5 ms·

I've done some work in steel factories, though only for offline/closed systems that have no interaction with the main control code. Factories like this one pro

by joshvm 12y ago

I've done some work in steel factories, though only for offline/closed systems that have no interaction with the main control code. Factories like this one probably operate at around 60%+ capacity, so they'll be operating sometimes all day, sometimes all night. If you ever get the chance to visit, do so, even if you don't really care about how steel is made. The sheer scale of everything is amazing. Everything is very big, very hot and if you have to hit the big red button, it costs a lot of money. Unscheduled downtime is very expensive. Steel tends to be workable when it's hot/molten and therefore pliable. If you suddenly stop a machine then you're left with solid steel in places you don't want it which takes a lot of time and effort to remove. One of the common reactions to this story is "Why didn't they hit the emergency stop?" - the answer is because it costs an absolute fortune to do so.

fennecfoxen 12y ago
To be more pedantic, the answer is "that was the emergency stop - there's a reason they only use it in emergencies".
rab_oof 12y ago
How do workers melt solid steel once it's cooled in places?
- userbinator 12y ago
  By heating it... large torches are probably required. I wouldn't be surprised if it was cheaper to replace a clogged assembly than to try to melt the steel back out of it.
  - kragen 12y ago
    I think typically they use thermic lances, because torches aren't even close to enough.
    - rab_oof 12y ago
      Oxygen on a stick.
- pgrote 12y ago
  I wondered the same and found this informative article: http://www.steelguru.com/article/details/Mzc%3D/_Blast_Furnaces.html http://www.steelguru.com/article/details/Mzc%3D/_Blast_Furna... Fascinating.
  - userbinator 12y ago
    Fascinating indeed. Here is a related article about an explosion that happened while trying to restart a chilled furnace: http://www.hse.gov.uk/pubns/web34.pdf http://www.hse.gov.uk/pubns/web34.pdf
    - fennecfoxen 12y ago
      One thing these news stories don't do a good job of getting across is exactly what a blast furnace is. So here's what I got out of that link: a blast furnace is something like a 10-story can, lined with fancy insulating bricks and a ton of embedded pipes for water-cooling so that the insulation doesn't melt. On the outside are a bunch of walkways and vents and ducts and pipes and stuff just like a scene out of Terminator. You chuck various rocks (iron ore, limestone, coal) into this multi-story brew and they gradually react with each other (the mixture heats itself) as you blow oxygen into openings at the bottom. Over a period of weeks the iron sinks to the bottom (and the waste sinks close to the bottom but not quite) where you extract it. Once or twice a decade you might stop making steel and empty it all out so you can replace the bricks and do maintenance. If you let it get too cold, the iron and the waste (slag) will freeze and clog the vents, so you drill into it with "a long, consumable, steel tube fed with pressurised oxygen gas" - it's not like you have heating coils built in, you just toss the fuel in with the rest of the stuff. I guess this is also why the "chilled hearth" at the bottom is such a problem (the point of having a blast furnace is that it's mostly-iron that collects down there, not fuel). Of course, the frozen steel and slag is still insanely hot, just solid now. On the other side of problem-land: if the cooling system leaks and too much water gets in, the whole thing might explode and jump about 2 or 3 feet in the air (this "too much water" is on the order of tons, mind you -- this can happen if parts of the cooling system melts). Yeesh. I'd been thinking they'd lost something an order of magnitude or so smaller -- more like the size of a cement mixer. And of course each of your top experts (water systems, electrical systems, etc) might want to go home before the 10+ year campaign is over, so you install remote monitoring and if there's a crisis you call the top expert and he can take a look at it and provide advice instead of getting up and spending half an hour to drive there and then give advice (possibly a very useful capability in many other crises)...
Fuxy 12y ago
The more interesting question is why is the industrial control computer connected to the internet. Shouldn't these things be on a separate network protected by an air gap all the time? Having stuff that doesn't need internet access connected to the internet is like asking for trouble.
- duaneb 12y ago
  > why is the industrial control computer connected to the internet. My guess is remote monitoring.
  - Fuxy 12y ago
    So what's wrong with a separate internet connection, network and a computer with all its USB ports glued up connecting trough a VPN to the facility computers. You can read all the stats off the screen. Slightly more insecure then complete isolation but i suspect still better then what they had.
    - waps 12y ago
      And that VPN would connect to ... the office network where everybody runs outlook ? Or does it connect to a set of machines that run ssh with passwords shared with forums on the internet ? This configuration, incidentally, is probably exactly what the factory was running. There are a number of things that are commonly brought up as solutions to security. VPN's, Anti-virus, IDS, disabling USB, nat, ... none of them are. The solution to security problems is knowing all possible interactions between your software and the outside world. If you don't, there is at least a good chance it can be hacked. Of course, not having to know all interactions, some would say, is the reason we have computers in the first place.
      - walterbell 12y ago
        The VPN could connect to a Qubes-isolated VM.
        12y ago

by joshvm 12y ago

fennecfoxen 12y ago

To be more pedantic, the answer is "that was the emergency stop - there's a reason they only use it in emergencies".

