safely transporting fuel canisters in the car in the summer?

[Greg Pehrson]

Wondering about safety precautions for bringing fuel canisters in a car for a multi-day drive this summer. My car is a Subaru (no separate trunk area). When I’ve used canisters previously, I’m just driving to the trailhead and then taking them with me. This time, I’ll be stopping and visiting some folks on the way, and expecting some hot temps outside and know the car can get dangerously hot. Should I put my canisters in my cooler? In the spare tire compartment under the storage area? Wrap them in clothes? Take them out when we stop the car for any long period of time in the heat? Keep the windows cracked? Anything else I should be aware of besides keeping the plastic cap on to reduce likelihood of fuel leakage? I’m sure people do this all time with road trips but I’m not finding info when I search. Thanks in advance for sharing your knowledge.

Greg

[Jerry Adams]

The plastic cap is to keep dirt out.  There’s a hole to let out any fuel that leaks.

You could put a thermometer next to it, max temp is 120 F

It might help if the canister was only 90% full or so to let more room for fuel expansion

A cooler or wrapping it in clothes or other insulation would delay the time until it gets too hot.  Look at the thermometer to see how close it’s getting to too hot.

Crack windows, put shades against windows to reflect sunlight, park in the shade,….

[Jerry Adams]

If you put a gallon of water in a cooler, with the canister, that would further delay how long it gets to get hot.

[John K]

I’d use a cooler with a blue ice thingy. I’m not sure what part of the country you are in, but have seen hairspray cans blow a hole in the trunk lid when they explode in desert heat.  :(

[Ken Thompson]

No chance to purchase canisters after your visit?

Another Esbit advantage…

[David Thomas]

While the canisters have a listed maximum storage temperature, there’s still a safety margin.

The trunk is better than in the sun on the back seat if the windows are closed.  But in the foot well of the passenger compartment, on the shady side, with the windows cracked is far cooler than higher up in the passenger compartment.

I like having a soft-sided cooler in the car for many reasons.  Trader Joe’s has a nice, good-sized one for not much $$.

I use it as an additional reusable shopping bag and put the milk and ice cream in it (in the summer) and the lettuce and cut flowers in it (in the winter).  It folds up pretty flat when not in use.  On road trips, I keep dairy and cheese and meats in it for cheaper, healthier, on-the-road food.  I also put a few pre-made salads in it and a real metal fork to eat them with.  On week-long road trips, I score ice from hotel ice machines (cutting the spout but not the handle from a gallon milk jug makes a great ice cube carrier), or if my room has a fridge in it, I fill repurposed soda bottles 80% full of water, freezer them on their sides overnight and then use them like (free!) blue ice each day.

I often use it for transporting frozen salmon across state lines, sometimes for 20+ hours in transit.

Simply putting your canisters in a cooler will moderate their temperature.  The more water in the cooler, the more moderate temperature swings will be.  The more frozen bottles of water you include, the longer it will stay cool.

Putting the whole cooler in the freezer overnight (we all have 3 chest freezers in Alaska) helps.  So does wrapping the most critical stuff in towels, bubble-wrap, or Reflectix.  Sometimes, I’ll skip the soft cooler and just put the vac-packed fillets in a plastic bag, that wrapped in a towel, that in another plastic bag, then a jacket, etc and leave it all in the freezer for 12-24 hours.

Outside of the cooler in your car, spreading your sleeping bag over/around it helps A LOT.  It turns out – surprise, surprise – that your sleeping bag is quite good at insulating things.

[Roger Caffin]

DoT regulations require that all canisters survive 50 C without problems. I tested a canister in water (slowly heating):
https://backpackinglight.com/exploding_gas_canisters_the_hazard_of_overheating/
and it got up to nearly 100 C before it blew. It DID blow, with one hell of a bang, but that was well above the 50 C required.

Keep the canisters with you perhaps? If you can survive the temperature, so can they.

Do keep the cap on! It keeps the dirt out so the valve seals reliably.

