My garage gets mighty hot, the door gets Florida sunlight most of the afternoon. Is it risky to keep a container of gasoline in there?
Not really. It would have to be so hot you wouldn’t care about the gas exploding… because you’d be baked alive.
Actually, after I’m in there for a few minutes, people start asking “What smells so good? Is there a roast in the oven?” 
My car has a container of gas in it all the time and it doesn’t seem to matter that the garage gets hot. I’ve heard that people even drive cars in Saudi Arabia where it gets over 120F.
How hot is your garage?
Don’t have a thermometer there.
::: Waves arms:::
Danger Will Robinson, Danger Danger
If your garage has any source of ignition in it like a water heater, furnace, or electrical contacts that make make and break with a spark there is a chance that you could launch the first garage into orbit.
If your gas can leaks vapors, and
The vapors collect and concentrate to the point where they will ignite, and
There is a source of ignition (pilot light for example)
Garage goes BOOM.
The only thing maybe is an automatic garage door opener.
This is obviously not impossible, but:
- There are lots of garages in warm climates, exposed to the sun
- Many have automobiles parked in them
- Most of those autos have gas tanks
- Rather few garages seem to be exploding
So it seems that the danger here is not especially severe.
I thought about that, but I speculated that the gas tanks in cars might be very different from the containers one uses to store gasoline.
Yeah, I think that typically gas tanks in cars are much better insulated from leaking vapors than gas cans used to store gasoline.
Anecdotal evidence: A grade-school friend of mine lost her house to a fire in just about exactly the way that Rick described. They kept a can of gasoline stored in their garage, and also had one of those kerosene heaters going in the basement rec room down the hallway. One winter day, my friend’s mom came home, opened the door connecting the garage to the hallway, and when the vapors from the gas can reached the flame in the kerosene heater, there was an explosion. The subsequent fire destroyed their house. Friend’s mom spent some time in the hospital, but luckily everybody survived with minimal injuries.
However, this was not caused by storing gasoline in a hot garage, but rather by storing gasoline in an area adjacent to a spark/open flame. Still, ever since that happened to my friend, we’ve been scrupulous about keeping containers of fuel stored outside the house.
Slight hijack:
Is there a commercially-available gasoline storage container that eliminates or minimizes vapor leakage? Essentially a beefed-up version of the familiar 5-gallon gas can?
Gas vapors are highly explosive.
Yes, but only in the proper fuel-to-air ratio. The LEL and UEL for gasoline/air mixtures is 1.4% and 7.6%, respectively, according to one source. These figures are the percentage of gasoline vapors in air by volume. If the percentage is higher or lower than these figures, then no boom.
True. But not unheard of, either. Found quite a few other cases as well with a Google search.
The lesson seems to be that if you’re going to store gas in a garage, then you want it to be adequately ventilated so that the fumes don’t build up. And make sure that there are no ignition sources, particularly close to the ground.
Given that gas will vaporize much more readily in hot weather, you are increasing the likelihood of a problem if you have an open container of gas (e.g. leave the vent open on a gas container.) I would think that the increased pressure might also occasionally cause a carelessly sealed container of gas to blow its lid.
So…yeah, very hot weather probably increases your risk, provided conditions are right.
Addendum: It looks like most gas containers are deliberately vented to keep pressure from building up. So…keep your garage ventilated. Avoid sparks. Make sure your water heater and other utilities are nowhere near the garage, and, if they are, don’t keep gas there.
It all depends. If your garage does not have a source of ignition, and is well ventlated yes the risk is minimal. However even then the risk is >0.
If you have a gas water heater in your garage, the pilot is only about say 6" ff the floor. If you were to park a gas can nearby. (And yes I have heard news reports where the homeowner did just that) the chance of an explosion / fire is much >0.
Anyway to answer some of the other questions that have been brought up, the fuel system in any car sold in the US for the last 25 years is sealed and has a charcoal canister that catches most if not all of the gas vapors so that they are not released into the air and create smog. So the presence of a car with a fuel tank is an apples to kumquats comparsion. Your gas can does not have an evaporative emission control system.
Yes you can buy a better gas can They are way more money than what you will pay at Wally World however.
And yes I do agree that gas will only ignite in a fairly narrow range of air fuel ratios. I am now willing to bet my home and possibly my life that the ratio is either too lean or too rich. I don’t feel that lucky.
It’s a one-car garage, that opens generally twice a day when I leave for my commute to work and return. Would that be considered “well ventilated”?
Some other points not mentioned thusfar: most garages which connect directly to a dwelling unit should have a minimum of 7-8" step up into the dwelling. Here in the mid-Atlantic, that became standard practice around the 1960’s, but there are exceptions to be found. Where there is no step, or if a fossil fueled water heater is in the garage, it should be elevated above the floor plane a minimum of 8"-local codes may call for greater elevation.
If you want to be completely safe, then buy a flammable storage locker and put all your solvents, gas cans, flammable liquids, etc. inside. But be prepared to spend a lot of money.