Critical Point

The critical point (critical temperature and critical pressure) means the substance has gone above the point when there is no longer a boundary between liquid and gas.

A substance above its critical point is always in the gaseous state.

At temperatures below the critical point, all types of refrigerant in pressure reservoirs exhibit both a liquid and a gas phase meaning there is a layer of gas above the liquid.

As long as there is still gas present in the cylinder next to the fluid, pressure is dependent on ambient temperature. Refer to REFRIGERANT VAPOR PRESSURE TABLE .