Cheers

[David Thomas]

Shorter version:  That canister in the store?  It got there in an non-refrigerated truck, that could have been sitting in the sun all day, in Phoenix, in the summer.  There’s a very significant safety margin.

[David Thomas]

Every time I reread that article of Roger’s, consider the temps I encounter on my Alaskan trips, and how cheap bulk propane is. . . .

Which is very much NOT the lesson he wanted anyone to take away from that.

Greater CO generation is NOT an issue using propane in a butane device.  But stuff blowing up if you ever exceed moderate canister temperatures in storage and IN USE has to monitored far more closely!

[Nick Gatel]

Wrap them in your quilt, sleeping bag, or down jacket when you leave home. Multi-use. No need to bring a dedicated cooling solution — extra weight, you know ;-)

[Roger Caffin]

Hi David

Yeah, tricky problem with propane, that.

If I was gearing up for a serious Arctic or Antarctic trip, especially avoiding mid-summer, and could fill the canisters from bulk propane at the destination at temperatures around 0 C, I would be tempted. Looking at the temperature/pressure curves would suggest a safe upper temperature (depending on your risk factor).

In-use temperatures? Just keep the canister screened from the burner. That would be quite enough in the snow.

But I don’t understand the comment about greater CO production. I cannot really see there being much difference. And keeping an eye on the separation between burner head and pot base is all that is needed.

Cheers

EDIT: looking at my graphs and noting the DoT requirement that canisters must handle 50 C without failure, I see that a 30% propane 70% isobutane mix hits 10 atmospheres pressure at the top. If the canister can handle that (which it must do), it can handle 100% propane up to about 30 C.
At 40 C pure propane would be a bit over 13 atm (+30%), which is starting to strain the friendship a bit.

Question with zero evidence: ‘who says that an LPG can holds 100% propane?’ We have seen that cheap ‘butane’ cans contain a mix of n-butane and isobutane. What is really in cheap LPG? I don’t know.

[Jerry Adams]

you mean I should refill my canisters with straight propane? : )

[David Thomas]

My bad.  I flipped them in my head.  Butane needs more air than propane (31 liters per liter versus 24 liters per liter of air).  So running propane in a stove designed for butane will run a little LEANER, not richer.

When you convert an appliance from natural has (85% methane) to propane, you change out the jets / orifices.  The methane jets are larger and the propane jets are smaller.  Butane jets would be smaller still.

That jet of gas then induces much more ambient air into the pre-mix tube in the right ratio.  A set volume of propane needs more air than methane does (as you know).

For the same gas, smaller jets give a leaner mixture.  Larger jets give a richer mixture.

If you did the reverse: run butane in an appliance set up for propane, you’d get a richer mixture, potentially one with a yellower flame and more CO production.

I go edit my previous post.

[Greg Pehrson]

Thanks BPL for all the helpful, thoughtful and quick! responses.

I will be driving through the desert (southern Utah, then Nevada). John, I’ve seen pictures of explosions like that, hence my concern–hoping it wasn’t your trunk that exploded.

The easiest solution might be, as Ken suggested, to buy the fuel later in the trip. We will do a little desert car camping on the way while visiting, but maybe we could go no-cook during that time. But if not, I feel like I’ve got a lot of good ideas here. I totally accept the premise that I may be overly worried, as the desert is not my normal habitat.

Again, thank you!

Greg

[Roger Caffin]

Greg:
If you are desert-walking, the temps will be high. I would suggest finding some straight butane canisters, or at least ones with the lowest % of propane. They will be safer.

Jerry
See my post a few up.

Cheers

[Jerry Adams]

Of course my suggestion to use straight propane was mostly just humor, but 30 C (86 F) would be possible to keep a canister below in the winter

‘who says that an LPG can holds 100% propane?’

good question, I like the skepticism

the difference in boiling point between N and iso butane is about 20 F, the difference between propane and butane is more like 60 F, so easier to isolate pure propane than isolate N butane from a butane mixture.  Easy enough to figure out if you can find a space that’s that temperature, -43 F.  Maybe a freezer.  Or Alaska.  Find the temperature where there’s just barely no flow out of the propane canister.

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