rab_oof 12y ago

How do workers melt solid steel once it's cooled in places?

userbinator 12y ago
By heating it... large torches are probably required. I wouldn't be surprised if it was cheaper to replace a clogged assembly than to try to melt the steel back out of it.
- kragen 12y ago
  I think typically they use thermic lances, because torches aren't even close to enough.
  - rab_oof 12y ago
    Oxygen on a stick.
pgrote 12y ago
I wondered the same and found this informative article: http://www.steelguru.com/article/details/Mzc%3D/_Blast_Furnaces.html http://www.steelguru.com/article/details/Mzc%3D/_Blast_Furna... Fascinating.
- userbinator 12y ago
  Fascinating indeed. Here is a related article about an explosion that happened while trying to restart a chilled furnace: http://www.hse.gov.uk/pubns/web34.pdf http://www.hse.gov.uk/pubns/web34.pdf
  - fennecfoxen 12y ago
    One thing these news stories don't do a good job of getting across is exactly what a blast furnace is. So here's what I got out of that link: a blast furnace is something like a 10-story can, lined with fancy insulating bricks and a ton of embedded pipes for water-cooling so that the insulation doesn't melt. On the outside are a bunch of walkways and vents and ducts and pipes and stuff just like a scene out of Terminator. You chuck various rocks (iron ore, limestone, coal) into this multi-story brew and they gradually react with each other (the mixture heats itself) as you blow oxygen into openings at the bottom. Over a period of weeks the iron sinks to the bottom (and the waste sinks close to the bottom but not quite) where you extract it. Once or twice a decade you might stop making steel and empty it all out so you can replace the bricks and do maintenance. If you let it get too cold, the iron and the waste (slag) will freeze and clog the vents, so you drill into it with "a long, consumable, steel tube fed with pressurised oxygen gas" - it's not like you have heating coils built in, you just toss the fuel in with the rest of the stuff. I guess this is also why the "chilled hearth" at the bottom is such a problem (the point of having a blast furnace is that it's mostly-iron that collects down there, not fuel). Of course, the frozen steel and slag is still insanely hot, just solid now. On the other side of problem-land: if the cooling system leaks and too much water gets in, the whole thing might explode and jump about 2 or 3 feet in the air (this "too much water" is on the order of tons, mind you -- this can happen if parts of the cooling system melts). Yeesh. I'd been thinking they'd lost something an order of magnitude or so smaller -- more like the size of a cement mixer. And of course each of your top experts (water systems, electrical systems, etc) might want to go home before the 10+ year campaign is over, so you install remote monitoring and if there's a crisis you call the top expert and he can take a look at it and provide advice instead of getting up and spending half an hour to drive there and then give advice (possibly a very useful capability in many other crises)...

Fuxy 12y ago

The more interesting question is why is the industrial control computer connected to the internet. Shouldn't these things be on a separate network protected by an air gap all the time? Having stuff that doesn't need internet access connected to the internet is like asking for trouble.

duaneb 12y ago
> why is the industrial control computer connected to the internet. My guess is remote monitoring.
- Fuxy 12y ago
  So what's wrong with a separate internet connection, network and a computer with all its USB ports glued up connecting trough a VPN to the facility computers. You can read all the stats off the screen. Slightly more insecure then complete isolation but i suspect still better then what they had.
  - waps 12y ago
    And that VPN would connect to ... the office network where everybody runs outlook ? Or does it connect to a set of machines that run ssh with passwords shared with forums on the internet ? This configuration, incidentally, is probably exactly what the factory was running. There are a number of things that are commonly brought up as solutions to security. VPN's, Anti-virus, IDS, disabling USB, nat, ... none of them are. The solution to security problems is knowing all possible interactions between your software and the outside world. If you don't, there is at least a good chance it can be hacked. Of course, not having to know all interactions, some would say, is the reason we have computers in the first place.
    - walterbell 12y ago
      The VPN could connect to a Qubes-isolated VM.
      - 12y ago