Liquefied petroleum gas, or commonly referred to as LPG is a flammable mixture of hydrocarbon gases that are used as fuel in heating appliances and in vehicles. The LPG gases can be compressed into a liquid at relatively low pressures. The most common gases present in LPG include:
Propane
Butane
Isobutane
Ethane
Ethylene
Propylene
Butylene
Isobutylene
The percentage of propane and butane in LPG depends on where you are. For instance, LPG is just propane in the US and Australia. In New Zealand, LPG is a mix of propane and butane. The percentage is usually determined based on what is available on the supply side.