LPG is stored under pressure, as a liquid, in a gas bottle

It turns back into a gas by 'boiling' into gas vapour.

This happens at the very low temperature of -42°C.

To boil, the liquid LPG draws heat from the steel walls of the gas bottle.

This, in turn, makes the gas bottle feel colder than the ambient temperature.

The gas bottle gets even colder when you are actually using the gas.

So, with sufficient humidity and when you are using gas very rapidly, condensation or ice can form on the gas bottle.

The visible condensation or frost line indicates the level of the liquid gas remaining in the gas bottle.The gas vapour that forms in the gas bottle moves downstream to the point at which it is used.

But before making its way to the LPG appliances in your home, it passes throughyour gas regulator, where the pressure is reduced to the appropriate level.

The regulator delivers a constant safe pressure while the gas bottle pressure can significantly vary, depending on the ambient temperature and the amount of liquid gas remaining in the bottle.

As the LPG passes through the regulator, it expands, resulting in very cold gas vapour temperatures.

This causes the regulator to also reach extremely cold temperatures, as the cold gas vapour passes through it.

Depending on the humidity of the surrounding air and the rate at which the gas is being used, condensation or even ice will form on the regulator.

The faster the gas is used, the colder the regulator will get.

This is why, under normal operation in warm and humid climates, the outside of a gas regulator will feel cold to the touch and may also be wet, frozen or frosted.