Don't store Oxygen and Acetylene together in an LPG bottle and attempt to weld

[Psi]

Pretty self explanatory, really,

https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12119555

[TerraHertz]

Wow, ignorance and stupidity brings us another instant Darwin Award winner.

[BradC]

Wow, ignorance and stupidity brings us another instant Darwin Award winner.

According to the article he had a 15 year old daughter, so he not qualified for a Darwin.

[m3vuv]

god what a plonker!

[Cerebus]

Yeash! Compressed acetylene is dangerous enough on its own*, mixing it under pressure with oxygen is quite simply suicidal. I'm not one for needless rules and regulations but acetylene is one of those things that you ought not to be able to buy without a licence that proves you have adequate training to store and use it safely.


*For those not in the know, it's quite possible for an acetylene cylinder to turn into a bomb all on its own, with surprisingly little provocation. If it isn't in a specialist acetylene cylinder (where it's actually stored absorbed in a solvent and/or a porous matrix) a sound hammer blow to the cylinder can be sufficient to detonate it. Even with a specialist cylinder an otherwise trivial fire may be enough to get a cylinder of acetylene to 'cook off'.

[amyk]

Ironically enough I was reading an old welding book recently, where they certainly knew and discussed the dangers of pressurised acetylene and its tendency to detonate... over 100 years ago.

[coppercone2]

I want to know his idea of how chemical reactions work. I blame the school system honestly.

Does he think the flame front is going to move at like a snails pace and be pushed out? Can't he tell how it works every time he ignites a torch? It seems intuitive.

Maybe they never had a bunsen burner in his class room. I could see this happening if he read about flame in a text book and never ever saw a gas burn before.

[alpher]

Nobody stores acetylene in liquid/or gaseus form in pressurized cylinders.
The story as presented holds a little water, as even the almost fully discharged oxygen bottle has a pressure that almost certainly is bound to burst your run of the mill propane bottle.

[Ian.M]

Propane cylinders can operate at up to 320 PSI, and their burst pressure is much higher than that, so its not unreasonable that an idiot could put a significant pressure of oxygen into one.

Also acetylene forms explosive compounds with copper and several other transition metals that are extremely sensitive detonators (to the point that they are too sensitive for practical use) and has the widest range of explosive limits of any commonly used gas^{ref}.

You absolutely do not re-purpose other valves, fittings, regulators, hoses or piping for acetylene due to the risk of explosive metal acetylide formation.  That's probably what finally triggered the timebomb the deceased had constructed. He probably got away with it initially because there was no metal acetylide buildup.  Leave it a while then move any part of the improvised valvegear and a detonation was the most likely outcome.

Acetylene cylinders need that porous packing to break up the volume of the headspace enough so that if it starts decomposing in one pore, there isn't enough energy released to overcome the small activation energy barrier and start decomposition in an adjacent pore.  Without the packing or some other means to rob energy from the reaction quickly enough (e.g. cold walls of a narrow bore pipe) decomposition propagates explosively.   The *ONLY* place its permissible to have acetylene gas at a pressure above 15 PSIG is in the pores of the packing in the headspace of the cylinder, and in the short narrow passages of the cylinder valve and acetylene regulator.  *ANY* impact that causes the cylinder to 'ring' enough to compress the packing is a really bad idea - if the culmunitive damage compresses the packing enough to open up a significant void, you've then got a timebomb sitting there
 
As for the level of stupidity involved in mixing *any* fuel gas with oxygen under pressure in a cylinder - well I don't understand how the deceased  made it to the age of 39 without getting killed off by some other hazard.   To even contemplate mixing acetylene and any oxidiser other than at the tip of a purpose designed and properly maintained acetylene torch or burner is just plumb crazy.

[james_s]

Yeash! Compressed acetylene is dangerous enough on its own*, mixing it under pressure with oxygen is quite simply suicidal. I'm not one for needless rules and regulations but acetylene is one of those things that you ought not to be able to buy without a licence that proves you have adequate training to store and use it safely.

