Propane gas

Like butane gas, propane gas is a liquefied petroleum gas (LPG). Both of these gas types are used extensively in the leisure and outdoor activity industries. This frequently sees them as the natural power supply for everything from heaters in camper vans to the burners in garden and patio heaters.

In the UK butane gas is supplied in blue bottles and cylinders, however propane, which has a more extensive range of uses, is supplied in two different coloured containers.

Red bottles and cylinders are generally used for propane intended for internal use within the home or a building whilst propane intended for use in the garden, e.g. a patio heater, is supplied in a green bottle or cylinder.

Characteristics of propane gas

Propane gas has a lower boiling point than butane gas and this lends it to outdoor applications where it will still ignite in much cooler temperatures that butane. For this reason it tends to be the gas of choice for the tower style garden heaters with top burners. The advantage that it has over butane is that it can be used during cooler Autumn (Fall) days when butane is less suitable.

The British Standard governing both propane and butane is BS4250.

Propane is approximately one and a half times denser (heavier) than air and the result of this is that, rather than distributing and dissipating in the air, it will sink bellow the air and remain there. For this reason propane cannot be stored in any underground environment, or any location where a leak or escape could build up and form a hazard.

Propane becomes flammable when mixed with air in the ratio of between 2% and 10%. It will not ignite if the mix is outside of this range.

Like butane, the reason for the popularity of propane gas is that when compressed it liquefies very easily and this means that is possible to hold large amounts of the gas in bottles or cylinders. The bottles can then be housed in limited space areas like the garden heater base.

Other features

Propane does not have a smell or a visible colour to its gas and therefore it is undetectable in its natural state. This means that if it is untreated, leaks and escapes have the potential to go unnoticed. For this reason natural propane has an artificial odour added to it to help with recognition. This ensures that any propane escape can be quickly detected and remedial action taken.

Both propane and butane are stable gases.

Information comparing the running (energy) costs of different heater types can be found here the cost of running a garden heater.