I work at a fairly large nationwide grocery store chain, and they have me exchange propane tanks for customers when they are empty. So anyways, I was wondering, what would it take to cause a propane tank to explode? Would it explode? How large of an explosion would it create?
I was under the impression that if you shot the propane tank with a handgun it would rupture and explode from pressure differences. I have no idea how valid that is.
Thanks.
BTW, No I’m not trying to blow up my grocery store or anything, I’m just curious to see how safe it is to keep those things out in the open like they are right now.
Out in the open? :eek: . They really should be in a steel cage or they should have a chain threaded through all the handles and then bolted to a wall or something. This way if they do explode they don’t go flying across the parking lot and end up killing someone.
Also IIRC a couple of years ago there was a video of some kids shooting a LP tank with a handgun. I think once they finally hit it right it took off fairly violently. I bet someone here can dig it up again.
Probably as safe as underground tanks at gas stations (people dispense the actual fuel from these all the time ;)). The propane tanks that you see at stores and gas stations are required to have a metal lip, or a shield around the valve incase it’s ever dropped or anything. And I think what he meant by “open”, is that the tanks are so close to entrances and all that.
The weakest point of a tank is the place where you have fittings. With a propane tank, it will be on the top, and why there is a raised guard flange all around.
The tanks themselves rarely explode; usually explosions are from gas escaping to the atmosphere, then igniting.
When I was an active balloonist, I went to a safety seminar that showed a demonstration film about propane accidents. Accidents involving broken fittings or bad seals were stressed as the most common accidents. In a different part of the film, a consumer grade tank was punctured by a shot from a high-powered rifle of undeclared caliber. The tank rupture spectacularly and catastrophically, but did not explode on the way. The tank was recovered about a quarter mile away.
BTW, the tanks are difficult to pierce.
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- In my misspent youth, friends and I occasionally shot the smaller Coleman propane lamp/camping stove tanks and handheld propane-torch tanks with various different kinds of guns and ammo. We couldn’t get them to explode even if shot with 5.56mm incendiary ammo, To get them to ignite you had to leave them close to a fire, and then shoot them–and then they didn’t really “explode” so much as “whoosh”, flash and go out.
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- What will make them explode is putting the whole thing into a fire. Even if they are basically empty of fuel, the air pressure alone will do it once they heat up enough; the air expands and the metal weakens until it really does explode. Of course should you ever feel the need to do this, then remember to run, fast, in any direction that’s “away”. A couple different kids died at two different parties locally a few years back from empty beer kegs exploding by being thrown on a bonfire. The ironic part is, the parties were two weeks apart and the groups of people were totally unrelated, and the people at the second party decided to try it after someone mentioned it happening at the first party.
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- Well nuts: I meant to mention, we shot the smaller tanks, but never tried a 20-lb barbecue-size tank. But the ones we shot never did ignite just from the bullet.
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- Well nuts: I meant to mention, we shot the smaller tanks, but never tried a 20-lb barbecue-size tank. But the ones we shot never did ignite just from the bullet.
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When propane gas escapes into the atmosphere and finds a source of ignition, there is an explosion, provided the mixture is in between the upper and lower explosive limits for the gas, which are 9.5% and 2.1% respectively. (NIOSH) What is of greater concern is when a tank is exposed to direct flame impingement above the liquid level. If the pressure relief valve cannot vent the overpressure quickly enough, and the tank wall is weakened by physical and/or thermal stress, eventually a catastrophic rupture and explosion called a Boiling Liquid Expanding Vapor Explosion or bleve occurs. Parts of road tankers or railcars have been recovered close to a mile from the blast site, to give an idea of the energy being released. :eek: This is why we do a quick size-up at the beginning of an incident, and if I know I can’t cool the tank quickly enough to prevent failure, plan B (run) is implemented.
In the open air there is no explosion from the vapor. I had a bad gas leak in my boat, when the vapor reached the open flame of the heater the gas lite off. It burned here, it burned there, and the only complication was the decoy bags that had some fuzz on them were damaged. But a leak in your home can enrich the atmosphere and burn at a much faster rate(if fast enough it will cause the building to literally explode. In minor gas ignitions the larger windows(more surface area) will be more likely to be in the neighbors yard. I have seen the walls all pushed off foundation. same can happen with steam, as in hot water heating system’s not being maintained.
From what I’ve learned as a volunteer fireman, the tank rarely explodes as there is no oxygen inside of the tank to support combustion and the pressure inside the tank is greater than the atmospheric pressure so the flame cannot get “sucked” back inside the tank thus causing an explosion. I’d think that if tanks stored in a rack were shot with a rifle and the escaping gas were to ingite, it would set off a chain reaction among the other tanks as things heated up and the pressure vents opened up to release the pressure. Then its anybodies guess as to what would happen next. I’d hate to be close to the deal, anyway.