I for one am glad that I can buy acetylene without jumping through a bunch of legal hoops. Millions of people have oxy acetylene rigs and incidents like this are extremely rare. You can't ban everything someone could possibly blow themselves up with. I'd be willing to bet that a lot more people are injured by improper use and storage of gasoline/petrol than acetylene and absolutely anyone can buy that.

[KL27x]

Where did he get acetylene and oxygen gas under pressure? The guy must have had access to proper acetylene and oxygen bottles to begin with. As well, you figure he had a proper acetylene torch. And if he had gotten it to "work," already, why is he removing the regulator to get the torch to connect, there at his friend's house?

I think the writer confuses the function of a regulator with flame arrestor, but that's another problem.

It's sad this happened. Super tragic that his friend recognized the danger but couldn't talk him out of it.

I don't understand how the deceased  made it to the age of 39 without getting killed off by some other hazard

I can see how you can acquire this stuff without really understanding how it works, I suppose. Then one thing leads to another.

[hendorog]

Where did he get acetylene and oxygen gas under pressure? The guy must have had access to proper acetylene and oxygen bottles to begin with. As well, you figure he had a proper acetylene torch. And if he had gotten it to "work," already, why is he removing the regulator to get the torch to connect, there at his friend's house?

I think the writer confuses the function of a regulator with flame arrestor, but that's another problem.

It's sad this happened. Super tragic that his friend recognized the danger but couldn't talk him out of it.

I don't understand how the deceased  made it to the age of 39 without getting killed off by some other hazard

I can see how you can learn to use and acquire this stuff through trade without really understanding how it works, I suppose.

He was employed as a welder.
https://www.stuff.co.nz/auckland/local-news/western-leader/106796944/man-who-died-in-west-auckland-explosion-was-a-welder-by-trade

[KL27x]

^Ahh, yeah. Maybe he only had access to this stuff at work. Hence the jury rig.

I imagine a big string of bad luck for him to get that far with no one else noticing and setting him straight, to the point of physically stopping him. Too sad.

[station240]

AvE is going to have an interesting time if he makes a video on this.

[KL27x]

Ian.M seems to have covered it, already. Simply putting acetylene gas under pressure is waiting for an accident. Mixing pressurized acetylene with oxygen is ensuring more collateral damage.

Most people who are interested in getting an oxyacetylene torch for themselves would surely learn the dangers. There is actually an order to turning the gases on and off, even. But people who learned it as a job with someone else handling the equipment puchasing and refilling maybe doesn't care to know the specifics. Or they are just desensitized to the danger. Even with the friend refusing to be near, he shrugged it off. The friend was maybe not that well informed, either, and deferred somewhat to the professional welder.

Even if the tank didn't spontaneously ignite due to being dropped or wrenched on, I don't know if a flame arrestor could be trusted to work on the premixed gases. 

If he wanted to just cut or bend or braze, oxy propane (in separate tanks) would have been relatively safe, I think. But you probably can't get a lot of oxygen in a 300 psi tank. I bet he sneaked the gas from his employer on the sly, without asking; otherwise, he probably would have gotten a more thorough lessen about the dangers.

I don't think AvE could do a video on this. The guy died; it makes for a difficult vijayo.

[amyk]

Even the Wikipedia article mentions its instability under pressure, and just search YouTube for acetylene to see how powerful the explosions are... shows that some people, just don't really think.

[Cerebus]

Yeash! Compressed acetylene is dangerous enough on its own*, mixing it under pressure with oxygen is quite simply suicidal. I'm not one for needless rules and regulations but acetylene is one of those things that you ought not to be able to buy without a licence that proves you have adequate training to store and use it safely.

I for one am glad that I can buy acetylene without jumping through a bunch of legal hoops. Millions of people have oxy acetylene rigs and incidents like this are extremely rare. You can't ban everything someone could possibly blow themselves up with. I'd be willing to bet that a lot more people are injured by improper use and storage of gasoline/petrol than acetylene and absolutely anyone can buy that.

