LPG is the most efficient form of energy with high combustion efficiency. LPG (liquefied
petroleum gas) is a collective name for a number of petroleum gases consisting of propane, butane
or mixtures of these gases that can be condensed to form a liquid. There may be small
concentrations of other C3, C4 and C5 hydrocarbons such as propylene, isobutane, butylene,
isobutylene and isopentane. When stored under pressure it becomes a dense liquid allowing large
quantities of gas to be stored in a relatively small space.
LPG exists as a gas at normal atmospheric pressures and temperatures but may be liquefied by the
application of moderate pressure. If the pressure is released, the liquid will revert back to vapor.
LPG as a liquid is colorless and as a vapor, cannot be seen. Pure LPG has no distinctive smell so
for safety reasons, a stanching agent is added during production to give it a pungent, unpleasant
smell and so aid detection by the human nose at very low levels. LPG is non-toxic but at very
high concentrations in air, LPG vapor acts as an anesthetic and subsequently as an asphyxiate by
diluting or decreasing the available oxygen.
When LPG is mixed with air, a highly flammable mixture is produced. The flammability range is
between 2% to *1% by volume of gas to air. Outside this range, any mixer is either too weak or
rich to propagate a flame. One volume of liquid will produce approximately **0 volume of gas
vapour. LPG vapour is heavier than air. Any escape will find its way to the lowest level where it
can remain and form a flammable mixture; Therefore, LPG vessels must be sited away from
drains and appliances and must not be sited in basements or cellars.