A propane tank will freeze if there isn’t enough heat to convert the liquid propane into gas in a process called vaporization. The heat typically comes from the ambient air, but if it’s too cold outside or the liquid-to-surface ratio in the tank is too low, the tank can freeze.
A Problem with Temperature or Volume
A frozen tank is typically only a problem for people living in cold climates. When the temps start to drop, there will be a point at which propane isn’t going to work.
If it’s too cold outside, a propane tank can’t get the heat it needs from the air to convert the liquid.
Low levels of liquid propane can also pose a problem when the air turns cold. Propane uses ambient heat absorbed from the sides of the tank. So the more liquid there is the more area to absorb heat. (The design of a horizontal propane tank allows more liquid to be exposed to the tank’s surfaces.)
If you’re using a burner with a high BTU/hr. rate and running it at its highest level, that will empty the tank faster, decreasing the amount of liquid to surface ratio and that may eventually cause your tank to freeze.
For more details on how this process works, check out our article, “Why Does My Gas Fire Pit Flame Height Drop Over Time.”
Why Doesn’t the Tank Freeze on My Gas Grill?
A standard outdoor grill uses a lot less propane than a fire pit. So, the demands on the vaporization process are much lower. If your propane tank is full and the outdoor temperature is not extremely low, your propane grill may still work without freezing the tank.
In contrast, a fire pit requires a lot more liquid propane to vaporize at a higher rate than a grill. In a cold environment, there isn’t enough ambient heat to sustain a rapid burn.
Is it Dangerous When a Propane Tank Freezes?
If your tank is standing upright it is not dangerous when the propane tank freezes. When a propane tank freezes you’ll experience a reduction in the flow of gas resulting in a lower flame height, or even a loss of the flame entirely. The propane tank is freezing because it can’t absorb enough heat to change the liquid propane to gas, which is why it’s reducing the gas output.
If your propane tank is freezing because it’s laying on its side, this is very dangerous as the propane tank is designed to stand upright so it can dispense gas. When the tank is incorrectly placed on its side it may disperse liquid propane which is very dangerous. Read more about this in our article Why is My Propane Regulator Frozen.
How Can I Prevent My Propane Tank from Freezing?
- Reduce the flame. One way to prevent the tank from freezing is to turn down the flame on your gas fire pit. This reduces the rate of vaporization. The higher the BTU/hr. you are running the fire pit, the faster the tank needs to transform the liquid into gas. Turning down the flame also conserves the amount of liquid in the tank.
- Move Your Tank to a Location Where It isn’t as Cold. Although often this is not an option, if you have the ability to move the tank to where it isn’t as cold this will help. For instance, if the tank is exposed to the elements, putting it inside an enclosure can help block the wind and prevent snow and ice from gathering on the surface.
- Keep the Tank Full (or Mostly Full). Keep an eye on tank levels. Allowing the level of propane in the tank to drop will mean the liquid in the tank has less surface area from which to absorb heat. The fuller, the better. But to avoid wasting gas, this will mean taking your tank in to be refilled instead of doing a tank swap.
- Use Two Propane Tanks. Purchase a second tank and a “y-connector” so you’re pulling propane from two tanks. This will reduce the vaporization rate on each tank allowing it to keep up with the demand for your gas fire pit.
- Invest in a Larger Propane Tank or a Horizontal Tank. Horizontal tanks are designed to lay on one side providing more surface area. But you must use a specially designed tank. Never lay a standard tank on its side. It is very dangerous!
- Invest in a Propane Tank Heater. In extreme cold, you can use a propane tank heater. It wraps around the tank, plugs into the wall, and warms the tank.
An electric blanket is a low-cost alternative. But beware, most electric blankets are not safe to use if they get wet. So, be sure to bring the blanket back inside when it’s not being used. Never leave an electric blanket outside–even the moisture in the air can be dangerous.
If you are highly motivated to outsmart the cold, these suggestions may help you succeed. Remember, you’re battling the cold ambient air and trying to optimize the liquid inside the tank. Or, you might decide to simply curl up in front of your indoor fireplace and wait for a milder evening in spring.