Liquefied Petroleum Gas (LPG) is the generic name used for a mixture of certain hydrocarbons, mainly propane and butane. When these mixtures are lightly compressed, they change from a gaseous state to a liquid.

LPG is colourless, odourless and heavier than air. A sulphur based chemical (ethyl mercaptan) is added to give it a smell like rotten cabbage so that even a very small leak can be easily detected.

LPG burns readily in air and has an energy content similar to petrol.

Automotive LPG (Autogas) is not the same as the LPG used for heating or cooking (as in BBQ bottles). The quality of LPG for automotive use is higher, and it is controlled to ensure consistent vehicle performance under all driving conditions.

This very much depends on an individual's perception of value. In the past, people have tended to view cost-saving as being their primary reason for conversion. In more recent times, a growing number of people have opted for LPG because it burns cleaner and therefore outputs fewer exhaust emissions.

LPG typically has around 10 and 15 per cent lower greenhouse gas emissions and only one-fifth of air toxics emissions.

LPG is available at more than 3500 retail outlets around Australia. Most oil company websites have a listing on which sites have LPG, or you can also look up on the Australian LP Gas Association website. If planning a long country road trip, it is advisable to plan your refueling stops before you leave home.

Throughout Queensland, all mechanics must possess a license and undertake special technical training to allow them to install and repair LPG components. All LPG fuel system components meet rigid criteria set down by Standards Association Australia before they may be fitted to a vehicle.

LPG storage tanks should be manufactured to comply with AS 3509 and installed to meet the stringent safety requirements of AS 1425.

Because LPG does not contain the same amount of energy as petrol, both fuel consumption and power will be slightly affected. Later model vehicles are generally less affected.

It costs no more to have your car converted to dual-fuel than it does have it dedicated to LPG only. So if it's possible, it makes sense to go dual-fuel and give yourself the added flexibility of being able to use two types of fuel.

A simple flick of a switch is usually all that is required to change from one fuel to another. Many late model EFI vehicles actually start on petrol before automatically switching over to LPG.

LPG engines are serviced as before, although special engine oils available specifically for LPG engines. The only point to remember is that in a dual-fuel application it is still necessary to use petrol regularly to ensure the petrol system components remain in working order.

In most cases, your statutory rights to a warranty and the Trade Practices Act will not be affected by the installation of an LPG system. We do however recommend that you check with the vehicle manufacturer before converting.

You can find a calculator on the Australian LPG website.