As fall rolls along and some RVers are thinking about winterizing and storing their rigs for the winter, we thought this would be a good time to address the question, “Does propane go bad?”
We’ve previously investigated gasoline and diesel in our posts entitled “Does Gasoline Go Bad?” and “Does Diesel Go Bad?” But we’ve never written a post about the shelf life of propane.
Does propane have an expiration date? Are there certain things we need to do to store propane safely?
Let’s find out!
Why Is It Important to Know If Propane Goes Bad?
Not only do some RVers store their rigs for the winter (often with partially full propane tanks), but lots of people store partially full portable propane gas tanks used for summer barbequeing.
Many RVers rely on propane for heating, cooking, and hot water. As the fall nights get chilly, some are getting ready to bring out their portable propane-powered heaters for winter camping. But, they’ve been stored away for a long time.
For all of these people, it’s important to know whether propane degrades over time. More important, however, is whether a stored propane tank presents a risk. Can propane tanks explode in the cold, for example?
These are important questions to know the answers to before you store a propane tank of any kind.
OK, So… Does Propane Go Bad?
The answer is no. Propane doesn’t go bad – it does not expire. In fact, this is an advantage that propane has over other fuel sources.
Propane, (LPG or liquefied petroleum gas), is a component of natural gas that is compressed and stored as a liquid. And, it has a very long shelf life.
Why Does a Propane Tank or Gauge Have an Expiration Date?
When you see an expiration date on a propane tank or gauge, what you’re actually seeing is the date when the tank’s safety inspection expires. Essentially, the date on the tank is a reminder to get the tank itself inspected because it’s the tank that needs to be replaced – not the propane.
In the United States, PORTABLE propane tanks/cylinders with a capacity of 100 pounds or less will have an expiration date 12 years out from the manufacturing date, as required by the DOT standard they are certified to. (They have a 10-year expiry in Canada.)
You should see the date stamped on the collar of a portable cylinder in a month/year format. (Example, 09/22 for September of 2022.)
After that date, you’ll need to have the tank inspected to determine if it needs to be replaced or requalified/recertified. Requalified/recertified tanks will receive a new expiration date of 5, 7, or 12 years out, depending on the type of recertification and the method.
Brand new, larger, BUILT-IN RV propane tanks are manufactured with thicker walls and are certified by ASME (just like permanently installed propane cylinders for residential use), not the DOT, and don’t need to be recertified. However, it’s still a good to check regularly them for signs of rust and leaks.
Can Propane Tanks Explode?
Propane tanks can rust and leak. Since a gas leak is never a good thing, it’s important to prevent rust and to monitor tanks for the development of rust. It’s also why propane tanks have an “expiry” date – a reminder that it’s time to get the tank inspected.
As for the potential to explode, there are a few things that are important to know.
First, propane tanks rarely explode, but it CAN happen under extreme circumstances.
There are safety mechanisms built into propane tanks. As long as you maintain your tanks and respect the propane as you use it, your propane tank exploding (or imploding) is highly unlikely.
One of the most important things you can do is to avoid leaks. This includes maintaining your propane tank and having it regularly inspected.
Leaks can develop around valves, of course, but if rust penetrates the tank, you’ve got a real problem on your hands. The important thing is to make sure your tank never gets to that point!
It’s also important to make sure that a propane tank isn’t exposed to extreme heat for long periods of time. If temperatures outside the tank are so high that they cause the temperature inside to rise excessively, the tank can explode if the built-in safety release systems fail.
However, this is an unusual situation and would require the liquid propane inside a faulty tank to come to a boil and expand. That expansion could cause the tank to explode. For this to happen, your tank would need to be stored in a place with temperatures of 120℉ or higher for an extended period.
How to Store a Propane Tank Safely
There are a few things you can do to be sure your propane tank is safe:
- It’s always best to store a propane tank (or a rig with a built-in propane tank!) in a place that is cool and dry. Lower storage temperatures ensure the tank, and the LP inside it, remain at a safe, low temperature. Again, it’s best to store propane at temps below 120 degrees Fahrenheit.
- Do not store rusty propane tanks. Get the tank replaced if rust is an issue.
- When storing a propane tank (or an RV with a propane tank onboard) be sure to shut the valve off prior to storing. You don’t want a gas leak developing.
- Never store a propane tank indoors. If a gas leak were to develop, this could be very dangerous.
- Always store portable propane tanks upright on a flat surface in a cool, dry area… and monitor them for rust over time.
Can I Check the Propane Level In My Tank Without a Gauge?
Yes, you can! If you don’t have a working gauge on your propane tank, the best way to check the level of propane in the tank is actually quite simple.
We’ll let Peter show you how it’s done.
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Monday 10th of October 2022
There is an odd tank out there. I have a couple of portable FRP tanks made by Viking/Ragasco that require 5 year inspections. You mostly see these used in a marine environment. I have a couple I use for camping because they are light weight.
Monday 10th of October 2022
Thanks great tip!
Tuesday 4th of October 2022
Great tip as usual!
Tuesday 4th of October 2022
Sunday 2nd of October 2022
Another important thing to know is that the valve in the propane cylinder also has an expiration date, after which it must be replaced. A tank owner can get an expired tank re-qualified at twelve years but he/she will also need to replace the valve at the same time.
Sunday 2nd of October 2022
The 20% ullage is extremely important. I have seen posts on RV sites where a person attempts to "squeeze in" to the tank as much gas a possible. The 20% vapor space is calculated to provide enough expansion of the gas as temperature rises (around 140 deg F), so that the container will not go liquid full. In that event, the hydraulic expansion can exert very high pressures, very quickly on the tank walls. If the safety valve is compromised by damage, dirt or debris, or by an unsophisticated user defeating the safety mechanism (I have participated in lawsuits where a user turned the safety tang inward tightening the spring, so as to stop the safety valve from "leaking" when they fill the tank "all the way up"), the tank will rupture catastrophically with a sudden release of all that contained energy. Even if a rupture does not occur the safety valve will attempt to do its job and relieve the internal pressure. What happens is the valve will spew liquid propane gas all over. The kinetics of propane is such that the gas being heavier than air will not disperse. It will lay low and travel along the ground searching for an ignition source. There are many ignition sources all over an RV. This is why I argue that RV'er should never travel with a propane refrigerator running. Blowing a tire or simply running over a piece of road debris could sever an unprotected propane line resulting in a release and saturation of the underside of the rig with an extremely flammable gas.