Propane standby systems generally work as follows:

• Liquid is withdrawn from the storage tank and, if required, the pressure is raised via motor-driven pump.
  
  
• The liquid is heated in a vaporizer and converted to a super-heated vapor.
  
  
• Vaporized propane is sometimes piped directly to consuming appliances that are each equipped for dual-fuel (NG & LPG) firing. Most often, propane vapor is first diluted with air to produce a "propane-air" mix. Propane-air is then distributed via the natural-gas piping for use without changes to individual burners.