LPG or Liquid Petroleum Gas is a type of gas which is widely used as a source of energy throughout the world. Used for anything from cooking to heating, LPG is present in almost every home. A combination of the natural gases propane and butane, LPG is made as a by-product of the refining process of natural gases and crude oil. One of the more recent and interesting uses for LPG is as an alternative fuel source for vehicles, as opposed to traditional fuels such as petrol and diesel. In comparison to its traditional fuel counterparts, LPG is more environmentally friendly, produces fewer emissions and is more affordable.


So how exactly is LPG used to fuel vehicles? Well, in order for a vehicle to run on LPG autogas, it would need to be specially converted to have dual fuel capabilities. This includes having a specialised steel tank, made up of a fuel gauge, filling valve and the multivalve which is comprised of various valves including the excess flow and pressure relief valves. The reason that a vehicle has to be specially converted to run on LPG is because LPG, unlike traditional fuel, does not stay in liquid form unless it is kept cool; rather, it turns from a liquid to a gas as soon as it is exposed to room temperature. This means that in order to keep the LPG cool enough to stay in liquid form, it needs to be stored in specialised pressurised storage tanks or cylinders, both at the petrol station and in the vehicle itself. In order to fuel the vehicle, the LPG is converted from a liquid to a gas in the engine. Once the liquid LPG has been converted into a gas in the engine, it is then combined with specially filtered air. This gas and air mixture then enters the combustion chamber where it is ignited in order to create the energy to fuel the vehicle. 


Using LPG Autogas as an alternative fuel source is uncommon but not unheard of in South Africa as hybrid vehicles are not readily available in the country and therefore in order to pursue a more environmentally friendly path and give your vehicle dual fuel capabilities and you would have to convert your vehicle yourself.   

The difference between propane and LPG

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You have probably heard of both LPG and propane gas, but what exactly is the difference between the two? 

LPG and propane are essentially the same thing and difference between the two, if any, is dependent on what country you are in. Certain countries, such as the United States and Australia use LPG that is 100% propane gas, while other countries use an LPG that is made up of a mixture of propane and butane gases, usually at a ratio of 60:40.

The LPG, or liquified petroleum gas, which we use in our gas cylinders in South Africa, is a mixture of propane and butane, rather than the 100% propane LPG used in the United States. Propane gas is classified as liquid petroleum gas, along with butane, however it is important to note that while propane is an LPG, not all LPG is propane. 

Butane and propane are similar in that they are both flammable hydrocarbon gases. LPG and, by extension, propane and butane, are all by-products of natural gas processing and the crude oil refining process and are then pressurised into a liquid form, after which they are stored in gas cylinders. 

LPG mixture and 100% propane are liquids at a cold temperature, however they both become vapour (gas) once exposed to room temperature air. Propane has the highest vapour pressure and therefore has a lower boiling point (-42°c) and is better in colder weather. Butane on the other hand has the lowest vapour pressure and therefore a higher boiling point (-0.4°c), this means that the mixed LPG that we use in South Africa has a lower boiling point than pure propane.

Both LPG and propane are used as thermal fuel in various applications, including in the refineries themselves; as well as for heating water and rooms, cooking and as fuel for certain vehicles.

Why it is so important to check for a branded company seal on your gas cylinders.

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When you purchase a new gas cylinder there are certain things which you always have to look out for, to ensure your safety. This includes checking whether or not your gas cylinder has a seal with the gas company’s name on it and which matches the name printed on the cylinder itself. 

It is crucial that you ensure that the gas cylinder you purchase has a seal with the company’s name or logo on it, as this proves that the cylinder was filled by the gas company in question. You should always purchase your gas cylinders from a reputable company so that you can be sure that the cylinders have been legally filled to meet the requirements set out by the Occupational Health and Safety Act’s pressure equipment regulations. 

