Your LPG gas cylinder bottles used at home need to free up of some space/air. In the same way when you need a refill, because poo pressure in an LPG gas cylinder bottle can make refilling difficult. So, this means that the pressure in a domestic LPG gas container depends on the size of the tank, and also depending on the surrounding temperature. But a normal domestic LPG gas cylinder bottle ranges between 100 PSI - 200 PSI at room temperature.

An abnormal pressure can affect any attached utilities connected to the gas cylinder bottle. It can cause it to malfunction. One other thing to consider is trapped air Inside LPG gas cylinder bottles. Somehow, air finds it way into LPG gas cylinder. This occurs mostly during a refilling, unknowingly air passes through the refilling hose pipe to your domestic gas cylinder, causing a lot of pressure buildups at the top side valve. 

Remember, there is a need to free up some space of empty air, so to allow expansion and free flow of movement.