Liquefied Petroleum Gas (LPG) is a blend of light hydrocarbon compounds. It mainly consists of butane (C4H10) or propane (C3H8) or a mixture of both. At room temperature, both gases are colorless and odorless. Propane has its boiling point at -42 ℃ and butane at -0.5 ℃ . Under modest pressure or in cooler conditions, LPG transforms into a liquid state. LPG in domestic cylinders used for cooking generally comprises more butane than propane because the fuel value per kilogram of butane is higher than propane and it liquefies under much lower pressure than propane and thus the handling is safer. National and international standards specify the minimum content of butane and a maximum LPG vapor pressure. When liquefied under pressure, the volume of butane and propane is reduced to around 1/260 of the gaseous aggregate state. The specific calorific value of LPG is around 46 MJ/kg or 12.78 kWh/kg depending on the composition of LPG. ..