What happens if a set full size welding oxygen and acetylene gas tanks were in a fire? Would it explode and level a few houses in the neighborhood? The reason I ask is my neighbor's house was on fire and the oxygen tank (small one for from hospital) went off like bomb blast and rocked my house - I'm three doors down. There was no incident form the blast (the walls contain the blast) but the house burn down to the ground.
I bet your neighbor's oxygen tank was going at the time.
A woman I once knew well (the mother of one of my boyhood friends) wound up on oxygen. She fell asleep on her couch with the oxygen mask on, woke up in the middle of the night and went off to bed, leaving the oxygen mask going on the couch. In the morning, her roommate sat down on the couch and lit a cigarette.
The ensuing house fire killed her roommate and completely destroyed the home.
I can't answer your question, though. An oxygen cylinder's walls are about 3/8" thick. I bet your local fire department could answer your question.
Grant
This is what I was taught in my welding classes...
Welding tanks have safety features to deal with the issue of fire.
Acetylene tanks have a fusible plug on the top which melts at about the boiling point of water (212F). If it gets too hot, the plug melts and acetylene streams out the top. If it's in a fire, it will feed the fire, and create a lot of heat, but won't explode. Don't let hot metal drop on the plug or else you will have a non stoppable torch on your hands. I was told a story about a guy putting the fire out with his gloved hand after a small leak in the plug was started because of globs of metal hitting the plug. It seems the guy did get the fire out, but I wouldn't advise that - running in the opposite direction and letting it burn itself out is probably wise since you can't stop the leak once it starts anyway.
Oxygen tanks have a pressure release value built into the valve stem. If you look at the valve on an O2 tank, you will see one knobs sticking out two sides. One is where you attach the regulator, the other (sticking out the other direction from the valve stem) is the safety release valve. If the pressure gets too high because of a fire, a disk in the safety valve will rupture letting the O2 out. And yes, it will make the fire burn hot as hell - melting and burning everything around it, like steel buildings, and the O2 tank itself. But it won't blow up and turn into a bomb.
If the O2 tank for health care blew up, I guess it didn't include the same type of safety device that welding tanks normally have - which seems odd - why wouldn't they have it???
I don't know what other types of tanks normally have, but I just went out to the garage to look at my 75/25 argon/C02 tank and I see it's got the same sort of pressure release value as an O2 tank. I guess all the high pressure welding tanks have that to keep them from blowing up in a fire. I guess the Argon/CO2 tank might even be a good think to have in a fire - the sudden release of a lot of Argon and CO2 might even put the fire out (as long as it goes off before the O2 tank does :)).
"Grant Erwin" wrote: (clip) A woman I once knew well (the mother of one of my boyhood friends) wound up
^^^^^^^^^^^^^^^^^^^^^^ I have no doubt that the roommate is responsible for the fire, resulting in her own death and the destruction of the house. However, I question the role played by the medical oxygen cylinder. I've lost count of the number of medical oxygen cylinders I hooked up and used up before my wife died. A cylinder that was left running when the woman went to bed would most likely be empty by morning. Further, the volume in one of those portable tanks is not much compared to the volume of a typical room. 10' x 12' x 8' = 960 cu ft. A large, completely full oxygen cylinder contains 220 cu ft--less than
1/4 the volume of the room. A medical oxygen cylinder would be WAY less. Think about it. A person breathing medical oxygen with one of those little "nostril couplers" is releasing almost all of it into the room. Have you ever heard of a fire resulting from this?What probably happened is that the roommate dropped a lit cigarette on the couch and set a fire. Since she died, there is no way to get any details.
Oxygen can saturate some materials. Imagine a sofa where the cloth gets O2 flowed into it for hours, in a room with relatively still air the sofa may well have a great fraction of the O2 still in it after the tank runs dry. O2 is slightly heavier than air. Combine a flammable material with a lot of strong oxidizer, add a spark and it will burn very hot and fast, this is exactly how gunpowder works. These incidents are not unknown, they have occurred in laboratories where oxidizers or O2 saturate lab coats, and in industrial settings.
Years ago I was told IIRC that a 2% increase in the oxygen level compared to normal produces about a 25% increase in combustion rate. That being the case then the O2 level doesn't need to be raised greatly to make the fire far more serious.
Likely the foam or cloth of the cushion was saturated in oxygen due to the location and position. Not room mixing. The couch provided the fuel, and the oxygen the oxygenater all it needed was heat for ignition.
Foam is specifically bad as the cell structure are like pores and the foam is rich in hydro-carbon to instantly or almost convert to another material.
Mart> "Grant Erwin" wrote: (clip) A woman I once knew well (the mother of one of
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We were warned to stay in our cars/trucks and to turn off ignition .... if ever around a oxygen tanker in a wreck. The act of walking on an oxygen cloud flowing across the blacktop can detonate the roadway. Driving across does it also - and a spark from a cracked plug wire ... is just enough to continue the process. Lots of petro-chemical lay awaiting.
I worked near a fab line and with and for semiconductor companies. I'm certified for INTEL fab admittance. I was a consultant and vendor to Intel and others. So the tankers were Hydrogen or other bizarre chemicals used in the process steps and our safety classes covered all of this and more.
Martin
Mart> Leo Lichtman wrote:
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There's nothing like that on this side of the pond as far as I know.
Just plain bottles with a single valve and connection on top. Both will simply go bang in a fire, and cause a major amount of damage. If there is a fire involving OA bottles in the uk, the firemen won't enter the building due to the risk, unless they know the bottles are safe, or can be made safe. Even if they did have a safety device fitted, they're still going to do an awful lot of damage in a fire.
Off course, the flame going back into the actylene bottle is another problem, but it can be mostly prevented with suitable flashback arrestors and check valves.
I know that LPG tanks do have a pressure relief valve (set to 125psi), as that was part of a gas testing course I done.
Medical O2 cylinders do have a "burst disk" in the valve stem- it is usually on the opposite side of the stem from the regulator, behind a middlin-small screw that has a hole drilled through it. This disk ruptures at at about 3000 lbs pressure, or melts at approx 212 deg F.
We've had welders go POOF before, when they've been complacent enough to blow themselves down with O2 from the torch (high volume, usually pushing 80 psi) then reach for a smoke...
All the gas cylinders that I'm aware of have some sort of pressure relief device. Look up the acronym, BLEVE, short for Boiling Liquid- Expanding Vapor Explosion. Firefighters are well trained to NOT EXTINGUISH a flame from the tank- instead, keep the body of the tank cool (water stream) and let the gas burn. That's far better than letting a fuel gas escape along the ground and blow up after you thought it was "safe."
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