Exploding Gas Canisters: The Hazard of Overheating

[Benjamin Smith]

Companion forum thread to:

Exploding Gas Canisters: The Hazard of Overheating

[Chris Jackson]

This guy got hit by the fireball.

This guy got hit by the flying gas cannister.

[Forrest G McCarthy]

I am considering a compressed gas cooking system for ultra-light wilderness ventures. The benefits of weight, efficiency, and ease of use of the Jet Boil and MSR Reactor are attractive. My hang ups regard environmental and practical concerns. While most manufactures advertise these cartridges can be recycled, I find this to be very difficult in most locals. Nor do I see the practicality, on extended expeditions, of hauling multiple canisters.

For these reasons I have been exploring the use of a re-usable composite bottle. Driven by the popularity of paintball guns, small carbon fiber reinforced compressed gas cylinders are mass produced and readily available (http://www.airhog.com/mini_tanks.htm). The compressed gasses typically used in these bottles require higher PSI values then butane or even propane. The bottleneck in employing these tanks for ultra-light stoves is both the valve system and ability to refill them.

For a propone tank under 4 pounds an OPD (overfill protection device) is not required. However, standard propone refill stations (Suburban Propane) are not equipped to handle small tanks. Isobutene and propone/butane mixes are not readily available. We do not have a gas/welding supply outlet in my town so I have not been able to inquire about their capabilities. It appears a personal refill station maybe required.

To my knowledge the Lindal Group does not produce a valve that would work with composite bottles nor designed for refilling. Standard propane valves are heavy and would negate many of the benefits of a re-usable composite bottle.

Has anyone else thought of this? What did your learn? Any ideas regarding valves, re-filling, legality, and hazards are welcome.

[Rick Dreher]

I've imagined exactly what you're describing, if for no other reason than to avoid accumulating all those partial canisters!

Some countries sell bulk isobutane/butane, which would make the concept a lot easier to accomplish due to the much lower vapor pressures involved. You can even buy canister refill kits. But I can't imagine self-fill propane canisters ever gaining traction in the States, which is a pity since propane is such a great-performing fuel. Developing a truly foolproof system would be a huge challenge for such a relatively miniscule market.

[Bill Fornshell]

Hi Forrest,

I think the bottle you are talking about is called "The Pigmee" and weighs about 3 pounds empty and without the valve assembly. The bottle is aluminum with carbon fiber over it someway.

Great idea just not light.

[Forrest G McCarthy]

The Airhog website states that the “pigmee” ways 4 pounds full with a valve assembly. That is only one of many composite bottles on the market. Luxfer (http://www.luxfer.com) and SCI (http://www.scicomposites.com) are the two main manufacturers of composite bottles. Depending on the length of an outing they may, or may not, be lighter then standard aluminum cartridges. On a month long ski traverse a composite bottle has the potential to save a lot of weight in both the container(s) and unused fuel. Probably not the lightest option for a weekend outing.

[Bill Fornshell]

Hi Forrest,

I have been on the web site and have talked to
Martin at Air Hog.comtwice now.

The total empty weight of the bottle and the valve is just a little less than 4 pounds.

The bottle weighs 2 pounds 3.2 ounces and the valve weighs 1 pound 8.2 ounces. Martin weighed them for me as we were talking.

I gave him this web site and he found it as we were talking. I showed him your comments. He is very interested in any new ways to use their products.

He said he was an Adventure biker – motor – and is always looking for lighter gear. He said he would give BMW a good look over this evening.

He aslo said to give him a call if you need more information about your ideas.

[Forrest G McCarthy]

Bill,

Thanks for looking into it. I tried speaking with someone at SCI and Luxfer but go nowhere. I think it would be possible to save weight with a lighter valve assembly and possibly an even lighter bottle. As I understand compressed butane and even propane, though highly flammable, require less PSI and a lighter cylinder and valve. The roadblock maybe getting them filled. I do think there is potential here for longer winter, alpine, and polar expeditions.

I will call Martin @ Airhog. It is always nice when I find somebody willing to listen to one of my wacky ideas.

[Roger Caffin]

Well, I am reluctant to offer any encouragement here. The potential for an accident is a little higher than normal. But a standard screw-thread gas canister seems a LOT lighter than the ones you are talking about.

> I've imagined exactly what you're describing, if for no other reason than to avoid accumulating all those partial canisters!
I have a lot of totally empty canisters. I do not have more than one or two partially empty ones. I monitor what's left in each canister as I use it (when I get home), and write the weight on the bottom. When a canister has too little gas left for an overnight trip (30 g/day), I use what's left on day trips (8-9 g per morning tea). Works great.

OK, a few canisters get used up while testing stoves for BPL too … :-)

[Mark Regalia]

By heating with an outside source the tester failed to create an actual situation. A few years ago Itried running my stove full on with a shield around it and a pot of water on it. It not just did not overheat it got very cold. It never heated up.

The reason is simple physics. The liquid fuel expands into a gas as it leaves the canister. In order to expand it has to absorb a great deal of heat. So the canister acutally got cold rather than hot – quite cold in fact. This is the same principle used in refrigerators.

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