It has become more and more commonplace for unauthorised people to take and illegally fill gas cylinders that belong to a reputable brand and then sell these cylinders to unsuspecting people. Illegally filled cylinders pose a huge risk to you and your family, as you cannot be sure that they have been filled according to safety guidelines, or that the cylinder and its valves and pipes are properly connected and in good condition, which could ultimately lead to a gas leak in your home. People who fill gas cylinders illegally are unlikely to use the correct equipment, which may lead to the cylinder being over or underfilled. Gas cylinders should be filled to 80% capacity and without the correct equipment, this cannot be assured.

In closing, it is important that you do your due diligence when purchasing a gas cylinder by ensuring that there is a seal with the company’s name or logo. You should also check the inner side of the cylinder stay plate for the due date of test and ensure that the date has not passed. If either of these safety measures are not up to standard, you should take care not to purchase the cylinder.

How to detect a gas leak in your home.

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Gas leaks, if undetected can be very dangerous in your home, threatening both your health and safety. In some cases, gas leaks can even be life threatening, which is why it is crucial that, if you use gas or gas appliances in your home, that you familiarise yourself with the signs of a gas leak. 

Here are some signs to look out for when detecting a gas leak in your home:

Sulfuric smell
Gas has a very distinctive, unpleasant, musty odour which can be easily identified. If you smell sulphur or rotten eggs, especially in locations near your gas appliances, you may have a gas leak. If there is an exceptionally strong odour it is critical that you turn off your gas supply immediately and consult a professional.

Hissing noise
A gas leak often makes a faint hissing or whistling noise as the gas escapes the loose connection. If you hear a hissing sound near a gas pipe or appliance, it is possible that you may have a gas leak. It is important to note, however, that not all gas leaks make a noise.

Check the flames 
Check the colour of the flames on your gas stove as this can be an indicator of a gas leak. The flames of a gas stove should be blue, if your stove flames are yellow or orange this could be as a result of a gas leak, which is causing the natural gas to not completely burn.

Check your houseplants
Plants need a steady supply of carbon dioxide to thrive and a gas leak could disrupt this supply. If you use gas in your home and find that your plants are inexplicably wilting, then this may be as a result of a gas leak. You can also keep plants near appliances that use gas in order to warn you of a potential leak.

Check your gas bill
Is your gas bill inexplicably high or are you running out of gas a lot faster than usual? This could mean that you have a gas leak, but it is important to compare these to your older bills so as to ensure that it is not just an increase due to colder weather.

How do you feel?
If you’re feeling unnaturally dizzy or lightheaded, this could be as a result of a gas leakage. If you are concerned that you may have a gas leak, check your gas outlets and appliances for any of the other aforementioned signs.

It is important that, in the event of a gas leak in your home, you consult a professional to assist you in locating the source of the leak and to assist in fixing the leak, rather than attempting to sort the problem out yourself, as this can be dangerous.

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Everyone has seen a gas cylinder at some point in their lives, perhaps even used one, but do you know how they are made?

We’re looking at the behind the scenes process of manufacturing gas cylinders:

Gas cylinders are usually made from welded steel, however other materials such as aluminium, stainless steel and galvanised steel can also be used.

  • A gas cylinder starts out its life as a circular sheet of steel which is then fed through a hydraulic press which presses the steel into a half cylinder shape.
  • In order to make the cylinder, the two separate half cylinder shapes are then welded together in a rotary welding station. Once the separate pieces have been welded together to form a single unit, the cylinder is then tempered in a furnace to ensure the correct hardness. 
  • A hole is then punched into the cylinder, onto which the valve flange is then welded. A valve flange serves as the connection between the cylinder and the valve.
  • Next, steel strips are punched into circular shapes, which will form the foot and neck rings on the cylinder. The foot ring is then welded onto the bottom of the cylinder, while the neck ring is welded onto the top of the cylinder. The neck ring also serves as a handle for the cylinder.
  • The brass cylinder valve is then screwed on and tightened.
  • Once the valve has been connected to the cylinder, the manufacturer will then use a hydraulic stamp to put their information on the cylinder, along with the date of manufacture, empty weight, water capacity and test station identification.
  • Once the cylinder is completed it undergoes rigorous testing and safety and quality assurances before it is finally filled with gas.

Now, next time you see a gas cylinder, you’ll know the process behind its manufacturing.

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