Does Propane Go Bad? What To Expect! 

Many different types of natural gas such as gasoline and diesel fuel degrade after long enough periods of time. Typically three to six months and six to twelve months respectively. As such you may be wondering, does propane go bad? If so, how long will liquid propane fuel last by comparison along with how do propane tanks affect the longevity of this natural gas.

Table of Contents

• Does Propane Go Bad?
• Propane and LPG Shelf Life
  • If Propane Fuel Doesn’t Expire Then Why Do Propane Tanks Have An Expiration Date? 
• How Long Will Propane Burn?
  • How To Measure The Burn Rate Of A Propane Tank
• Can Propane Tanks Explode?
• How To Store Propane Safely
• Final Thoughts – Does Propane Go Bad?
• FAQs Relating To The Expiration Of Propane

Does Propane Go Bad?

Contrary to popular belief and what you’d expect based on how diesel fuel works a full propane/Liquefied Petroleum Gas (LPG) tank won’t ever expire. Due to this theoretically indefinite shelf life of propane, it can act as an excellent and dependable fuel source. For this reason, propane stored in gas bottles or another form of propane container will often be used to fuel portable stoves, emergency generators, and barbeque grills.

Propane and LPG Shelf Life

The only limiting factor when you store propane tanks will be leakage from the gas tank itself. This means that whilst it doesn’t have the very limited shelf life of other natural gas variants the infinitely longer shelf life will ultimately mean very little if propane gas is stored improperly.

If Propane Fuel Doesn’t Expire Then Why Do Propane Tanks Have An Expiration Date?

It is often the propane tank that leads to confusion and leads to the question of does propane expire or not. This is because many vessels that are used for storing propane such as propane tanks will have what looks like an expiry date printed on them.

So why is there a date then?

Well, the answer is simple. An expiry date isn’t used for the propane/LPG as it would for other fuel sources diesel fuel. Instead, this printed date is actually for the gas bottle or storage the propane is contained within or for the gauge on the tank.

The reason these dates are necessary is that whilst the propane/LPG won’t expire, a propane tank or indeed the tank’s valve will degrade over time. As such the infinitely longer shelf life of propane compared to other fuels may cause it to outlive its container. 

Some good news though is that the right containers will likely last quite a while. However, eventually, natural degradation of rubber seals or potentially a faulty safety relief valve can cause leaks.

As such, it is recommended that you have any propane tanks inspected by a professional on a somewhat regular basis. This will help reassure you that they are still in good shape, along with helping to ensure they are stored properly.

How Long Will Propane Burn?

How long the contents of your propane tank will burn can vary depending on how it is being used. Certain tasks will require more propane at once whilst others may take longer to do but drain less propane gas per minute.

On average if grilling with an average-sized barbeque grill a twenty-pound tank should be good for roughly twenty hours. However, a larger, more thirsty grill may burn through the tank’s contents in about half as much time. These aren’t universal numbers of course but on average they can be a handy rule of thumb to remember.

How To Measure The Burn Rate Of A Propane Tank

To more accurately gauge how long a propane tank will last, you can also attempt to calculate its burn rate. This can be done by a professional, who will probably get a more accurate answer as the process is a bit complicated. 

However, it is possible to do this at home by yourself. For a good indication of how to calculate the burn rate of a propane tank, use the following steps:

1. Figure out how much the actual tank itself weighs. This should be found somewhere on the tank itself. The tank’s weight is often known as the “tare weight”.
2. Subtract the tare weight from that of the total weight of the tank plus the propane. This will give you the weight of your propane.
3. Divide the total weight of propane by 4.24. This is done to understand the weight in gallons which simplifies things greatly. For reference, 4.24 pounds of propane is equivalent to one gallon of it.
4. Check the burn rate of the appliance you will be using propane for. This should be denoted somewhere on either the appliance itself or any instructions it came with.
5. Divide the total gallon of propane by the burn rate of the appliance. This will show you how long it would take that appliance to burn through the propane in the tank.

For a quick way of gauging roughly how much propane is left in your tank, the video below can be very helpful:

Can Propane Tanks Explode?

With many sources of fuel, there is always a concern about whether they will explode or implode. Naturally, for many, this is a concern with a propane tank as well. However, whilst it is potentially possible for a propane tank to explode, it is very unlikely that this will happen. 

Despite this though you should still be cautious with propane/LPG. This is because like with any other fuel source, explosions are still possible. As such, you should be vigilant of any leaks along with avoiding keeping it near any sources of extreme heat.

How To Store Propane Safely

As mentioned above, you should always be conscious to keep propane tanks away from extreme heat sources along with watching for leaks. However, to ensure that your propane will be as safe as possible, there are a few other steps you should take when storing it.

Propane tanks are best kept in cool dry places. This will help to keep the propane/LPG within cool whilst preventing any rust from forming on the tank entirely. Ideally, this storage location should be below 120°F (roughly 50°C). 

Additionally, it is safer to keep propane tanks outside rather than inside. This is because indoor conditions are often warmer. Additionally, the consequences of a propane leak are potentially much worse when they happen indoors.

When stored outside, however, ensure that the area is dry and covered in a plastic coating to prevent rusting. Additionally, you should also ensure the tank is elevated slightly from the ground to keep it dry along with being level so it won’t topple over.

Final Thoughts – Does Propane Go Bad?

Despite what you’d expect based on knowledge of other fuel sources, propane, or LPG as it is also known doesn’t expire. However, whilst the answer to does propane go bad is no, the same isn’t necessarily true for propane tanks. This is because over time they can degrade which can cause propane to leak. As such they should be stored properly in level, dry and cool areas along with being regularly checked.

FAQs Relating To The Expiration Of Propane