How to Tell If a Gas Cylinder is Almost Empty: 3 Simple Tips & Tricks to Check the Level of Gas

Whether you are using propane, butane, or another LPG bottle for an industrial job, or you just happen to have a gas cylinder that is used in your home BBQ or campervan, you might be in a bit of an awkward situation should you suddenly find the bottle is empty.

But how do you tell if you are about to run out of gas? Luckily, you do not need to wait until the gas runs out completely before refilling or replacing the cylinder.

How to Check If You Are Running Out of Gas

There are a few easy things you can do to check the level of gas in your bottle before it runs out. We’ve provided tips below as a simple guide on how to tell if a gas cylinder is almost empty:

1. Check the Tare Weight

All gas cylinders have something that is known as a ‘tare weight’ (or T.W.), which is the empty gas cylinder’s total weight. To find the precise amount for a T.W. you can inspect the cylinder for a stamped marking that states the weight, typically in kilograms. The T.W. is usually on the neck.  

You then need to put the cylinder on a scale, which may be difficult with a large one, to calculate the mass of the remaining gas. After this, subtract the T.W. from the weight on the scale. For example, if you have a 15 kg T.W. and the cylinder weighs 16 kg, then there is 1 kg of gas left.

2. Pour Hot Water on the Side of the Tank

If you are unable to weigh or calculate how much gas is left there is a more sensory approach you can take. The gas will be cold if it is still in the bottle, so you can gently pour some hot (but not boiling) water down the side, then slowly run your finger down where you have poured it. 

When you start to feel the cold in your finger, this is where the gas level is currently. As a result, you might find there is more gas in the tank than you expected. Then again, you could just as easily find that it is very low or that you can barely feel the cold at all.

3. Shake the Gas Bottle

Perhaps the easiest way to check the level of gas in your bottle is to pick it up and give it a good shake. If you have recently put a full one in place you may feel the weight difference already, which can give you a clue of how low the level of remaining gas might be.

So, you might have a sufficient level of LPG gas to use the cylinder. Just pick it up, shake it and listen to the sound of the liquid in the cylinder to check how much is left. Although gas comes out aerosolised, it is pressurised as a liquid in the bottle, so this is an easy check to do.

What to Do If You Have an Empty Gas Cylinder

If your butane, propane, or LPG gas cylinder is empty you will have to get it refilled. However, this is only available from certain specialist suppliers and should only be done by a professional.

Otherwise, you will have to get another one. If you use an LPG cylinder for occasional camping, sporadic barbecues, or other infrequent uses, this should not present much of a problem. 

However, if you are staying in a caravan park and using gas frequently you will need to refill or replace cylinders regularly. A smart idea is to have a backup cylinder for when it is running low.

Tips to avoid running out of gas include checking it regularly, not running gas unless you have to, and trying to avoid using it for heating purposes. Many alternative sources of heat can be used, so campers can try to use blankets, curtains for caravans, and other techniques. It is also a good idea to order a new cylinder or arrange a refill as soon as you see signs it might be empty.

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