8

The canisters that I have purchased so far have included a warning not to let the canister get above 120 degrees Fahrenheit. It looks like the inside of car can get well above that, hot enough to bake cookies.

I would prefer not to leave on a backpacking trip with an extra canister left in my vehicle and come back to find that it had exploded. What are some things that I can do to prevent that from happening?

7

The background

It took me a moment to find it, but an example of a car in which this happened can be seen here. If the fuel in the canister becomes sufficiently warm the pressure can rupture the canister. Usually the bottom everts first, popping outwards, although I have heard of instances where this was immediately followed by it coming apart, so this should not be considered any form of early warning measure. At this point you have a few ounces of liquid butane that's rather far above its boiling point and suddenly under very little pressure, so it almost instantaneously transitions to gas and vapor.

Such an event is called a BLEVE (boiling liquid expanding vapor explosion). Fire does not need be involved; in the referenced image above there are no signs of fire damage. If you are particularly unlucky, friction or sparks can ignite the cloud of vapor, possibly resulting in a fuel-air explosion.

How to avoid it

Don't park your car in the sun, or don't keep fuel canisters in it. However, on some trips this might be unavoidable. I suggest considering the following:

  • For vehicles with a separate trunk, store the canisters in the trunk and not in the passenger compartment, which will be heated more due to the greenhouse effect of the windows.
  • Find a way to insulate the canisters, such as placing them in an ice chest or wrapping them inside a blanket or sleeping bag.
  • Depending on your area, caching them outside the vehicle may be considered. Of course, that also makes them more likely to grow legs and walk away.
  • Sunshades, car covers, and cracked open windows may also help.
  • If you cannot isolate them use the cooling trick of putting wet towels on/around them. – Jan Doggen Oct 14 '18 at 18:43
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I kept a spare in my trunk for two years in the southeastern US and I never had a problem (YMMV). This, like most things in life, is not perfectly safe. So you should decide if you really need to store this in your car. If you do, things you should consider:

  • Keep it somewhere that minimizes the risk of puncture.
  • Keep the cap on it.
  • Store away from sources of ignition (engine, muffler, etc)

By far your largest risk is from puncture. Rupture due to heat appears to be something that happens after "prolonged exposure to fire or intense heat". Even if the canister ruptures, it isn't at all likely to turn into a fireball without an ignition source.

https://pubchem.ncbi.nlm.nih.gov/compound/isobutane
MSDS: https://www.mesagas.com/images/Isobutane.pdf

All that being said, most recommendations are to store at less than 125 degrees Fahrenheit. So don't go parking your car in directly sunlight in the summer.

Lot's more interesting reading on canister failures here.

  • Yes there are risks in life and that is a very deadly risk. If it leaks and ignites the passengers in the car would be burnt if not killed. lancashiretelegraph.co.uk/news/… – paparazzo Aug 26 '16 at 15:17
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    Nothing in this article indicates the relative risk of storing a backpacking can in a car. First, the valve was opened. Second a secondary explosion was caused by yet another gas leak. Thirdly it happened in a home, not a car. Fourthly, we have no idea of the size of the canister (however given the other facts of the article, one could reasonably assume a large propane style can, not a 4oz backpacking canister). Yes, most liquid fuels can explode. Most fuels are dangerous. However it does not speak whatsoever to the relative danger of a specific fuel stored in a specific fashion. – Russell Steen Aug 26 '16 at 16:17
  • If you don't get from that that can butane can go poof and burn you badly then I cannot help you. Most liquids do not explode. I have a degree in chemical engineering, worked inside plants, served on the fire team, and went to fire school at Texas A&M. Fine take your chances - life if full of risk. – paparazzo Aug 26 '16 at 16:26
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    Liquids do not explode when liquid. Liquid fuels made for camping are made to vaporize easily at low temps. They certainly can explode when vaporized. Isobutane is in liquid form in the can (it only becomes gas when released). White gas easily vaporizes. Both can explode. MANY things have risks. Virtually every activity in TGO has a risk. What is important is the relative risk. Having a degree doesn't mean you are the worlds foremost expert on every fuel under every condition (as in this case). – Russell Steen Aug 26 '16 at 16:30
  • Let us continue this discussion in chat. – Russell Steen Aug 26 '16 at 16:42
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Keeping it low down against the bottom of the car and insulated is best. The spare wheel well is ideal (and used when you get a can of tyre foam instead of a wheel; they have similar limits) or those compartments you sometimes get under the boot floor. These places are much cooler than the rest of the car, especially with the parcel shelf closed. If they aren't an option, under the front seats with insulating material on top is probably your best bet.

Also do what you can to keep the car cooler - reflective windscreen covers etc.

-1

Don't store them in the car. Hide them in the engine compartment or under the car. I don't even store butane in my house.

Hopefully they have a pressure relief valve that they don't actually explode but I still would not store them in the vehicle. Combined with an ignition source you have a very nasty if not fatal fire. It is technically not an explosion but it goes boom and is very hot.

Think how many meals you can cook and getting that much heat once.

If you really need to store fuel in the car then consider liquid fuel.

A leak and ignition would be very bad if not fatal.
Nelson man died after gas from leaking butane cylinder exploded in his home

Butane is odorless so unless they mark it with a scent you would no even know it leaked.

I see this got a down vote and don't want to argue with you but leaving a butane cylinder in the car is a bad idea.

  • 2
    Isobutane (the fuel commonly used in the kind of hiking can ref'd) and many other fuels (propane, etc) may be odoless by nature, but they have an agent added that give them a very distinct odor. White Gas (the most common liquid fuel used for camping) is remarkably more dangerous than an isobutane can. It vaporizes easily when heated and the vapors are extremely flammable. It is certainly no safer. – Russell Steen Aug 26 '16 at 16:20
  • @RussellSteen White gas is not more dangerous here. The white gas is not pressurized. – paparazzo Aug 26 '16 at 16:58
  • The MSDS for white gas -- readers can draw their own conclusions - nafaa.org/Coleman_MSDS.pdf – Russell Steen Aug 26 '16 at 17:16
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    Assuming you have the credentials you claim, then you should be able to provide a better answer containing things like - At what temp is the can likely to rupture? When it ruptures, will it ignite without a spark? At what temperature and pressure does isobutane ignite without a spark? etc. These are things that would make an informative answer. As it stands your answer is "It's dangerous and as proof I cite this story of a man who died under completely different circumstances and these credentials you can't see; trust me" – Russell Steen Aug 26 '16 at 17:38
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    Don't trust me. The label says 120 F as stated in the question. As for rupture I clearly clearly state would probably bleed off from the relief valve - still real bad for you. If you think think the interior of your car will not produce an ignition source then fine take your chances. How much does a butane lighter take? After all that you still don't get that it is about failure scenario. For the 4th time butane is pressurized. – paparazzo Aug 26 '16 at 17:54

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