The need for vaporization
LPG is stored as liquid, but used as gas and hence requires vaporization. The vaporization process absorbs heat (latent heat). Every gas system larger then a domestic stove-top requires more heat than is naturally available. With increased demand and / or cold conditions, the gas does not vaporize and the heating process is interrupted.
Vaporization is the most crucial issue in LPG applicability. It determines whether LPG can be used in a specific climatic zone, and the kind of gas mixture that should be supplied there: Propane -- more volatile but expensive, or Butane -- less volatile and less expensive, or a mixture of both.