My thread was removed because a second issue was introduced which proceeded to a an apparent violation of guidelines.
Yhis is a reintroduction of the original topic in the hopes that the technical discussion on handling chenicals can continue without specific reference to the tragedy that brought the issue to my attention.
I do suggest, however, that the original thread be reposted with all postings of arguments not related to the technical topic deleted from the thread and then the thread locked. That way, the technical matters already posted can be referenced for this thread. Thank you,
I’m sure that Tree can give much better examples, but I have seen some strange things. You don’t always need spark or flame contact to ignite a fire. If air is heated above the kindling temperature of solid combustables that it surrounds, they can light up like a candle. I’m sure that “fumes” are even more so at risk to ignite.
The term is autoignition temperature. Most flammable liquids and flammable gasses are in the range of about 800 degrees F. This is low enough that exhaust manifolds can ignite a flammable mixture, but the walls of a container, or truck, or boxcar never get anywhere near the autoignition temperature. Of course you need a leak from the container to release any flammable vapors and containers are designed not to leak in normal transportation.
The notion being promoted is a ghost story/bit of propaganda. Take your choice.
No, it’s a new topic and very little if anything from the Middle East accident is necessary for a proper and on-point technical discussion.
Ammonium nitrate derives some of its hazard from having the element nitrogen in two different ‘valence’ states. It also contains oxygen that when energetically released can support combustion in materials that are ‘oxidizable’ including carbon and aluminum. The first peculiar concern is that both decomposition and any subsequent combustion can be greatly accelerated in speed over normal fuel combustion: this is why ANFO readily detonates with good yield.
However, the chemical can also start deflagrating (chemically dissociating with substantial rate of exothermic heat release to sustain or worsen, much as a fire does with regular combustion) and for a number of reasons the rate at which the dissociation speed increases with more and more heating can reach the speed of sound in the local material. At this point faster burning creates a shock wave causing prompt dissociation, which can propagate at many thousands of feet per second through the remainder of a contiguous mass. This is the deflagration-to-detonation threshold I mentioned in the dead thread.
Ammonium nitrate is difficult to vaporize, and its vapor is not terrifically dangerous in air. So having it up against a hot surface is not a ‘vapor’ danger, and even if it were, a BLEVE is impossible because there is no boiling expansion to generate a fuel-air critical mixture in the presence of good flameholding.
Someone like Tree can, and should, quote us current best practice on fighting fires where ammonium nitrate (or
It’s noteworthy how many people seem to believe that some precautions are “overkill”, because accidents only happen to “stupid” people. Until, that is, a sequence of events, however improbable …manage to all align at just the most inopportune moment.
I’m not saying the “propaganda” is plausible…but strange things do ocassionally have a knack of happening. [X-)]
Personally, I still have my money riding on “sabotage”, but perhaps that’s just the tinfoil hatter in me?
No, I’m not buying the sabotage angle myself, if sabotage caused this they’re really going to have to prove it to me.
Probably just an unfortunate series of events that lead to the disaster. No oversight, no safety inspections, an “It’s not my job!” attitude from various and sundry officials, or some baksheesh to other officials, and there you go. Boom.
As a first responder (firefighter), I’m going straight to the “Orange Book” once I identify the substance. Ammonium nitrate (in various forms UN numbers 0222, 1942, 2067, 2071, 2426, and 3375) calls for Guide 140 (except for AN-fuel, which is 113), and ammonium perchlorate (UN numbers 0402 and 1442) calls for Guide 143.
For fire, the ERG calls for an 800 meter isolation zone, as well as considering evacuation for 800 meters - a half mile. That’s if the container is involved. If the AN itself is involved, that expands to one mile.
For ANFO, we start at isolation for 1,600 meters (a mile).
The ERG is guidance for about the first 10 minutes. After that, the Incident Commander should have guidance from other sources as well.
The ideal situation calls for big water (flooding quantities), applied from unmanned devices. This assumes there is time to set up big water, and that big water is even available.
Texas City, West, and now Beirut underline the wisdom of immediate observance of these distances.
The ERG is available on-line, and for smart phones. Railfans
IIRC, the quantity involved with West was about one RR carload’s worth.
A couple of things come to mind with haulage of AN:
First is separating AN carrying train from petroleum carrying trains.
Second may be a coating on the cars to at least briefly block the heat from a fire and allow enough time for an evacuation.
Threads used to get locked; now they are totally removed, twice in a row. In any case, moderators us usually take action only after receiving abuse reports. I wonder who felt the need to do that?
It’s strictly a “report” button," what the “powers that be” do with the report is up to them. I got no questions as to “whys” or “wherefores” from any moderators whoever they may be, nor any promise as to any actions that might be taken.
If the topic is not to your liking, don’t look at it. There was no flaming or abuse whatsoever. Free speech is part of our American heritage.
Euclid and I usually disagree, but we have both always upheld the value of open discussions as long as the language is civil. Heavy-handed censorship is un-American.
It wasn’t personal abuse directed towards me, I can take whatever’s thrown at me, I’m a big boy. Besides, in my lifetime I’ve been worked over by churlish amateurs and trained professionals and learned how to deal with it.
WHY I pushed the button is for me to know, and free speech, which I have no problem with as a “small ‘d’ democrat” had nothing to do with it.
So don’t ask. Consider it a point to ponder.
Let’s just say my pushing the button was due to a horrendous drift from published Forum guidelines, and if the moderators aren’t paying attention I’ll do my best to see that they do.
At any rate, I didn’t complain about the previous Beirut explosion thread, I found it quite interesting and wouldn’t have commented myself if I didn’t find it so.
As far as threads I did complain about, well I’m not going to hide behind the anonymity of the Internet, if in fact the moderators did act on my complaints and didn’t find out about it themselves.