Liquefied petroleum gas (LPG) is extracted from natural gas or derived as a by-product of the petroleum refining process. It actually describes a whole group of products consisting of one or a mixture of the hydrocarbons propane, propylene, butane and butylene.
In Australia, two grades of LPG are commonly used. The two types aren’t interchangeable:
- The LPG you use for your BBQ or other appliances is propane only.
- Car LPG is a blend of mainly propane and butane.
It’s stored under pressure as a liquid. When the pressure is reduced (for example, for combustion), the liquid turns into gas and expands to about 270 times the liquid volume. This means LPG is very convenient to transport and store.
The gas is heavier than air and very explosive. LPG therefore contains a strong odorant (‘rotting cabbage’), so you’re quickly aware of any leaks. If there is a leak, you must immediately remove any potential ignition sources: switch off any electric appliances and motors, extinguish all open flames and ensure good ventilation.