I didn't say ban, I said license. I don't know about where you live but here you need a license to run a petrol station, you need a license to possess explosives, you need a license to install gas fittings and appliances, you need a license to drive and lastly you need a license to compress acetylene or charge cylinders with it. All activities that can be done safely, if you you have the requisite training and knowledge, but which have potentially fatal consequences for other people if you don't have the requisite knowledge and training. I'm all for libertarianism, up to the point where other people's lives are put at risk by 'being able to do whatever you want', at that point a modicum of control and organization is called for. To suggest otherwise is to pursue doctrine in the face and teeth of common sense.

[rhb]

Where you live you need a license to carry a small pocket knife.  Once Britain conquers "knife crime" it will then have an outbreak of "hammer crime".

*Any* fuel and oxidizer combination will detonate above a certain pressure.  Principle of the diesel engine.

[KL27x]

lastly you need a license to compress acetylene or charge cylinders with it.

That wouldn't have stopped this. A petrol station can prevent you from using their pump to fill a garbage bag full of petrol. But once you take your approved container full of gasoline away from their premises, it's out of their control. It sounds like this welder decided to take some gas home with him from work. From his employer, who has to go get his proper certified acetylene tanks filled at a certified dealer. He didn't walk into a store and ask someone to fill his propane tank full of acetyene.

[CJay]

Where you live you need a license to carry a small pocket knife.

Who's told you that rubbish?

Let's quash that particular BS right now though, a link, to a government page:

https://www.gov.uk/buying-carrying-knives

[BradC]

*Any* fuel and oxidizer combination will detonate above a certain pressure.  Principle of the diesel engine.

No it's not.

A) There is a difference between detonate and deflagrate. Diesels that detonate don't last long. Most fuel/oxidiser reactions are a deflagration. Acetylene is easier than most to coax a detonation. Actually, better to say it takes care to prevent it detonating.

B) The ignition source in a diesel is heat. That the heat is caused by *rapid* compression is neither here nor there when comparing it to compressing combustible gasses.

C) I can carefully compress a huge number of fuel/oxidiser combinations to the limit of my ability to compress them. As long as I don't impart enough instantaneous energy to ignite them (ie compress them relatively slowly and keep them cool), they won't burn, let alone "detonate". Again, Acetylene can be coaxed to go off all by itself. No oxidiser required. So adding oxygen potentially makes it worse when it does go off.

[Bud]

I don't think AvE could do a video on this. The guy died; it makes for a difficult vijayo.

Not for someone who has no moral in the first place.

[tggzzz]

In the 6th form I used to go to lectures at the Royal Institution.

One of the lectures was detonating stoichiometric mixtures of gasses and oxygen. The last one was, from memory <mumble> years ago, acetylene. It was in a glass milk bottle surrounded by several layers of protection including but not limited to steel cans, armoured glass, and with a wooden lab stool on top of the lot.

Detonation was, as expected , a hell of a bang. The lab stool's seat fractured, the armoured glass was no longer effective, and the milk bottle had completely disappeared - and was replaced by a small layer of glass dust.

Great fun.

[taydin]

If the only pre-condition for getting a license is completing a course on safely using an oxy-acetylene rig, then I would agree that everybody should get a license before being allowed to acquire oxygen/acetylene bottles.

But if that were to happen, I'm pretty sure there will be many extra requirements, like being a member to X, Y, Z associations, satisfying such and such conditions for the workplace, being regustered with Z organization and getting regular safety audits etc. The expense of satisfying these requirements would put oxy acetylene welding way outside of the realm of a hobbyist like myself, who has learned about all safety aspects, and applies them for his oxy acetylene set for years without any incident.

[CJay]

In the 6th form I used to go to lectures at the Royal Institution.

One of the lectures was detonating stoichiometric mixtures of gasses and oxygen. The last one was, from memory <mumble> years ago, acetylene. It was in a glass milk bottle surrounded by several layers of protection including but not limited to steel cans, armoured glass, and with a wooden lab stool on top of the lot.

Detonation was, as expected , a hell of a bang. The lab stool's seat fractured, the armoured glass was no longer effective, and the milk bottle had completely disappeared - and was replaced by a small layer of glass dust.

Great fun.

And there's a very good chance it could be available in their archives if it was filmed