unless the wind was from the south, the atmospheric conditions are going to be “hot” and “wet”, like Galveston, TX in the summertime.

    The spherical white ball around the explosion is the pressure wave super-compressing the air until the water vapor condenses at the wavefront surface, then it instantly evaporates behind the wavefont. This has a little in common with the conditions that make altocumulus lenticular clouds (like Joe photographed a few days ago), but that’s not a pressure-related behavior in the same manner.

    A more direct comparison would be to find a picture of the Blue Angels as one of the solo-flyers does a low high-speed pass in front of the crowd… over a body of water like Lake Washington. See the white clouds that seem to be attached to the aircraft? That’s the pressure waves coming off the airframe as it gets closer to the speed of sound, and with high humidity air and a pressure wave, you get a standing condensation/evaporation effect. The effect gets larger with more speed, thus stronger compression, and definitely with higher humidity, but inverse-square law governs the intensity of the compression, so the effect has a limited size.

    For the Beirut explosion, the white sphere is also limited by inverse square law, where distance in this case has a relationship with time and the local speed of sound (pressure, humidity, temperature), so if you can work out the critical pressure for spontaneous condensation, you could work backwards from the time between the explosion and when the surface of the sphere disappearing, multiple that by the speed of sound, that gives you an radius R value, square that, multiple it by the critical condensation pressure, and that’ll give you a good approximation for the initial pressure intensity at the blast center. After that, someone who knows their boomage could probably work out the effective equivalent in TNT, then do some conversions based on the known chemical composition to work out what the mass of original material was.

    Then you make a meme on the internet that says “You want to blow up your own port? Because that’s how you blow up your own port.”

  6. Tell me again how Tim McVeigh blew interior columns out of a building but didn’t leave a crater…

    Convince this former Combat Engineer…

    And it was RDX in the center of a 40 lb. cratering charge tootsie-pop…

    • 1) I didn’t know there wasn’t a crater. Citation?
      2) I didn’t know the interior columns were damaged. Citation?
      3) That’s not my area of expertise.
      4) I do know that he created a shaped charge with the arrangement of the drums in the truck.

      Having spent all of about 30 seconds thinking about it the walls of the building would be much more fragile than the pavement. The walls were probably structurally important to keeping the floors and exterior columns in place. With the walls blown out, the floors partially blown out and sagging the interior columns would have been stressed with bending moments rather than the expected compression loads. This could have caused interior columns to fail.

      Other than that, I’d have to look at blueprints and blast pictures to speculate further.

  7. An interesting tidbit, for those interested in conspiracy theories. says that the problem of AN storage was reported to the authorities years ago but no action was taken.
    The simple answer is “bureaucratic incompetence” and that is a good assumption. The conspiracy theory answer would be that Hezbollah liked having 2700 ton of bomb making starting material at their fingertips, and stopped attempts to make it go away (after all, they basically own the Lebanese government).
    Which answer do you like?

      • It’s certainly plausible. But it would have been relatively easy to edit a few frames of the video to be convincing.

        I stopped listening after the commentators started talking about the anti-gravity ships.

      • I have no idea. But almost all useful explosives are nitrogen compounds of some sort, which means ammonium nitrate is a useful precursor material. If you have your pick of starting compounds it might not be the optimal one, but if I needed to do some basement chemistry involving the creation of interesting nitrogen compounds, that one would certainly warrant consideration.

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